Chuanshuoge: opencv 16 image gradients

Wednesday, 17 March 2021

An image gradient is a directional change in the intensity or color in an image.

gray scale

Laplacian transform, edges are detected

sobelX detects edge along Y axis

sobelY detects edge along X axis

sobelXY detects all edges

#main.py

import numpy as np

import cv2

cap = cv2.VideoCapture("assets/Santa Barbara.mp4")

while True:

ret, frame = cap.read()

width = int(cap.get(3))

height = int(cap.get(4))

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

lap = cv2.Laplacian(gray, cv2.CV_64F, ksize=3)

lap = np.uint8(np.absolute(lap))

sobelX = cv2.Sobel(gray, cv2.CV_64F, 1, 0)

sobelY = cv2.Sobel(gray, cv2.CV_64F, 0, 1)

sobelX = np.uint8(np.absolute(sobelX))

sobelY = np.uint8(np.absolute(sobelY))

sobelCombined = cv2.bitwise_or(sobelX, sobelY)

cv2.imshow('frame', frame)

cv2.imshow('gray', gray)

cv2.imshow('laplacian', lap)

cv2.imshow('sobelX', sobelX)

cv2.imshow('sobelY', sobelY)

cv2.imshow('sobelCombined', sobelCombined)

if cv2.waitKey(1) == ord('q'):

break

if cv2.waitKey(1) == ord('p'):

# wait until any key is pressed

cv2.waitKey(-1)

cap.release()

cv2.destroyAllWindows()

reference:

Chuanshuoge