如何计算图像中每个矩形中的白色像素？

Question

我有数千张 1000X2000 像素的图像，我只想计算 100X200 图像的每个小 windows 中的白色像素，并在向量数组中写入计数请问我如何通过 python openCV 做到这一点？

示例图片：

Answer 1

Opencv 和 Numpy 在这方面做得很好。您可以使用 numpy 切片来定位每个框，并 numpy.sum 计算切片中白色像素的数量。

import cv2
import numpy as np

# count white pixels per box
def boxCount(img, bw, bh):
    # declare output list
    counts = [];
    h, w = img.shape[:2];
    for y in range(0, h - bh + 1, bh):
        line = [];
        for x in range(0, w - bw + 1, bw):
            # slice out box
            box = img[y:y+bh, x:x+bw];

            # count
            count = np.sum(box == 255);
            line.append(count);
        counts.append(line);
    return counts;


# load image
img = cv2.imread("jump.png");
img = cv2.resize(img, (1000, 2000));
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY);

# define box search params
box_width = 100;
box_height = 200;

# get counts
counts = boxCount(img, box_width, box_height);
for line in counts:
    print(line);

如何计算图像中每个矩形中的白色像素？

how to counting white pixels in every rectangle in over image?

opencv

numpy

image-processing

computer-vision

image-preprocessing