Question 9 - mock exam 2021

Question 9 - mock exam 2021

by Mouadh Sadani -
Number of replies: 3

In question 9 of exam 2021, when you say the region growing algorithm always converges, do you mean that it always finds a solution no matter if it is optimal or not or do you mean it is always optimal? Because as I understand, choosing the right initial seeds is important and affects the segmentation performance

In reply to Mouadh Sadani

Re: Question 9 - mock exam 2021

by Corentin Dumery -
Hi Mouadh,

Yes you understood correctly, "the algorithm converges" doesn't imply that the solution is necessarily optimal. It only means that the algorithm will stop changing at some point, so you can use this criteria as a terminating condition. You could not do that if it was alternating between two solutions at the end, for example.

Corentin
In reply to Corentin Dumery

Re: Question 9 - mock exam 2021

by Mouadh Sadani -
Thanks for you answer,

In question 10 of the same exam. Can you explain to me why the region growing does require some examples before processing and why CNNs do not ?
In reply to Mouadh Sadani

Re: Question 9 - mock exam 2021

by Corentin Dumery -
The question states "for each image processed", so that's not necessary for a CNN, it only needs to see labels during training.

For region growing, see the thread with Cyril and Anar (right before your question).