1,081 questions
1
vote
0
answers
20
views
Draw a border(s) around a hand-drawn SVG path with fabric.js
I'm using fabric JS free drawing mode to generate a bunch of hand-drawn SVGs. I then composite these onto a canvas. I convert them to a bitmap Image for rendering so that I can easily union all of the ...
- 2,305
0
votes
0
answers
59
views
Detecting rectangular border in images
I am trying to detect the inner part of a rectangular border in images of engineering drawings to get rid of it. These images are scans of images so they are black and white (white background and ...
0
votes
2
answers
85
views
Finding a faint line in a very noisy image with variable background noise
I have a very noisy greyscale image where the noise level modulates along one axis. Within this image, there may be a very faint line of some unknown width. I want to be able to identify when this ...
0
votes
0
answers
81
views
OpenCV trouble with consistency: edge detection / contours
Here is a generalized example of the house photo's I am referring to. I’m using OpenCV to detect and outline the roof of a house in a set of images by drawing contours around the roof edges. The issue ...
- 1
2
votes
1
answer
720
views
How to detect edges in image using python
I'm having problems trying to detect edges in images corresponding to holes in a glass sample.
Images look like this:
images
Single sample:
Each image contains part of a hole that was cut into a ...
- 23
2
votes
1
answer
154
views
Horizontal Line detection and measure distance in between with OpenCV
Hi I'm quite new in OpenCV, I am currently trying to detect horizontal lines in an image using HoughLinesP function in opencv, in order to calculate the ratio between x and y.
The line detection ...
- 23
0
votes
0
answers
133
views
Create stroke around transparent image
I want to create a die-cut sticker design. In my app, user should be able to upload any png file with transparent background. App should create double border around the image, to look like a die-cut ...
- 111
-2
votes
2
answers
344
views
Detecting a contour in a noisy image
I am trying to detect the contour of the die edge in the picture, but there is an obstacle on the right top of the image.
Original picture:https://pan.quark.cn/s/0cdf6fe9784f
Whole dataset: https://...
- 7
0
votes
0
answers
60
views
OpenCV - Detect triangles within detected rectangle in real-time video
For a project I want to detect the edges of triangular shapes within a detected rectangular object (tray) in real-time on a Raspberry Pi IR camera, for the follow up to a next step.
For now I've ...
- 1
2
votes
0
answers
93
views
How do I calculate the width of hot steel from a row of pixel values?
Background:I want to get the width of the hot steel by manipulating a row of pixel values ,such as the green line in the picture.This pixel value change has been processed to be between 0 and 255.
...
- 49
0
votes
2
answers
57
views
Image not uploading using flask (shows no file selected when I click upload). IDE shows 302
I am learning flask, trying to write code for edge detection in an image, and let users upload the image, using flask. I believe I'm unable to upload the image correctly, it shows 'no file selected' ...
- 1
0
votes
0
answers
279
views
How to find contours from a Sobel edge detection image
I am doing this to apply Sobel edge detection to an image
# Sobel edge detection
grad_x = cv2.Sobel(blurred_image, cv2.CV_64F, 1, 0, ksize=3)
grad_y = cv2.Sobel(blurred_image, cv2.CV_64F, 0, 1, ksize=...
- 53
-1
votes
1
answer
108
views
Unable to get left and right road edge
I am trying to find the points representing the left and right edge of a road mask(binary image). I have tried using contour detection but it is giving contour of whole image(including upper and lower ...
- 3
1
vote
2
answers
177
views
edge detection and selection with with brightness differences
I have a liquid bow wave that is recorded by a high-speed camera. This gives me a lot of images that I want to analyze automatically. I want to determine the outer contour of the liquid and preferably ...
- 21
0
votes
0
answers
52
views
Edge detection shader (Passing 3 vertex positions to the shader program)
I've been trying to render the effect of having triangle faces in one solid colour, and their edges another, ideally I wanted a soft glow of a different colour on the edges. I looked around for some ...
- 1
1
vote
2
answers
398
views
Extracting vector line segments from an image
I'm trying to find the edges on satellite imagery. While I've tried using canny edge detection, I've found much better results by passing the imagery through a structured random forests model ...
- 77
0
votes
1
answer
210
views
Implementing Harris Corner detector, by following standard material, it ends up detecting edges
Hi Thanks for your attention, I'm trying to implement Harris Corner Detection Algorithm, and have been following the standard Algorithm given on most souces one of them being Wiki Page I follow all ...
- 622
1
vote
0
answers
54
views
I have an image which has a lot of rectangular smaller images on it. how to extract and save them in python?
I have a group of images. Each image is a collage of multiple images.
I want to extract all the smaller images from the collage. I have tried multiple edge detection algorithms. Please suggest an ...
2
votes
1
answer
42
views
check50 saying CS50 filter-more edges is not correct?
// Detect edges
void edges(int height, int width, RGBTRIPLE image[height][width])
{
// Copying
RGBTRIPLE copy[height][width];
for (int i = 0; i < height; i++)
{
for (int j = ...
0
votes
0
answers
28
views
Error in image dimensions while using edge detection model based resnets
import os
import cv2
import numpy as np
import matplotlib.pyplot as plt
from tensorflow.keras import layers, models
from tensorflow.keras.optimizers import Adam
# Define the Residual Block
def ...
0
votes
2
answers
807
views
Advice on preprocessing steps for edge detection on license plate images
I am currently working on a university project for which I want to explore different computer vision techniques. My goal is to do automatic number plate recognition (ALPR) on chinese license plates. ...
0
votes
1
answer
29
views
difference between png image saved after imshow and png from videocapture frame
I am trying to detect yellow colors from my usb camera image.i am using yellow mask to filter objects and draw rectangles around the found contours.
If I save frame obtained from usb camera and then ...
- 1
0
votes
1
answer
219
views
Is there a way to eliminate the disconnected elements of an image?
I'm working on surface roughness of an image, and I used the edge detection function from opencv, but it also detected the pores from the image. Is there a way to get rid of the pores?
picture of ...
0
votes
1
answer
83
views
OpenCV: Detection of clearly delineated object boundary failing
I have the following image:
I want to detect the edge of the document placed on the table in the image. I tried the following code (the earlier approaches are commented out).
def detectDocEdge(...
- 651
0
votes
0
answers
62
views
Getting lines composing a shape using Canny edge detection in OpenCV
I am trying to get a geometrical representation of an image (ultimately into a WKT string, but any geometrical encoding is fine). I'm using OpenCV's Canny edge detection method to detect edges, and ...
0
votes
1
answer
103
views
OpenCV: Multiple Lines Detected for Rectangular Edges and Incorrect 'y' Edge Drawing
I'm working with the OpenCV library in Python and trying to detect the long and short edges of a rectangular shape in an image. I have used the Canny edge detector and then applied the Hough transform ...
3
votes
1
answer
172
views
How to detect barely visible lines on the grayscale image and calculate their length
I am trying to write computer vision code based on the OpenCV library in Python to detect horizontal lines with intensity close to background. See example of the image below.
I have tried 2 ...
- 51
0
votes
0
answers
188
views
Detecting Ellipses and Rectangles in Edge-Detected Image using OpenCV (Python)
In my situation, I discovered the edges of an object that resembles a rectangle and has a shape similar to a rectangle. Now, when I take away the rectangular object, the edge takes on an ellipse shape....
0
votes
0
answers
61
views
How to delete the black background of this image and crop out the target part from it?
How can I remove the black background from this image and crop the label out?
I tried edge detection, but I found that due to the target being only on the right side of the image, the boundary cannot ...
0
votes
0
answers
257
views
Correct Thresholding for Canny algorithm, on physical variable
I'm trying to use Canny edge detection algorithm in python(newbie) for daily fields of temperature data on cartesian coordinates.
For example Temperature= size(X,Y,time), 365 days of temperature data ...
- 27
1
vote
1
answer
180
views
using terra::focal() with even sided weight matrix
i want to use the terra::focal() with an even sided matrix (e.g. to apply "Roberts cross" edge detection; https://en.wikipedia.org/wiki/Roberts_cross).
However, focal() only accepts windows ...
- 15
1
vote
2
answers
106
views
Accurately detect the semicircular region in the given grayscale image
I've an almost semicircular object in a grayscale image for which I intend to create a mask.
I've tried some preprocessing + edge detections + filtering. however, there are still some irregularities .
...
- 55
3
votes
1
answer
298
views
Python open-cv find lines in noisy image
I want to find the dark gray diagonal line in this
the background is quite noisy and has a gradient in brightness.
(The line is barely visible when opening the .png but if I read it as grayscale the ...
- 33
0
votes
0
answers
125
views
Detect the white background license plate region using opencv(Edge Detection, Contour Detection)
I want to detect the white number plate region using contour detection and edge detection using opencv
I have tried a variety of solutions. These work for sharp images but don't work for low res ...
- 121
0
votes
0
answers
845
views
How to I fix this? [ WARN:[email protected]] global loadsave.cpp:248 cv::findDecoder imread_('licensed-image.jpg'): can't open/read file: check file path/
I am trying to a write Python program for edge detection and I am getting these problems and errors and I don't understand why.
Here is my program:
import cv2
import numpy as np
# Load the image
...
1
vote
0
answers
209
views
OpenCV Python detect black rectangular area of film and draw contour around frame
I am trying to use opencv and python to detect the edges of a film frame to know it is in position to snap a picture with my raspberry pi camera. My plan is to detect the edges of a frame that must be ...
- 11
0
votes
0
answers
130
views
Find accurate approximate contour of a warped card with rounded corners with OpenCV
I have written an algorithm to find and extract a Magic card in an image based on using OpenCV functions FindContours and ApproxPolyDP. Essentially, I clean up the image (blur, adaptive threshold, etc....
- 106
0
votes
0
answers
278
views
Raspberry PI: Counting the raising and falling edge at a frequency?
I am reading this 1/0 pulse on a GPIO physical pin 22 and I am trying to count the number of pulses occurring in the frequency of 100. I have two questions:
I am reading and detecting the edges ...
- 4,534
0
votes
1
answer
329
views
Cube Edge detection
I am trying to get the edges of a cube in the image below using the Hough transform in the Scikit-Image library .
Update
Here is the code I am working with:
smoothed_image = filters.frangi(gray_image)...
- 33
0
votes
0
answers
384
views
Python edge detection of a fairly dark image with low contrast
My aim is to detect all the contours, then run a circular Hough transform on them, to detect the circles on them and display them on the base image, then follow up with other actions. I should point ...
- 1
0
votes
0
answers
284
views
How to smoothly interpolate and fill in edge detected closed shapes?
I'm working on segmentation of plant epithelial cells. My goal is to isolate cells from microCT scans and then run various metric analyses on them. Right now I am able to segment and edge detect these ...
- 1
1
vote
1
answer
271
views
Using OpenCV in Python, how do I get the extreme point of a distinct detected contour?
I want to detect a contour and draw its extreme points, my problem is how to get the extreme points from a distinct detected contour as the shape is not always continuous.
I want to detect the contour ...
- 32
-1
votes
1
answer
221
views
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 ...
- 1
0
votes
1
answer
126
views
How to detect and calculate angle of a prism from this image?
I am currently trying to detect the edge of a prism shape materials and find the angle of that shape.
I have an original image like this:
I wrote a Python program that detects the edge between ...
- 99
0
votes
1
answer
388
views
javascript edge detection on a video blob
I'm trying to record a video from a webcam, then to apply an edge detection filter to this video using openCV.js (properly included in my html file). The recording works, I'm doing it with WebRTC. It ...
- 31
0
votes
1
answer
586
views
In this image, how can I use OpenCV to detect "bubbles" while filtering the "blotches"?
I am working on a project to detect the size and number of bubbles on a surface. My current algorithm works okay, except on images that have dark blotches on them. These blotches are mistakenly ...
0
votes
0
answers
2k
views
AttributeError: module 'cv2.cuda' has no attribute 'createCannyEdgeDetector'
I have been trying to implement image edge detection using cuda in python and for that I was following this blog.
So after running the code block for 'OPENCV PYTHON CODE USING CPU AND GPU WITH CUDA' I ...
1
vote
3
answers
379
views
STEM image analysis using OpenCV
I am analyzing TEM/STEM scanned image. The white circles are the atoms whereas the black is the background. The captured image is noisy. The circle boundary is not clear.
Is there any way to enhance ...
- 21
2
votes
2
answers
1k
views
getting edges / lines of vertical lines in an image
Original Post
I have a batch of similar images which I need to analyze.
After
thresholding
hole filling using skimage.morphology.reconstruction (example of usage here)
image closing
I get something ...
- 450
0
votes
0
answers
49
views
How to increase the efficiency of edge detection to count the number of rocks of different sizes on a conveyor belt
Problem Statement:
I need to write a code to most closely approximate the number of rocks that fall within a speficied size range. (Eg 30-40mm, 40-50mm, 50-60mm, 60mm+)
I have written a code to do the ...
