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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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problem with combining RGB binary image

im doing an edge detection which will detect edges of each RGB channel and then combine them to show it as a final output. im now having a problem with combining the three as it doesnt show me a binary image, instead it has some colors on it. i have…
gerry chocolatos
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How to change color of edge in MATLAB?

I have a script which takes an image to and applies some edge detection methods such as canny, sobel and log to it. When I run the file, a figure is drawn where the edges are white. Is there a way to change the color of the edges to a preferred…
Rajan
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Automatic ROI/rectangle recognition

I want to be able to pass on multiple images to python and detect the contour of the object in the picture. The pictures all represent money bills, hence the ROI is always going to be rectangular. Whatever ive tried, im not able to exactly detect…
Jacques
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License plate horizontal location

A horizontal projection profile is defined as the vector of the sums of the pixel intensities over each row. The image below shows a graph representation of the horizontal projection of the edge image, where the peaks of the graph indicate regions…
kogami2012
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Opencv-structured-forest or Fast-edge-detection (Android onPreviewFrame) too slow

I am using Java wrapper class to do this feature by opencv extra modules(Ximgproc) . this is the code below, Mat resizeMat = /* frames from android camera */ ; StructuredEdgeDetection pDollar =…
Shyam Kumar
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How to remove values on Edge and above Edge?

The resulting image needs to remove values on the strong vertical edges and above edge(black region) as they are not region of interest. Therefore, Edge detection applied.BW shows result of edge detection, size of BW(image size) is different with…
AI_NA
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Detecting Edges in a Region on Screen

Without getting into too much detail, I need to detect and trace an edge where there is a significant contrast change - but only in a small region of the screen. Is there a library that selects a region of interest, then traces it somehow? I'm doing…
Alex Borg
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CPP OpenCV - Trying to crop image according to its edges

I need to crop an image according to the edges i find(with a given epsilon) I have following the following instructions: Opencv c++ detect and crop white region on image with one change - i am trying to find the rectangle according to the edges…
user1322801
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Find corner coordinates in image using openCV

I'm new to image processing and hope someone can help/guide me in the right direction. So I have a picture in black/white and I want to find the corner coordinates of the inner black part of the preprocessed picture. My question is what kind of…
hfalk
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3D point cloud edge or wrap detection

after a segmentation step, I would like to detect the edge of every point cloud object in my scene. So does anyone know some alternative to do this in python?
mee
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Binary image is not displayed

I'm doing an image detection which I have to process on each red, green, and blue element to get the edge map (binary image in black and white form) and combine them become one to show the output. After I extract the element of each red, green, and…
gerry chocolatos
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How can I detect start and end points of an edge with Aforge C#

I am currently detecting the corners of an image using SusanCornersDetector class from Aforge. What I wanted to get is the set of edges from an image by pairing the corners that I got from SusanCornersDetector. Like: SusanCornersDetector scd = new…
user8595351
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how sobel operator works

i read https://en.wikipedia.org/wiki/Sobel_operator Say , we want to detect horizontal edges in a grey scale image. Please Note - i have written matrix as sequence of rows. Question 1 ) Then I should take [1,0,-1; 2,0,-2 ; 1,0,-1] (from Gx = matrix…
user1371666
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Android Studio Opencv Canny detection

I want to add canny detection for an image when I click to button. I cant take any exception but emilator stops working without starting. buton2.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { …
Altan YEŞİLKURT
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How can I modify this code so that canny edge detector can detect this red mark line?

I take an image using Microsoft Kinect. But all time canny edge detector missed that line. I don't know why? how can I detect this line? I attached here raw depth image & output of canny. Don't hesitate about black depth image. it works. When you…
sufian ahmed
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