Questions on the image processing capabilities implemented in Mathematica.

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53
votes
3answers
5k 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 ...
50
votes
1answer
4k 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 ...
25
votes
3answers
3k 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:
32
votes
5answers
4k 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 ...
23
votes
4answers
2k 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: ...
69
votes
4answers
5k 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? ...
64
votes
11answers
5k 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" ...
41
votes
2answers
2k 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 ...
44
votes
1answer
3k 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 ...
22
votes
3answers
1k 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 ...
33
votes
3answers
2k 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 ...
26
votes
5answers
1k 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 ...
37
votes
2answers
1k 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 ...
6
votes
4answers
4k views

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

Imagine I have a set of data like the following: ...
15
votes
2answers
1k 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 ...
2
votes
1answer
127 views

How to highlight image edge with spline/bezier when mouse moved over?

It is known that EdgeDetect can find image edges in an image. Suppose the image edges consists of sets of lines. Can the detected edge line near the mouse pointer be highlighted as spline/bezier when ...
159
votes
2answers
37k 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 ...
46
votes
2answers
2k 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 ...
43
votes
3answers
1k 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.
26
votes
5answers
1k 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.
36
votes
3answers
3k 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 ...
23
votes
3answers
1k 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 ...
11
votes
1answer
469 views

Ellipse counting from image

I have hundreds of images similar to this image: I'm looking to count the number of ellipses as well as their major and minor diameters. The ellipses are touching, hence, ...
19
votes
2answers
1k 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 ...
11
votes
3answers
676 views

Image levels: how to alter 'exposure' of dark and light areas?

I was working with some less than ideal photographs, and wanted to adjust them before continuing. I wanted to raise the levels of the very dark areas and lower the levels of the very light areas. I ...
7
votes
4answers
488 views

Image correlation

I have two images from motor scan, Image1 is shifted by MxN pixels from Image2. How can I find the shift between Image1 and Image2 ? Image -1 Image -2 If we compare the shift between the images ...
11
votes
3answers
3k views

Saving high-quality graphics through commands

Say I make and display a graph in a Mathematica notebook: graph = CompleteGraph[100] If I drag the corner of the graph to increase its size, and then save it to ...
10
votes
1answer
955 views

Implementing OCR without using TextRecognize

I am new to Mathematica and trying to figure out whether it is a good tool for algorithmic exploration. So I had the idea of implementing a simple OCR with Mathematica, just using standard ...
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) ...
47
votes
3answers
20k 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 ...
49
votes
5answers
8k 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 ...
30
votes
3answers
1k 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 ...
27
votes
1answer
1k 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 ...
15
votes
2answers
2k 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: ...
25
votes
4answers
1k 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
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 ...
18
votes
2answers
501 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 ...
20
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 ...
15
votes
6answers
1k 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, ...
18
votes
3answers
2k views

Data fitting with Image processing feature detection

I have some 2D data that once plotted looks like the following ...
14
votes
4answers
790 views

What is the fastest way to locate an image inside a larger image?

let b = let c = How to do: find[c,b] that returns the bounding box of c in b? ...
10
votes
1answer
2k views

Image Processing: Finding Orientation and Position of Symmetry Axes

Background I'm currently toying with Principles of Design by Charlotte Jirousek in order to learn some basics of image processing. As main principals she suggests Balance, Proportion, Rhythm, ...
10
votes
1answer
588 views

Count Elements in Image

I have the following image: img1 I'm trying to count al these colored cells and draw a circle around them. I really don't now how I can use SelectComponents for ...
18
votes
3answers
1k 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 ...
14
votes
3answers
2k 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 ...
11
votes
1answer
898 views

Copying an image from the clipboard, modifying it and returning it to the clipboard

I have a Mathematica script to help me copy images from PDFs and then make the (presumably white or nearly white) background transparent. Typically, I am looking at the PDF in Adobe Acrobat and I ...
9
votes
3answers
2k 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 ...
12
votes
2answers
746 views

How can I efficiently “remap” an image?

Many image processing libraries like OpenCV, Intel Performance Primitives or Octave have a useful function called "remap", that takes an image, an array with X coordinates and an array with Y ...
12
votes
3answers
548 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: ...
10
votes
3answers
458 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 ...