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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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OpenCV findContours issue

I have the following code which performs background subtraction and then uses findContours to draw a boundary around the foreground object. // frame - Input frame from a camera. // output - Output frame to be displayed. void process(cv:: Mat…
Madman
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Background Turns Black When Saving Bitmap - C#

I am currently trying to save a bitmap image, but the background is changing to black. I can "Save As" the image perfectly fine. I can also "Save" the image as well. Which was much more difficult because I had to overwrite the existing image.…
Johnrad
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How to make ImageTransformation produce an anamorphic version of image

I'm experimenting with the ImageTransformation function to try to make anamorphic versions of images, but with limited progress so far. I'm aiming for the results you get using the image reflected in a cylindrical mirror, where the image curves…
cormullion
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OpenCV Identifying Lines and Curves

I'm just starting to learn OpenCV programming. May I just ask about how can I identify lines and curves in OpenCV? My problem is that I have to identify if the image contains a convex or concave (horizontal or vertical curve) curve, a vertical,…
cmsl
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How to determine if image is dark? (high contrast, low brightness)

As part of a project I am working on, I need to simply analyze a picture using a CLI Linux application and determining if its dark image (high contrast, low brightness). So far, I figured out I can use ImageMagick to get verbose information of the…
Gregorio Di Stefano
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Background removal using Kinect: noise suppression around body shape

The objective is to display the person on a different background (aka background removal). I'm using the Kinect with Microsoft's Beta Kinect SDK to do so. With help of the depth, the background is filtered and we get only the image of the…
wormsparty
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Remove horizontal lines with Open CV

I am trying to remove horizontal lines from my daughter's drawings, but can't get it quite right. The approach I am following is creating a mask with horizontal lines (https://stackoverflow.com/a/57410471/1873521) and then removing that mask from…
Gorka
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Upload jpg/png, convert to pdf and save with PHP?

Been doing a fair bit of digging this morning, and not seeing an obvious answer - is it possible to save an image to pdf format using PHP (or one of it's many libraries)? I am fairly familiar with GD, although it doesn't seem to have a built in PDF…
Jonathan Coe
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Looking for an Image Comparison/Pattern Recognition Library

The end goal would be to see if contains . the compare needs to support minor distortion, scaling, color differences, rotation, and brightness differences. it can be in any language really. i will be running this algorithm as a webservice so its…
josh
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Javascript crop image client-side

I'd like to use javascript or jQuery to crop and compress an image on the client side before uploading to the server. WorkFlow: Select Image Crop Image to specific size Compress the crop Upload Has anyone done this before? What plugin or what do…
Shawn Mclean
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next js image component error "url" parameter is valid but upstream response is invalid

i am fetching data from tmdb api .But the image doesn't load so i open the image in the new tab .then it shows "url" parameter is valid but upstream response is invalid so how to resolve the issue
Hunter003
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Python: Sorting items from top left to bottom right with OpenCV

How can I go about trying to order the items of a picture from top left to bottom right, such as in the image below? Currently receiving this error with the following code . Error: a = sorted(keypoints, key=lambda p: (p[0]) + (p1))[0] # find upper…
mattsmith5
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How to rotate an image to align the text for extraction?

I am using pytessearct to extract the text from images. But it doesn't work on images which are inclined. Consider the image given below: Here is the code to extract text, which is working fine on images which are not inclined. img =…
Amish Sharma
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HOG Trilinear Interpolation of Histogram Bins

I am working on Histogram of Oriented Gradient(HOG) features and I am trying to implement the trilinear interpolation of histogram bins as described in Dalal's PhD thesis. And he explains the interpolation process as cited below: EDIT: Roughly…
Ahmet Keskin
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RAW Image file - what format is my data in?

I'm working on processing .raw image files, but I'm not sure how the image is being stored. Each pixel is a unsigned 16-bit value, with typical values ranging from 0 to about 1000 (in integer form). This isnt enough bits for hex values, and its not…
andrw
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