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2012-08-08 00:38:12 -0500 commented question tbb_debug.dll missing, but it's there...

I never heard about OpenCV 1.4? Where it came from?

2012-07-31 00:48:41 -0500 commented answer Question about vector paramenter

It means you are accessing values that doesn't exist. In your case it is accessing first value of array that zero size.

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2012-07-22 11:33:37 -0500 answered a question Sobel derivatives in the 45 and 135 degree direction

Warping the image is a very expensive operation, but if accuracy is important you will have to use it. If you can accept approximation of gradient than you can use formula you mentioned. This formula gives you a good approximation but don't think that the result is exact. Lets see an example to understand why this is happening:

Image 1: White and black regions separated by vertical line. Gradient in X direction is 1, Gradient in Y direction is 0. According to formula gradient in 45 degree direction is 1/sqrt(2), which is also correct. So far so good.

Image 2: White and black region separated by diagonal line. Gradient in X and Y directions is 1/sqrt(2). According to formula the gradient in 45 degree direction is 1/sqrt(sqrt(2)). Oops, it should be 1.

This approximation good for almost any practical purpose, so don't hesitate to use it.

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2012-07-22 06:00:50 -0500 answered a question 1D blobs with MSER

There indeed little info on MSER available. You can try to use this page.

The more important question is: are you really really sure you want to use MSER for solving your problem? MSER is an algorithm for image processing, and the question you are trying to solve does not belong to this field. MSER was designed to work with 2D arrays. Algorithms for analizing 2D arrays are MUCH more complicate than the ones working with 1D arrays. Algorithm from appropriate field will be faster and more robust. You can try for example algorithms for histogram analysis, and histogram auto-thresholding.