Feature tracking

Question 1

what is feature tracking

Answer 1

recognising patterns in image stacks

Question 2

What is coregistration/ allignment useful for?

Answer 2

correlating images when unknown projection, sensor characteristics and position.
Image deformation.
Camera motion

Question 3

Stereo photogrammetry (SfM) what is it?

Answer 3

determining surface geometry using two or more angles

Question 4

Give a satellite that uses SfM to create DEMs

Answer 4

ASTER - thermal - been doing it since early 2000s in 30m resolution

Question 5

How does ‘image matching’ work?

Answer 5

template on one image is matched with second image, based on intensity and features

Question 6

How is quality of mathcing measured

Answer 6

accuracy is measured as a function of pixel size - usually 1/10 pixel

Question 7

Optical flow

Answer 7

measures intensity gradient between images, direction and amplitude of motion
it’s faster than template based
smoother spatial/ temporal pattern

Question 8

Steps of image co registration

Answer 8

calculating offset using cross correlation of image grid then you resample by interpolating original values to new grid