opencv 用滑动条来控制 threshold

作用是，素描的时候可以清晰地看出明暗对比。

opencv_threshold.png

import numpy as np
import cv2 as cv

# todo 以后再看看其他的滤镜，然后再添加进来，最终是有一个比较丰富的功能。


def resize_img(img):
    return cv.resize(img, None, fx=0.6, fy=0.6, interpolation=cv.INTER_AREA)


def nothing(x):
    pass


img = cv.imread("d.png", 1)
print(img.shape, img.dtype, img.size)
if img.shape[0] > 1000:
    img = resize_img(img)

img2 = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
cv.namedWindow('image')

# 用一个滑动条来控制 threshold 的大小
cv.createTrackbar("thresh", 'image', 0, 255, nothing)

while 1:
    thresh = cv.getTrackbarPos('thresh', 'image')
    # THRESH_BINARY, THRESH_BINARY_INV, THRESH_TOZERO, THRESH_TOZERO_INV
    ret3, thresh3 = cv.threshold(img2, thresh, 255, cv.THRESH_BINARY)
    cv.imshow("image", thresh3)

    k = cv.waitKey(1) & 0xFF
    if k == ord('q'):           # press "Q" to quit.
        # todo save img before close window
        break

cv.destroyAllWindows()