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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 detect the center of each "block" in an image (matrix) in Python?

See the image below, there are 9 "blocks" and I wish to detect their centers
Venn
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MATLAB extractHOGFeatures returns empty struct

I am working on a Computer Vision project of extracting the digits from an image. After a bit of pre-processing, following is my image: I performed sobel edge detection and some other steps and extracted the digits from the image. Now when I apply…
aradhak
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MATLAB: single direction edge detection

I'm trying to use edge detection to find an uneven horizontal edge that is always bright on top and dark on the bottom. I have had decent luck with canny edge detecting but keep picking up other edges which are dark on the top and light on the…
user3470496
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Image has white border after Sobel Edge Detection

I try to find edge of image. The my main problem is, why my edge detection has white border? Here the code : public static BufferedImage executeSobelEdgeDetection(BufferedImage inputImage, int threshold) { int width = inputImage.getWidth(); …
Mr. Mike
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How to implement laplacian edge detection in verilog HDL

I want to implement laplacian edge detection in verilog HDl. Since it is a second order derivative, can anyone please tell me in what way can I implement it in verilog HDL language to a frame?
Sara
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Find vertex from a object by using vertex detection

I would like to find all vertex (e.g. return x, y positions) for the black object. I will use Java and JavaCV to implements. Is there any API or algorithm can help? Sorry for not enough reputation to post images. I post the link here. The original…
user3526130
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Calculating a bottle height and two diameter with OpenCv- Edge Detection

I have graduate project about calculate software with OpenCv. Firstly take a grey photo with webcam then detect the edge of bottle. The head and buttom side edge detect. Then calculate a value the bottle height with pixel. Getting reference form…
sszn
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How to get that when Frame Edge Touches another Frame Edge?

I have two rectangle as show below, both can rotate both can be resized. Now my question is, whenever yellow will move towards white Rectangle which is before 5px, Green rect edge. I should be notified when yellow rect will touch the white rect…
Sanoj Kashyap
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Which edge detection algorithm in OpenCV suitable for detecting objects?

I have to make a bot which has to overcome obstacles autonomously in an arena that will be filled with rocks. The bot has to find its way through this area and reach the end point. I am thinking of using edge detector operators like canny and sobel…
user2547319
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Clear path detection using edge detection

I want to create an application where a user can detect an unobstructed path using an Android mobile phone. I used a Gaussian filter for smoothing and then used canny edge detection to detect edges. I thought if I could find the concentration of…
Madz
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License plate detection

My task is to pin-point where is the plate number in an image. The image does not only contain the plate number. It may contain the whole car or anything. I used gaussian blur then grayscale then contrast then laplacian of gaussian to detect the…
Eunichi
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Image processing Error in MATLAB

I was given a defined set of images (.png), I am supposed to detect each images Edges, then apply some image processing, but I have a problem. First I an image array as follows : imgArray = {'image_1.png','image_2.png','image_3.png'} Then applied…
user1111726
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Mask the frosted part of a coin (the shape)

I need to automatically recognise any scratches of a coin, that are on the "clear" part (not the shape). I have used edge detection to create an outline of the shape, and now I am thinking of using masking to completely remove it, allowing me then…
Ioanna Deroukaki
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Is there a way to guarantee a certain number of lines detected with cv2.HoughLines()?

This question is an extension to my previous question asking about how to detect a pool table's corners. I have found the outline of a pool table, and I have managed to apply the Hough transform on the outline. The result of this Hough transform is…
user15936471
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Edge linking in Matlab

I am trying to link the edges in images like the image below: I've tried using dilation/erosion operations but the result isn't good. Is there any other way to link the edges? Here is the original image:
Katerina T
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