Questions on the image processing capabilities implemented in Mathematica.
2
votes
2answers
69 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 ...
5
votes
2answers
108 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
2answers
163 views
Derive a smooth circle with cusp from an image
question 1 get the center
(sample data)
sample is the black circle with cusp.
...
15
votes
2answers
324 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 ...
10
votes
4answers
264 views
+50
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
118 views
Image Restoration
I want to degrade the image, and then execute the restoration, such as a lena.jpg.
I tried this:
...
4
votes
2answers
128 views
Getting RGBA data of an image with ImageData
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 ...
13
votes
2answers
237 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 ...
-1
votes
0answers
138 views
How to make this image more clear? [closed]
Suppose I have a PNG file as above, I want to make it more clear, i.e. after scaled, I can still read it clearly. Did there any way to do this by mathematica?
I think this image is add some noise ...
3
votes
3answers
85 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 ...
6
votes
4answers
212 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 ...
118
votes
2answers
52k 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) ...
-4
votes
0answers
114 views
Find glasses on image [closed]
I have bunch of photos with the same person in similar positions. On some of the photos he has glasses, and what I want is to extract (identify) those photos. I guess the first step is to use ...
20
votes
4answers
648 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
75 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
142 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
93 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 ...
25
votes
1answer
556 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 ...
13
votes
6answers
856 views
How to find major color in a picture?
I want to find the major color (the color which appears most often) in a picture and do some analysis later.
For example, if I have this picture:
What I want to do is find out that gray, red, ...
0
votes
1answer
58 views
Outputting a set of graphics 3D objects with positions defined by one array and colors by another? [duplicate]
I have a set of 2- or 3-space coordinates in an array, $(v_1,...,v_N)$, and an array of RGB color values (outputs from ImageValue[]) for each coordinate, $(c_1,...,c_N)$. How can I output a ...
3
votes
1answer
240 views
Detection of horizontal lines in an image
Ok I'm trying to detect horizontal lines in an image. But the problem is that the line is quite obscure. So I'm not sure if it is even possible to extract that. I tried many different filters, but ...
5
votes
4answers
353 views
How can I return the color at a coordinate in an image?
I have an imported and cropped image:
TestPicture = Import["filepath.jpg"];
TestPictureCropped = ImageCrop[TestPicture, Min[ImageDimensions[TestPicture]]];
How ...
2
votes
1answer
49 views
How do I access the binary matrix underlying an EdgeDetect output?
Applying EdgeDetect to an image generates a black and white edge-detected image, which I suspect corresponds to an underlying binary matrix. How can I access this ...
5
votes
4answers
153 views
How do I overlay corresponding values over each frame of an animation?
I recorded a phenomenon using video capturing (phen.avi, imported into Mathematica) and simultaneous measurement of some electrical properties of that phenomenon (a ...
1
vote
2answers
88 views
Image processing - How can I apply an operation to several images at once?
I imported pictures into Mathematica, and used names for them that follow the easy scheme "name" string joined with an integer, ranging from 14 to 20. Printing these images on screen works nicely:
...
3
votes
0answers
132 views
looking for a generalised Hough Transform function or a least a function to locate circles
I am looking for a generalised Hough Transform function or a least a function to locate circles (position of center and radius) in a image. There is the standard Hough line search function ...
0
votes
0answers
23 views
How to use an arbitrary closed region to extract an image region of interest [duplicate]
I am working on images and I need to be able to extract into a list all the image points that fall within a closed region, such as gotten from using "get coordinates". I can extract the points from ...
0
votes
1answer
147 views
How can I find lines of a certain angle(s)?
ImageLines implements the Hough transform, but how do I search for only lines within some threshold of a certain angle(s)?
5
votes
5answers
356 views
Get Coordinates in Image Processing
I'm new to Mathematica. I'm very impressed about it's abilities. It's very easy to achieve complex tasks. But I fail the simple ones.
How can I get coordinates in image processing?
I'd like to ...
10
votes
3answers
212 views
Rotate a grid, made up of lines, so that it aligns with the xy axes
While working on an answer for another problem I hit upon one of my own.
I took the image given in that question and cleaned it up so that I could detect the grid lines:
...
17
votes
3answers
735 views
How to detect crosses and circles in 60x60 raster images?
I have hand-written 60 pixel times 60 pixel squares. I need to detect whether they are empty, x or circle. TextRecognize function fails. Is there some other function to process this kind of raster ...
20
votes
3answers
700 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 ...
0
votes
2answers
131 views
Find white regions in image
At the white regions of this image I want to add a few random arrows.
I would like to realize two different of adding the random arrows:
The arrows may not leave the white region
The arrows have to ...
8
votes
3answers
581 views
Composing an image with a plot
I'm trying to illustrate the solutions to a textbook problem dealing with quadratic functions.
This will involve plotting a quadratic and overlaying the plot and the image.
Here is the textbook ...
2
votes
1answer
88 views
Round image corners [duplicate]
I just read StackExchange blog It’s OK to Ask and Answer Your Own Questions which even encourages it and decided to ask about a problem I now know how to solve. But I found an elegant answer only ...
2
votes
4answers
142 views
Find components which have intersections with designated lines
I have an image with several disconnected components, and I want to find all the components which have intersections with some designated lines which I generated previously.
The image:
And the line ...
6
votes
2answers
156 views
Applying a transformation rule on an Image
I haven't been able to figure out why the following doesn't work:
...
8
votes
1answer
286 views
Search the neighborhood area along a line in an image
I am trying to search for the black areas along a line (the horizontal line shown below). Though it is straight in this picture, it could be of irregular shape in other cases. It seems that the ...
10
votes
3answers
335 views
Extract connected components from PNG image file and write to individual PNG files
Given the PNG image below with the three leaves in it, I'd like to extract each individual leaf and write it to its own PNG file, using Mathematica 9. Note that in the original image, the box bounding ...
0
votes
1answer
132 views
Automatically shrink stretched images back to their original dimensions
We all sometimes find images on the web that are carelessly stretched to larger dimensions than original, which results in nothing but a reduction of the detail / dimensions ratio.
See Original vs ...
5
votes
3answers
274 views
Parameters for the CIE XYZ Color Space in Mathematica
In Mathematica, producing a color based on its RGB parameters is easy; one can use (for example)
...
5
votes
1answer
81 views
Scaling an image with “Drawing Tools” primitives on it
Imagine I doodle with the "Drawing tools" pen, or place lines on an image after importing it. Now say I want to scale this image by some constant factor $C$ while maintaining the same aspect ratio. ...
2
votes
2answers
157 views
Introduction of bias during brightness and contrast manipulation of an image
Quoting from Nature magazine's "Image integrity" guidelines:
Processing (such as changing brightness and contrast) is appropriate
only when it is applied equally across the entire image and is ...
6
votes
1answer
121 views
Digital Elevation Maps (DEM) are Warped yet ReliefPlot renders as a rectangle - how do i join?
I downloaded several USGS Digital Elevation Maps (DEM files) corresponding to 12 adjacent areas. Each file Imports[] into Mathematica and I can render the individual ...
1
vote
0answers
116 views
Exporting images leaves syntax artifacts [closed]
I'm exporting Images (using .Net MathLink) and finding syntax artifacts in:
Images:
RTF:
PDF:
I've tried a couple of things such as ...
0
votes
0answers
78 views
How to get Contours/maxima for an image in a useful form [closed]
I have some images in which I would like to find the locations of various maxima, plus the contour lines at a level e.g., 50% of that maximum intensity.
As a first step, I did a FourierDCT on the ...
5
votes
1answer
269 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 ...
12
votes
2answers
653 views
How can I detect a rectangular region of interest in a picture?
Here is a downsampled input image I converted to greyscale.
To select the rectangular region of interest we first preform preprocessing:
...
2
votes
1answer
159 views
Weird resampling when I try to export an Image
Mathematica language newbie here. I wrote the following code to quantize an image:
...
18
votes
5answers
608 views
Voronoi diagrams for generators other than points
Any suggestions how to determine Voronoi diagram for sites other than points, as e.g. in the picture below? Input is a raster image.
