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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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Sobel Edge Detection output for 16bit grayscale image

I've seen many Sobel Edge Detecting Operations in C++ and C#, but I'm having great difficulty converting the code to operate on a 16bit graphic. Most of the code I've seen is programmed to operate on R.G.B style bitmaps. The graphic I have is in a…
Robert Koernke
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Edge detection on monochrome pictures - Java

I've got a ridiculously insane Linear Algebra professor at uni who asked us this last Friday to develop a programme in Java that loads a monochrome picture and then applies an edge-detecting filter on it. The problem is nobody in my class has got…
92AlanC
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What information is gained not starting an edge detection method with a Gaussian?

Full Disclaimer, this is my first attempt at edge detection so when responding assume I know about software but not necessarily about computer vision/related fields. I am reading about various edge detection methods. A natural first step in many of…
Carlos Bribiescas
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Detect and draw shape inside of available space between lines

My goal is to detect the different regions within a simple drawing constructed of various lines. Please click the following link to view a visual example of my goal for clarification. I am of course able to get the position of the drawn lines, but…
WalterB
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Building A Gaussian Blur?

I am trying to write my own (or at least gain a better understanding of) Gaussian Blur filter using Python 2.7. I would really appreciate some direction. Everywhere else I have looked just uses built-ins...
KLS10
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Graph search algorithm without starting point

I have an edge map of a scene and would like to extract the edge which best separates the sky and terrain. This seems to be well framed as a graph traversal problem. However, popular search algorithms such as A* are reliant upon the use of a…
eagle34
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How do I crop/resize a background/border out of an image with GraphicsMagick

I have some images in a large set of images that have a white (or black) border that surrounds the image itself. How can I... Crop the image to a size without said background/border Resize the image to fill a given output size centered. For…
Tracker1
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Matching photographed image with screenshot (or generated image based on data model)

first of all, I have to say I'm new to the field of computervision and I'm currently facing a problem, I tried to solve with opencv (Java Wrapper) without success. Basicly I have a picture of a part from a Model taken by a camera (different angles,…
gemorra
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Making the edges more bright and narrow using opencv

I have two images as follows. I need to convert first image into the second. I am using Opencv. What should I use? Canny is giving the following response, so I don't think it will work. Any other suggestion.
user3747190
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Python OpenCV detect circles from black and white mask

I have created a black and white mask using various OpenCV filters. There are four circles that are clearly visible I am trying to outline these circles using HoughCircles, but it gives many false positives and generally bad results: circles =…
Jacob Brunson
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OpenCV Background Segmentation/Subtraction From Single Image

I'm looking for a bit of guidance... I have a single image of a passport photo. What I would like to do is separate the person and the background. I will then analyse the background colour, pattern, etc. I've done some research into segmentation and…
LKB
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Edge Detection using Opencv createTrackbar

I am new in image processing and attempting to write a Scala program for edge detection in an image. I tried this sample in here: https://code.ros.org/trac/opencv/browser/trunk/opencv/samples/cpp/edge.cpp?rev=4079 but there are some problems with my…
Mahsa
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Find edge orientations of strongly unclosed edges in unsharp point clouds

I want to extract orientations of strongly unclosed edges from a binary image. The image consists of blobs, blob rows and unsharp edges as shown below. In the end every pixel should be assigned to an information about the orientation of the edge. If…
user3885854
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OpenCV Remove smaller contours

I want to identify and extract the contour of the largest leaf of the following image using OpenCV and C++. I applied Canny edge detector to the image and got the following result. Canny(img_src, img_edge_detected, 20, 60, 3); Now I want to…
Grant
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how can i apply blob extraction on an edge image?

I have an edge image and I want to do Blob (object) detection , i have tried do typical blob analysis with CvBlob but the result is poor(i'm working with OPENCV ) here is an example of and input image. http://postimg.org/image/6uvzhdqad/
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