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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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image processing to improve tesseract OCR accuracy

I've been using tesseract to convert documents into text. The quality of the documents ranges wildly, and I'm looking for tips on what sort of image processing might improve the results. I've noticed that text that is highly pixellated - for…
user364902
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Checking images for similarity with OpenCV

Does OpenCV support the comparison of two images, returning some value (maybe a percentage) that indicates how similar these images are? E.g. 100% would be returned if the same image was passed twice, 0% would be returned if the images were totally…
Boris
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OpenCV C++/Obj-C: Detecting a sheet of paper / Square Detection

I successfully implemented the OpenCV square-detection example in my test application, but now need to filter the output, because it's quite messy - or is my code wrong? I'm interested in the four corner points of the paper for skew reduction (like…
dom
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Fast Bitmap Blur For Android SDK

Currently in an Android application that I'm developing I'm looping through the pixels of an image to blur it. This takes about 30 seconds on a 640x480 image. While browsing apps in the Android Market I came across one that includes a blur…
Greg
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UIImage: Resize, then Crop

I've been bashing my face into this one for literally days now and even though I feel constantly that I am right on the edge of revelation, I simply cannot achieve my goal. I thought, ahead of time in the conceptual phases of my design, that it…
Carson C.
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converting a base 64 string to an image and saving it

Here is my code: protected void SaveMyImage_Click(object sender, EventArgs e) { string imageUrl = Hidden1.Value; string saveLocation = Server.MapPath("~/PictureUploads/whatever2.png") ; HttpWebRequest…
anthonypliu
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cv2.imshow command doesn't work properly in opencv-python

I'm using opencv 2.4.2, python 2.7 The following simple code created a window of the correct name, but its content is just blank and doesn't show the image: import cv2 img=cv2.imread('C:/Python27/03323_HD.jpg') cv2.imshow('ImageWindow',img) does…
top.eng
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Face recognition Library

I'm looking for a free face recognition library for a university project. I'm not looking for face detection. I'm looking for actual recognition. That means finding images that contain specified faces or libraries that calculate distances between…
Janusz
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Extracting text OpenCV

I am trying to find the bounding boxes of text in an image and am currently using this approach: // calculate the local variances of the grayscale image Mat t_mean, t_mean_2; Mat grayF; outImg_gray.convertTo(grayF, CV_32F); int winSize =…
Clip
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Algorithm to compare two images

Given two different image files (in whatever format I choose), I need to write a program to predict the chance if one being the illegal copy of another. The author of the copy may do stuff like rotating, making negative, or adding trivial details…
Lam Luu
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Convert image from PIL to openCV format

I'm trying to convert image from PIL to OpenCV format. I'm using OpenCV 2.4.3. here is what I've attempted till now. >>> from PIL import Image >>> import cv2 as cv >>> pimg = Image.open('D:\\traffic.jpg') #PIL Image >>>…
md1hunox
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Get Image size WITHOUT loading image into memory

I understand that you can get the image size using PIL in the following fashion from PIL import Image im = Image.open(image_filename) width, height = im.size However, I would like to get the image width and height without having to load the image…
Sami A. Haija
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How to merge images in command line?

I would like to try the CSS Sprite technique to load a few thumbnails as a single image. So I need to "merge" a few thumbnails in a single file offline in the server. Suppose I have 10 thumbnails of the same size. How would you suggest I "merge"…
Michael
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How can I sharpen an image in OpenCV?

How can I sharpen an image using OpenCV? There are many ways of smoothing or blurring but none that I could see of sharpening.
AruniRC
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Converting RGB to grayscale/intensity

When converting from RGB to grayscale, it is said that specific weights to channels R, G, and B ought to be applied. These weights are: 0.2989, 0.5870, 0.1140. It is said that the reason for this is different human perception/sensibility towards…
ypnos
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