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Questions tagged [edge-detection]

Edge detection is a tool in computer vision used to find discontinuities (edges) in images or graphs. Use this tag when asking about finding and manipulating edges or edge interaction.

Edge detection is a part of computer vision where the goal is to find edges in images. This often involves computing derivatives of the image with respect to the coordinates, because intuitively if the difference between two neighboring pixels is high, it is likely that there is an edge in the image. A popular edge detection algorithm is the Canny edge detector. Other edge detection algorithm includes Laplace & Sobel.

Discontinuities in image are likely to correspond to

  • discontinuities in depth
  • discontinuities in surface orientation
  • changes in material properties and
  • variations in scene illumination
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How to simulate clothes changes in 2D image?

I'm working on small project which requires: Change clothes (shirt/pants etc.) of a person in any 2D image he chooses to upload. So somehow edges needs to be detected and relevant areas are supposed to be filled with new patterns. I do see a lot of…
understack
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1D non-maximum suppression in Python/scipy

Do you happen to have a 1D non-maximum suppression algorithm written in Python. I need it for making a Canny edge detector in Python using scipy that takes as input a 1D intensity vector. I've looked around on the web and there is a lot of…
citn
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What's a simple and efficient method for extracting line segments from a simple 2D image?

Specifically, I'm trying to extract all of the relevant line segments from screenshots of the game 'asteroids'. I've looked through the various methods for edge detection, but none seem to fit my problem for two reasons: They detect smooth…
zergylord
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ActionScript Face Detection

I'm looking to get the edges of user's head when the user is in front of a web-cam. I tried googling but to no avail. Can someone point me to some ActionScript examples for the same ? Peace \m/
codemaniac
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Implementing ridge detection

I'm trying to write a ridge detection algorithm, and all of the sources I've found seem to conflate edge detection with ridge detection. Right now, I've implemented the Canny edge detection algorithm, but it's not what I want: for example, given a…
Jesse Beder
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How to extract a specific section of an image using OpenCV in Python?

I am trying to extract a portion of an image by performing Canny edge detection. I have succesfully created a mask of that object. But when I perform a bitwise_and operation with the original image, to extract the foreground section, I am getting…
Boudhayan Dev
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Edge detection on colored background using OpenCV

I am using following code to detect edges from given document. private Mat edgeDetection(Mat src) { Mat edges = new Mat(); Imgproc.cvtColor(src, edges, Imgproc.COLOR_BGR2GRAY); Imgproc.GaussianBlur(edges, edges, new Size(5, 5), 0); …
Gunaseelan
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OpenCV canny edge detection is not working properly on ideal square

I am using this binary square image of 15*15 pixels. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 …
Aditya Kanade
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Point/Feature detection from upper and lower threshold of curvature - Curvilinear Quadrilateral Shape Detection algorithm

Is it possible to create a polygon from a set of points along a line with rough curvature, such that the points are selected between two values of curvature? I am attempting to retrieve an approximated curvilinear quadrilateral shape from a given…
chase
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Time complexity of Canny edge detector

I am currently writing a research paper about a new steganography algorithm. I have used canny edge detector at some point in my algorithm. In the paper I need to write the time complexity of the novel approach, which in turns depends on the time…
Mangat Rai Modi
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detecting object in Homogeneous Intensity image

I have image of Tiger's Pugmark (footprint impression) in mud. I want to detect the boundary of the pugmark but the image is uniform in intensity that is foreground and background cannot be distinguished based on intensity variations. What can i do…
Suvidha
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Need only one edge in Canny edge algorithm

When i use the canny edge algorithm, it produces the 2 edges opposite the thick colored line as expected, but i want only one edge to be displayed so as to make my line and curve detection algorithm much less complicated, any ideas on how i can make…
Gambit King
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DETECT the Edge of a Document in iPhoneSDK

I am looking something like attached image, How can I implement this in iPhoneSDK. Can anybody suggest me some open source API or Algorithm Code to detect the corners of captured image of a document. Some How, I got an open source API called OpenCV…
Ajay Sharma
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OpenCV - find blackboard edges on video and images

UPDATE You can find all the images I have for testing on my GitHub here: GitHub repository with sources There are also 2 videos, where the detection should work on as well ORIGINAL QUESTION I tried to use OpenCV 4.x.x to find the edges of a…
Lars
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openCV vs GIMP, edge detection fails in openCV

I am doing Sobel edge detection in openCV using the with following parameters: cv.Sobel(mat, edgemat, 1, 1) # mat -> source image # edgemat -> taget output image # 1 -> xorder (int) – Order of the derivative x # 1 -> yorder (int) – Order of the…
Xolve
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