Tagged Questions

Questions on the image processing capabilities implemented in Mathematica.

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9
votes
1answer
847 views

Measure length and diameter of objects in an image

I am new to Mathematica, and I am trying measure length and diameter of rectangular objects in an image. I wanted to fit rectangles in the objects, and then get the values. Can I do that with ...
0
votes
0answers
364 views

Metric Parameters such as Pratt Figure of Merit (Pratt-FOM) for Edge Detection

I have developed a new algorithm in Mathematica v9.0 for the Edge Detection and want to compare it with the existing Roberts, Sobel, Prewitt etc, operators in the presence of Noise. I have evaluated ...
2
votes
2answers
528 views

Generating x,y coordinates for an edge detection

I'd like to be able to process a number of graphics that have edge contours and output a list of $x$, $y$ coordinates to be used for generating a spline in another program, or in Mathematica, to make ...
1
vote
1answer
178 views

in search for mathematica function similar to imagesc in matlab

Simple question: Is there any built in function for images that acts similar to imagesc in matlab, i.e. take grayscale image scale it to use full [0,1] range and then use some kind of colorgradient to ...
2
votes
0answers
243 views

Understanding “IntensityData” coordinates

Update - Playing around a bit, is it true that we need to process the list of "IntensityData" values $r$ as follows: r = Partition[r,k]; r = Transpose@r; And ...
14
votes
4answers
820 views

Measure perimeter of black edge in Mathematica

I have a pattern like the one below. How could I measure the total length of the perimeter of the black/white edge? This would give me a measure of spatial frequency. Any tips would be great! Thanks! ...
1
vote
1answer
151 views

Understanding the computation of IntensityCentroid?

If I have an image img, and I ask ComponentMeasurements to return "IntensityValues" for the ...
-2
votes
1answer
400 views

Peak Signal to Noise Ratio of Images

I am filtering a blurred image, and want to evaluate the performance of Peak Signal to Noise Ratio (PSNR) in Mathematica version 9.0. But I am facing the problem of evaluating the PSNR. Could anyone ...
4
votes
4answers
584 views

Identifying and counting closely spaced particles

Following in the footsteps of this blog post: http://blog.wolfram.com/2011/09/09/building-a-microscopy-application-in-mathematica/, I took a microscope picture of some particles on a surface, and ...
-4
votes
2answers
317 views

Image Processing Mag and Phase Spectrum of Sobel, Roberts Mask [closed]

How to find the Magnitude and Phase Spectrum of Sobel, Roberts etc. etc. Mask of Image Processing using MATHEMATICA 9.0 platform....
5
votes
1answer
228 views

Cropping an image to a minimum bounding box for a set of points

Imagine a define a pointlist inside of an image: Provided a pointlist for the set of red dots around the toy horse, is there a way for me to automatically crop to a minimum bounding box for this ...
2
votes
3answers
290 views

Defining and isolating a region of an image internal to a bounding curve

I was recently looking over this very nice question by March Ho: Counting elements which are inside another element on a different colour channel There are often times where I find myself wanting to ...
1
vote
1answer
155 views

Can I use SelectComponents with measurements that take into account the value of underlying pixels?

Normally, we can ask for the mean, median, etc. underlying pixel values for morphological components with the command: ...
1
vote
1answer
145 views

How can I use SelectComponents to select for components that have a pixel within a certain RGB range within their convex hull?

I calculate a set of morphological components: Components = MorphologicalComponents[Binarize[image,0.1]]; We can now use SelectComponents to filter for ...
8
votes
1answer
350 views

Counting elements which are inside another element on a different colour channel

I have a 3-channel image which shows red and green points (certain labelled proteins) inside blue regions (cell nuclei). After applying some segmentation filters, the resulting image is as follows: ...
3
votes
2answers
203 views

How can I detect and modify one area of an image while preserving the rest

I have an image with a big black disk bounded by a white boundary in its center. The image contains some other stuff outside of the spot and its boundary. This stuff has colors which include both ...
0
votes
1answer
231 views

How Can I Transform a Colored Image into Pre-defined Matrix?

I am new to Mathematica and I would like to use it to postprocess some of the experimental data I measure. I would like to visualize voltage measurements over a non-uniformly segmented plate. I would ...
0
votes
3answers
113 views

Formatting the output of ComponentMeasurements

I have some code written here which uses ComponentMeasurements to output some data, specifically the one below: ...
1
vote
1answer
137 views

ImageLines Segmented options

I have tried utilising the ImageLines function, and its accompanying Segmented setting. However, the segmentation doesn't appear to allow for its variables to be fine tuned, at least not according to ...
7
votes
1answer
391 views

Removing the edge features of an image while enhancing internal connectors

I picked up the following leaf today while going for a walk. And wanted then to run the same analysis that @Vitaly Kaurov did for rivers under this posting Measuring Fractal Dimensions of natural ...
3
votes
3answers
211 views

Is there a fast method of generating a Standard Deviation image from a frame stack?

Imagine I have a stack of image frames, $(f_1, ..., f_N) \in F$, where each $f_i$ has the same set of $(x,y)$ dimensions. Using these frames, I'd like to create an image where each pixel in the image ...
1
vote
1answer
335 views

Problem with Fourier and InverseFourier function

I have the following code Image[img, ImageSize -> 300] data = ImageData[img]; fdct = Fourier[data] tdata = InverseFourier[fdct]; Image[tdata] but it seems to ...
1
vote
3answers
198 views

Defining a polygon by clicking on an image [duplicate]

Imagine I have some image, $I$, and I'd like to define a polygon by sequentially clicking on the image to define vertices $(v_1, ...) \in V$, where vertices $v_i$ and $v_j$ share an edge if $j = ...
-4
votes
1answer
2k views

Determine the 2D-Fourier transform of an Image

I am new to Mathematica and using Version 8.0. I want to calculate the 2D-Fourier Transform of a digital image and see its Magnitude and Phase Spectrum, and reconstruct it.
2
votes
2answers
244 views

Intersection & Complement operations for lists of Morphological Components?

I have an array of $M$ sets of morphological components corresponding to the same image, however computed in different ways. For example, we might have: ...
1
vote
3answers
359 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 $C$, ...
1
vote
1answer
260 views

Selecting morphological components, of a certain size, centered on points of interest in an image

I have a set of points in an image, for example: ...
12
votes
1answer
256 views

Use TextRecognize to grab timestamps from a video frame

I have microscope videos that have a timestamp overlay to them, and it would be great if I could extract this for each frame to add to my metadata. TextRecognize ...
1
vote
1answer
120 views

Is there an easy way to create a “IntensitySquaredCentroid” using ComponentMeasurements?

One of the options in ComponentMeasurements is to compute a centroid based on the pixel values of some underlying image. We can write: ...
1
vote
2answers
219 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 = ...
6
votes
4answers
5k views

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

Imagine I have a set of data like the following: ...
0
votes
1answer
126 views

Returning a bounding disk or box centered on a coordinate in a 2D image

Provided a coordinate $c_k$ in a two-dimensional image, how can I return all of the pixels in a bounding disk or rectangle centered on $c_k$ of some specified dimension $d$? Update: Hat tip to Kuba ...
18
votes
1answer
398 views

Color scheme used by Colorize?

The Colorize function is often used to display the results produced by MorphologicalComponents: ...
0
votes
1answer
137 views

Returning lists of pixels connected through their Moore neighborhoods

I have a binarized image in Mathematica 9, and I would like to generate a list of coordinates for clusters of pixels connected through their Moore neighborhoods, e.g. ...
4
votes
1answer
259 views

Volumetric Rendering of cylinder symmetric radial image

I would like to render a cylinder symmetric radial cross-section with Image3D. As an example one could use the propagation of a Bessel Beam through a Lens: Here the cylinder axis is the bottom of ...
10
votes
3answers
468 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 ...
13
votes
2answers
373 views

Improve TextRecognize[] on numbers

I have an image contain only numbers, and TextRecognize fail to recognize some numbers: img=; TextRecognize[img] (*826718*) The documentation says that "The ...
0
votes
3answers
436 views

Derive a smooth circle with cusp from an image

question 1 get the center (sample data) sample is the black circle with cusp. ...
23
votes
2answers
1k views

Find radii of concentric circles in image

I have an image of concentric circles, I would like to find the radii of the circles (only the innermost few are important). I've had a go using what I could find in previous posts, but am a bit ...
16
votes
4answers
938 views

Digital filter of image in Fourier space

Consider the contour plot below, of a function f(x,y) - which is calculated numerically by solving some equations. If one looks carefully, one can observe two types of waves, to the left and right of ...
1
vote
2answers
330 views

Image Restoration

I want to degrade the image, and then execute the restoration, such as a lena.jpg. I tried this: ...
5
votes
3answers
348 views

Getting RGBA data from an image

What is going on with returned data in the following examples? It appears ImageData returns different types depending on the what data is passed into ...
15
votes
2answers
571 views

Twirl Image Transformation

I am looking to reproduce the functionality of Photoshop's "Twirl" filter, which twists an image that originally looks like this (pulled from this page): Into this: Ideally, I'd like it to ...
4
votes
3answers
157 views

Maintaining map dimensions after using Colorize

I am trying to beautify a map by using Colorize as demonstrated in the Mathematica documentation. First, I import a shapefile from DIVA-GIS for France which ...
10
votes
4answers
1k views

How do I find the coordinates of points in this image?

I have never used image processing with Mathematica. I need to get the coordinates of the red points from this image I made in Illustrator. Is there a way to get Mathematica to read or detect the ...
140
votes
2answers
56k views

QR Code in shopping cart handle

This week, the market people from my work wanted to put QR codes in shopping cart handles, but when they tested it, the QR code did not work. I noted that the cylindrical curvature (even small) ...
21
votes
4answers
2k views

How can I detect an ellipse in a photo?

I tried to detect the rim of the following cup as an ellipse. I've tried the solutions given in How to find circular objects in an image? to detect the ellipse, but the detection result was not ...
3
votes
1answer
152 views

Resampling when using image as Texture

How to get sharp pixel boundaries with Texture? I'd like to have only black/white in the example below, no gray. ...
2
votes
3answers
290 views

Using ImageTransformation[] with a lookup table

I need to transform images by ImageTransformation in a time critical application. Therefore I precalculate a lookup table lut of ...
0
votes
1answer
140 views

TextRecognize with crosses, circles and spaces results into oddities, why?

I am investigating this answer here about detecting crosses and circles with TextRecognize. I tried to solve this problem here by directly using the builtin command TextRecognize but it does not work ...