[Technical Field of the Invention] [0001] The present invention relates to a method, a device, a program, and a recording medium, for estimating generating regions or source regions of a surface shape defect generated when performing a deformation processing with respect to a workpiece. Priority is claimed on Japanese Patent Application Na 2015-012325, filed on January 26, 2015, the content of which is incorporated herein by reference. [Related Art] [0002] Most of vehicle members, such as a door or a bumper, home electronics members, and building materials, are produced by press forming of a steel sheet. In recent years, a requirement for reducing the weight with respect to the members (press-formed article) has been increased, and in order to realize the requirement, it is suggested to make a steel material thin by using a steel material having a high strength. [0003] However, as the strength of the steel sheet increases, it became necessary to strictly manage ensuring of the shape of the members made by press forming. In the management, important issues are such as generation of spring back which is a deformation due to an elastic recovery for the elastic deformation of the steel sheet, and is a deformation using a residual stress as a driving force generated in the steel sheet during press forming, and generation of wrinkles caused by bending during the press forming. [0004] In particular, recently, in order to reduce the number of development processes and costs of a vehicle or the like, there is a tendency that the planning stage of investigating a forming method of the formed member starts at the same time as the design stage. However, when the design changes at the design stage, the formed member at the planning stage also changes at the same time, and thus, the number of processes or costs at the planning stage of investigating a forming method of a formed member are serious problems from the viewpoint of development processes or development costs of the vehicle or the like. Above, in recent years, a method which can estimate generating regions or source regions of "spring back" or "wrinkles" described above at a planning stage of investigating the forming method, that is, at a stage before practically performing the forming, is desirable. [0005] In the Patent Documents 1 to 3, as a method of specifying the source regions of the spring back, a method of specifying the source regions of the spring back by dividing a stress state into a plurality of specified regions at a bottom dead point of forming, by arithmetically computing the stress of the specified regions, and by performing spring back calculation, by a finite element method, is described. [Prior Art Document] [Patent Document] [0006] [Patent Document 1] Japanese Patent No. 5068783 [Patent Document 2] Japanese Patent No. 4894294 [Patent Document 3] Japanese Unexamined Patent Application, First Publication No. 2009-286351 [Disclosure of the Invention] [Problems to be Solved by the Invention] [0007] In the related art, as described in Patent Documents 1 to 3, a method of estimating the generating regions or source regions of the "spring back" by objective indices, such as a residual stress, is investigated, but a method of quantitatively estimating the generating regions or the source regions of a surface shape defect, such as "wrinkles" or "surface deflection" generated during the press forming has not been investigated yet, and it has been required to establish the method. Not being limited to the press forming of the steel sheet, similar problems also exist in a case of a roll forming of a steel material having a longitudinal shape or hydroforming of a steel pipe. In addition, a material of a workpiece is also not limited to steel, and even in a case of a metal material, such as aluminum or titanium, a glass fiber reinforced resin material, such as FRP or FRTP, and a composite material of these materials, similar problems exist. [0008] Considering the above-described situation, an object of the present invention is to provide a method, a device, a program, and a recording medium, for estimating generating regions and source regions of a surface shape defect generated when performing deformation processing with respect to a workpiece. [Means for Solving the Problem] [0009] The gist of the present invention for solving the problem is as follows. [0010] (1) According to an aspect of the present invention, there is provided a surface shape defect generating region estimating method for estimating generating regions of a surface shape defect of a deformation-processed product obtained by performing deformation processing with respect to a workpiece from a deformation processing starting point of time TSTART to a deformation processing ending point of time TEND, the method including: a first stress distribution obtaining process of obtaining first stress distribution 0(TI) which is distribution of a stress of the workpiece at a first working point of time Tj that is after the deformation processing starting point of time TSTART and before the deformatipn^rocessing ending point of time TEND, by a finite element method; a second stress distribution obtaining process of obtaining a second stress distribution o(T2) which is distribution of a stress of the workpiece at a second working point of time T2 that is after the first working point of time Ti and before or at the same time as the deformation processing ending point of time TEND, by the finite element method; a comparative stress distribution obtaining process of obtaining comparative stress distribution a(n, T2) which is distribution of a comparative stress of the workpiece based on comparison of the first stress distribution ogi) and the second stress distribution 0(ny, a division comparative stress distribution obtaining process of obtaining division comparative stress distribution ODIV(TI.T2) which is distribution of comparative stresses of each of divided regions DK, by dividing the comparative stress distribution O and the second divided region D2 including two elements that are a combination in which a difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized may be defined as one of the plurality of divided regions DK in the comparative stress distribution G(TL T2) obtained by removing the first divided region Dj from the comparative stress distribution C(TI. T2)- - 6 - [0012] (8) In the surface shape defect generating region estimating method according to any one of (1) to (7), the second working point of time T2 may be deformation processing ending point of time TEND- (9) In the surface shape defect generating region estimating method according to any one of (1) to (8), the workpiece may be metal. (10) In the surface shape defect generating region estimating method according to any one of (1) to (9), the deformation processing may be press forming. (11) In the surface shape defect generating region estimating method according to any one of (1) to (10), the surface shape defect may be wrinkles. [0013] (12) According to a second aspect of the present invention, there is provided a surface shape defect source region estimating method, the method including: a region dividing process of specifying the generating regions of the surface shape defect estimated by the surface shape defect generating region estimating method according to any one of (1) to (11) as a reference region mo, and dividing the periphery of the reference region m0 into a plurality of peripheral regions nik (k = 1,2, 3,... n); a correction first stress distribution obtaining process of obtaining correction first stress distribution e'en) m a case of changing a stress value of an, arbitrary peripheral region m„ among the plurality of peripheral regions nik for each of the peripheral regions nik in the first stress distribution OfTij; a correction second stress obtaining process of obtaining correction second stress distribution o'(T2) for each of the peripheral regions irik by performing forming analysis with respect to the correction first stress distribution G\TI) by a finite element method to the second working point of time T2; a correction comparative stress distribution obtaining process of obtaining correction - 7 - comparative stress distribution G'(TLT2) which is distribution of the correction comparative stress of the workpiece, based on comparison of the correction first stress distribution a'(ii) and the correction second stress distribution o'(T2), with respect to each of the peripheral regions mk; and a surface shape defect source region estimating process of estimating whether or not each of the peripheral regions mk is a surface shape defect source region, based on a comparative value p^ mo) of a surface shape defect source evaluation index p(mk> in the reference region mo acquired by using the correction comparative stress distribution o"'(Ti,T2) of each of the peripheral region m^ and a surface shape defect source evaluation index p(mo) in the reference region mo acquired by using the comparative stress distribution G(TLT2)- (13) In the surface shape defect source region estimating method according to (12), the surface shape defect source evaluation indices p^) and p(m0) may be the minimum values of the correction comparative stress. (14) In the surface shape defect source region estimating method according to (12), the surface shape defect source evaluation indices p^) and p(m0) may be the maximum values of a difference in correction comparative stress between two elements separated from each other. (15) In the surface shape defect source region estimating method according to (12), the surface shape defect source evaluation indices p(mk) and p(mo> may be the maximum values of a difference gradient obtained by dividing a difference in correction comparative stress between two elements separated from each other by the separation distance. [0014] (16) According to a third aspect of the present invention, there is provided a surface shape defect generating region estimating device which estimates a generating - 8 - region of a surface shape defect of a deformation-processed product obtained by performing deformation processing with respect to a workpiece from a deformation processing starting point of time TSTART to a deformation processing ending point of time TEND, the device including: a first stress distribution obtaining portion which obtains first stress distribution and a second divided region D2 including an element of which the comparative stress is the minimum may be defined as one of the plurality of divided regions DK in the comparative stress distribution a(Ti,i2) obtained by removing the first divided region Di from the comparative stress distribution (J(TI,T2)- (21) In the surface shape defect generating region estimating device according to any one of (16) to (19), in the division comparative stress distribution obtaining portion, the first divided region Di including two elements that are a combination in which a difference in comparative stress between the two elements separated from each other becomes maximized may be defined as one of the plurality - 10 - of divided regions DK in the comparative stress distribution G(TL T2), and the second divided region D2 including two elements that are a combination in which a difference in comparative stress between the two elements separated from each other becomes maximized may be defined as one of the plurality of divided regions DK in the comparative stress distribution 0(11,12) obtained by removing the first divided region Di from the comparative stress distribution C(TKT2)- (22) In the surface shape defect generating region estimating device according to any one of (16) to (19), in the division comparative stress distribution obtaining portion, the first divided region Di including two elements that are a combination in which a difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized may be defined as one of the plurality of divided regions DK in the comparative stress distribution am T?V and the second divided region D2 including two elements that are a combination in which a difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized may be defined as one of the plurality of divided regions DK in the comparative stress distribution G(TI, 12) obtained by removing the first divided region Di from the comparative stress distribution obtained according to the second stress distribution obtaining process S12 is illustrated. [0030] At the first working point of time Ti and at the second working point of time T2, as illustrated in FIGS. 3 and 4, a part at which a residual stress partially increases _(for example, an arrow illustrated in FIG 4) can be confirmed. The part is a part at which a working ratio is high and excessive forming is performed, and is a part at which a material flows in from the peripheral part. In other words, a possibility that the wrinkles (or bending portion) are generated at the part also cannot be denied, but similar to the estimating method according to the shading view of the related art, it is not possible to distinguish whether the part is the wrinkles or the shape (design) to be processed. In addition, even when it is estimated that the wrinkles are generated, it is difficult to quantitatively estimate the size or the like of the wrinkles. [0031] In addition, the numerical analysis by the finite element method can be performed by using a commercial finite element method (FEM) analyzing system (for example, commercial software PAM-STAMP, LS-DYNA, Autoform, OPTRIS, ITAS-3D, ASU/P-FORM, ABAQUS, ANSYS, MARC, HYSTAMP, Hyperform, SIMEX, - 21 - Fastform3D, and Quikstamp). By using the finite element method (FEM) analyzing systems, based on properties of the steel sheet, such as shape data (sheet thickness, length, or width) of the press-formed steel sheet S, a strength, or elongation, it is possible to set a forming condition, such as shape of a die (shape of a die and a punch, a curvature, and a lubricating condition), or pressing pressure (temperature or pressure), to perform press forming analysis, and to quantitatively estimate the stress distribution of a formed article after the press forming. [0032] (Comparative Stress Distribution Obtaining Process S13) In the comparative stress distribution obtaining process S13, based on comparison of the first stress distribution G(TI) and the second stress distribution CJ(T2), comparative stress distribution G(TI.T2) which is distribution of a comparative stress of ji first stress and a second stress is obtained. __ More specifically, by comparing the first stress distribution <5(TI) and the second stress distribution 0(i2), and by acquiring a difference or a change ratio of the stress of each finite element, it is possible to obtain the comparative stress distribution 0~(TLT2)- In FIG. 5, a contour view of the comparative stress distribution C of the steel sheet S at the second working point of time T2 at which the deformation processing has further proceeded than the first working point of time Tj, and by displaying the result of calculation by the contour view, it is possible to clearly observe the part at which the wrinkles are generated (illustrated by an arrow in the drawing). [0034] (Division Comparative Stress Distribution Obtaining Process S14) In division comparative stress distribution obtaining process S14, by dividing the comparative stress distribution CT(TI, T2> into a plurality of divided regions DK (k = 1, 2, 3,... n), division comparative stress distribution ODIV(TL T2) which is distribution of comparative stress in each of the divided regions DK is obtained. In FIG. 6., an example of a case where the comparative stress distribution ogi, T2) is divided into divided regions Do to Dm is illustrated. In addition, in FIG. 7, the division comparative stress distribution ODIV(TIST2) of each of the divided regions Do to Dm illustrated in FIG. 6 is illustrated. Furthermore, in FIG. 7, Min indicates "minimum value of comparative stress (GPa)", Max indicates "maximum value of comparative stress (GPa)", Max-Min indicates "maximum value of difference in comparative stress between two elements separated from each other (GPa)", and Grad.Max indicates "maximum value of a difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by a separation distance (GPa/mm)". Furthermore, a defining method of the divided region DK is not particularly limited, but the method which will be descried later may be used. [0035] - 23 - (Surface Shape Defect Generating Region Estimating Process S15) In the surface shape defect generating region estimating process SI5, by using the division comparative stress distribution aDrv(Ti,T2), based on a surface shape defect generation evaluation index a acquired with respect to each of the divided regions DK, it is estimated whether or not each of the divided regions DK is the wrinkle generating region. As the surface shape defect generation evaluation index a, for example, the following evaluation index can be used. Surface shape defect generation evaluation index al: the minimum value of the comparative stress. Surface shape defect generation evaluation index a2: the maximum value of the difference in comparative stress between two elements separated from each other. Surface shape defect generation evaluation index a3: the maximum value of the difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance. [0036] (Surface Shape Defect Generation Evaluation Index al) In a case of using the surface shape defect generation evaluation index al, the divided, region DK in which the "minimum value of comparative stress" is smaller than athreshold value in each of the division comparative stress distributions ODTV(TI,T2) is estimated as the wrinkle generating region. The bending portion which is an origin of the wrinkles is generated at the first working point of time Ti, and after this, the bending portion is pressed as the forming proceeds. Therefore, at the second working point of time T2, the compressive residual stress caused by the pressed bending portion (wrinkle) or the bending portion - 24 - (wrinkle) which is being pressed is generated. Therefore, in the divided region DK in which the compressive residual stress is large, it can be said that a possibility that the wrinkles are generated is high. Due to this, it is possible to estimate the divided region DK in which the "minimum value of comparative stress" is smaller than the threshold value, as the wrinkle generating region. [0037] To give a specific example, considering the value of "Min" illustrated in FIG. 7, for example, in a case where the threshold value is set to be -0.700 (GPa), it is possible to estimate the divided region Do, the divided region D5, and the divided region D7, as the wrinkle generating regions. [0038] The threshold value in a case of using the surface shape defect generation evaluation index al may be determined by whether or not the wrinkle having any height is allowed in a final product (press-formed article). In other words, for example, in a case of the press-formed article used in a severer environment, since even a small wrinkle largely acts on the performance of the product, by setting the threshold value to be "low", it is possible to more strictly evaluate the generation of the wrinkles. [0039] (Surface Shape Defect Generation Evaluation Index ct2) In a case of using the surface shape defect generation evaluation index a2, the divided region DK in which the "maximum value of the difference in comparative stress between two elements separated from each other" is greater than the threshold value in each of the division comparative stress distributions ODIV(TI,T2> is estimated as - 25 - the wrinkle generating regions. As described above, the bending portion which is an origin of the wrinkles is generated at the first working point of time Ti, and after this, the bending portion is pressed as the forming proceeds, and at the second working point of time T2, the compressive residual stress caused by the pressed bending portion (wrinkle) or the bending portion (wrinkle) which is being pressed is generated. Furthermore, around the compressive residual stress, the tensile residual stress is generated. Therefore, in the divided region DK in which the difference between the maximum value and the minimum value of the residual stress is large, it can be said that a possibility that the wrinkles are generated is high. Due to this, it is preferable to estimate the divided region DK in which the "maximum value of the difference in comparative stress between ike two elements separated from each other" is greater than the threshold value, as the wrinkle generating region. [0040] To give a specific example, considering the value of "Max-Min" illustrated in FIG. 7, for example, in a case where the threshold value is set to be 1.500 (GPa), it is possible to estimate the divided region Do, the divided region D5, and the divided region D7, as the wrinkle generating regions. [0041] The threshold value in a case of using the surface shape defectgeneration evaluation index , the first divided region Di including "tAvo elements of a combination in which the difference in comparative stress between two elements separated from each other becomes the maximum" is defined as one of the plurality of divided regions DK- In addition, in the comparative stress distribution O, the first divided region Di including "two elements of a combination in which the difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized" is defined as one of the plurality of divided regions DK. In addition, in the comparative stress distribution 0(TI,T2) obtained by removing the first divided region Di from the comparative stress distribution 0(TI, T2), the second divided region D2 including "two elements of a combination in which the difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized" is defined as one of the plurality of divided regions DK. [0053] By repeating the similar defining method, it is possible to automatically, define the divided region DK- The number of times of repetition of the similar defining method is not particularly limited, but for example, the above-described method may be repeated until the "maximum value of the difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance" in the comparative stress distribution G(TI. T2) obtained by removing the defined divided region DK becomes 50% or less of the "maximum value of the difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance" of the first divided region Di. [0054] Furthermore, the divided region defining method 1 is a method which considers the surface shape defect generation evaluation index al, the divided region - 31 - defining method 2 is a method which considers the surface shape defect generation evaluation index ct2, and the divided region defining method 3 is a method which considers the surface shape defect generation evaluation index a3. Therefore, in a case of defining the divided region by using the divided region defining method 1, it is preferable to use the surface shape defect generation evaluation index al. [0055] Furthermore, in the embodiment, the first working point of time Ti may be appropriately determined based on the shape of the press-formed steel sheet S, the properties of the steel sheet, the shape of a die, and press condition. For example, the first working point of time Ti may be a working point of time at which the separation distance from the bottom dead point of the upper die 101 becomes more than 0 mm and 5 mm or less, or may be a working point of time at which the separation distance from the bottom dead point of the upper die 101 becomes a height that is 1 to 5 times the height of the wrinkles allowed for each part of the press-formed article. In addition, it is preferable that the second working point of time T2 is a working point of time at which the upper die 101 becomes the bottom dead point, that is, the deformation processing ending point of time TENO- [0056] According to each of the steps described above, it is possible to quantitatively estimate the wrinkle generating regions of the press-formed article, and to reduce the number of processes or costs at the planning stage of investigating the forming method of the press-formed article. [0057] - Furthermore, "correction comparative stress distribution O\TI.T2) of the peripheral region mi" means the correction comparative stress distribution o\TL T2) obtained based on comparison of the correction first stress distribution o'gi) of the - 36 - peripheral region mi and the correction second stress distribution o'(T2) of the peripheral region mi. Similarly, "correction comparative stress distribution O\JI.TT, of the peripheral region 1TI2" means the correction comparative stress distribution O'(XL T2) obtained based on comparison of the correction first stress distribution G'(TI) of the peripheral region m2 and the correction second stress distribution O\T2) of the peripheral region m2. In the embodiment, since ten peripheral regions mi to mio exist, ten correction comparative stress distributions O;(TI,T2) are obtained. In FIG. 12, a contour view of the correction comparative stress distribution o'cri, T2) of the peripheral region m] obtained by comparing the correction first stress distribution CT' of the reference region m0 in the comparative stress distribution G(Ti. T2>". In addition, the peripheral region mt is estimated as the wrinkle source region - 38 - based on whether the comparative value is larger or smaller than the predetermined threshold value. [0066] Furthermore, with respect to the peripheral region mk estimated as the wrinkle source region, it is possible to execute a countermeasure for wrinkle generation by installing a pad to a corresponding location of a die, by changing the material planning, and by changing a die in which the wrinkle generation is expected. [0067] Hereinafter, a case where the "maximum value of the difference in correction comparative stress between two elements separated from each other" is used as the surface shape defect source evaluation indices p(mo) and p(mk) will be described as an example. .[0068] _ In Table 1, values of Min, Max, and Max-Min with respect to each of the peripheral regions mi to mm are illustrated. For example, a field of a row of Max of a column of ml means the maximum value (GPa) of the correction comparative stress of the reference region m0 in the correction comparative stress distribution a'(Ti:T2) of the peripheral region mi. Comparative values are further illustrated in Table 1. Here, since the "maximum value of the difference in comparative stress between two elements separated from each other" is used as the surface shape defect source evaluation indices p(nio) and p^), a value obtained by dividing (1) the "maximum value of the difference in comparative stress between two elements separated from each other" of the reference region m0 in the correction comparative stress distribution C'(TI,T2) of the peripheral region mk by (2) the "maximum value of the difference in comparative - 39 - stress between two elements separated from each other" of the reference region mo in the comparative stress distribution 0(TI,T2) (= 1.528 GPa), is calculated as a change ratio. Furthermore, here, the change ratio of both of the values is considered as the comparative value, but the difference may be considered as the comparative value. [0069] [Table 1] Peripheral region nil 1&2 m3 m; m_i mG m1 m8 niri mio S °-738 1 °-863 0.828 0.81 0.792 0.825 0.768 0.835 0.806 0.802 Mi* .0 79 (GPa) U-/y -0.831 1 -0.778 -0.755 -0.791 -0.788 -0.769 -0.784 -0.793 -0.79 Max-Min (GPa) 1.528 1.694 ' 1.606 1.565 1.583 1.613 1.537 1.619 1.599 1.592 ' Comparative value 1.528 /1.528 1.00 1.694 /1.528 1.606 A .528 1.565 /1.528 1.02 1.583 1.528 f.613 71,528 1.06 1.537 /1.528 1,01 1.619 /1.528 1.06 1.599 /1.528 1.05 1.592 /1.528 Change ratio 1.11 1.05 1.04 1.04 [0070] In addition, the peripheral region nik in which the comparative value (change ratio) is greater than the threshold value is estimated as the wrinkle source region. For example, in a case of setting the tlireshold value to be 1.10 (110%), the peripheral region m2 is estimated as the wrinkle source region. [0071] In addition, similar to the first embodiment, the "threshold value" which is an evaluation reference for estimating the wrinkle source region may be determined by whether or not the wrinkle having any height is allowed in a final product (press-formed article). [0072] As described above, in the surface shape defect source region estimating method according to the embodiment, it is possible to quantitatively evaluate how much the peripheral region nik of which the stress is changed to the predetermined - 40 - value influences the wrinkle generating region, by paying attention to the variation of the residual stress of the reference region mo including the wrinkle generation part at the second working point of time T2, and to estimate which peripheral region m^ is the wrinkle source region of the press-formed article. As a result, it is possible to quantitatively estimate the wrinkle source region of the press-formed article, and to reduce the number of processes or costs at the planning stage of investigating the forming method of the press-formed article. [0073] [0077] In the division comparative stress distribution obtaining portion 14, the division comparative stress distribution CDrv, and the periphery of the reference region mo is divided into the plurality of peripheral regions mk. [0082] In the correction first stress distribution obtaining portion 22, in the first stress distribution G(Ti), the correction first stress distribution o'gi) in a case where the stress value of an arbitrary peripheral region mn among the plurality of peripheral regions mk is changed is obtained for each of the peripheral regions m^. [0083] In the correction second stress obtaining portion 23, the correction second stress distribution o'(T2) is obtained for each of the peripheral regions mk by performing the forming analysis by the finite element method to the second working point of time T2 with respect to the correction first stress distribution O'(TI). [0084] In the correction comparative stress distribution obtaining portion 24, the correction comparative stress distribution a,(TLi2> is obtained by comparing the correction first stress distribution o'cri) and the correction second stress distribution o'(T2) with respect to each of the peripheral regions mk. [0085] In the surface shape defect source region estimating portion 25, it is estimated whether or not each of the peripheral regions mk is the surface shape defect source region, based on the comparative value p(nlk,m0) of the surface shape defect source evaluation index P(mk) in the reference region mo acquired by using the correction . 44 - comparative stress distribution C'(TI,T2) of each of the peripheral regions nik and the surface shape defect source evaluation index p(mo> in the reference region mo acquired by using the comparative stress distribution G(TLT2)- [0086] In the surface shape defect source region estimating device 20 according to the embodiment, similar to the surface shape defect source region estimating method described in the second embodiment, it is possible to quantitatively estimate the wrinkle source part of the press-formed article, and to reduce the number of processes or costs at the planning stage of investigating the forming method of the press-formed article. [0087] In FIG. 15, a system bus which operates a computer program is illustrated. [008_8] ..__ _ A function of each unit that configures the above-described surface shape defect generating region estimating device 10 or the surface shape defect source region estimating device 20 can be realized by operating a program stored in a RAM or a ROM of the computer. Similarly, each step of the surface shape defect generating region estimating method and the surface shape defect source region estimating method can be realized as the program stored in the RAM or the ROM of the computer is operated. A storing medium which is readable by the program and the computer in which the program is recorded is included in the present invention. [0089] Specifically, the program is recorded in the recording medium, such as a CD-ROM, or is provided in the computer via various transmission mediums. As the recording medium in which the program is recorded, in addition to the CD-ROM, it is - 45 - possible to use a flexible disk, a hard disk, a magnetic tape, a magneto-optical disk, or a nonvolatile memory card. Meanwhile, as the transmission medium of the program, it is possible to use a communication medium in a computer network system for spreading and supplying program information as a carrier wave. Here, examples of the computer network include LAN, WAN, such as Internet, or a wireless communication network, and examples of the communication medium include a wired circuit or a wireless circuit, such as optical fiber. [0090] In addition, the program included in the present invention is not limited to a program which realizes functions of the above-described embodiments as the computer executes the supplied program. For example, even in a case where the functions of the above-described embodiments are realized in cooperation with OS (operating system) or other applications which are operated by the program in the computer, the program is included in the present invention. In addition, even in a case where the functions of the above-described embodiments are realized as the entirety or a part of the processing of the supplied program are performed by a function extension board or a function extension unit of the computer, the related program is included in the present invention. [0091] For example, FiG. 15 is a schematic view illustrating an inner configuration of apersonal user terminal device. In FIG. 15,1200 indicates apersonal computer (PC) provided with a CPU 1201. The PC 1200 executes device control software which is stored in a ROM 1202 or a hard disk (HD) 1211 or which is supplied by a flexible disk (FD) 1212. The PC 1200 integrally controls each device connected to a system bus 1204. - 46 - [0092] By the program stored in the CPU 1201 and the ROM 1202 or the hard disk (HD) 1211 in the PC 1200, each order in the embodiment is realized. [0093] 1203 indicates RAM, and functions as a main memory or a work area of the CPU 1201. 1205 indicates a keyboard controller (KBC), and akeyboard (KB) 1209 controls instruction input from devices or the like which are not illustrated. [0094] 1206 indicates a CRT controller (CRTC), and controls display of a CRT display (CRT) 1210. 1207 indicates a device controller (DKC). DKC 1207 controls access to the hard disk (HD) 1211 in which a booting program, a plurality of applications, an editing file, a user file, and a network management program are stored; and the flexible disk (FD) 1212. Here, the booting program is an initiating program, that is, a program for starting the execution (operation) of hardware or software of a personal computer. [0095] 1208 indicates a network interface card (NIC), and bidirectionally exchanges data with a network printer, other network devices, or other PCs via a LAN 1220. [0096] According to the above-described personal user terminal device, it is possible to quantitatively estimate the wrinkle generating region and the wrinkle source region of the press-formed article. In this manner, the present invention includes the program for executing the surface shape defect generating region estimating method described in the first embodiment, the program for executing the surface shape defect generating region - 47 - estimating method described in the second embodiment, and further, the recording medium which is readable by the computer in which the programs are recorded. [0097] Above, the present invention is described in detail based on the embodiments, but the above-described embodiments are merely specific examples for realizing the present invention, and the technical range of the present invention is not limitedly interpreted only by the embodiments. For example, in the description of the above-described embodiments, the press forming of the steel sheet is described as an example, but the present invention is not limited thereto, and the present invention can also be employed in roll forming of the steel sheet having a longitudinal shape or a hydro forming of a steel pipe. In addition, the material of the workpiece is not limited to steel, and a metal material, such as aluminum or titanium, a glass fiber reinforced resin material, such as FRP or FRTP, and a composite material of these materials, may be used. In addition, wrinkles are described as an example of the surface shape defect, but the present invention can also be employed in a method for estimating a surface shape defect, such as a surface deflection. [Industrial Applicability] [0098] According to the present invention, it is possible to provide a method, a device, a program, and a recording medium, for estimating generating regions or source regions of a surface shape defect of a deformation-processed product generated when performing deformation processing with respect to a workpiece. [Brief Description of the Reference Symbols] [0099] - 48 - S STEEL SHEET 101 UPPER DIE (PUNCH) 102 BLANK HOLDER 103 LOWER DIE (DIE) SI 1 FIRST STRESS DISTRIBUTION OBTAINING PROCESS 512 SECOND STRESS DISTRIBUTION OBTAINING PROCESS 513 COMPARATIVE STRESS DISTRIBUTION OBTAINING PROCESS 514 DIVISION COMPARATIVE STRESS DISTRIBUTION OBTAINING PROCESS 515 SURFACE SHAPE DEFECT GENERATING REGION ESTIMATING PROCESS 521 REGION DIVIDING PROCESS 522 CORRECTION FIRST STRESS DISTRIBUTION OBTAINING PROCESS 523 CORRECTION SECOND STRESS OBTAINING PROCESS 524 CORRECTION COMPARATIVE STRESS DISTRIBUTION OBTAINING PROCESS 525 SURFACE SHAPE DEFECT SOURCE REGION ESTIMATING 11 FIRST STRESS DISTRIBUTION OBTAINING PORTION 12 SECOND STRESS DISTRIBUTION OBTAINING PORTION 13 COMPARATIVE STRESS DISTRIBUTION OBTAINING PORTION 14 DIVISION COMPARATIVE STRESS DISTRIBUTION OBTAINING 5 SURFACE SHAPE DEFECT GENERATING REGION ESTIMATING PORTION 21 REGION DIVIDING PORTION 22 CORRECTION FIRST STRESS DISTRIBUTION OBTAINING PORTION 23: CORRECTION SECOND STRESS OBTAINING PORTION 24 CORRECTION COMPARATIVE STRESS DISTRIBUTION OBTAINING PORTION 25 SURFACE SHAPE DEFECT SOURCE REGION ESTIMATING PORTION CLAIMS 1. A surface shape defect generating region estimating method for estimating generating regions of a surface shape defect of a deformation-processed product obtained by performing deformation processing with respect to a workpiece from a deformation processing starting point of time TSTART to a deformation processing ending point of time TEND, the method comprising: a first stress distribution obtaining process of obtaining first stress distribution G(ri) which is distribution of a stress of the workpiece at a first working point of time Ti that is after the deformation processing starting point of time TSTART and before the deformation processing ending point of time TEND, by a finite element method; a second stress distribution obtaining process of obtaining a second stress distribution omi which is distribution of a stress of the workpiece at a second working point of time T2 that is after the first working point of time Ti and before or at the same time as the deformation processing ending point of time TEND, by the finite element method; a comparative stress distribution obtaining process of obtaining comparative stress distribution am, T2) which is distribution of a comparative stress of the workpiece based on comparison of the first stress distribution G(TI> and the second stress distribution 0(ny, a division comparative stress distribution obtaining process of obtaining division comparative stress distribution ODrv(Ti,T2) which is distribution of comparative stresses of each of divided regions DK, by dividing the comparative stress distribution 0(TI. T2) into a plurality of divided regions DK; and a surface shape defect generating region estimating process of estimating - 51 - whether or not each of the divided regions DK is a generating region of the surface shape defect, based on a surface shape defect generation evaluation index a acquired with respect to each of the divided regions DK, by using the division comparative stress distribution ODIV(TI.T2)- 2. The surface shape defect generating region estimating method according to claim 1, wherein the surface shape defect generation evaluation index a is the minimum value of the comparative stress. 3. The surface shape defect generating region estimating method according to claim 1, wherein the surface shape defect generation evaluation index a is the maximum value of a difference in comparative stress between two elements separated from each other. 4. The surface shape defect generating region estimating method according to claim 1, wherein the surface shape defect generation evaluation index a is the maximum value of a difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance. 5. The surface shape defect generating region estimating method according to any one of claims 1 to 4, - 52 - wherein, in the division comparative stress distribution obtaining process, a first divided region Dj including an element of which the comparative stress is the minimum is defined as one of the plurality of divided regions DK in the comparative stress distribution G(TI.T2), and a second divided region D2 including an element of which the comparative stress is the minimum is defined as one of the plurality of divided regions DK in the comparative stress distribution a(Ti,T2) obtained by removing the first divided region Di from the comparative stress distribution 0(TI, T2)- 6. The surface shape defect generating region estimating method according to any one of claims 1 to 4, wherein, in the division comparative stress distribution obtaining process, the first divided region Di including two elements mat are a combination in which a difference in comparative stress between the two elements separated from each other becomes maximized is defined as one of the plurality of divided regions DK in the comparative stress distribution G(TI,T2)S and the second divided region D2 including two elements that are a combination in which a difference in comparative stress between the two elements separated from each other becomes maximized is defined as one of the plurality of divided regions DK in the comparative stress distribution G(TKT2) obtained by removing the first divided region Di from the comparative stress distribution G(TI.T2). 7. The surface shape defect generating region estimating method according to any one of claims 1 to 4, wherein, in the division comparative stress distribution obtaining process, the first divided region Di including two elements that are a combination in which a - 53 - difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized is defined as one of the plurality of divided regions DK in the comparative stress distribution CT(TLT2), and the second divided region D2 including two elements that are a combination in which a difference gradient obtained by dividing the difference in comparative stress between two elements separated from each other by the separation distance becomes maximized is defined as one of the plurality of divided regions DK in the comparative stress distribution G(TLT2) obtained by removing the first divided region Di from the comparative stress distribution 0(TLT2>. 8. The surface shape defect generating region estimating method according to any one of daims 1 to 7, _ wherein the second working point of time T? is deformation processing ending point of time TEHD- 9. The surface shape defect generating region estimating method according to any one of claims 1 to 8, wherein the workpiece is metal. 10. The surface shape defect generating region estimating method according to any one of claims 1 to 9, wherein the deformation processing is press forming. 11. The surface shape defect generating region estimating method according to any one of claims 1 to 10, - 54 - wherein the surface shape defect is wrinkles. 12. A surface shape defect source region estimating method comprising: a region dividing process of specifying the generating regions of the surface shape defect estimated by the surface shape defect generating region estimating method according to any one of claims 1 to 11 as a reference region mo, and dividing the periphery of the reference region mo into a plurality of peripheral regions rrik (k= 1, 2,3,... n); a correction first stress distribution obtaining process of obtaining correction first stress distribution c'(Ti) in a case of changing a stress value of an arbitrary peripheral region mn among the plurality of peripheral regions nik for each of the peripheral regions m^ in the first stress distribution G(TI>; a correction second stress obtaining process of obtaining correction second stress distribution o'(T2) for each of the peripheral regions irik by performing forming analysis with respect to the correction first stress distribution of a surface shape defect source evaluation index p(mk) in the reference region m0 acquired by using the correction comparative stress - 55 - distribution G'(TI.T2) of each of the peripheral region nik, and a surface shape defect source evaluation index p(mo) in the reference region m0 acquired by using the comparative stress distribution ocn,T2). 13. The surface shape defect source region estimating method according to claim 12, wherein the surface shape defect source evaluation indices (3(mj<) and p(ml» are the minimum values of the correction comparative stress. 14. The surface shape defect source region estimating method according to claim 12, wherein the surface shape defect source evaluation indices fl^ and p(mo) are the maximum values of a difference in correction comparative stress between two elements separated from each other. 15. The surface shape defect source region estimating method according to claim 12, wherein the surface shape defect source evaluation indices (3(mk) and j3(mo) are the maximum values of a difference gradient obtained by dividing a difference in correction comparative stress between two elements separated from each other by the separation distance. 16. A surface shape defect generating region estimating device which estimates a generating region of a surface shape defect of a deformation-processed product obtained by performing defonnation processing with respect to a workpiece - 56 - from a deformation processing starting point of time TSTART to a deformation processing ending point of time TEND, the device comprising: a first stress distribution obtaining portion which obtains first stress distribution O"(TI) which is distribution of a stress of the workpiece at a first working point of time Ti that is after the deformation processing starting point of time TSTART and before the deformation processing ending point of time TEND, by a finite element method; a second stress distribution obtaining portion which obtains second stress distribution o"(T2) which is distribution of a stress of the workpiece at a second working point of time T2 that is after the first working point of time Ti and before or at the same time as the deformation processing ending point of time TEND, by the finite element method; a comparative stress distribution obtaining portion which obtains comparative stress distribution G(TLT2) which is distribution of a comparative stress of the workpiece based on comparison of the first stress distribution 0(TI> and the second stress distribution o~(T2); a division comparative stress distribution obtaining portion which obtains division comparative stress distribution aDiv3 and a second divided region D2 including an element of - 58 - which the comparative stress is the minimum is defined as one of the plurality of divided regions DK in the comparative stress distribution 0(TI,T2) obtained by removing the first divided region Di from the comparative stress distribution CT of each of the peripheral region mk, and a surface shape defect source evaluation index p(m0) in the reference region mo acquired by using the comparative stress distribution C(TI,T2)- 28. The surface shape defect source region estimating device according to claim 27, wherein the surface shape defect source evaluation indices p^) and p(m0) are the minimum values of the correction comparative stress. 29. The surface shape defect source region estimating device according to claim 27, wherein the surface shape defect source evaluation indices p(mk> and p(mo) are the maximum values of a difference in correction comparative stress between two elements separated from each other. 30. The surface shape defect source region estimating device according to claim 27, wherein the surface shape defect source evaluation indices p(mk) and p(m0) are the maximum values of a difference gradient obtained by dividing a difference in correction comparative stress between two elements separated from each other by the separation distance. 31. A program which performs the surface shape defect generating region estimating method according to claim 1. 32. A program which performs the surface shape defect source region estimating method according to claim 12. 33. A recording medium which is readable by a computer in which the program according to claim 31 is recorded. 34. A recording medium which is readable by a computer in which the program according to claim 32 is recorded.