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Questions tagged [image-processing]

Anything related to digital image processing, i.e. the theory and the techniques used to extract or manipulate information from digital images.

Image Processing involves any kind of signal processing in which the input is an image. The output can also be an image, or it can be information relative to the input image. Most image processing techniques involve treating the image as a two-dimensional array and applying standard signal processing techniques to it. Though optical and analog image processing are both well defined in the space of image processing, the tag image-processing in SO solely refers to digital image processing.

A good start on the field is having a look at the next links:

For an in-depth collection of explanations of a number of image processing topics, have a look at CVonline.

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Forcing Ghostscript to use antialiasing when converting a PDF to PNG?

I'm using GPL Ghostscript 9.07 (2013-02-14) on OS X (10.8.4) to convert many PDFs to PNGs. It works fine except for one of the PDFs which turns into a PNG with jagged edges. In other words, Ghostscript turns off antialiasing for that particular PDF…
Dae
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OpenCV: How to get the number of pixels?

How to get the number of pixels in an image? Following is my code, and I need to get the total number of pixels in Mat "m". int main() { Mat m = imread("C:/Users/Public/Pictures/Sample Pictures/Penguins.jpg"); namedWindow("Image"); …
System.Windows.Form
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color object tracking in openCV keeps detecting the skin

What I intend to do is as follows: Fix a colored object. Track it across video frames using histogram-backprojection approach with camshift. I use the following code and it always ends up detecting the skin. I understand I am making some terribly…
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Robust detection of grid pattern in an image

I have written a program in Python which automatically reads score sheets like this one At the moment I am using the following basic strategy: Deskew the image using ImageMagick Read into Python using PIL, converting the image to B&W Calculate…
chthonicdaemon
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How can i work with Android EffectFactory Class?

I tired to Develop a sample application with image processing, in my app i need to add some color effects (Grayscale, sepia) over my bitmap i referred the developer documents Doc 1 and Doc 2, in this document there is no practical examples, so need…
Aerrow
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Weird result from the Kuwahara filter

I am implementing a Kuwahara filter in C++, with OpenCV to help opening and displaying images. The idea is quite straight forward but somehow I got weird result from it. Here' the cose: #include "opencv2/opencv.hpp" #include #include…
Max
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Remove points which contains pixels fewer than (N)

I tried almost all filters in PIL, but failed. Is there any function in numpy of scipy to remove the noise? Like Bwareaopen() in Matlab()? e.g: PS: If there is a way to fill the letters into black, I will be grateful
wilbeibi
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PHP, detecting watermarked images?

I have a library of like 1 million images, and roughly half of these are watermarked with the same, half transparent watermark in the same spot. Where do I begin, detecting the images with the watermarks? Is there some standard tools for this…
Kristian Rafteseth
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Allowing users to crop and resize images Ruby on Rails

Sorry for the fairly generic question but I was wondering whether anyone had any recommendations on how to best allow users to crop and edit their own images. What I would like to happen is that when a user uploads their image on my app for the app…
Tom Pinchen
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How to detect Hotspots in an image

How to detect a hotspot in an image using opencv? I have tried googling but couldnt get a clue of it. Description: I need to filter good images from a live video stream. In this case I need to just detect the Hotspot in a frame. I need to do this in…
2vision2
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Prerequisites for understanding Wavelet theory

I have a degree in computer science and I have taken the following math courses. Calculus I Calculus II Discrete Mathematics and Number Theory Linear Algebra Probability Logic Automata Theory What other courses should I take in order to prepare…
joemoe
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Python: process image and save to file stream

I need to process an image (apply filters and other transformation) using python and then serve it to the user using HTTP. Right now, I'm using BaseHTTPServer and PIL. Problem is, PIL can't write directly into file streams, so I have to write into a…
Elad Alfassa
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Threshold of blurry image - part 2

How can I threshold this blurry image to make the digits as clear as possible? In a previous post, I tried adaptively thresholding a blurry image (left), which resulted in distorted and disconnected digits (right): Since then, I've tried using a…
1''
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Retrieve the pixel values of an image with Haskell

Is there a way or a library available that can load an image (jpeg, png, etc) and assign the pixel values of that image into a list or matrix? I'd like to do some experiments with image and pattern recognition. A little nudge in the right direction…
subtlearray
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how to merge 2 images without using set alpha?

I am a Fresher Developer in iPhone . I want Merge Two Images and Get Only One Image In UIImageView without set alpha. This is my code. This code is working using alpha, but I want set without set alpha. MYCODE:- -(UIImage *)maskingImage:(UIImage…
The Rock
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