Automated_Localized_Strain_Analysis

A novel method was developed to perform automatic surface strain analysis. The algorithm could overcome the shortcomings of Harris corner detection and Shi Tomasi algorithm when used with images having noise. The developed software system was deployed on low-cost hardware (generic USB Microscope) and was capable of measuring strain with a maximum error of 1.22%, which is within the limits of ASTM-2218-02 standard.

Publication

Wankhede Pankaj, Sriram Kodey, Kurra Suresh, Sudha Radhika, A low cost surface strain measurement system using image processing for sheet metal forming applications, Measurement, 2021, 110273, ISSN 0263-2241

Overview

1. Single point surface strain analysis using automated measurement of distortion in Square Grid pattern.
2. Quadrilaterals identified from images of grid patterns captured using a microscope.
3. Equations of sides of quadrilateral calculated using Hough Transform and K-Means Clustering.
4. Corners of quadrilateral calculated from these equations.
5. Projective Transformation was applied using the calculated corners to inscribe ellipses inside convex quadrilaterals, for single point surface strain analysis.

Flowchart Description

Results

Output

Dimensions

Major Axis: 419.257 Pixels

Minor Axis: 196.775 Pixels

Converted to standard units (mm, cm etc.) by calibrating the setup.