DESC:TITLE OF THE INVENTION
A method of automatic engineering calibration for hairiness measurement in an evenness tester

CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from the Provisional Application No. 201641041062 filed on 1st Dec 2016, the full disclosure of which is hereby incorporated by reference herein.

FIELD OF THE INVENTION
[0002] The present invention relates to a method of calibrating the yarn hairiness measurement module automatically using the engineering calibration.

BACKGROUND OF THE INVENTION
[0003] Evenness tester comprises various modules for measuring properties of yarn, sliver and roving. Various modules include Mass module, Hairiness module, Hair count module, Foreign fibre module, Diameter module, Linear density module etc.

[0004] Hairiness module measures the hair property over the surface of the yarn. The protruding hairs are measured by the evenness tester and expressed as various hairiness properties. Some popular yarn hairiness properties include Hairiness Index, Hair Count etc.

[0005] In Evenness testers, generally a variability in test result can be due to either the textile material tested or alternatively due to other factors such as environment, drift in the system etc. In order to eliminate the variability due to other factors, it becomes essential to calibrate the measurement module with standards periodically. Manual calibrations are usually subject to errors.

[0006] US3278842 provides a method for checking the accuracy and calibrating the electrical testing devices meant for determining the mean deviation of a variable quantity from its mean value. A resilient cord is inserted in the measuring apparatus instead of the test material to be tested. The cord is then subjected to periodic and varying stretching so that precisely defined variations in cross sectional area are produced. The values are compared to the references. In this method, only the method of checking the accuracy of the measurement system is disclosed but not the method of corrections based on the results.

[0007] Hence there is a need in the art to develop a method for calibrating the hairiness module by engineering calibration technique. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.

OBJECTS OF THE INVENTION
[0008] The main object of the present invention is to provide a method of calibrating the yarn hairiness measurement module automatically using the engineering calibration technique.

[0009] Other objects of the invention will be apparent from the description of the invention herein below.

SUMMARY OF THE INVENTION
[0010] Accordingly, the present invention relates to a method for engineering calibration of the hairiness module of an evenness tester.

[0011] Evenness tester contains hairiness module which measures the hairiness properties of textile material using optical principle. In one aspect of the invention, the method comprises a light source at one side of the textile material and a light receiver on the other side of the textile material. The light falls over the yarn and the deflected / diffracted / scattered light based on the hairs falls over the light receiver. The light information is received by the detector of the light receiver and the hairiness value is calculated by the system.

[0012] In another aspect of the present invention, the hairiness module is calibrated automatically when no textile material is present for measurement. The Hairiness engineering calibration device is placed in between the light source and light receiver of the hairiness module automatically by the system. The light received by the receiver is measured and compared to the standard value which is used for correcting the hairiness module.

BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention is described in the detailed description and not by way of limitation, in the figures of the accompanying drawings, and in which
Figure 1 shows the setup of the present invention meant for hairiness module calibration.
Figure 2 shows the flow chart explaining the method of correcting the hairiness module using engineering calibration.

DETAILED DESCRIPTION OF THE INVENTION
[0014] For the better understanding of the object, technical solution and advantage of the present invention, the present invention will be further explained in detail with respect to embodiments and accompanying drawings below. It should be understood that the specific embodiments described herein only be used for explaining the present invention but not used to limit the present invention.

[0015] Hairiness measurement module of an evenness tester measures hairiness properties by optical principle. Due to factors like environment, drift in the system etc., it becomes necessary to calibrate the system to ensure correct results. The present method provides a method to calibrate the hairiness module automatically based on engineering calibration technique to avoid such result deviations due to the factors explained.

[0016] The present invention relates to a method for automatically calibrating the hairiness measurement module of an evenness tester comprising a light source (1), light receiver (4) and hairiness engineering calibration device (5) characterized in that wherein the hairiness engineering calibration device (5) is positioned in between the light source (1) and light receiver (4); light (2) falls over the hairiness engineering calibration device (5) and the deflected / diffracted / scattered / obstructed light information (3) falls over the light receiver (4);the measured value based on the deflected / diffracted / scattered light/ obstructed light information (3) by the light receiver (4) is compared with the pre-defined limits; and the correction is initiated if the measured value of the deflected / diffracted / scattered/ obstructed light information (3) is outside the pre-defined limits.

[0017] In the preferred embodiment of the present invention (Figure1), the hairiness module of an evenness tester comprises a light source (1) and a light receiver (4). Usually the textile material is passed in between the light source (1) and the light receiver (4). When there is no testing done, during the automatic calibration as explained in the present invention, the hairiness engineering calibration device (5) is made available in between the light source (1) and light receiver (4) automatically. The light (2) from the light source (1) falls over the Hairiness engineering calibration device (5) and the light (2) gets deflected / diffracted / scattered / obstructed and the deflected / diffracted / scattered /obstructed light information (3) fall over the light receiver (4). The light receiver (4) is further connected to the control system (6) which comprises a storage device (7) and a correction circuit (8). The correction circuit (8) is connected to an adjustment device (10). The control system (6) on one side is connected to the power circuitry (9) which is further connected to the light source (1). On the other side, the control system (6) is connected to a computer (11). The standard value of light (2) received by the light receiver (4) is pre-determined, known and stored in the storage device (7) of the control system (6) and / or in a computer (11). If the value received by the light receiver (4) for the given hairiness engineering calibration device (5) is within the permissible limits from the predetermined reference value, then no corrective action will be performed by the control system (6). Alternatively, if value received by the light receiver (4) for the given hairiness engineering calibration device (5) is outside the permissible limits from the predetermined reference value, then a corrective action will be initiated by the control system (6).

[0018] In one embodiment, the corrective action is done by more than one method. In one of the method of correction, the light (2) received by the light receiver (4) is transferred to a correction circuit (8) which compares the value received from the light receiver (4) and the predetermined reference value. Based on the difference between the value received from the light receiver (4) and the predetermined reference value, correction takes place by adjusting the gain of the correction circuit (8) using an adjustment device (10) like digital POT meter, gain amplifier or any such similar electronic devices and circuits.

[0019] In another alternate embodiment, the intensity of the light source (1) is modified by means of adjusting the power circuitry (9) which is connected to the light source (1) and controls the same.

[0020] In yet another alternate embodiment, correction is done using an algorithm which resides in the computer (11) and the algorithm adjusts the output hairiness value directly based on the adjustment value determined.

[0021] In all the above three embodiments, the system works on a closed loop method to ensure that the difference between the value received from the light receiver (4) and the predetermined reference value are within the specified limits. It takes one or more iterations to adjust the hairiness measurement module unit to achieve the required value. The limits for identifying the deviation can be user entry, or by using statistical tools.
[0022] Figure 2 represents the flow chart for correcting the measured value of deflected / diffracted / scattered /obstructed light information (3). If the measured value of deflected / diffracted / scattered light (3) is within the limit, then no correction will be done. If the measured value of deflected / diffracted / scattered / obstructed light information (3) is not within the limit, then correction of measured value will be done by the earlier mentioned methods i.e. either by adjusting the gain of the correction circuit (8) using adjustment device (10) or by adjusting the intensity of light source (1) through the power circuitry (9) or alternatively correction using an algorithm which resides in the computer (11).
,CLAIMS:We Claim:
1. A method for automatically calibrating the hairiness measurement module of an evenness tester comprising a light source (1), light receiver (4) and hairiness engineering calibration device (5) characterized in that wherein the hairiness engineering calibration device (5) is positioned in between the light source (1) and light receiver (4); light (2) falls over the hairiness engineering calibration device (5) and the deflected / diffracted / scattered / obstructed light information (3) falls over the light receiver (4);the measured value based on the deflected / diffracted / scattered light/ obstructed light information (3) by the light receiver (4) is compared with the pre-defined limits; and the correction is initiated if the measured value of the deflected / diffracted / scattered/ obstructed light information (3) is outside the pre-defined limits
2. The method according to claim 1, wherein the light receiver (4) is further connected to the control system (6) which comprises a storage device (7) and correction circuit (8).
3. The method according to claim 2, wherein the correction circuit (8) is connected to an adjustment device (10).
4. The method according to claim 2, wherein the control system (6) on one side is connected to the power circuitry (9) which is further connected to light source (1) and on the other side is connected to a computer (11).
5. The method according to claims 1 to 4, wherein the correction is done by adjusting the gain of the correction circuit (8) using the adjustment device (10) automatically.
6. The method according to claims 1 to 4, wherein the correction is done by adjusting the intensity of light source (1) through power circuitry (9).
7. The method according to claims 1 to 4, wherein the correction is done by using an algorithm which resides in the computer (11) and the correction is done directly on the hairiness value measured by the hairiness module of the evenness tester.