Month: February 2023

Unable to use fitz with python 3.8

Posted on by jiseung

I use pymupdf to automatically sign my document. But the package name is pymupdf even the warning is that “fitz”  is not installed. If come across an error message like import fitz File “/home/phsamuel/p3/lib/python3.10/site-packages/fitz/__init__.py”, line 1, in <module> from frontend import * File “/home/phsamuel/p3/lib/python3.10/site-packages/frontend/__init__.py”, line 1, in <module> from .events import * File “/home/phsamuel/p3/lib/python3.10/site-packages/frontend/events/__init__.py”, line…

Create trackbar example in OpenCV

Posted on by jiseung

I was not aware that OpenCV has a built-in slider, I usually use cvui for that. But for simple application, the built-in function is more handy import cv2 cap=cv2.VideoCapture(0) low_H=99 high_H=125 def on_low_H_thresh_trackbar(var): global low_H low_H=var def on_high_H_thresh_trackbar(var): global high_H high_H=var cv2.namedWindow(‘frame’) cv2.createTrackbar(‘Low H’,’frame’,low_H,255,on_low_H_thresh_trackbar) cv2.createTrackbar(‘High H’,’frame’,high_H,255,on_high_H_thresh_trackbar) while True: ret, frame=cap.read() color=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV) frame=cv2.inRange(color,(low_H,0,0),(high_H,255,255)) cv2.imshow(‘frame’,frame) if cv2.waitKey(50)…

OpenCV and QT on 22.04

Posted on by jiseung

I got error Could not load the Qt platform plugin “xcb” in “” even though it was found Even following this did not solve the problem. But it seems that going headless works. That is, pip uninstall opencv-python pip install opencv-python-headless