Andrey Rubshtein
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Image transformation where a curve becomes a straight line
1 votes

I would recommend a grid transform. Each point of the grid has a $(dx,dy)$ offset, and a point in the middle of a square is interpolated according to the control points. Specifically in your case, you ...

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Balance brightness and contrast between two images
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1 votes

The images you are working with are probably with gamma compensation, you should remove it first by applying inverse gamma. More accurately, each camera has its own tone curve mapping. You can build a ...

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How to apply a 2D -2D homography matrix to an image?
1 votes

You should use the function maketform to create your homography, and apply it on image by using imtransform. Don't forget to apply transpose on your matrix, because Matlab works on pixels as rows, not ...

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Detecting the Prescence of a "Tail"
1 votes

You could check how "circular" a blob is, by computing the ratio between area and the square of perimeter. For a circle that would be: $A = \pi r^2 , P = 2 \pi r$, which implies that $ \frac{A}{P^...

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Estimating Velocity from Fuzzy Position Data with Known Uncertainty
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1 votes

Yes it is. That what's Kalman filter is all about. Your measurement includes position data, and there is a hidden velocity parameter. You will need some kind of model, like constant-velocity. You can ...

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Decompose an image into better compressible components
1 votes

Assuming that the image is gray level (not color) Use Otsu's thresholding method to detect whether the image has bi-modal histogram. If Otsu tells you with high confidence that the image is bi-modal, ...

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Detecting Individual Photos on a Scanned Page
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1 votes

Most of the image processing/computer vision algorithms are ad hoc. Your algorithm is good. However, I think that a few points can be improved: Instead of finding median color, you could do use the ...

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How to calculate Noise and distortion of an image?
1 votes

You should do it on a known set of calibration targets. For example, this type of calibration target is being used to measure noise. You should find the patches locations, and measure the noise by ...

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Breaking a convolution into smaller pieces
1 votes

The convolution operation is associative. $(S ** g) ** h = S ** ( g ** h ) $ This means that if you find two kernels $g,h$ such that $g**h = k$, (where $k$ is your kernel), you can split your ...

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Pattern recognition using 2D fft in matlab
1 votes

DFT is a great tool to find periodic patterns in signals. However, you should understand what kind of period you want to find. If you want to find a series of points that lie on a regular grid (with ...

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Converting Gamut3D from RGB colorspace to LAB colorspace
1 votes

The so-called Gamut in the code, is nothing but a 3d color histogram. Colors from the image are collected into it, and then each unique (r,g,b) is being shown as a scatter point. In order to show the ...

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Understanding FFT of an Image
1 votes

You are missing the abs command. Try the following: f = fft2(a) shft = fftshift(abs(f)); imshow(log(shft)) %stretching

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Good inhomogenity measures in images?
0 votes

Another good texture measure would be gray-level co-occurence matrix, which is implemented in Matlab as graycomatrix. By the way, in your case a simple Otsu threshold might do the trick as well.

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Hough lines and Convex Hull methods give jagged lines
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You could solve the problem in several ways: Image pre-filtering (smoothing) with some kind of Gaussian filter, before doing edge detection, will yield smoother edges. Morphological operations, such ...

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Image Projection with SIFT
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-1 votes

The logo you are looking at is symmetric. For example, you could rotate it by 120 degrees and get the same pattern. If you take a look, many of the "errors" are not really errors. The same pattern ...

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