Stack Overflow
Stack Overflow

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
1057 questions
-1
votes
1 answer

How to detect gas station prices with python and OpenCV

I am trying to create a python script to extract gas price information from gas station totems. I'm thinking about using number recognition that is built in opencv-python, but firstly I need to somehow extract the totem from the picture itself. For…
opth
  • 1
  • 2
-1
votes
1 answer

How to detect edge in complex flame image using Python?

For my combustion related research I need to detect a flame front using any kind of edge detection. I have applied a combination of filters and thresholding steps to achieve my goal, however they proof to be inaccurate. Any idea is welcome! I have a…
Luuk Altenburg
  • 1
  • 1
-1
votes
1 answer

Finding distance between two irregular edges in a binary image

I'm trying to find the distance between two irregular edges in a Binary image at various intervals. I want to find the distance/ length of the red line (the distance between the black edge at the bottom to the black peak edge at the top) Not sure…
Starcode1619
  • 55
  • 7
-1
votes
1 answer

How can I detect an edge and represent that edge as a line of specified pixel thickness?

I have an iOS app that does image processing. The images are black background with a single solid white body that is a complicated shape. I can use openCV or CIEdges filter to get an image of the edge as shown below. But the thickness of that edge…
Bob
  • 45
  • 1
  • 5
-1
votes
2 answers

Matplotlib shows black & white image as gray

I have a simple code that loads RGB image, converts it to grayscale and then runs Canny edge detector algorithm. The returned image contains only 0 and 255 values, and yet when showing the image using matplotlib it shows the image as grayscale (and…
ChikChak
  • 936
  • 19
  • 44
-1
votes
1 answer

Detect very faint circles, not clear edge. Hough Transform not working

I'm doing work where the output is a faint large circle. I can see the circle is there, and I know from the experiment that it is a uniform solid circle. But I am having issues recognising it with python. I tried using Hough Transforms, because the…
James Blackwell
  • 29
  • 9
-1
votes
2 answers

Which edge detector

I need to detect the edges of an object (like a hand) which I know it is located in the center of the photo. My most concern is the reliability of the result, (because I want to use it for commercial purposes), currently I am working with Canny…
Nima
  • 969
  • 3
  • 10
  • 14
-1
votes
1 answer

Is there a way to access the coordinated of the required edge in OpenCV Python?

Image for setting the reference In the image shown, i need to detect the edge and draw a straight line through the points connecting the edges on both the sides and set this line as the origin for measuring the position of the indents on the key. I…
Ashwini
  • 31
  • 1
  • 4
-1
votes
1 answer

Is there any edge detection in opencv(python) with white background?

Is there any edge detection filter in OpenCV like canny but I want the background to be white and the edges in black color
Amirhossein Foroughi
  • 13
  • 2
  • 4
-1
votes
1 answer

Fill the circular paths in image

I have many images consisting of circles(varying from 1 to 4) in each image. I am trying to get a clear circle images by filling the missed pixels along the circle path. I have tried Hough-transform, but its parameters are image specific: for each…
Rajesh
  • 221
  • 4
  • 16
-1
votes
1 answer

Find arc() edge while using p5js

I can't understand how i can find arc() edge. Currently i control White line with mouse. And goal is to change that line to Red, if mouse is outside Yellow zone. I use this code: arc( xloc, yloc, size - i * steps, size - i * steps, 60, 90 );
Pastuh
  • 376
  • 2
  • 12
-1
votes
1 answer

Deblurring an image in order to perform edge detection

I have this image: I am trying to put the background into focus in order to perform edge-detection on the image. What would be the methods available to me (either on space/frequency filed)? What I tried is the following: kernel =…
Stefano Pozzi
  • 529
  • 2
  • 10
  • 26
-1
votes
2 answers

Any possibility to get CGPoint from particular color of UIImage in iOS?

Consider the below sample irregular shape of images.How to get CGPoint from the border color. All are separate images. i'm trying to get border path.
Karuppasamy Pandian
  • 123
  • 8
-1
votes
1 answer

Edge Detection in Frequency Domain

How to apply filter to detect edges in Frequency Domain? I have applied the Discrete Cosine Transform to the input image. I don't know how to apply filter to detect the edges. Can anyone please help to detect the edges?
Jeyanth
  • 531
  • 2
  • 6
  • 19
-1
votes
1 answer

Eliminate all vertical and diagonal lines in MATLAB

Here is the input image 5.png: Here is my code: clear all; close all; clc; %Input Image A = imread('C:\Users\efu\Desktop\5.png'); % figure, imshow(A); C=medfilt2(A,[3 5]); % figure,imshow(C); D=imfill(C); % figure,imshow(D); %Image obtained…
Mohammad Yakub
  • 7
  • 1
  • 7
1 2 3
…
70 71