如何使用 tkinter 在 tiff 图像上选择矩形区域并提取矩形内的像素值？

Question

I want to select a rectangle region over an image using mouse events and extract the values within the rectangle as a list or an array or a tuple. I have found no way of how to achieve this.

Does anyone know any way of achieving this or any tips or suggestions?

Thank you so much for reading.

Answer 1

The function to use is cv.selectROI

It can take different arguments. The simplest case is just taking an image (numpy array). Here's an example where also the window name is specified.

Personally I also prefer to use the fromCenter argument.

import numpy as np
import cv2 as cv

im = cv.imread(cv.samples.findFile("lena.jpg"))

bbox = cv.selectROI("lena", im, fromCenter=True)
cv.destroyWindow("lena")

print("region:", bbox)

(x,y,w,h) = bbox

subregion = im[y:y+h, x:x+w]
cv.imshow("lena subregion", subregion)
cv.waitKey(-1)
cv.destroyWindow("lena subregion")