Appendix

Figure 8: Set the threshold colour to black and adjust the brightness so that you can clearly see most of the ellipses. Don’t worry about the shapes near the center or at the edge of the lens since their distortion is not caused by weak lensing effects.

Figure 9: Choose these measurements so that you have the relevant measurements of the ellipses.

Figure 10: Set the lower bound of particle size to about 40 or 50 so that you only analyze relevant ellipses and not background noise in the image.

Figure 11: You’ll need the position and major and minor axes to determine the radial position and ellipticity of the ellipses.