Questions on the image processing capabilities implemented in Mathematica.
133
votes
2answers
35k 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 ...
57
votes
4answers
4k views
How to peel the labels from marmalade jars using Mathematica?
How can I detect and peel the label from the jar below (POV, cylinder radius, jar contents are all unknown)
to get something like this, which is the original label before it was stuck on the jar?
...
54
votes
8answers
2k views
Artistic image vectorization
The question is
how can we use Mathematica to create vectorized versions of low-resolution images? The goal is to get an image suitable for quality printing at any resolution.
Since "true" ...
42
votes
1answer
3k views
Torn edge paper effect for images
In my answers to Plotting Error Bars on a Log Scale I used a so called "torn edge" effect from on one of the images. @SjoerdC.deVries commented: "BTW I liked the ripped-out look of your InputForm ...
41
votes
5answers
5k 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 ...
40
votes
3answers
2k views
Recovering data points from an image
Unfortunately, some data can only be obtained in picture form (Japanese publications anyone?). Since this cannot be worked with, it has to be converted to a dataset that can; I was wondering whether ...
35
votes
2answers
2k views
Programmatic approach to HDR photography with Mathematica image processing functions
The High dynamic range imaging (HDR or HDRI) direction in photography and image processing became very popular recently. Besides obvious photo art applications (see examples), there are many great ...
35
votes
3answers
11k views
How to create new “person curve”?
Wolfram|Alpha has a whole collection¹ of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica ...
34
votes
2answers
831 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 ...
33
votes
3answers
809 views
Image processing: Floor plan - detecting rooms' borders (area) and room names' texts
Here is a simple building floor plan. I would like to derive the rooms as (rectangular) components and the names of the rooms. This is very common representation of building floor plans.
The ...
32
votes
3answers
850 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.
28
votes
2answers
4k 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 ...
25
votes
3answers
901 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 ...
25
votes
5answers
2k views
How can I extract data points from a black and white image?
Consider the following graph (source):
Is there any way to extract the data points from this image in a semi-automatic way? I have seen, and tried the methods suggested in this question, but they ...
25
votes
2answers
731 views
Remove image background of headshot in Mathematica?
For example, using ExampleData[{"TestImage", "Girl2"}]:
what's a general way to make the background transparent? I've tried various combinations of ...
25
votes
1answer
421 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 ...
24
votes
5answers
708 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 ...
24
votes
2answers
408 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 ...
23
votes
1answer
422 views
The correct way to linearize colorspace before resizing, blurring etc
There was an interesting discussion on MathGroups dealing with the fact that image-processing functions in Mathematica (and many other software, including Adobe Photoshop) work with RGB, Grayscale ...
22
votes
4answers
831 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.
...
22
votes
2answers
573 views
Cleaning mildew from old documents using Mathematica (Image processing)
While visiting family over the holiday period, I managed to have some good mother-daughter bonding over how far back I’ve managed to trace the family tree (Mom is in her 80s and doesn’t do computers). ...
20
votes
3answers
651 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 ...
20
votes
3answers
759 views
How to extrude a 3D image from a binary 2D image
I'm trying to extrude a nice 3D form from the 2D binary image below using the code posted, but I haven't had any luck in figuring out the error that's keeping ...
20
votes
2answers
302 views
How to retrieve the parameters calculated and used by ImageAdjust?
When ImageAdjust is called with an image, i.e. with one parameter, it returns an automatically adjusted Image. I would like to ...
19
votes
1answer
908 views
Is there a way to convert an image into a Graph?
I'm trying to convert an image with several overlapping dots into a Graph. The goal is to be able to derive the Kirchhoff matrix for the randomly created "network ...
19
votes
0answers
881 views
Measuring fractal dimension of natural objects from digital images
This is a useful topic. A college physics lab, medical diagnostics, urban growth, etc. - there is a lot of applications. On this site by Paul Bourke about Google Earth fractals we can get a high ...
18
votes
5answers
588 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.
18
votes
3answers
687 views
How to make a drop-shadow for Graphics3D objects
What's the best way to make a drop shadow for a 3D object?
image = Graphics3D[Sphere[], Boxed -> False]
I can get a blurry black outline of this:
...
18
votes
3answers
938 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 ...
18
votes
1answer
530 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 ...
17
votes
3answers
695 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 ...
17
votes
0answers
615 views
Identifying critical points of 2/3D image/cubes
Upshot
I am interested in identifying critical points of a 3D field/cubes (maxima, minima, tube-like and wall-like saddle points) and 2D field/image (maxima, minima, saddle points). I.e. the ...
16
votes
4answers
517 views
How to fill in an irregular border of an image
I have the following code which draws a graphic, and colors the regions in it different colors:
...
16
votes
3answers
840 views
Data fitting with Image processing feature detection
I have some 2D data that once plotted looks like the following
...
16
votes
1answer
585 views
Using ImageCapture to access a USB webcam in linux
Is it possible to access a USB webcam through Mathmatica on Linux? When I run
ImageCapture[]
I get the following output
...
16
votes
2answers
346 views
Why does ImageData need four times more memory?
Background
We are dealing with very large TIFF image files that are imported, processed and exported using Mathematica 9. Many of our algorithms only work with an array representation of the images, ...
16
votes
3answers
627 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 ...
15
votes
6answers
574 views
How do I make an image “nearly” black and white?
Using the following code, I downloaded an image from the web and adjusted the image to obtain the "negation" of the image:
...
15
votes
2answers
612 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 ...
15
votes
1answer
897 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
votes
2answers
691 views
How can I create a glass distortion effect in an image?
I'd like to overlay a glass jar onto an image with realistic light bending. Can anyone think of a way to automate this effect (perhaps this can be done with the raytracing package rayica)?
14
votes
3answers
391 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 ...
13
votes
2answers
989 views
How to find circular objects in an image?
How could I use morphological processing to find circular objects in an image? More specifically, I need to detect road signs.
I need to get the "80 speed limit" sign from this image:
13
votes
4answers
319 views
How to separate paths from the output of EdgeDetect?
I have been trying to find a way to separate the various closed paths that can be output by EdgeDetect. For example, taking the output of:
...
13
votes
3answers
794 views
Filtering pixels of a certain color
What is the best way to filter an image so that only the pixels close to a certain color are left?
I've downloaded some satellite images from the web where a specific pixel color corresponds to a ...
13
votes
2answers
534 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 ...
13
votes
2answers
316 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:
...
13
votes
3answers
452 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
1answer
207 views
Problems with images caused by which stylesheet is used
Update
This looks now like it was a bug in Mathematica version 8, because
everything works as expected - at least for this minimal example - in
version 9. (As an aside, I couldn't seem to find ...
12
votes
6answers
558 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, ...
