Questions tagged [image-processing]

In general, image processing is any form of signal processing for which the input is an image, such as a photograph or video frame.

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Open Source Implementation of 3D Thinning algorithm

I am looking for open source implementation of thinning algorithm in 3D. Thinning algorithm: Convert binary shapes to 1-pixel wide lines, without shortening it or breaking it apart. For example, ...
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214 views

How to amplify regions with specific color in an image?

I want to amplify regions with a specified color in an image. For this purpose I have defined a simple function $B(x,y)=s_r(x,y) \cdot w_r + s_g(x,y) \cdot w_g + s_b(x,y) \cdot w_b$ which produces a ...
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Find a specific line in a picture

I want to find the line between color blue and color gray in the following picture: More exactly, the end points of that line. Is the Hough transform a choice? If yes how should I set up the picture ...
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995 views

How do I reconstruct text from an image using only morphological operations?

I want to reconstruct the text from the following image as best as possible. The tricky part is that I want to do it only using morphorogical operations on the image I tried using erosion, dilation, ...
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1answer
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How to compute 2D displacement vector for binary image registration?

My inputs are several binary images like: They have globally the same content but may be unregistered as they are produced from a hand camera. What I would like to compute is the 2D displacement ...
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How to implement a gradient based Hough transform

I am trying to use the Hough transform for edge detection, and would like to use gradient images as the basis. What I have done so far, given the image I of size <...
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1answer
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Detecting a fixed template image out of a semi-constant frame of video

There are a number of videos that I'm looking to process of different video games to detect various "states" in them. The first game that I am tackling is any edition of Super Street Fighter 4. In ...
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1answer
8k views

FFT of image data: “mirroring” to avoid boundary effects

I load and display an image of some rice in Matlab: g = imread('rice.png'); imshow(g); I take the FFT of this image and shift it: ...
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Why is anisotropic diffusion useful in image processing?

I am working on anisotropic diffusion and the two coefficients proposed by Perona & Malik. I wanted to know what is the use of diffusion in image processing? Why is anisotropic diffusion ...
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5k views

Texture detection and region properties on an image

I have an interesting problem that I'm trying to solve. So for example, if we have a black and white image containing two textures (A and B), I'm interested in knowing the pixel values of the ...
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229 views

Checking the “cleanliness” of an image for Optical Character Recognition

Is there some mechanism to say whether the image is "clean" for the purpose of image processing? For example, in the following image, the topmost row is the cleanest and the bottom one is the least ...
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Making objects stand out?

Lets say I have two objects very close to each other. There is a colour difference between them, but the difference is small. Therefore when finding contours, both the objects are treated like on ...
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1answer
156 views

Data decomposition method invariant to small shift and scale?

Is there a data decomposition method similar to eigenvalue that estimates projection matrix to reduce dimensionality but does not project similar vectors too far away in euclidian distance terms from ...
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Profile Matching in a Point Cloud

A point cloud is generated using uniform random function for (x,y,z). As shown on the following figure, a flat intersecting plane (profile) is being investigated ...
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1answer
613 views

Can I simultaneously remove salt and pepper noise and improve the image resolution?

What should my approach be towards designing a filter that can simultaneously remove salt & pepper noise and improve the resolution?
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Surface detection

How would one segment large area's of gray (ranging from white to black) from an image ? (If you know this in opencv, you may answer by saying what you would do in opencv). For example given this ...
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1answer
155 views

What is the easiest learning curve to develop a Mark Reader software?

I am a C# programmer and have a project to create a Mark Reader software. Bubble sheets that have been filled in by students are scanned using a general scanner (as opposed to a special scanner for ...
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760 views

How to find the color channel shifting of an RGB image that was supposed to be greyscale?

I am using a recording device that seems to shift the colors horizontally and I would like to find the amount of unshifting I have to do on 2/3 of the channels in order to obtain an image with minimal ...
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Literature on noise removal in OCR applications

Could someone point out the core texts or articles most useful on techniques for the removal of noise from scanned text for OCR applications?
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XDR data format

I have binary XDR data file representing radar data. What is XDR data formatting? What is useful for? How to visualize this binary file? Is there any kind of software that converts this data format in ...
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1answer
548 views

Measuring length of DNA fibers from an image of single molecules

I am a biologist with very little experience with image processing but have sufficient knowledge of MATLAB and have the image processing toolbox. Ideally I am looking for a MATLAB based solution, but ...
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How is the Laplacian used for Unsharp Mask?

Some unsharp algorithms (e.g. Matlab's fspecial) use a Laplacian kernel to achieve sharpening of the image. From what I know, the image needs to be blurred first, and then the blurred image is ...
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1answer
2k views

Cross-correlation matrix

In my group, we have developed an algorithm which shows abstract information from quantum mechanical systems as images. This way, given a quantum system, we obtain an associated image which has the ...
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monochrome (1-bit black-and-white) image conversion

When converting scanned text to a 1-bit black-and-white image what are some filters that one can apply in the process to improve the result? Right now I am running into the problem where dithering ...
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5answers
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How can I compare two pictures from the camera and tell if there are enough differences to detect movement?

I want to use my phone as a CCTV system to control a room in my house, and display an alert when something is moving. For now, what I have succeeded in doing is to grab a picture every minute and ...
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1answer
97 views

How do I reconstruct a covered-over part of a regular pattern

I have a set of images which consist of a fairly regular pattern - essentially a set of roughly concentric distorted ellipses - with a small area (<1% of the total image area) obscured by a ...
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How can I lowpass filter by only reducing peak data?

I have a 2D image, which I want to lowpass filter, with these constraints / quality metrics: I can not "add" light to the image, so each pixel in the result should be <= the corresponding pixel in ...
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1answer
500 views

find a line go through the center mass and that line must be inside object area

I have an object (orange color object) and I know its centroid/center mass C. I want program to automatically find another point ( can be point 1, point 2, point 3 or point 4 and so on) such that the ...
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1answer
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Removing Glare from Image

Disclaimer: I am in NO way engaged in signal processing. Just very curious... Ny question is, very simply: is it possible to apply software processing to an image to remove or reduce headlight glare?...
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114 views

How to statistically quantify the coverage of features in the data?

I have an image. I find features on it using different methods. I want to quantify that which method performs the best. The creteria is how many features per unit area of the image are and how they ...
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1answer
878 views

How does google map put together satellite pictures?

Just out of curiousity, does anyone know how does google map put together all those massive quantity of satellite pictures with with high accuracy? What advanced computer science technology has it ...
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1answer
74 views

Given some parameters, how do you determine how much of an image sensor an object will consume? [closed]

If I have the details of a scene and a camera, how can I tell how much of my camera's image sensor will be taken by a certain object in space? For example, if I have a painting that is 1m by 1m, it ...
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1answer
1k views

Skel to infinity morphological operations on 3D volume

I have a 3D volume image that consists of 2D tomographic images. In MatLab, for 2D images, we can use bwmorph and call for 'skel' operation to infinity to get a pixel thick overall outline of the ...
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470 views

Image analysis - fiber recognition

I am completely new to image analysis. Do you know how to binarize this image in such a way to get the fibers only? A step by step procedure would be awesome, but any hint is appreciated as well. I ...
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846 views

How do you measure “detail” of a signal?

I have an image and I would like to measure the amount of detail in it. Another way to look at it is to measure how blurry an image is. One way is to analyse the high frequency components in the ...