# \#canny **URL:** https://forum.opencv.org/tag/canny/135.md [Latest](https://forum.opencv.org/latest.md) · [Categories](https://forum.opencv.org/categories.md) · [Tags](https://forum.opencv.org/tags.md) --- ## [Problem When using canny edge detection, black picture returned](https://forum.opencv.org/t/problem-when-using-canny-edge-detection-black-picture-returned/20234)
**Author:** [@Ricky\_W](https://forum.opencv.org/u/Ricky_W)\ **Replies:** 1\ **Last updated:** [February 17, 2025, 3:30am UTC](https://forum.opencv.org/t/problem-when-using-canny-edge-detection-black-picture-returned/20234 "2025-02-17T03:30:32Z")
I am creating a program to give me a trackbar that can adjust the value of minv and maxv for the canny edge detection. Strangely, when I not include any resizing into it, it worked. When I resized the picture all it does… --- ## [Does get pose estimation on ball or spherical shape possible on tomato?](https://forum.opencv.org/t/does-get-pose-estimation-on-ball-or-spherical-shape-possible-on-tomato/18364)
**Author:** [@thesharkgeek](https://forum.opencv.org/u/thesharkgeek)\ **Replies:** 1\ **Last updated:** [July 28, 2024, 9:06am UTC](https://forum.opencv.org/t/does-get-pose-estimation-on-ball-or-spherical-shape-possible-on-tomato/18364 "2024-07-28T09:06:46Z")
Hi, im looking for a solution for my last assignment in polytechnic. I already implement canny edge and centroid estimate radius with some smoothing gaussian, deque every 2 sec is bit slow but can get job done for singl… --- ## [Edge detection and contour drawing on some part of the image](https://forum.opencv.org/t/edge-detection-and-contour-drawing-on-some-part-of-the-image/17060)
**Author:** [@Manz](https://forum.opencv.org/u/Manz)\ **Replies:** 0\ **Last updated:** [March 28, 2024, 5:47am UTC](https://forum.opencv.org/t/edge-detection-and-contour-drawing-on-some-part-of-the-image/17060 "2024-03-28T05:47:45Z")
the output u can see over there the edges on some of the window are discontinued which i need to detect and draw contour because of the tree being overlaid on them . #include #incl… --- ## [Edge detection of a 7x7 px image using Canny algorithm](https://forum.opencv.org/t/edge-detection-of-a-7x7-px-image-using-canny-algorithm/16814)
**Author:** [@D\_T\_NGUY\_N\_D\_C](https://forum.opencv.org/u/D_T_NGUY_N_D_C)\ **Replies:** 0\ **Last updated:** [March 14, 2024, 3:16pm UTC](https://forum.opencv.org/t/edge-detection-of-a-7x7-px-image-using-canny-algorithm/16814 "2024-03-14T15:16:24Z")
I have a 7x7 px image matrix. I want to use the Canny algorithm to detect edges. Below is my code: #include "opencv2/opencv.hpp" using namespace cv; using namespace std; int main() { Mat src\_img; Mat src = (Mat\_ \ **Author:** [@Me17](https://forum.opencv.org/u/Me17)\ **Replies:** 6\ **Last updated:** [June 23, 2023, 12:54pm UTC](https://forum.opencv.org/t/how-to-determine-the-blurness-of-an-image-after-using-the-canny-filter/13614 "2023-06-23T12:54:57Z") I would like to get a “blurness” value after using the cannyfilter on a siemensstar image, to check the blurness level. After usind the canny filter the images looks like these: Question: How can I determine now wh… --- ## [Convert the black and white image after canny edge detection to color image](https://forum.opencv.org/t/convert-the-black-and-white-image-after-canny-edge-detection-to-color-image/6660)
**Author:** [@Mk\_Veee](https://forum.opencv.org/u/Mk_Veee)\ **Replies:** 7\ **Last updated:** [December 23, 2021, 3:49am UTC](https://forum.opencv.org/t/convert-the-black-and-white-image-after-canny-edge-detection-to-color-image/6660 "2021-12-23T03:49:54Z")
import cv2 import sys import numpy as np from matplotlib import pyplot as plt ### First way of cropping and edge detection ​ img = cv2.imread("plug.jpeg") if img is None: sys.exit("Could not show image") rsz\_img =… --- ## [Bent pins in connector](https://forum.opencv.org/t/bent-pins-in-connector/4133)
**Author:** [@Antrac1t](https://forum.opencv.org/u/Antrac1t)\ **Replies:** 2\ **Last updated:** [July 13, 2021, 1:00pm UTC](https://forum.opencv.org/t/bent-pins-in-connector/4133 "2021-07-13T13:00:54Z")
Hi, I started working on checking data connector for servers where we facing with bent pins problems (just edge pins can be bent) and sometimes with foam contamination (part of foam cover 1-n pins). Part of first probl… --- ## [Railway detection with noisy input](https://forum.opencv.org/t/railway-detection-with-noisy-input/2231)
**Author:** [@Guilherme\_Augusto](https://forum.opencv.org/u/Guilherme_Augusto)\ **Replies:** 4\ **Last updated:** [March 18, 2021, 9:24pm UTC](https://forum.opencv.org/t/railway-detection-with-noisy-input/2231 "2021-03-18T21:24:17Z")
I’m working on a railway detection algorithm with the following steps : Get the frame and turn it into grayscale. Apply Gaussian blur. Apply Sobel operator on x-axis. Apply Canny edge detector. Apply Hough-transform to…