为什么openCV存储的文件比原始文件大(kB)? [英] Why does openCV store a file larger(kB) than the original?

问题描述

我有以两种不同方式加载和保存图像的代码-第一种使用openCV，第二种使用PIL.

I have code that loads and saves the image in two different ways - first using openCV, the second using PIL.

import cv2
from PIL import Image

img = cv2.imread("/home/myname/png/image.png")
cv2.imwrite("/home/myname/png/image_save.png", img)

img = Image.open("/home/myname/png/image.png")
img.save("/home/myname/png/image_save_pil.png")

原始图像的大小为204.6 kB.openCV的结果为245.0 kB，PIL的结果为204.6 kB.

The original image is 204.6 kB in size. The result obtained with openCV is 245.0 kB, the result of PIL is 204.6 kB.

为什么用openCV保存的图像尺寸更大?

Why does the image saved with openCV have a larger size?

推荐答案

大小差异与ZLIB压缩设置有关.

The size difference has to do with the ZLIB compression settings.

• 默认情况下，PIL最多使用9(请参见这里)

使用OpenCV，您可以使用以下代码将压缩率设置为9(来自此

Using OpenCV you can set compression to 9 using this code (from this answer)

cv2.imwrite('image.png', img,  [int(cv2.IMWRITE_PNG_COMPRESSION), 9])

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