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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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Image Segmentation From Edge Detection

How can i apply segmentation technique through edge detection in android? what i want to do is run edge detection on a picture and extract some part of choice from the picture. Could be a bitmap or a jpeg. Is this possible in android? is there a…
UriBaba
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Edge Detection Along Blood Vessel in Matlab

I am trying to specify a line across a blood vessel in an image, and then have matlab specify the edges of the vessel (which are contained within the line). The next part will be comparing changes in the distance between these edges over time (so…
SimonStern
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OpenCV to find specific co-ordinates in an image

I'm working on an iOS app with OpenCV. I am trying to locate the position of the box around the person. I would like to start by getting the width of the box. I'm converting the image to Greyscale and then using a Canny edge detector. Link to…
geekchic
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Get largest structure (Canny Edge Detection)?

I am using the library found at this link: https://code.google.com/p/simple-iphone-image-processing/ I implemented Image.h and Image.mm and I get the Canny Edge Detection filter by using this code: - (IBAction)findEdges { ImageWrapper…
SimplyKiwi
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2-D GABOR wavelet representation

Is their any way to Perform GABOR wavelet representation of an image in Python. I have searched google a lot but cannot find a satisfying solution. Please help
xor
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Need to apply edge filtering algorithm on series of images

i wanna write a code in matlab which will accept images from an implicitly given directory and apply Sobel edge detection algorithm on each image on-the-go. Please Help
Fabianski Benjamin
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Edge Detection on Screen

I have a edge collision problem with a simple game that i am developing. Its about throwing a coin across the screen. I am using the code below to detect edge collisions so i can make the coin bounce from the edges of the screen. Everything works as…
koraxis
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How to detect the end and start-point of an edge with OpenCV?

i really want to know what the best way of detecting and extracting the start and end-point of an edge is, if i got images like this, with different angles of the black material. I found some ideas which are using a gaussian blur and the…
Sebastian Boldt
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Scaling Laplacian of Gaussian Edge Detection

I am using Laplacian of Gaussian for edge detection using a combination of what is described in http://homepages.inf.ed.ac.uk/rbf/HIPR2/log.htm and http://wwwmath.tau.ac.il/~turkel/notes/Maini.pdf Simply put, I'm using this equation : for(int i =…
metsburg
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Edge change Ratio

I am working on Edge change Ratio Algorithm for Video shot Detection. I have the basic idea of the algorithm and have implemented a part of it using OpenCV which includes identifying edges using Canny's Algorithm. But I am confused about how to…
pratpor
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Lua: detect rising/falling edges in a bitfield

I'm calling a function that returns an integer which represents a bitfield of 16 binary inputs each of the colors can either be on or off. I'm trying to create a function to get the changes between the oldstate and the new state, e.g. function…
Ryan Leach
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Edge detection using fuzzy threshold value in matlab

Can someone explain why I am getting the following error in my code? I=imread('lena.jpg'); [M,N]=size(I); p = zeros(256,3); for ii=1:256 p(ii,1)=ii-1; end; p(:,2) = imhist(I); p (p(:,2)==0,:) = []; % remove zero entries in p % Calling Shannon…
pritha biswas
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Matlab: Extracting the line segments from the Canny Edge Detector

Is there a way to get all the line segments from the built in Canny edge detector in Matlab? edgeImage = edge(image, 'canny') <-- does Matlab have method to make the line segments in edgeImage accessible?
ElectronAnt
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WPF image tooltip edge detection

I'm a bit new to WPF but I'm having an issue were I'm trying to place a tooltip over an image or button with a background image. Basically what I'm trying to do is I want the tooltip to only show up where the image actually exists and not the…
Melky
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Separate edges from canny edge detector

I want to get a set of all 8-connected paths that are produced by canny edge detection algorithm so I can analyze them independently. Is there a way to do it using OpenCV or any other C++ library without having to implement it myself? I already have…
ButterDog
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