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Intro to Image Processing: Section 13 Exercises 13.3-4

I have completed all of the exercises for this course, but I am having trouble getting "Check My Solution" buttons to show "Correct" on a a couple of questions, even though I am getting good results. I realize there are numerous ways to solve problems using Wolfram Language, and sometimes the Auto Grader doesn't like one technique over another, but I have tried many variations and have not been able to get the AutoGrader to pass me. I feel like I have a good understanding, but having come this far it would be nice to have the Level 1 Certificate of Completion.


ImageTrim[#, FindFaces[#]] & @ 
  "Exercise Images for Introduction to Image Processing MOOC", "Kids"]


 ImageTrim[#, FindFaces[#]] & @ 
   "Exercise Images for Introduction to Image Processing MOOC", 

Thank you in advance.

13.3 13.4

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Thanks for posting Aurelius. Yes, the autograder for the exercises in the interactive courses can be very particular about the type of solution it accepts. In this particular lesson, it was expecting the simplest possible solution. Having said that, it should have accepted your original solution as well. We are working on improving the autograder to accept multiple different solutions, but sometimes it can be very inflexible :)

If you are fairly certain of a solution and would like it to be accepted, can we request you to email, once you are done with all the exercises? We will be happy to manually grade the exercises where the autograder refuses to co-operate and ensure that these do not stand in the way of your achieving the course certification.

Thank you Abrita, you're very kind. Since Wolfram U's policy is to pass people with a 60-70% score and not display the final score, I have found it very easy to pass most of the courses I have taken even with some of my good answers being marked incorrect. I think that's actually a great policy because allows me to focus on understanding rather than revert to a student psychology of getting the best grade. :)

Glad it worked for you. The Wolfram U team is always happy to receive feedback on our courses.

Dear Abrita,

I have the same issues with some of my exercises solutions in some sections. The autograder marks mine as incorrect, and I am sure they are correct. For instance, when I substract the image solution expected to mine, I get zeros (a black image, no negative pixel values), so the solution is right, though is graded as incorrect.

Anyway, I can read that sometimes the autograder cannot check all possible solutions. If the autograder is still evaluating my solutions incorrectly, can I submit all my exercises by email?

I am almost finished the course, and I can say that is very satisfying to pass it. I found it very instructive and a good introduction to Image processing. I have remembered some things what I learnt some years ago, and learned some news.

I recommend it to those interested in Image Processing using Mathematica.

Absolutely. Please feel free to email us at, once you are done with all the exercises. So glad to hear you found the course useful. Thank you for your feedback.

I was able to get things to work with:

FindFaces[ResourceData["Exercise Images for Introduction to Image Processing MOOC", "Kids"], "Image"]


Classify["FacialGender"][FindFaces[ResourceData["Exercise Images for Introduction to Image Processing MOOC", "Kids"], "Image"]]

This was one of the few times WolframU was very particular on how things were done.

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