Questions on the image processing capabilities implemented in Mathematica.

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23
votes
3answers
1k 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
202 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 ...
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 ...
2
votes
1answer
121 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 ...
3
votes
4answers
242 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 ...
7
votes
3answers
229 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
722 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
622 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
271 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
500 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
122 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
255 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
192 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 ...
5
votes
1answer
419 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 ...
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: ...
3
votes
1answer
205 views

Weird resampling when I try to export an Image

Mathematica language newbie here. I wrote the following code to quantize an image: ...
26
votes
5answers
936 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.
10
votes
1answer
284 views

Precise cropping with ImageCrop

The built-in ImageCrop function "effectively removes borders from image whose pixel value distribution is almost uniform" (emphasis mine). I need an efficient ...
2
votes
1answer
400 views

Extract data from plots in papers including error bars

I would like to know how to extract data from plots in a paper and, also, how to do that in a way that include error bars. I know there are specific softwares to do that, e.g. Plot Digitizer, which ...
0
votes
2answers
197 views

Number of edges to each polygon of a graph constructed from an image

I have an image which looks like from How to convert an image to a graph and get the positions of the edges? which by using MorphologicalGraph becomes a graph ...
34
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 ...
2
votes
1answer
159 views

How does DistanceFunction work with images in ClusteringComponents?

Does anyone know the syntax to DistanceFunction? I am trying to define my own function to use with ClusteringComponents; e.g., ...
3
votes
1answer
264 views

Filter bright dots from the gradient of the image

I am wondering how to filter out bright dots in the picture, which are caused by background noise. I have used gradient filter in mathematica but it doesn't help. Is there anyway, that I can plot ...
3
votes
2answers
190 views

How to remove border points from InputForm?

I have this code, and it generates the below ListStreamPlot. The second graph is the ListStreamPlot overlaid with the points ...
4
votes
1answer
320 views

How can I find a particular character in an image that has many similar Chinese characters? [duplicate]

The Chinese characters "竟" and "竞" are very similar in their appearance. I am trying to find "竟" in the following picture. I tried use TextRecognize but it ...
15
votes
1answer
656 views

How to extract metadata from an image of a business card?

I'm trying to digitize some documents, and I came across a very cool app called camscanner app which performs parallax transform and ocr very nicely, now I'm implementing it in mathematica... Given ...
15
votes
3answers
789 views

How to remove constant background from an image?

I'm not sure how to remove the paper background from this logo with v9. This is really not the same as this question, but I think similar methods apply.
3
votes
3answers
290 views

How to find Image Size of a control object?

I want to find the ImageSize or at least dimensions of any control object irrespective of it being an image or an any other control such as ...
3
votes
2answers
406 views

HSB -> HSL Converter

Starting from an image I would like to apply a custom filter to an image. I have thought and implemented this filter in HSL space and it goes like this : Boost the saturation of the pixels that ...
43
votes
3answers
19k 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 ...
0
votes
2answers
150 views

Automating the “Get Indices” right click function

Is there a way to do this? What I am trying to do is allow a user to take a lineout averaged over the rows of a user defined ROI (Region of Interest) of an image. I have the bit of code that allows ...
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 ...
24
votes
2answers
801 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). ...
7
votes
3answers
326 views

Radon function result's repeatability

I want to get a Hough transform of some edged image. When I compare the same transformation on the same image I got different results. ...
9
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, ...
16
votes
6answers
814 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: ...
12
votes
2answers
244 views

Why does DominantColors keep shuffling the order of the results?

This graphic is produced by running DominantColors (new in Mathematica 9) with different values, using the Lena image as the source: Each row is a list of the ...
24
votes
1answer
1k 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 ...
5
votes
2answers
1k views

Deformed style when exporting eps files

I want to export a plot into an eps file. Below I present a sample plot code in order to demonstrate the two issues that appear. (1). LabelStyle: When I use ...
4
votes
2answers
248 views

How can I superimpose points or disks on an image at specified coordinates?

I have a TIFF image of 640 x 640 pixels, over which I would like to plot a list of points or disks of small radius. I have been testing different alternatives and I found ImageCompose command. ...
11
votes
2answers
1k views

Push-pin Art – Convert image to R-Y-B-W-Blk color space

After seeing an example of what is called “Push-pin Art”, I assumed that Mathematica would be able to handle the kind of image processing required to convert an image to this format. I am not well ...
9
votes
2answers
764 views

How to transform a 3D image by an affine transformation matrix

I have a question concerning Image Processing: I have a stack of images, which I can compose to a 3D image using Image3D. Additionally I have a 4x4 affine transformation matrix. I would like to ...
2
votes
2answers
200 views

Take part of image under locator

How to create Manipulator with Locator to take part of an image?
25
votes
2answers
579 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 ...
10
votes
1answer
537 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 ...
5
votes
2answers
372 views

What is ImageDistance measuring?

What quantity is ImageDistance measuring, and what do the numbers mean? I found the ImageDistance command in Mathematica 9, but ...
10
votes
2answers
212 views

How to extract a specific element from EXIF photographic metadata?

It's now possible to import photographs into Mathematica and import the EXIF data at the same time: i = Import["ExampleData/coneflower.jpg", "ImageWithExif"] ...
1
vote
1answer
455 views

HOG descriptor for image processing

I did not find in Mathematica a function for Histogram of Oriented Gradients (HOG) descriptors. Is there any similar function? Do you have an implementation you are willing to share?
26
votes
1answer
971 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 ...
20
votes
2answers
529 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 ...