## CS1674: Homework 4 - Written

**Due:** 9/26/2016, 11:59pm

This assignment is worth 15 points. I expect it will take you 1-2 hours to complete.

- How are feature distinctiveness and feature repeatability at odds with each other? Why is each of those properties desirable (in moderation)?
- Describe the process of extracting the locations of corners from images, starting with the use of image gradients.
- Why do we say that the Harris corner detector is not scale-invariant?
- How can we compute a histogram of gradient orientations, when generating a SIFT descriptor?
- What is the effect of gradient magnitude on the histogram of gradient orientations, in the computation of the SIFT descriptor?
- Why do we have to normalize the SIFT histogram a second time, after clipping all values to be at most 0.2?