Questions tagged [image-processing]

Questions on the image processing capabilities implemented in Mathematica.

Filter by
Sorted by
Tagged with
197
votes
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 ...
189
votes
2answers
61k 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) ...
97
votes
3answers
12k 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 ...
93
votes
12answers
9k 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" ...
91
votes
4answers
11k 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?
84
votes
9answers
17k views

How to make an inkblot?

How to effectively create a polygon that looks like a realistic inkblot? So far, I could come up with this (borrowing from Ed Pegg Jr.'s Rorschach demonstration): ...
77
votes
4answers
42k views

How to create a 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 ...
70
votes
4answers
14k 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 ...
66
votes
4answers
2k views

Reconstruct text pages cut by shredder

Q1: I have a page of a printed text file, but it was cut by a paper shredder (from top to bottom). You can download all the paper fragments here. Here are some of them. How can I reconstruct it? Q2: ...
63
votes
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 ...
63
votes
3answers
5k 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 ...
60
votes
3answers
22k 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 problem ...
59
votes
2answers
7k 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 ...
58
votes
2answers
3k views

How can I add drop shadows and specular highlights to 2D graphics?

I thought I'd share some code in the form of a self-answered question, but other answers are of course welcome. Drop shadows are a familiar visual effect, giving the impression of a graphical element ...
54
votes
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
votes
3answers
3k views

Composition à la Mondrian

I would like to paint something like this or,even better, like this I have tried ...
53
votes
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 ...
50
votes
5answers
14k views

How to ask Mathematica to imitate Andy Warhol's pop-art painting?

I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe's portrait so that it looks like Warhol's world famous pop-art painting. However, the result shown below is far from ...
50
votes
2answers
6k 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 ...
49
votes
4answers
4k views

Mollweide maps in Mathematica

Context In my field of research, many people use the following package: healpix (for Hierarchical Equal Area isoLatitude Pixelization) which has been ported to a few different languages (F90, C,C++, ...
48
votes
7answers
3k views

Character edge finding

The following line of code finds the edge of a character: ...
48
votes
5answers
9k 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 did ...
47
votes
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 ...
47
votes
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 ...
45
votes
2answers
10k 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 few ...
43
votes
1answer
14k 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?
41
votes
2answers
8k views

The correct way to linearize colorspace before resizing, blurring etc

There was an interesting discussion on MathGroup dealing with the fact that image-processing functions in Mathematica (and many other software, including Adobe Photoshop) work with RGB, Grayscale etc. ...
40
votes
4answers
3k 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 ...
40
votes
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 ...
40
votes
3answers
4k views

Identifying critical points/lines 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 ...
39
votes
7answers
2k views

Voronoi diagrams for generators other than points

Any suggestions on how to determine a Voronoi diagram for sites other than points, as e.g. in the picture below? The input is a raster image.
39
votes
2answers
3k 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 ...
38
votes
1answer
2k views

May the Fourth be with you

Happy Star Wars day. I was playing around with the image manipulation functions in Mathematica in an attempt to recreate the Star Wars crawl. There's an HTML/CSS implementation which is in my ...
37
votes
4answers
5k views

How to make a drop-shadow for a 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: ...
36
votes
3answers
12k 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:
36
votes
2answers
1k 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). ...
34
votes
2answers
3k views

Create the source image for this cool animated illusion

Have a look at this very awesome video: https://www.youtube.com/watch?v=lvvcRdwNhGM You have a vertically discretized image, which is composed of 5 or 6 images, which are shifted by an increment, as ...
34
votes
4answers
3k views

How to make a stereogram in Mathematica?

Given a background and a pattern jpg files, is there a quick and easy way to produce a stereogram by using Mathematica? The following picture was produced from Photoshop, spent about half an hour. ...
34
votes
1answer
1k views

Drawing Clifford Attractors in Mathematica

I came upon the "Clifford Attractor" today, which are equations of the form: $$x_{n+1}=\sin(a\ y_n) + c \cos(x_n)$$ $$y_{n+1}=\sin(b\ x_n) + d \cos(y_n)$$ They create some incredible images by ...
33
votes
5answers
2k 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 ...
33
votes
5answers
11k 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 quite ...
33
votes
2answers
4k views

How do I remove grid from this photo?

I found this cat a month ago, and I'm not his owners' friend so the mosquito grid was the inevitable problem. I would like to post-process this photo to get rid of it, but I don't know exactly how ...
33
votes
4answers
3k 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. ...
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 ...
33
votes
2answers
2k views

How to make a curve selectable from a scaned image and convert it to a list of coordinates

I have a scanned image (binary-ized): Is there any way to reduce one of these curved lines (full or dotted) to a series of its coordinates (e.g., sampling interval of 0.01 on x-axis)? I've read ...
32
votes
5answers
12k views

How to create effect like Van Gogh's stroke brush?

I need to apply Van Gogh's stroke brush effect to a random image Take the following image as an example: Thank you so much if you could help!
32
votes
1answer
4k views

How to generate image like QR code with Mathematica

How to generate such form of QR code which displays an image itself but is still scan-able?
31
votes
4answers
4k views

How can Mathematica be used to create images like these?

Here are two examples of artistic image interpolation using just black lines: TRIANGULATION: ANGULAR CELEBRITIES DRAWN WITH A PEN Interpolation for Triangulation-represented Digital Image The ...
31
votes
3answers
2k 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 ...
31
votes
2answers
1k views

Generating animations of clouds with Mathematica

I'd like to generate some visually-pleasing animations of clouds, fog or smoke with Mathematica. My idea of "visually-pleasing" is along the lines of one of the images on the Wikipedia article for ...