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Systems And Methods For Reconstructingsuper Resolution Images Under Total Aliasing Based Upon Translation Values

Abstract: Systems and methods for reconstructing super-resolution images under total aliasing based upon translation values. Traditional systems and methods provide for extracting super-resolution (SR) image/s from low-resolution (LR) image/s but include aliasing as a background noise which degrades the performance or include aliasing into an image model which leads to an enormously high computational complexity. Embodiments of the present disclosure provide for reconstructing super-resolution images based upon translation values by taking aliasing in consideration by capturing a set of LR images, estimating, using a Fast Fourier Transformation, a set of translation values based upon the set of LR images, obtaining, using a multi-signal classification technique, one or more optimized frequency spectrums based upon the set of translation values and reconstructing one or more SR images based upon the set of translation values.

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Notices, Deadlines & Correspondence

Patent Information

Application #
Filing Date
08 December 2017
Publication Number
24/2019
Publication Type
INA
Invention Field
ELECTRONICS
Status
Email
ip@legasis.in
Parent Application
Patent Number
Legal Status
Grant Date
2024-01-01
Renewal Date

Applicants

Tata Consultancy Services Limited
Nirmal Building, 9th Floor, Nariman Point, Mumbai 400021, Maharashtra, India

Inventors

1. KUMAR, Achanna Anil
Tata Consultancy Services Limited, Tata Consultancy Services, #152, Gopalan Global Axis, Opposite Satya Sai Hospital, ITPL Main Road, EPIP Zone, Whitefield, Bangalore - 560 066, Karnataka, India
2. N, Narendra
Tata Consultancy Services Limited, Tata Consultancy Services, #152, Gopalan Global Axis, Opposite Satya Sai Hospital, ITPL Main Road, EPIP Zone, Whitefield, Bangalore - 560 066, Karnataka, India
3. CHANDRA, Girish M
Tata Consultancy Services Limited, Tata Consultancy Services, #152, Gopalan Global Axis, Opposite Satya Sai Hospital, ITPL Main Road, EPIP Zone, Whitefield, Bangalore - 560 066, Karnataka, India
4. PURUSHOTHAMAN, Balamuralidhar
Tata Consultancy Services Limited, Tata Consultancy Services, #152, Gopalan Global Axis, Opposite Satya Sai Hospital, ITPL Main Road, EPIP Zone, Whitefield, Bangalore - 560 066, Karnataka, India

Specification

Claims:1. A method for reconstructing super-resolution images under total aliasing based upon a set of translation values, the method comprising a processor implemented steps of: capturing, using an image capturing device, a set of low-resolution images comprising of one or more aliased images; estimating, using a Fast Fourier transformation, the set of translation values from the set of low-resolution images for obtaining one or more optimized frequency spectrums to reconstruct one or more super-resolution images, wherein the set of translation values comprise translational shifts of the set of low-resolution images; obtaining, using a multiple signal classification (MUSIC) technique, the one or more optimized frequency spectrums from the set of translation values for extracting the one or more super-resolution images; and reconstructing, using an Inverse Fourier transformation, the one or more super-resolution images from the one or more optimized frequency spectrums. 2. The method of claim 1, wherein the step of estimating the set of translation values further comprises: (i) determining, using a normalized cross power spectrum technique, a set of initial translational values based upon one or more low-resolution images and enhancement factors for updating a second set of translational values; and (ii) updating the second set of translational values based upon the set of initial translational values and one or more gradient values to extract the one or more super-resolution images. 3. The method of claim 2, wherein the step of updating the second set of translational values comprises identifying the one or more gradient values for updating one or more integer values closest to the set of translational values to extract the one or more super-resolution images. 4. A system comprising: a memory storing instructions; one or more communication interfaces; and one or more hardware processors coupled to the memory via the one or more communication interfaces, wherein the one or more hardware processors are configured by the instructions to: capture, using an image capturing device, a set of low-resolution images comprising of one or more aliased images; estimate, using a Fast Fourier transformation, a set of translation values from the set of low-resolution images for obtaining one or more optimized frequency spectrums to reconstruct one or more super-resolution images, wherein the set of translation values comprise translational shifts of the set of low-resolution images; obtain, using a multiple signal classification (MUSIC) technique, the one or more optimized frequency spectrums from the set of translation values for extracting the one or more super-resolution images; and reconstruct, using an Inverse Fourier transformation, the one or more super-resolution images from the one or more optimized frequency spectrums. 5. The system of claim 4, wherein the one or more hardware processors are further configured to estimate the set of translation values by: (i) determine, using a normalized cross power spectrum technique, a set of initial translational values based upon one or more low-resolution images and enhancement factors for updating a second set of translational values; and (ii) update the second set of translational values based upon the set of initial translational values and one or more gradient values to extract the one or more super-resolution images. 6. The system of claim 5, wherein the one or more hardware processors are further configured to update the second set of translational values by identifying the one or more gradient values for updating one or more integer values closest to the set of translational values to extract the one or more super-resolution images. , Description:FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENT RULES, 2003 COMPLETE SPECIFICATION (See Section 10 and Rule 13) Title of invention: SYSTEMS AND METHODS FOR RECONSTRUCTING SUPER-RESOLUTION IMAGES UNDER TOTAL ALIASING BASED UPON TRANSLATION VALUES Applicant: Tata Consultancy Services Limited A company Incorporated in India under the Companies Act, 1956 Having address: Nirmal Building, 9th Floor, Nariman Point, Mumbai 400021, Maharashtra, India The following specification particularly describes the invention and the manner in which it is to be performed. TECHNICAL FIELD The present disclosure generally relates to reconstructing super-resolution images under total aliasing based upon translation values. More particularly, the present disclosure relates to systems and methods for reconstructing super-resolution images under total aliasing based upon translation values. BACKGROUND A super-resolution image finds applications in many areas such as in satellite and aerial imaging, medical imaging etc. and there are many techniques available for obtaining super-resolution images. There has been an increasing trend of removing the front end anti-aliasing filter in cameras to increase the image sharpness. Removal of this filter causes total aliasing of a low-resolution image spectrum. Aliasing, is a well-known phenomenon caused due to sampling of signals below the Nyquist sampling rate and is usually considered as nuisance. However, aliased signals contains information about high frequency components and reconstructing the signal by resolving these high frequency components from multiple, slightly different aliased signals (also referred as low resolution (LR) signal) has many applications. One such key application being the image super-resolution (SR). Aliasing may lead to loss of detailed information or high frequency components from the images. An image or signal processing method, called super-resolution image reconstruction, can increase image resolution without changing the design of the optics and the detectors. In other words, super-resolution image reconstruction can produce high-resolution images by using the existing low-cost imaging devices from a sequence (or a few snapshots) of low resolution images. The emphasis of the super-resolution image reconstruction algorithm is to de-alias the under sampled images to obtain an alias-free or, as identified in the literature, a super-resolved image. When the entire band is affected, the traditional systems and methods include aliasing as a background noise which may degrade the performance. Alternatively, if aliasing is included into an image model, the computational complexity becomes enormously high. For example, even for a nominal LR dimension of size 10×10 and the SR dimension of size 100×100, the order of the matrix to be handled may be in the range of 100×10000 which may be enormously high. Furthermore, due to the iterative nature of the algorithm, these large dimensional matrices must be handled at each iteration. Super-resolution image reconstruction generally increases image resolution without necessitating a change in the design of the optics and/or detectors by using a sequence (or a few snapshots) of low-resolution images. Super-resolution image reconstruction algorithms effectively de-alias under sampled images to obtain a substantially alias-free or, as identified in the literature, a super-resolved image. Thus, a SR image is not just merely an up-sampled and interpolated image, but it also contains additional details due to the incorporation of high frequency information. SUMMARY The following presents a simplified summary of some embodiments of the disclosure in order to provide a basic understanding of the embodiments. This summary is not an extensive overview of the embodiments. It is not intended to identify key/critical elements of the embodiments or to delineate the scope of the embodiments. Its sole purpose is to present some embodiments in a simplified form as a prelude to the more detailed description that is presented below. Systems and methods of the present disclosure enable reconstructing super-resolution images under total aliasing based upon translation values. In an embodiment of the present disclosure, there is provided a method for reconstructing super-resolution images based upon translation values, the method comprising: capturing, using an image capturing device, a set of low-resolution images comprising of one or more aliased images; estimating, using a Fast Fourier transformation, the set of translation values from the set of low-resolution images for obtaining one or more optimized frequency spectrums to reconstruct one or more super-resolution images, wherein the set of translation values comprise translational shifts of the set of low-resolution images; obtaining, using a multiple signal classification (MUSIC) technique, the one or more optimized frequency spectrums from the set of translation values for extracting the one or more super-resolution images; reconstructing, using an Inverse Fourier transformation, the one or more super-resolution images from the one or more optimized frequency spectrums; determining, using a normalized cross power spectrum technique, a set of initial translational values based upon one or more low-resolution images and enhancement factors for updating a second set of translational values; updating the second set of translational values based upon the set of initial translational values and one or more gradient values to extract the one or more super-resolution images; and updating the second set of translational values by identifying the one or more gradient values for updating one or more integer values closest to the set of translational values to extract the one or more super-resolution images. In an embodiment of the present disclosure, there is provided a system for reconstructing super-resolution images under total aliasing based upon translation values, the system comprising one or more processors; one or more data storage devices operatively coupled to the one or more processors and configured to store instructions configured for execution by the one or more processors to: capture, using an image capturing device, a set of low-resolution images comprising of one or more aliased images; estimate, using a Fast Fourier transformation, a set of translation values from the set of low-resolution images for obtaining one or more optimized frequency spectrums to reconstruct one or more super-resolution images, wherein the set of translation values comprise translational shifts of the set of low-resolution images; obtain, using a multiple signal classification (MUSIC) technique, the one or more optimized frequency spectrums from the set of translation values for extracting the one or more super-resolution images; reconstruct, using an Inverse Fourier transformation, the one or more super-resolution images from the one or more optimized frequency spectrums; determine, using a normalized cross power spectrum technique, a set of initial translational values based upon one or more low-resolution images and enhancement factors for updating a second set of translational values; update the second set of translational values based upon the set of initial translational values and one or more gradient values to extract the one or more super-resolution images; and update the second set of translational values by identifying the one or more gradient values for updating one or more integer values closest to the set of translational values to extract the one or more super-resolution images. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as clamed. BRIEF DESCRIPTION OF THE DRAWINGS The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which: Fig. 1 illustrates a block diagram of a system for reconstructing super-resolution images under total aliasing based upon translation values according to an embodiment of the present disclosure; Fig. 2 is a flowchart illustrating the steps involved for reconstructing super-resolution images under total aliasing based upon translation values according to an embodiment of the present disclosure; Fig. 3(a) illustrates visual representation of a low-resolution image captured using an image capturing device according to an embodiment of the present disclosure; Fig. 3(b) illustrates visual representation of one or more optimized frequency spectrums obtained based upon translation values according to an embodiment of the present disclosure; and Fig. 4 illustrates visual representation of a super-resolution image reconstructed by estimating translational values according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. The embodiments of the present disclosure provide systems and methods for reconstructing super-resolution images under total aliasing based upon translation values. Super-resolution enhances the resolution of an image. Super-resolution images may be generated from one or more than one low resolution image(s). Super-resolution image reconstruction can increase image resolution without changing the design of the optics and the detectors. In other words, super-resolution image reconstruction can produce high-resolution images by using the existing low-cost imaging devices from a sequence (or a few snapshots) of low resolution images. The emphasis of the super-resolution image reconstruction algorithm is to de-alias the under sampled images to obtain an alias-free or, as identified in the literature, a super-resolved image. The traditional systems and methods consider aliasing into the image model for reconstructing super-resolution image/s when the entire band is affected. The technique may work under total aliasing but the computational complexity may be enormously high. For example, the dimensions of the matrix to be handled may be very large even for a nominal LR and SR image sizes. Super-resolution image reconstruction comprises improving image resolution without necessitating a change in the design of the optics and/or detectors by using a sequence (or a few snapshots) of low-resolution image/s. Super-resolution image reconstruction algorithms effectively de-alias under sampled images to obtain a substantially alias-free or, as identified in the literature, a super-resolved image. Thus, a SR image is not just merely an up-sampled and interpolated image, but it also contains additional details due to the incorporation of high frequency information. The traditional systems and methods consider aliasing as a background noise and hence the super-resolution image reconstruction performance is quiet low in case of total aliasing. Hence, there is a need for technology that may consider the problem of super-resolution (SR) image reconstruction from a set of totally aliased low resolution (LR) images with different unknown sub-pixel offsets. The technology must provide for the joint estimation of the unknown shifts and SR image spectrum as a dictionary learning problem and alternating minimization approach to resolve the problem of joint estimation. The technology must also provide for smaller matrices size to be handled during the computation, typically based upon number of images and enhancement factors, and is completely independent on the actual dimensions of the LR and SR images hence requiring significantly lesser resources than the traditional systems and methods. Referring now to the drawings, and more particularly to FIGS. 1 through FIGS. 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments and these embodiments are described in the context of the following exemplary system and/or method. FIG. 1 illustrates an exemplary block diagram of a system 100 for reconstructing super-resolution images under total aliasing based upon translation values in accordance with an embodiment of the present disclosure. In an embodiment, the system 100 includes one or more processors 104, communication interface device(s) or input/output (I/O) interface(s) 106, and one or more data storage devices or memory 102 operatively coupled to the one or more processors 104. The one or more processors 104 that are hardware processors can be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor(s) is configured to fetch and execute computer-readable instructions stored in the memory. In an embodiment, the system 100 can be implemented in a variety of computing systems, such as laptop computers, notebooks, hand-held devices, workstations, mainframe computers, servers, a network cloud and the like. The I/O interface device(s) 106 can include a variety of software and hardware interfaces, for example, a web interface, a graphical user interface, and the like and can facilitate multiple communications within a wide variety of networks N/W and protocol types, including wired networks, for example, LAN, cable, etc., and wireless networks, such as WLAN, cellular, or satellite. In an embodiment, the I/O interface device(s) can include one or more ports for connecting a number of devices to one another or to another server. The memory 102 may include any computer-readable medium known in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or non-volatile memory, such as read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes. FIG. 2, with reference to FIG. 1, illustrates an exemplary flow diagram of a method for reconstructing super-resolution images under total aliasing based upon translation values in accordance with an embodiment of the present disclosure. In an embodiment the system 100 comprises one or more data storage devices of the memory 102 operatively coupled to the one or more hardware processors 104 and is configured to store instructions for execution of steps of the method by the one or more processors 104. The steps of the method of the present disclosure will now be explained with reference to the components of the system 100 as depicted in FIG. 1 and the flow diagram. In the embodiments of the present disclosure, the hardware processors 104 when configured the instructions performs one or more methodologies described herein. According to an embodiment of the present disclosure, at step 201, a set of low-resolution images comprising of one or more aliased images may be captured using an image capturing device. The image capturing device may comprise of (but not limited to) a camera array to capture the set of low-resolution images comprising of different unknown multi-pixel offsets. In an embodiment, not only the set of low-resolution images (to be captured) are aliased but further, due to the absence of anti-aliasing filter, the entire spectrum of the set of low-resolution images are totally aliased. According to an embodiment of the present disclosure, the k^th(1=k=K), LR image g_k (n) of size N_x × N_y may be modelled as: g_k (n) =h(L_n + c_k ) + ?(n) equation (1) where h(t), t?R^2 denotes the 2-D image scene, {n =[n_x,n_y ]^T | n ? Z^2,0=n_x=N_x-1,0=n_y=N_y-1},c_k=[c_xk,c_yk ]^T,L=(¦(L_x&0@0&L_y )),L_x,L_y denotes the enhancement factors along x-axis and y-axis respectively (where the factors L_x,L_y are also referred to as decimation factors), c_xk,c_yk which reside in the range of 0?_h @c_?k^((i)) )¦ where sign(ß)=+1 if ß=0,else it is-1. equation (8) Table 2 Initialization (with normalized cross power spectrum technique) Iteration 1 Iteration 2 Iteration 3 Low-resolution image 1 (0,0) (0,0) (0,0) (0,0) Low-resolution image 2 (-5,-0.1) (-2,-0.1) (-0.5,-0.1) (-0.5,-0.1) Low-resolution image 3 (1,-6) (0.2,-4) (0.2,-2) (0.2,0.3) Low-resolution image 4 (-1,3) (-0.1,1.4) (-0.1,0.3) (-0.1,0.3) In an embodiment, referring to table 2, the one or more gradient values computed at each of the iteration may be referred. Referring to tables 1 and 2, if the set of initial translation values are (2,7) and the gradient values of the LR image 3 are (1,-6), iteration may be performed, and after the iteration 1 the set of initial translation values for the LR image 3 may be obtained (using equation (8)) as (3,6). In an embodiment, gradient threshold may be kept as 1 and the set of translational values may further be changed (incremented or decremented) only when the gradient is not less than 1. Thus, referring to table 2 again, at the end of iteration 3, it may be noted that all the gradient values are less than 1, and hence the iterations may be stopped and the second set of translational values thus obtained (when the gradient values are less than 1) may be retained. Thus, taking an example, referring to table 1 again, if the set of translational values of the LR image 3 are (3,4) when the gradient values are less than 1, set of translational values may finally be obtained as (3,4). In an embodiment, the condition |(?F(A_? )/(?c_?k ))|>?_hensures that blind updation (or iteration) is not performed even when the gradient value is insignificant. This further supports faster convergence and more initialization errors may be adjusted. Thus, as discussed above, if the set of translational values of the LR image 3 are (3,4) when the gradient values are less than 1, set of translational values may finally be obtained as (3,4). In an embodiment, after updating the second set of translational values, the sparse spectrum may be computed again using the MUSIC technique for determining the gradient of error. If the gradient of error falls below error threshold, the iterations may be performed again to obtain the second set of translational values, else the iterations may be stopped. According to an embodiment of the present disclosure, based upon the equation (5), the F(A_?) comprises of N_x N_y summations and the gradients may be computed separately for each of the enhancement factor, since the dictionary is different for each of the enhancement factor. However, due to sparse nature of the frequency spectrum of images, only the optimum frequency spectrum images, that is, the ones having significant energy may be considered. The optimum frequency spectrum images may be selected by putting a threshold on the spectrum of LR images, G_k (f). Therefore, based upon equation (8) obtained above and selecting only the optimum frequency spectrums, faster convergence and savings in computation may be achieved. According to an embodiment of the present disclosure, for reconstructing the one or more SR images, the following conditions must be satisfied: L_x and L_y must be co-prime, that is, GCD(L_x,L_y )=1, and a_s

Documents

Application Documents

# Name Date
1 201721044207-STATEMENT OF UNDERTAKING (FORM 3) [08-12-2017(online)]_44.pdf 2017-12-08
2 201721044207-STATEMENT OF UNDERTAKING (FORM 3) [08-12-2017(online)].pdf 2017-12-08
3 201721044207-REQUEST FOR EXAMINATION (FORM-18) [08-12-2017(online)]_13.pdf 2017-12-08
4 201721044207-REQUEST FOR EXAMINATION (FORM-18) [08-12-2017(online)].pdf 2017-12-08
5 201721044207-FORM 18 [08-12-2017(online)].pdf 2017-12-08
6 201721044207-FORM 1 [08-12-2017(online)]_24.pdf 2017-12-08
7 201721044207-FORM 1 [08-12-2017(online)].pdf 2017-12-08
8 201721044207-FIGURE OF ABSTRACT [08-12-2017(online)].jpg 2017-12-08
9 201721044207-DRAWINGS [08-12-2017(online)].pdf 2017-12-08
10 201721044207-COMPLETE SPECIFICATION [08-12-2017(online)].pdf 2017-12-08
11 201721044207-Proof of Right (MANDATORY) [23-01-2018(online)].pdf 2018-01-23
12 201721044207-FORM-26 [23-01-2018(online)].pdf 2018-01-23
13 201721044207-ORIGINAL UNDER RULE 6 (1A)-310118.pdf 2018-08-11
14 201721044207-REQUEST FOR CERTIFIED COPY [05-02-2019(online)].pdf 2019-02-05
15 201721044207-CORRESPONDENCE(IPO)-(CERTIFIED COPY)-(7-2-2019).pdf 2019-02-11
16 201721044207-FORM 3 [29-05-2019(online)].pdf 2019-05-29
17 201721044207-OTHERS [26-02-2021(online)].pdf 2021-02-26
18 201721044207-FER_SER_REPLY [26-02-2021(online)].pdf 2021-02-26
19 201721044207-COMPLETE SPECIFICATION [26-02-2021(online)].pdf 2021-02-26
20 201721044207-CLAIMS [26-02-2021(online)].pdf 2021-02-26
21 201721044207-FER.pdf 2021-10-18
22 201721044207-PatentCertificate01-01-2024.pdf 2024-01-01
23 201721044207-IntimationOfGrant01-01-2024.pdf 2024-01-01

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1 searchE_17-08-2020.pdf
2 searchAE_20-05-2021.pdf

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