I am using opencv 4.60, and I am attempting the simplest of things, drawing on a black image.

I am using stereoRectifyUncalibrated() method which generates two homography matrices H1 and H2 for image rectification. I have checked both H1 and H2 by displaying the results of the rectified images and seems good. However, I now need to compute the new rectified P1 and P2 matrices and thereafter the new Q matrix for 3D projection.
Here comes the issue: the rectification matrices R1 and R2 derived from R = invK * H * K is not a true rotation (R.T *R != Identity AND det R =1)
I am not able to compute the new projection centres pertaining to the Q matrix based on the computed homographies.

The first picture below is the original image, showing a net. The ropes in the net are of two types: thick and thin. It is necessary to distinguish which are thick ropes and which are thin ropes through OpenCV, and measure their angles respectively.

my program generates 2D contours using scipy.spatial ConvexHull. I get the same error for any hull

I am working on a project using OpenCV in Python to process images and detect contours. I have a function get_contours which takes several parameters, including minArea to filter out small contours. However, it seems that the minArea parameter is not taking effect when I call the function.
Here is my get_contours function in my_utils.py:
import cv2
import numpy as np

I’m trying to run OpenCV in a remote Docker container and display image windows, but I’m encountering issues. Here’s my setup:

I am trying to create a function using OpenCV that overlays an image onto a defined polygon (using 4 points) in another image. How can I handle the rotation of the image so that the overlay looks natural?
Example:
enter image description here
My code:

I need code that extracts text inside the green rectangle below. Can someone please help me with it? I had to strike out some words in the middle, that would be some textual characters there.
enter image description here

I want to achieve a bumpy feeling in the brushstrokes of oil painting, and the desired brushstroke effect is like waves

I want to clearly identify and draw the contour of two adjacent liquid layer, the sample image is as shown in the link
sample image