Exer6: Erosion-Dilation

For this exercise we were tasked to detect the shaded and count the shaded circles in the evaluation forms.

There were the following problems/concerns in the exercise:

• 'x' marks exist in some forms where the answers were changed. 'x' marks should not be detected as a circle
• some circles are lightly shaded

In order to get the desired output, we used a lot of preprocessing techniques (blurring, erosion, dilation, binarization, etc.) to enhance the image before detecting the circles.

Successfully detected image!

Unable to distinguish 'x' marks from circles

As seen on the second image, we were not able to distinguish the 'x' marks.