OpenCV: How to Improve Contour Detection Accuracy in Noisy Handwritten Text Images?
I've hit a wall trying to I just started working with I've encountered a strange issue with I'm stuck on something that should probably be simple... This might be a silly question, but I’m working on a project that involves detecting contours in images of handwritten text using OpenCV 4.5.3 in Python. However, I’m facing challenges with noise affecting the accuracy of contour detection. When I apply edge detection using `cv2.Canny`, the resulting contours are often fragmented or completely missed, especially in areas with overlapping strokes or shadows. Here’s a snippet of my current approach: ```python import cv2 import numpy as np # Load image image = cv2.imread('handwritten_sample.jpg', cv2.IMREAD_GRAYSCALE) # Apply Gaussian blur to reduce noise blurred = cv2.GaussianBlur(image, (5, 5), 0) # Canny edge detection edges = cv2.Canny(blurred, 50, 150) # Find contours contours, _ = cv2.findContours(edges, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE) # Draw contours on the original image output = cv2.cvtColor(image, cv2.COLOR_GRAY2BGR) cv2.drawContours(output, contours, -1, (0, 255, 0), 2) cv2.imshow('Contours', output) cv2.waitKey(0) cv2.destroyAllWindows() ``` I’ve tried different kernel sizes for blurring and adjusted the thresholds in `cv2.Canny`, but the results are still not satisfactory. Many contours are either missing or inaccurately detected, leading to poor performance in downstream tasks like text recognition. I also considered using morphological operations like `cv2.morphologyEx` to enhance the edges or fill gaps but haven’t implemented it yet. Has anyone dealt with similar issues in contour detection for handwritten text? Any suggestions on preprocessing steps or adjustments I can make to improve the accuracy? Also, would it be beneficial to experiment with adaptive thresholding before applying edge detection? For context: I'm using Python on macOS. Has anyone else encountered this? For context: I'm using Python on Ubuntu. How would you solve this? My development environment is macOS. My development environment is Windows 10. Could this be a known issue? Cheers for any assistance!