为什么使用PIL进行仿射变换后图像颜色会改变？

Question

我正在使用Python Imaging Library中的image.transform将仿射变换应用于面部检测图像，以根据眼睛位置校准面部。 结果正确，但是图像的颜色如下更改。 为什么？ 代码如下。 最后两行是tranform函数的调用。

def ScaleRotateTranslate(image, angle, center = None, new_center = None, scale = None, resample=Image.NEAREST):
    if (scale is None) and (center is None):
        return image.rotate(angle=angle, resample=resample)
    nx,ny = x,y = center
    sx=sy=1.0
    if new_center:
        (nx,ny) = new_center
    if scale:
        (sx,sy) = (scale, scale)
    cosine = math.cos(angle)
    sine = math.sin(angle)
    a = cosine/sx
    b = sine/sx
    c = x-nx*a-ny*b
    d = -sine/sy
    e = cosine/sy
    f = y-nx*d-ny*e
    return image.transform(image.size, Image.AFFINE, (a,b,c,d,e,f), resample=resample)

def Distance(p1,p2):
    dx = p2[0] - p1[0]
    dy = p2[1] - p1[1]
    return math.sqrt(dx*dx+dy*dy)



image_center = ((eye_left[0]+eye_right[0])/2,(eye_left[1]+eye_right[1])/2)
rotatedImg = ScaleRotateTranslate(pilIm,center=image_center,angle=rotation)

Answer 1

试过这个：

import Image
import math

def ScaleRotateTranslate(image, angle, center = None, new_center = None, scale = None, resample=Image.NEAREST):
    if (scale is None) and (center is None):
        return image.rotate(angle=angle, resample=resample)
    nx,ny = x,y = center
    sx=sy=1.0
    if new_center:
        (nx,ny) = new_center
    if scale:
        (sx,sy) = (scale, scale)
    cosine = math.cos(angle)
    sine = math.sin(angle)
    a = cosine/sx
    b = sine/sx
    c = x-nx*a-ny*b
    d = -sine/sy
    e = cosine/sy
    f = y-nx*d-ny*e
    return image.transform(image.size, Image.AFFINE, (a,b,c,d,e,f), resample=resample)

def Distance(p1,p2):
    dx = p2[0] - p1[0]
    dy = p2[1] - p1[1]
    return math.sqrt(dx*dx+dy*dy)


pilIm = Image.open('/Users/carlos/Downloads/image.jpg').convert('RGB');
eye_left = (10,10)
eye_right = (40,30)
rotation = 0.3;

image_center = ((eye_left[0]+eye_right[0])/2,(eye_left[1]+eye_right[1])/2)
rotatedImg = ScaleRotateTranslate(pilIm,center=image_center,angle=rotation)
rotatedImg.save('out.jpg')

收到：

所以我想，答案是它对我有用。 尝试检查您的PIL安装和您使用的是RGB编码。