# CS代考 CPSC 425 Stereo, Motion and Optical Flow 20/21 (Term 1) Practice Questions – cscodehelp代写

CPSC 425 Stereo, Motion and Optical Flow 20/21 (Term 1) Practice Questions
Multiple Part True/False Questions. For each question, indicate which of the statements, (A)–(D), are true and which are false? Note: Questions may have zero, one or multiple statements that are true.
Question 1. Consider conditions under which an epipolar constraint used in stereo matching holds between images from two cameras. Which of the following condi- tions are true? Which are false? Note: You can assume that the cameras perform standard perspective projection.
(A) The two cameras must have coplanar projection planes.
(B) The two cameras must face in the same direction (i.e., have parallel optical axes).
(C) The two images must be rectified.
(D) There are no restrictions on camera locations or orientations, an epipolar constraint always applies.
Question 2. Stereo matching can be performed by correlating windows of pixels between the two images. But, it is difficult to know what window size to use. The following statements identify problems when the selected window size is too large. Which are true? Which are false?
(A) There will be more false matches due to ambiguity and image noise.
(B) The exact location of correct matches will be known with less accuracy. (C) Places where depth is discontinuous will be poorly matched.
(D) The epipolar constraint is not as effective to limit the number of matches.
Question 3. The Lucas–Kanade method makes several assumptions about motion and optical flow. Which of the assumptions, (A)–(D), are true of Lucas–Kanade and which are false? Note: This is a question about the Lucas–Kanade method, not about assumptions that may or may not be true, in general, about the world.
(A) Corresponding points in a sequence of images of a moving object have ex- actly the same brightness values.
(B) Sampling in x, y and t is frequent enough that the partial derivative, Ix, Iy and It, are well-defined
(C) The motion, [u,v], is constant in the selected window about each image point, [x, y].
(D) The matrix
􏰂 􏰄Ix2 􏰄IxIy 􏰃
􏰄IxIy 􏰄Iy2
has rank 2 in the selected window about each image point.