我想遍歷圖像并在圖像中繪制邊界框，然后使用圖像的子矩陣進行一些計算。我試圖讓下面的代碼在python中工作C++（取自這里的答案）。for (int y = 0; y<resizedImage.cols - 32; y += 32) { for (int x = 0; x<resizedImage.rows - 32; x += 32) { // get the average for the whole 32x32 block Rect roi(x, y, 32, 32); Scalar mean, dev; meanStdDev(resizedImage(roi), mean, dev); // mean[0] is the mean of the first channel, gray scale value; }}我想計算平均值并打印 ROI。這是我使用Pillow的Python代碼。我用于代碼的圖像在這里。image = Image.open(path)draw = ImageDraw.Draw(image)step = 64original_rows, original_cols = image.sizerows = original_rows + stepcols = original_cols + stepimage_arr = np.asarray(image)for row in range(0, rows, step): if row <= rows - step: for col in range(0, cols, step): if col <= cols - step: box = (col,row,step,step) region = image.crop(box) print(np.asarray(region)) draw.rectangle([col,row,step,step], width = 1, outline="#FFFFFF")image.show()由于圖像是，而我的步驟是，我期望打印16個區(qū)域，但它只打印第一個區(qū)域，其余的似乎是空的（看看Pillow對象的大?。?。我也不明白為什么它打印了24次（），而我期待16次。這是我的輸出：256 x 25664<PIL.Image.Image>[[[255 0 0 255] [255 0 0 255] [255 0 0 255] ... [255 0 0 255] [255 0 0 255] [255 0 0 255]]]]<PIL.Image.Image image mode=RGBA size=0x64 at 0x11937F5F8><PIL.Image.Image image mode=RGBA size=0x64 at 0x10E9A4748><PIL.Image.Image image mode=RGBA size=0x64 at 0x11937F3C8><PIL.Image.Image image mode=RGBA size=0x64 at 0x1193618D0><PIL.Image.Image image mode=RGBA size=64x0 at 0x11937F5F8><PIL.Image.Image image mode=RGBA size=0x0 at 0x10E9A4748><PIL.Image.Image image mode=RGBA size=0x0 at 0x11937F3C8><PIL.Image.Image image mode=RGBA size=0x0 at 0x1193618D0><PIL.Image.Image image mode=RGBA size=0x0 at 0x11937F5F8><PIL.Image.Image image mode=RGBA size=64x0 at 0x10E9A4748><PIL.Image.Image image mode=RGBA size=0x0 at 0x11937F3C8><PIL.Image.Image image mode=RGBA size=0x0 at 0x1193618D0>按照這里的答案，我明白我需要在打開圖像后立即將圖像轉(zhuǎn)換為NumPy數(shù)組，但是，這無濟于事。我做錯了什么？我將不勝感激任何幫助。
1 回答
翻翻過去那場雪
TA貢獻2065條經(jīng)驗 獲得超14個贊
我想知道，為什么你使用PIL，特別是你的代碼源是基于OpenCV的，無論如何你都需要處理NumPy數(shù)組。
這就是我的解決方案：
import cv2
import numpy as np
# Read input image; create additional output image to draw on
image = cv2.imread('ZsyOG.png')
image_out = image.copy()
# Parameters
step = 64
cols, rows = image.shape[:2]
# Actual processing in loop
i_region = 0
for row in np.arange(0, rows, step):
for col in np.arange(0, cols, step):
mean = cv2.mean(image[row:row+step, col:col+step])
image_out = cv2.rectangle(img=image_out,
pt1=(row, col),
pt2=(row + step, col + step),
color=(255, 255, 255),
thickness=1)
image_out = cv2.putText(img=image_out,
text=str(i_region),
org=(int(col+1/2*step), int(row+1/2*step)),
fontFace=cv2.FONT_HERSHEY_COMPLEX_SMALL,
fontScale=1.0,
color=(255, 255, 255))
print('Region: ', i_region, '| Mean: ', mean)
i_region += 1
cv2.imshow('image_out', image_out)
cv2.waitKey(0)
cv2.destroyAllWindows()
輸出圖像：
打印輸出：
Region: 0 | Mean: (0.0, 0.0, 255.0, 0.0)
Region: 1 | Mean: (0.0, 0.0, 255.0, 0.0)
Region: 2 | Mean: (0.0, 255.0, 255.0, 0.0)
Region: 3 | Mean: (0.0, 255.0, 255.0, 0.0)
Region: 4 | Mean: (0.0, 0.0, 255.0, 0.0)
Region: 5 | Mean: (0.0, 0.0, 255.0, 0.0)
Region: 6 | Mean: (0.0, 255.0, 255.0, 0.0)
Region: 7 | Mean: (0.0, 255.0, 255.0, 0.0)
Region: 8 | Mean: (0.0, 0.0, 0.0, 0.0)
Region: 9 | Mean: (0.0, 0.0, 0.0, 0.0)
Region: 10 | Mean: (255.0, 0.0, 0.0, 0.0)
Region: 11 | Mean: (255.0, 0.0, 0.0, 0.0)
Region: 12 | Mean: (0.0, 0.0, 0.0, 0.0)
Region: 13 | Mean: (0.0, 0.0, 0.0, 0.0)
Region: 14 | Mean: (255.0, 0.0, 0.0, 0.0)
Region: 15 | Mean: (255.0, 0.0, 0.0, 0.0)
希望有所幫助！
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System information
----------------------------------------
Platform: Windows-10-10.0.16299-SP0
Python: 3.8.1
NumPy: 1.18.1
OpenCV: 4.2.0
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