Module 04 Knowledge Check
5 questions. Pass mark 4 out of 5. Answer every question before checking the answer key below, then retry after reading the feedback.
1. An edge detector responds to…
- A. object boundaries only
- B. any intensity change, including shadows and printed lines
- C. colour changes only
- D. regions rather than boundaries
2. Two objects that touch produce…
- A. two contours
- B. one contour
- C. no contours
- D. one contour per object plus a merged one
3. Otsu's method solves…
- A. uneven lighting
- B. the choice of a global threshold without tuning
- C. the touching-objects problem
- D. noise
4. Classical segmentation assumes…
- A. good lighting
- B. the target has a consistent, describable appearance
- C. high resolution
- D. a fixed camera
5. IoU alone is insufficient because it…
- A. is hard to compute
- B. does not say which direction the prediction is wrong
- C. ignores small objects
- D. requires a threshold
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Answer Key and Explanations
Check these only after attempting every question.
1. B - any intensity change, including shadows and printed lines
It measures gradient. The interpretation as an object boundary is yours.
2. B - one contour
They are one connected region, and the information needed to split them is not in the binary mask.
3. B - the choice of a global threshold without tuning
It picks one number optimally, which does not help when no single number is correct.
4. B - the target has a consistent, describable appearance
Where that assumption fails, parameter tuning is time spent on something that is wrong rather than mistuned.
5. B - does not say which direction the prediction is wrong
'Too big' has perfect recall and poor precision; the direction determines the fix.
Practical Check
Apply this module to your own work: complete the module activity for *Edges, Contours, Thresholding and Segmentation Intuition*, then write one sentence naming what your result shows and one naming what it does not.
Strong Answer Pattern
A strong answer names the task, the evidence used, the check performed, and the remaining limitation. It avoids "proved", "guaranteed", or "always" unless the evidence genuinely supports it.