Questions tagged [image-processing]
Questions on the image processing capabilities implemented in Mathematica.
1,297
questions
5
votes
0answers
134 views
How to efficiently apply PCA followed by SVD to extract the components of PCA?
I am working on segmenting a textured image using Gabor Filters. This is based on this paper. There exist a Matlab implementation of this as well. Earlier I managed to do up to this. With the help of ...
4
votes
2answers
390 views
Transform a black-and-white image into a list or a function
I met such an image in a paper:
It represents an in-plane distribution of a light intensity, J=J(x,y). It is assumed that the white color intensity shows the light intensity. I would like to get this ...
5
votes
1answer
125 views
5
votes
1answer
149 views
Find centroids and average intensities of regions in an image
The image below shows an approximately triangular array of bright spots. The intensity falls off towards the edges (Gaussian decay). There are some defects (the elongated smudge and the sharper ...
5
votes
3answers
199 views
Performance of ImageApply
I would like to optimize this code
fadeAndShine[old_, new_] := If[old == new, {1, 0.8, 0.2}, new];
ImageApply[fadeAndShine, {imageA, imageB}]
Is it possible, and ...
4
votes
2answers
127 views
Count number of connected regions/meshes
I want to count number of connected region. For ex I have a region below which has 2 connected region.
And also, How to check whether the function ...
1
vote
0answers
84 views
Contour of an splashing droplet
I have pictures of the evolution of a splashing droplet, and I would like to get the contour. It´s not difficult for early times (first figure) but I could not find the way for the later times. Any ...
1
vote
0answers
89 views
How to segment a textured image using Gabor Filters?
I am following a matlab implementation of texture segmentation using Gabor filters. My test image (img) is from Brodatz and as ...
10
votes
3answers
240 views
Measuring distances between image components
MorphologicalComponents can break an image into components.
How can we measure the pairwise distance between these components efficiently? Performance is ...
2
votes
1answer
218 views
How to count the number of eggshells in the image
My goal for this is to simply count the number of eggshells in the image.
Using color negate only leads to this
...
3
votes
1answer
265 views
How to compare histograms of two Images?
Is there any function in Mathematica that I can use for comparing the image histogram ? There is a built-in function in OpenCV cv2.compareHist for distance measures ...
1
vote
2answers
80 views
How to nicely label the colors in Colorize?
I have an image segmentation and I'd like to label with a SwatchLegend[]. Here's a MWE:
...
4
votes
2answers
186 views
Quality of ImageRestyle
There is an application of image restyle here. It is an example in following:
But if I just use ImageRestyle of Mathematica
<...
2
votes
3answers
303 views
Masking an image with an annulus
I have an image where I would like to do 2 things:
a) Put a disk of radius r on an specific $\{x,y\}$ position on the image such as the result is the original image within the disk and black color ...
6
votes
1answer
347 views
FindFaces in Mathematica 11.3
I just upgraded to Mathematica 11.3. but now my FindFaces instructions do not work anymore.
I guess they changed the syntax in 11.3.
Here is the original code:
<...
44
votes
1answer
15k 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?
2
votes
0answers
88 views
Why can't ImageTransformation be parallelized?
I have a rather complicated code for an ImageTransformation, which would benefit from some acceleration. Since every pixel is independend of every other, I tried Parallelize, which, in a simplified ...
2
votes
0answers
60 views
Unable to create ClassifierMeasurements for NetGraph
I am trying to check the accuracy of a neural network by using ClassifierMeasurements. I take the MNIST as example:-
Code for setting
...
6
votes
3answers
148 views
How to know the layout about these points
I have such points
pts=Uncompress[FromCharacterCode[
Flatten[ImageData[Import["http://i.stack.imgur.com/hkAK8.png"],"Byte"]]]];
...
0
votes
0answers
234 views
How to perform local Fourier Transform of an image?
Consider an image (img) as
A nice explanation of the Fourier transform of an image can be found here. However, I want to perform the Fourier transform locally. For ...
3
votes
0answers
89 views
How to flatten a scanned image which is from scanner [duplicate]
I have a image from scanner:
You can see that the right side of this paper is very flat, but it's curved in the left side. I think maybe I can detect the edge of this paper and then build some model ...
3
votes
1answer
132 views
Single Neuron Dream Example (from Markus van Almsick's Presentation WTC 2017)
I'm teaching myself about Mathematica 11.3 Neural Net capabilities, and I can't get a demonstrably previously working example to work. I've been trying for quite a while without success.
In Martin ...
2
votes
0answers
55 views
How to get ImageTransformation to not compute the function at *every* pixel
I am using ImageTransformation with a slow function. Is there a way to get ImageTransformation to compute the function at only a ...
2
votes
1answer
115 views
Smoothing EdgeDetect - image processing
I have to make a program that analyzes the image of saw tooth and later find the function that can describe it (or just part of it). Now I have a problem with smoothing the edges detected with ...
3
votes
0answers
145 views
Image Segmentation: (Efficient Graph-Based)
This question is two-fold; First, it is about how to get the speed efficiency this algorithm should provide in Mathematica. In addition, it has a small question about the algorithm (Efficient Graph-...
0
votes
0answers
93 views
Extract pixel value and positions to a txt
I have an image, for example
img = Import["https://i.stack.imgur.com/fPZM7.jpg"]
I would like to save in a text file the pixel positions and their values. At ...
2
votes
1answer
173 views
Signed distance function from grayscale image
I have a grayscale image and I would like to convert it to a signed distance function.
Right now I'm using DistanceTransform but I do not like the result.
...
2
votes
1answer
99 views
Error using accuracy and ConfusionMatrixPlot of ClassifierMeasurements
EDIT: Here is the complete code that i have used:
...
3
votes
0answers
254 views
Image Generator with a Neural Network (CIFAR-10)
As some of you may know, CIFAR-10 is a data base which has 60,000 images (which are 32x32 in size) of 10 different categories (airplane, dog, cat, frog, deer, bird, horse, ship, automobile and truck). ...
5
votes
4answers
276 views
How to select the mark items from the image
I have such image
I want to select all mark items from it. Of course, I can use such code to implement it
DeleteSmallComponents[ColorNegate[Binarize[img]], 700]
...
3
votes
0answers
95 views
How to perform unsupervised texture classification?
Consider a texture mixture (img) from Brodatz.
I want to classify the five different texture patterns and segment the corresponding regions.
Following this,
I ...
11
votes
1answer
182 views
How to make Texture unblurred?
This post is related to this post, But somewhat different. Since Wizard focus on alpha channel, and didn't got an answer. So I made this post.
My system is Windows 10, and Mathematica 11.2
If I run
...
4
votes
2answers
459 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 ...
5
votes
4answers
957 views
How to double (or triple) each element of equation?
x^2/3+y^2/9==1
(0.5x)^2/3+(0.5*y)^2/9==1
Looks at above two equation,I multiply 0.5 to each element of second equation,which means when plotting, each point ...
0
votes
0answers
61 views
How to convert vector graph to equation?
I read post about convert bitmap to equation,but bitmap is not so accurate as vector graph, then I want to find a method for convert vector graph to equation.
This is the examle pdf file.I already ...
1
vote
0answers
54 views
How does DominantColors work?
I'm trying to understand the algorithms behind DominantColors[]. Unfortunately Trace[] and ...
1
vote
1answer
143 views
Fitting a slanted edge using error function
I am trying to fit a function to my data that looks like the image below. This image is a slanted edge that is kept at an angle $a$ w.rt. the y-axis. For this, I am using the error function (Erf[]) in ...
1
vote
1answer
305 views
rotate image around fixed point
How can I painlessly rotate a tiff image by some small angle around a point with specific coordinates? The image shouldn't be altered otherwise, it can be padded with zeros if necessary, and then ...
1
vote
1answer
73 views
Ignoring text to compute regions in image?
Given this image (from Sculley et al "Hidden Technical Debt in Machine Learning Systems"), how can the relative areas of the boxes be computed?
In particular, the text interferes with most ...
6
votes
3answers
320 views
How to make the boundaries thin and smooth of a binary image? [duplicate]
Consider a binary image img as
How can I make the edges thin and smooth?
6
votes
2answers
163 views
determine number of fibers at junctions
I work on a structural analysis of SEM image of a gel. I extracted the center of fibers by binarizing ane seletonizing the picture in ImageJ (in red). Then I extracted the positions of junctions where ...
0
votes
1answer
248 views
How to design a custom image filter for edge detection?
Consider a sample image img as
If I apply a GradientFilter on it followed by a padding,
...
2
votes
1answer
71 views
DynamicImage with a Dynamic
This is probably a very simple thing, but I could not figure it out.
I am trying to create a window were I can display an image while being able to zoom, pan and scroll while adjusting contrast and ...
0
votes
0answers
55 views
1
vote
2answers
115 views
Try to find the number of points near the black color ؟
Given this RGB image
I want to find the number of points that are, or almost, black ؟
1
vote
0answers
190 views
How do I use Discrete Wavelet Transform for feature extraction on MRI DICOM image? [closed]
As an example, I would like to extract different features from the following image:
I could do this in 3D slicer but since I could code a bit in Mathematica (I just moved to Mathematica 11 from 9 ...
6
votes
2answers
248 views
Fit a circle to a region of an image
I would like to develop a routine that associates a size with images such as that below. My idea is to find the radius of the circle (centered at the origin) that contains (say) 95% of the total ...
7
votes
1answer
146 views
Mean RGB value of a locator region?
i am working at a color deconvolution using Ruifrok and Johnston's method (as described here).
To get a custom stain, I need to realize a vector with mean RGB values of a region in a given image. So ...
1
vote
0answers
397 views
How to change image data (2D matrix) from cartesian to polar coordinate system? [duplicate]
I have a 2D matrix corresponding to the shown image in Cartesian coordinates. In image, the horizontal axis is x and vertical corresponds to y-axis. How to change this 2D matrix to polar coordinate ...
0
votes
0answers
68 views
Detection the coordinates of all points of a curve on an image file [duplicate]
I have a plot of a curve (the black curve without dashes) on an image file.jpg:
http://s000.tinyupload.com/index.php?file_id=48857135704766357735
I'd like to detect the coordinates of all point of ...
