Questions tagged [image-processing]

Questions on the image processing capabilities implemented in Mathematica.

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13
votes
2answers
2k views

Detecting an ellipse in a glaucoma photo

For glaucoma diagnosis it is common to determine a "cup to disk ratio" which compares the diameter of the optic disk (VDD) and optic cup (VCD). The optical disk is visible as a circular red feature (...
4
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2answers
480 views

How can I extract trace points from an oscilloscope image?

I have the following oscilloscope image: I would like to extract the points of the yellow curve together with the correct values. Do you know how I could do it? Extracting the yellow curve from the ...
13
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3answers
1k views

Best method to find variation in width along the image of a slit?

EDIT: Solutions by @Alexey Popkov and @Vitaliy Kaurov are very intuitive and both can be used to find a solution for the task. I have a slit of 15-18 microns by 1 mm projected with magnified 4X onto ...
4
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2answers
404 views

Share a method to patch the discontinuous line in a image

Similar to this post which I have posted before(How to patch fingerprint ridges),Its solution's level higher than my expectation.So cost my these days to research this.Now I'm glad to share my fruit ...
13
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2answers
2k views

Creating 3D dice

How to create an image of a 3D die from the 2D images? There is an example in the Documentation Center I tried but it doesn't work.
11
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1answer
2k views

ImageTransformation: polar to cartesian

I am working on something that requires the polar transformation of some images. I implemented this transformation with ImageTransformation: ...
8
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1answer
3k views

Extract data from plots in papers including error bars

I would like to know how to extract data from plots in a paper and, also, how to do that in a way that include error bars. I know there are specific softwares to do that, e.g. Plot Digitizer, which ...
197
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2answers
40k views

Help find a bright object on Mars!

In today's news, scientists found a bright object on one of Curiosity's photos (it's near the bottom of the picture below). It's a bit tricky to find - I actually spent quite some time staring at the ...
47
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2answers
2k views

Generating stippled (Penrose-style) drawings of surfaces

In The Road to Reality there are plots of surfaces that use a variable density of dots to suggest curvature. You can see some examples here and here. I suppose they've been drawn by Penrose, but to ...
63
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5answers
12k views

How to create hedcut style images?

Yesterday the hedcut style was brought up in chat. How can we create a hedcut-like style automatically in Mathematica, using a photograph as a starting point? I am looking to create a similar ...
47
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1answer
2k views

Finding areas of beings in microscopic image

I've got lots of images of diatoms. I need to get a list of their equivalent radii. It's not crucial to get them all, as long as those missed don't mess with the radius distribution (as would happen ...
54
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4answers
3k views

Changing color of an object in an image

Consider the following image: How can I change all red colors in this image into (for example) blue.
53
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2answers
4k views

Image segmentation and object separation in 3D using Mathematica

I currently work on an image segmentation scenario to detect cell nuclei in 3D using Mathematica. The data I have are image stacks in the TIFF file format. I would like to keep the sequence of image ...
40
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1answer
4k views

FindFaces: how to improve the results of the face recognition feature

In Mathematica 9, the FindFaces command offers an easy way to detect faces. In some experiments, I've been getting reasonable results, but I'd like to know if there ...
26
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3answers
3k views

Finding a function that fits the shape of an image

How can I find a function that fits the given shape of an image? Or instead extract a point set from the shape and then find an interpolating function fits the shape. An example image is attached.
18
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4answers
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How to count number of small dots in a picture

I have this picture of small particles in a polymer film. I want to count how many particles in the figure, so that I can have a rough estimation of the particle density. But the image quality is poor,...
28
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3answers
4k views

How to find the center of a circular pattern?

I am writing an algorithm that finds the center of 500 x 500 pixels images coming from a live feed from a camera at 50 Hz. So it has to be quick! The images are images of an optical field which looks ...
19
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2answers
598 views

Creating graph out of particles images

I have recently started learning how to use Mathematica's brilliant image processing tools, and the image I've taken as first example is the following (source): So far I've tried to first use ...
16
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4answers
18k views

Fitting a two-dimensional Gaussian to a set of 2D pixels

Imagine I have a set of data like the following: ...
15
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2answers
774 views

Intersecting parabolas in an image

I have a friend who is a math teacher (like me) and while out cycling took this picture. The idea would be to create the equations of the quadratics that model the bridges and super-impose them on ...
19
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3answers
4k views

How can I efficiently “remap” an image?

Many image processing libraries like OpenCV, Intel Performance Primitives or Octave have a useful function called "remap", that takes an image, an array with X coordinates and an array with Y ...
22
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1answer
777 views

Color scheme used by Colorize?

The Colorize function is often used to display the results produced by MorphologicalComponents: ...
14
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3answers
876 views

Image Processing: Concrete test blocks

Background Concrete is mixture of aggregates and cement. Aggregates are composed of different sizes and colors. Core samples are taken by drilling in order to test the strength of concrete . They are ...
20
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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 ...
14
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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 ...
10
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5answers
469 views

Coloring an image with two Color schemes based on a Range

I would like to color an image generated from some data, using two color schemes based on two ranges of the data. This is my attempt: ...
17
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4answers
11k views

Saving high-quality graphics through commands

Say I make and display a graph in a Mathematica notebook: graph = CompleteGraph[100] If I drag the corner of the graph to increase its size, and then save it to ...
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....
8
votes
3answers
809 views

How can I capture a rectangular area from an image?

I am looking for a method to extract rectangular areas from an image. The image is divided up into rectangular problem spaces like the image shown below. Each numbered problem is given with some text ...
9
votes
1answer
1k views

How do I put an image on the complex plane?

I watched this video and became interested in transforming an image. But I have no good idea on how to embed an image in the complex plane using Mathematica. I have a method that seems to work, but ...
5
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2answers
1k views

Color mixing or blend

Color mixing seems not only one type. Here is RGB_color_model I wrote this one: ...
7
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3answers
866 views

Opacity and overlapping multiple polygons

Let's say I have 100 polygons that are all different but most of them overlap. All I want to do is to draw/plot them in one single graphic with linearly adding gray values; i.e., a point with ...
6
votes
1answer
1k views

Angle between two areas of an image of a 2D FFT

I'm trying to obtain the angle between the red line and the area surrounded by the red circle, related to the middle of the image. Usually the area surrounded by the red circle is lighter than the ...
15
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1answer
924 views

How to create a 3D model based on MRI cross-sections?

Recently, I stumbled upon the following surreal MRI-scan of broccoli: and ever since the moment that I saw this I've been wondering whether it is possible to recreate the broccoli based on these ...
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
1answer
171 views

Layout: Images and Text

I have a lot of images and text that goes with each image. Now I would like to automatically generate the following handout for each pair of image and text: The image is on top. The text should be ...
4
votes
1answer
1k views

How to get better quality EPS graphics

Yesterday, I was doing any Tables of 15 graphs similar to the next example, to save .eps and use in latex. In the generation of the graphs Mathematica spends many time. Is possible to reduce this ...
2
votes
1answer
1k views

Importing a Canon Raw file (.CR2)

This is a very top level question with no code examples attached. I have an interest in using Mathematica to read raw files coming from a Canon camera, before they are converted into jpg's, where ...
1
vote
3answers
720 views

Adjusting the pixel values underlying a morphological component when computing an “IntensityCentroid”

When calculating an "IntensityCentroid" with ComponentMeasurements, i.e. for an image $I$ and set of components $C$, calculating:...
15
votes
1answer
313 views

Why does ImageFilter fail with radius 1, but works with radius 2?

Bug introduced in 9 and persists through 12.0.0 When thinking on a way to answer this question using ImageFilter I have found (with Jason B's help) that we can ...
10
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2answers
254 views

Blur, GaussianFilter and ImageConvolve doesn't work on some images

In versions 8.0.4 and 9.0.1 applying Blur to an image gives expected result: ...
10
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2answers
863 views

How to get a smooth ridge from a binary image

I always have this demand,but Mathematica cannot implement this perfectly for me.For example,I have such binary image ...
4
votes
1answer
677 views

Butterworthfilter data filter

I am currently doing a signal analysis and filtering using Matlab. The filter I am using is Butterworthfilter model to filter scattered data (vector data). I am using Matlab as follows: ...
2
votes
2answers
750 views

Understanding the coordinate system for ImageTake

I have a point in an image which I can locate by right clicking and using my mouse. Call this point $p = (100,100)$. I'd like to use ImageTake to grab an image, centered on this spot $p$ with $k = ...
45
votes
1answer
16k views

How can I draw a Homer with epicycloids? [duplicate]

You may have seen this video: https://www.youtube.com/watch?v=QVuU2YCwHjw. How does this work, and how to do it with Mathematica?
25
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2answers
3k views

How to automatically remove text from images?

I'd like to remove the text in the center of images automatically. To use Inpaint[], you need a mask, but I don't have one. So really the problem is: How to build ...
28
votes
1answer
1k views

Interstellar Image Effects

I'd like to know how to create this type of gravitational lensing effect in an image (here are some star fields from the hubble) "I wrote down the equations and I tested them in Mathematica by ...
25
votes
1answer
8k views

How to use 2D Fourier analysis to clean the noise in an image

I have some other method to do this.But I desire to know how to use Fourier analysis to realize it. I found a base post about Fourier-analysis to use in Image-Processing--Calculate the 2D Fourier ...
33
votes
3answers
2k views

xkcdConvert routines perform slower in Mathematica 9

I am experiencing some rather large performance decreases in Mathematica version 9.0 using the xkcd-styled plotting routines. I had used the xkcdConvert code ...
23
votes
1answer
3k views

How can I detect if an image is of poor quality?

I need to filter out blurry or otherwise bad quality images from a set. I would like an efficient method to detect images that have any of the following three attributes: Out of focus or motion blur ...