Questions tagged [image-processing]

Questions on the image processing capabilities implemented in Mathematica.

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28
votes
2answers
1k views

Counting radial ridges on an image

After happily using the v9 image assistant to crop elliptically an image, and then the drawing tools to put a white disk in the middle, I turned this image: into the following one: that can be ...
2
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1answer
932 views

HOG descriptor for image processing

I did not find in Mathematica a function for Histogram of Oriented Gradients (HOG) descriptors. Is there any similar function? Do you have an implementation you are willing to share?
50
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2answers
6k views

Detecting grid lines in a raster image

Motivation: Last October 7 there was a presidential election in Venezuela. Although the opposition saw an unprecedented increase in its votes, the government votes increased even more resulting in the ...
23
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3answers
2k views

Download xkcd Click and Drag comic

Inspired by the recent question about xkcd styled plots I started looking at xkcd again and I came across a comic titled Click and Drag. And if you do that, you start exploring a larger drawing. A ...
13
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2answers
1k views

Finding the Centroid of the grid

Im trying to automate the processing of my shooting targets to measure my performance in the range. I was able to process the shots, but I still have to select the center of the target by the use of ...
5
votes
1answer
602 views

Accessing the graph Thinning produces without losing all the edges' lengths/slopes

This is a follow up to the OCR question I had earlier. What I want to do is to use Thinning to create "skeletons" of images of characters and then compare their shapes, utilizing such properties as ...
12
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2answers
3k views

Overlapping accurately Images and Graphics (without loss of resolution)

Context In a previous post, I learned how to produce these kind of plots, which are of interest in astrophysics and geophysics. I am now interested in combining them. Attempt For this purpose, @...
13
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1answer
2k views

Implementing OCR without using TextRecognize

I am new to Mathematica and trying to figure out whether it is a good tool for algorithmic exploration. So I had the idea of implementing a simple OCR with Mathematica, just using standard algorithms....
4
votes
2answers
4k views

Calculate mean and standard deviation from ImageHistogram

I am doing my PhD in Clinical Neuropsychology; I had someone helping me analyse images (.jpg pictures) in Mathematica, but it turns out this person made some really bad decisions, and well, now I have ...
27
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1answer
4k views

Vectorizing an image like “Trace Bitmap” in Inkscape

Lately, we had a nice question about artistic image vectorization which got very nice answers. As Szabolcs pointed out himself Since "true" vectorization performed by various specialized software ...
14
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1answer
2k views

Enlarge an image and increase its resolution

An ongoing purely recreational project. I got my introduction to image processing with this Rotating perspective... question and had a lot of fun with it. Now I want to take it to the next step. ...
6
votes
1answer
650 views

Clustering adjacent points in 2D

I need to find all clusters of adjacent white points in a binary image. By term "adjacent" I mean that coordinates of two points differ by no more than 1 (i.e. the points ...
18
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2answers
1k views

How to measure segment length and branch angle

I am trying to measure segment length and branch angle or bifurcation angle between each pair of segments. My image after thinning looks like this: ...
33
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4answers
3k views

Clustering of space-time data

Below is an example of a gaze sequence I recorded during a 3 seconds display. That is, where the eye was at every millisecond. While we should have 3000 points, we are missing some due to blinking. ...
15
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4answers
902 views

Poor results with ImageLines function

I'm trying to get my mind wrapped around Mathematica's image feature recognition functions. I'm intrigued by the ImageLines function for a couple future ideas I ...
23
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3answers
3k views
3
votes
2answers
281 views

How to create an ImagePartition type-of-function that generates parts of different sizes

Background: I partition images to polygons ( squares ) and color them with VertexColors. I want to use a minimal number of polygons while still showing a clear resemblance of the original image. - ...
13
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4answers
788 views

Reproducing Image Patterns with Mathematica

Surfing on the net I stared at this pattern. It´s a bamboo steam, and it´s awesome. I'm new to Mathematica so I'm a little lost, I'd like to try to reproduce this pattern, of course in a very ...
18
votes
2answers
4k views

How to convert an image to a graph and get the positions of the edges?

I am trying to convert an image to a graph. My image is already skeletonized and looks pretty much like this: What I need to do is identify all vertices and edges, and in particular get a list of ...
13
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2answers
2k views

Image Processing: Isolating areas of an image with internal irregularity

I am trying to isolate each of the blue painted fingernails in the image. However, I am not sure what approach should be considered due to the white design on each nail interrupting the otherwise ...
33
votes
5answers
2k views

Create magnified call-out loupe effect on image

I'm trying to create a Mathematica Manipulate that generates a graphical call-out using a 'loupe'-style or magnifying glass enlarger - a possible solution is shown ...
6
votes
3answers
452 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?

It seems that ImageCrop allows one to specify the final size of the image. For example, ImageCrop[image, size, spec] crops ...
11
votes
1answer
2k views

Construct 3D image from multiple 2D images

My goal: How to (1) construct 3D image for visualization. (2) how to write 3D array or image into binary raw file. Is there a way to accomplish this in Mathematica? Alternative_Answer for: (...
20
votes
3answers
3k views

Finding the centroid of a disk in an image

I got about 100 images of the sun and have to find the centre of the star in the images. I have binarized the images and used ComponentMeasurementsto find the ...
46
votes
2answers
10k views

Image Shadow Removal in Mathematica

The task is: Image shadow removal is an important topic in image processing. If you feel curious about it, you may take a look here, or just google for it image shadow removal There are also a few ...
1
vote
1answer
275 views

How do I slice an image of size “width × height” in n² pieces of size “width / n × height / n”?

Background: What I want is to make a jigsaw from an image. (A simple one where the pieces are polygons.) I have the following strategy in mind. Create a set of polygons and assign images (or just the ...
2
votes
2answers
506 views

How can I enhance ImageCompose to blend multiple layers?

Blend modes (or Mixing modes) in digital image editing are used to determine how two layers are blended into each other. Version 8 has functionality to perform binary and basic alpha blending but ...
1
vote
2answers
202 views

How can I crop manipulator from a plot

I wanted to know how can I crop a Manipulator from a plot. the code for plot is ...
8
votes
1answer
950 views

How to render a 3D tubular graphics from a 2D image path

Question: Is it possible to create a tubular 3D image like Extruding along a path using "Tube" function in mathematica for following images? Image (1) Image (2) Thanks I have been playing ...
2
votes
0answers
172 views

How to estimate time series from a plot? [duplicate]

Possible Duplicate: Recovering data points from an image Suppose you have a colored plot of several time series (say, from a paper), but not the raw data. How would you estimate the series, which ...
6
votes
1answer
1k views

Efficiently exporting many images as a video

I have many .gif images and I would like to export them as a single video file (I prefer .mov, but any video format is fine). But what if I have several tens of megabytes of .gif images? Is it ...
20
votes
1answer
3k views

Finding the area, algebraic curve and jaggedness of an arbitrary shape

I start with a photograph of a shape (physically made by the flow of a liquid into another), of which I can extract the border, manually or using Mathematica's feature detect feature : Using the ...
19
votes
1answer
2k views

Rotating perspective of an image in the z axis

A purely recreational question, but one I hoped the community would find interesting enough to suggest a way to approach it. Let me preface this question with the admission that I have done nothing ...
10
votes
2answers
281 views

How to record the stream of data (PixelPosition) dynamically?

I need to trace the moving of an object and get the coordinates of such movement. The set of coordinates will be used for the subsequent evaluation and analysis. I can easy get the current real-time ...
5
votes
1answer
825 views

Computing the distance between two curves obtained from image data?

I've got some image data that I've binarized. The image contains two curves, from which I'd like to compute the distance between (eventually computing an average radius for each point in the picture)....
6
votes
3answers
1k views

What's the difference between EdgeDetect and MorphologicalPerimeter (for a white background)?

I am trying to understand the differences between EdgeDetect and MorphologicalPerimeter (while researching this other question). ...
6
votes
2answers
651 views

How can I visualize features found in an image?

I am using Mathematica to explore the face detection feature of Core Image on Mac OS X Lion. To do this I have an Objective-C program which captures images from the iSight camera, runs face detection ...
0
votes
1answer
895 views

How to reduce the memory necessary for the image? [duplicate]

Possible Duplicate: Exporting graphics to PDF - huge file I have a figure that is created to use in a paper. Here it is: ...
14
votes
1answer
2k views

Copying an image from the clipboard, modifying it and returning it to the clipboard

I have a Mathematica script to help me copy images from PDFs and then make the (presumably white or nearly white) background transparent. Typically, I am looking at the PDF in Adobe Acrobat and I ...
18
votes
3answers
1k views

Selective blurring of areas of image to make seamless tiles

I'm trying to make seamless tiles - images that can be repeated on a grid without it being obvious where the joins are. So far, I've followed the classic strategy of getting the edges working ...
11
votes
2answers
841 views

Adding controls for multiple functions in Manipulate

I am learning Mathematica and the Image Processing functions. I have the following Manipulate procedure which works fine: ...
16
votes
3answers
841 views

Measure a DensityHistogram[] pair similarity

I study human vision and more specifically eye-movements. "If we display 2 symmetrical patterns (20 min one after the other), will our gaze distribution be symmetric is my research question." The 2 ...
13
votes
2answers
2k views

Symmetrical image transformation for a kaleidoscope-type image

I've been trying to write a little kaleidoscope-type manipulate, using images rather than graphics, and using ImageTransformation as a way in. However, I'm starting ...
2
votes
4answers
3k views

How can I extract the data from an image and process it pixel by pixel?

For example, to change the color of each pixel to the mean color of the three channels, I tried i = ExampleData[{"TestImage", "Lena"}]; Mean[i] but it just ...
7
votes
1answer
459 views

How to determine edgeweights from width of skeleton using MorphologicalGraph (or workaround)?

Background I'm trying to create a workaround for what seems to be a bug in MMA's graph functions related to edge weights: SO: How to Label Graph Edges with their weights According to MMA's ...
7
votes
2answers
982 views

Fit an image within a Rectangle [] in Graphics

Based on the following Code (yet the white text in the image is added with PPT), I would like to have an image fit within one of the rectangle. For Example the image from there : http://...
5
votes
3answers
712 views

Tile image on specific location without space between them [duplicate]

Possible Duplicate: How to combine images with the same dimensions in a grid? I would like to arrange images without any space between their edges as each piece is made to connect with others. ...
14
votes
2answers
297 views

Tuning ParallelMap when IO and computationally bound

I'm currently doing work on processing a number of images taken frame-by-frame from a video. As a result, I have a directory of around 16K PNG images that at most ~300K. That said, I have a routine, ...
14
votes
3answers
1k views

Image levels: how to alter 'exposure' of dark and light areas?

I was working with some less than ideal photographs, and wanted to adjust them before continuing. I wanted to raise the levels of the very dark areas and lower the levels of the very light areas. I ...
20
votes
2answers
3k views

How to combine images with the same dimensions in a grid?

I have the following images, both 480 x 270 pixels: I'd like to stitch them side by side in a 960 x 270 pixel image like so (scaled down): So far, I've been using ...