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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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Edge detection issue using OpenCV library

I am working on a project on image processing. I need to segment only the required object from the image and make the background white. For this I am detecting the edges in the image and then finding contours. I then draw the contour with the…
shreya
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Finding Shoulder and Neck points of Body

I need to find the shoulder points(humans body) of the image need help how to identify the coordinates, I am able to get the edges of the human body using imagemagick but having difficulties in finding Shoulder points A,B and neck point C. Original…
alianjum0
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Zoom in to an image while running getpts to mark correctly in MATLAB

I am marking the edge points on an image. The size is large, and hence marking the correct edge is difficult on my screen. I use 'getpts' to mark points. I want to do the following: 1. Mark the points in first iteration approximately. 2. Move the…
Prashant
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Separating an image into components using an edge detection program with opencv libraries for processing

image I want to detect edges from: click here edges drawn by finding canny edges in program: click here I am using the opencv library with processing so that I can perform edge detection in order to split my image into different objects /…
mrrussel
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imshow() error: Doesn't show edge image

what's wrong with the code below? >> x = imread('D:\Database\vehicle\35\1.jpg'); >> x1 = rgb2gray(x); >> x2 = edge(x1); >> imshow(x2); it gives this error: Error using ==> iptcheckinput Function IMAGEDISPLAYVALIDATEPARAMS expected its first…
Hadi GhahremanNezhad
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Sobel edge-detection, weird output

I´m trying to implement a Sobel algorithm for edge-detection for a YUV camera stream. Initially it seems quite easy but I´m not sure if this approach is correct: I´m applying the filter just to the Y pixel component and doing U and V = 0 (black and…
joe
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Flawed contour detection in an image python opencv

I would like to detect the contour of the giant black blob in the following image: So I used Canny edge detection to find the edges using the following code: edged = cv2.Canny(image, 30, 200) Then, when I try to find the contour, it gives me only…
Shalin Shah
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Enhanced Edge Detection algorithm in Image Processing

I am trying to detect filled shapes (mainly texts) from an image using edge detection algorithms like Sobel, Canny, Prewitt, Roberts etc. I am using C# as my programming language. Image can contain texts of different sizes. The result I am getting…
Umair Jameel
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Canny Edge Detection (Android OpenCV) app unfortunately stops

@Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == R.id.Canny_Edge) //Unfortunately stops the app when we use this option { ImageView i = (ImageView)…
user5766922
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Detecting rising edge synchronization of 2 different clocks

How do you detect rising edge synchronization of 2 different clocks(different frequencies) in VHDL programming using Xilinx software? There is a main clock of frequency 31.845 Mhz , and another clock of frequency 29.972 Mhz. So the basic aim is to…
KVK
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How can i show all edges in monogame?

I am using Monogame 3.5 and i have simple model of cube. I use BasicEffect to draw it. I want it transparent so i use effect.Alpha = 0.5f. Is it possible to show all edges something like on picture?
Pavol
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Edge points sampling in shape context

I'm recently preparing to use shape context and SVM to do character recognition. The histograms in shape context are considered as feature vectors of characters. However, after edge detection, how to sample the edge points of two characters' edges…
Paler
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how to remove the edge of an image after edge extraction using MATLAB?

I have an image in gray scale and I would like to remove the edge that is extracted by using an edge extraction method in MATLAB. Is it possible to do it? Below is my code that perform the edge extraction ： %load the image A=imread('MikuBW.jpg'); …
wesley
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how to autocrop business card images taken from camera using opencv in android

I am developing an app that captures a business card using custom android camera and then i need to autocrop the unwanted space in android and then store the image . I am using opencv for this. All examples i am seeing are in python . I need it in…
Mohamed Ibrahim
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Is here any way to find out whether an image is blurry or not using Laplacian operator

I am working on this project where I have to automate the sharpness calculation of an camera taken image without actually looking a the image. I have tried many detection methods, but finally I am going further with Laplacian operator using openCV.…
Ankit
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