PIL到OpenCV MAT会导致颜色偏移

Question

使用PIL和OpenCV加载png图像时,会出现颜色偏移.黑色和白色保持不变,但棕色变为蓝色.

我无法发布图片,因为此网站不允许新手发布图片.

代码编写如下,而不是使用cv.LoadImageM,因为在实际情况下,原始图像是通过tcp接收的.

这是代码:

#! /usr/bin/env python
import sys
import cv
import cv2
import numpy as np
import Image
from cStringIO import StringIO

if __name__ == "__main__":
    # load raw image from file
    f = open('frame_in.png', "rb")
    rawImage = f.read()
    f.close()

    #convert to mat
    pilImage = Image.open(StringIO(rawImage));
    npImage = np.array(pilImage)
    cvImage = cv.fromarray(npImage)

    #show it
    cv.NamedWindow('display')
    cv.MoveWindow('display', 10, 10)
    cv.ShowImage('display', cvImage)
    cv. WaitKey(0)

    cv.SaveImage('frame_out.png', cvImage)

如何修复色偏？

Answer 1

OpenCV的图像具有以BGR顺序排列的颜色通道,而PIL是RGB.你需要像这样切换频道:

import PIL.Image
import cv2

... 

image = np.array(pilImage) # Convert PIL Image to numpy/OpenCV image representation
image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR) # You can use cv2.COLOR_RGBA2BGRA if you are sure you have an alpha channel. You will only have alpha channel if your image format supports transparency.
...

@Krish:谢谢你指出了这个bug.我上次没时间测试代码了.

希望这可以帮助.