Take the 2-minute tour ×
Signal Processing Stack Exchange is a question and answer site for practitioners of the art and science of signal, image and video processing. It's 100% free, no registration required.

In a few days I have an exam of image processing. I'm currently having a look at the example exam and I came across this question. "Which transformation of this image is being done here. Explain the components in the quadrants NA (second image)."

enter image description hereenter image description hereNa

Can anyone help me with this ?

share|improve this question
Had this question on my exam. And the answer given here was that answer that i used. The answer was correct –  Ojtwist Feb 18 '12 at 11:15
add comment

1 Answer

up vote 5 down vote accepted

This to me looks exactly like the two-dimensional Haar wavelet transform. All four quadrants are a part of the transform, even though different operations have been performed on them. Upper left quadrant is a result of low-pass filtering with a 2x2 two-dimensional rect function (Haar wavelet) and decimation be a factor of 2, upper right is the output of a horizontal high-pass filter, lower left is the output of a vertical high-pass filter, and lower right is the output of a diagonal high-pass filter.

share|improve this answer
I had this question on my exam. I really hope you are correct :p –  Ojtwist Jan 17 '12 at 9:01
Well, that's what I would have put down. On the other hand, I have no idea what your professor might have called it. Haar wavelet transform, however, is the most common name. Let me know how it goes! = ) Also, what is the subject you're studying? –  Phonon Jan 17 '12 at 14:21
Engineering with multimedia and information technology major. We saw the haar wavelet transform. And from what I've studied, this seems to be correct. :D –  Ojtwist Jan 18 '12 at 9:11
add comment

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.