Matthias Odisio
  • Member for 9 years, 10 months
  • Last seen more than 3 years ago
2 answers
21 votes
12k views
How can I detect a rectangular region of interest in a picture?
13 votes

At his request, this is how I would edit @belisarius's answers (using 9.0.1): l = {"http://i.stack.imgur.com/t95sV.jpg", "http://i.stack.imgur.com/MVP47.jpg", "http://i.stack.imgur.com/...

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2 answers
3 votes
296 views
How to create an ImagePartition type-of-function that generates parts of different sizes
9 votes

It seems quad-tree decomposition would suit your needs: http://demonstrations.wolfram.com/QuadTreeImageDecomposition/

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2 answers
23 votes
1k views
How to retrieve the parameters calculated and used by ImageAdjust?
8 votes

With only one argument, ImageAdjust[img] performs histogram stretching, ie. pixel values, which run from min to max in img, are rescaled so they run from 0 to 1 in the ouput image. The setting {...

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2 answers
9 votes
2k views
How to transform a 3D image by an affine transformation matrix
7 votes

Edit: ImageTransformation and ImagePerspectiveTransformation accept Image3D objects and corresponding transformations as of Mathematica 10. Waiting for ImageTransformation to accept Image3D objects, ...

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4 answers
14 votes
3k views
Reshape vectors exactly like in MATLAB
7 votes

ArrayReshape (new in version 9) does just that.

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3 answers
8 votes
517 views
Radon function result's repeatability
7 votes

That was a bug which got fixed in Mathematica 9.0.1.

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3 answers
49 votes
5k views
Are built-in Mathematica functions already parallelized?
7 votes

Some, yes. For example, many image processing functions are multi-threaded. One way to see whether a function is leveraging multi-threading is to perform the same kind of tests as for ImageResize in ...

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3 answers
20 votes
1k views
Selective blurring of areas of image to make seamless tiles
7 votes

Since texture synthesis using Inpaint has already been mentioned, let me add for the record the obvious, easy, dirty, but sometimes satisfying technique of mirroring: i = ImageTake[ExampleData[{"...

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3 answers
7 votes
407 views
Is there a fast method of generating a Standard Deviation image from a frame stack?
6 votes

This is about 100 times faster than g3kk0's answer on my machine---the results are identical: imageStack = Image[ColorCombine@Import["ExampleData/CTengine.tiff", "ImageList"], "Real"]; ImageApply[...

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2 answers
3 votes
1k views
Is there a way to parallelize the convolution component of EdgeDetect?
5 votes

It is already the case that the "convolution component of EdgeDetect is multithreaded." EdgeDetect is composed of a sequence of operations. Some of these operations are indeed multi-threaded, and ...

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3 answers
5 votes
1k views
Getting RGBA data from an image
4 votes

This function first converts to "RGB", then inquires about the presence of an alpha channel. If there is none, it adds one. Then it returns the data cast as type "Byte" by default. Casting to 8-bit ...

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1 answers
6 votes
176 views
Possible bug in ImageFeatureTrack?
Accepted answer
3 votes

In your sequence, the first image has 2 corners that are too close to the boundary and ImageFeatureTrack has troubles tracking those. If you rerun your experiments with added padding, things work ...

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2 answers
42 votes
9k views
The correct way to linearize colorspace before resizing, blurring etc
3 votes

It is arbitrary to assign a color space to data that do not have one attached to them. What about using "XYZ" if one is looking for a linear color space? i = Import@"http://www.4p8.com/eric.brasseur/...

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4 answers
10 votes
245 views
ImageApply Performance Difference
3 votes

The function q3[#] & is not Listable and because the Interleaving option value is True by default, there is not much optimization that can be figured out automatically. Setting the Listable ...

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1 answers
2 votes
273 views
What are the min and max arguments to EdgeDetect?
3 votes

In EdgeDetect[image, radius, threshold], the radius is expressed in pixels, and the threshold corresponds to normalized pixel values (ie. in the range from 0 to 1). @Silvia, there may be differences ...

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1 answers
0 votes
998 views
How can I find lines of a certain angle(s)?
3 votes

To search only for lines at given angles, say between theta0 and theta1, you could: Compute the Hough transform using Radon[img, dims, {theta0, theta1}, Method -> "Hough"] Detect peaks in the ...

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3 answers
9 votes
1k views
Combining Image3D and Graphics3D
3 votes

Everybody seems happy already at the time of this answer. But the following resources will help a newcomer develop good habits: Volume Rendering And Processing Image3D (esp. the section Details and ...

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2 answers
3 votes
675 views
Introduction of bias during brightness and contrast manipulation of an image
3 votes

(Would have applied an "honorable" tag to the question if possible) It is fair to use ImageAdjust[image, {contrast, brightness}] both for your "control" image and "data" image, because with these ...

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1 answers
4 votes
420 views
Filter bright dots from the gradient of the image
Accepted answer
3 votes

We could do with ground truth data to assess the result. Is this acceptable as a first step? Manipulate[ HighlightImage[ i, result = Binarize[TopHatTransform[i, radius], thr]], ...

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2 answers
2 votes
834 views
Understanding the coordinate system for ImageTake
2 votes

Don't use ImageTake if your coordinates are (x;y) image coordinates and not (row;col) positions. ImageTrim[image, {{x,y}}, 10] works as expected. You may want to check out the section "Coordinate ...

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2 answers
2 votes
245 views
ImageDifference. Is there an ImageSame, or how would one do that?
1 votes

There is not a built-in function that can tell where two images have the same pixels, but it's not hard to build one: imageSame[image1_, image2_] := Image[ImageApply[Boole@TrueQ[#1 == #2] &, ...

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1 answers
1 votes
256 views
ImageLines Segmented options
1 votes

This functionality is not available in ImageLines in the sense that you can only select from the detected segments a posteriori, not guide the detection by restricting the range of allowed segments. ...

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3 answers
6 votes
491 views
Is it possible to snip a certain number of pixels from a specified side of an image, without specifying the image's final width and height?
1 votes

As an alternative to ImageTake, ImagePad will do the job using the syntax ImagePad[img, {{left, right}, {bottom, top}}]: img = Import["ExampleData/rose.gif"]; In[10]:= ImagePad[img, {{0, -10}, {0, 0}}...

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