edge-detection

问题 I'm writing a program that asks the user to choose between Prewitt and Sobel image filters to detect edges of objects of an image. I must use their filter templates, not the edge function. The user also tells if he wants to detect 'horizontal', 'vertical' or 'diagonal' edges. My problem is theoretical rather than about programming. In my notes i've got that to compute the magnitude of the gradient at each pixel, it is often approximated as sqrt(Gx^2 + Gy^2) where Gx would be the vertical

问题 I have been working with OpenCV for a fairly short time, and have performed Canny Edge Detection on an image, and also performed dilation after that to further separate the object (in my case a square) from the background. My problem, now is to identify graspable regions in 2D using an algorithm that requires me to handle co-ordinates of the points in those edges. Is there any way I can use OpenCV to get the co-ordinates of the corners so I can find the equation of the lines forming the edge

问题 I have been working with OpenCV for a fairly short time, and have performed Canny Edge Detection on an image, and also performed dilation after that to further separate the object (in my case a square) from the background. My problem, now is to identify graspable regions in 2D using an algorithm that requires me to handle co-ordinates of the points in those edges. Is there any way I can use OpenCV to get the co-ordinates of the corners so I can find the equation of the lines forming the edge

问题 I have an image and I want to create an edge histogram. I divide the image into 1100 image-blocks and try to find edge and its direction (horisontal, vertical, 45° diagonal, 135° diagonal or nondirectional) in each block. How can I extract that information about edges? Do you have any ideas? Regards! 回答1: I found the answer in this paper: Efficient Use of MPEG-7 Edge Histogram Descriptor by Won. My goal was to find following edges: Won divide each Image Block into 4 parts, calculate the

问题 For my college project I need to identify a species of a plant from plant leaf shape by detecting edges of a leaf. (I use OpenCV 2.4.9 and C++), but the source image has taken in the real environment of the plant and has more than one leaf. See the below example image. So here I need to extract the edge pattern of just one leaf to process further. Using Canny Edge Detector I can identify edges of the whole image. But I don't know how to proceed from here to extract edge pattern of just one

问题 Hi currently i am working on an OCR reading app where i have successfully able to capture the card image by using AVFoundation framework. For next step, i need to find out edges of the card , so that i can crop the card image from main captured image & later i can sent it to OCR engine for processing. The main problem is now to find the edges of the card & i am using below code(taken from another open source project) which uses OpenCV for this purpose.It is working fine if the card is pure

问题 I have an image which I want to detect edges on that. I found Canny has been used a lot ( I don't know whether I have a better option than that). I have set the values as follow: Imgproc.Canny(img, img, 10, 100, 3,true) I've changed threshold values but don't see that much of a change in my image. Can anyone explain to me if there is a logical way to figure out numbers for threshold values (my image is gray scale) Thank you... 回答1: I think this should be taken case by case, if you post some

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 years ago . I have an image, taken from a live webcam, and I want to be able to detect a specific object in the image and extract that portion of it to do some further processing. Specifically, the image would be of a game board, let's say for the purposes of this question that it's a Sudoku game board. My initial approach

问题 I am working with openCV on Android platform. With the tremendous help from this community and techies, I am able to successfully detect a sheet out of the image. These are the step I used. 1.Imgproc.cvtColor() 2.Imgproc.Canny() 3.Imgproc.GausianBlur() 4.Imgproc.findContours() 5.Imgproc.approxPolyDP() 6.findLargestRectangle() 7.find the vertices of the rectangle 8.find the vertices of the rectangle top-left anticlockwise order using center of mass approach 9.find the height and width of the

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . I have this image of a battery: I would like to determine the dimensions of the battery (in pixels). The problem I have is that the battery is rotated by an unknown angle. How can I detect the dimensions of this rotated battery? I was thinking of these algorithmic steps: First, I