人口普查变换在python openCV中

Question

我开始在与stereovision相关的项目中使用openCV和python.我在openCV中找到了关于C++中Census Transform的文档页面. 链接

有谁知道python实现是否有类似的功能？

(例如cv2.nameofthefunction)

谢谢你们!

编辑:PM 2Ring的优秀解决方案(再次感谢)可以使用openCV进行这一小改动:而不是使用Image.open

img = cv2.imread(img.png)
#some minor changes I needed like select some ROI and store them in img2[j] 
#then a for cycle in which I wrote
src_img = img2[j] 
h, w = src_img.shape

其中"shape"指令似乎将w和h的顺序与"size"命令进行比较.然后我粘贴PM 2Ring的其余代码,它工作得非常好

Answer 1

我不使用openCV,我不知道是否有人口普查变换的现有实现.但是,使用Numpy很容易实现.

这是一个简单的演示,它使用PIL来处理加载图像并将数组数据转换回图像.

#!/usr/bin/env python

''' The Census Transform

    Scan an 8 bit greyscale image with a 3x3 window
    At each scan position create an 8 bit number by comparing the value
    of the centre pixel in the 3x3 window with that of its 8 neighbours.
    The bit is set to 1 if the outer pixel >= the centre pixel

    See http://stackoverflow.com/questions/38265364/census-transform-in-python-opencv

    Written by PM 2Ring 2016.07.09
'''

import numpy as np
from PIL import Image

iname = 'Glasses0S.png'
oname = 'Glasses0S_census.png'

#Get the source image
src_img = Image.open(iname)
src_img.show()

w, h = src_img.size
print('image size: %d x %d = %d' % (w, h, w * h))
print('image mode:', src_img.mode)

#Convert image to Numpy array
src_bytes = np.asarray(src_img)

#Initialize output array
census = np.zeros((h-2, w-2), dtype='uint8')

#centre pixels, which are offset by (1, 1)
cp = src_bytes[1:h-1, 1:w-1]

#offsets of non-central pixels 
offsets = [(u, v) for v in range(3) for u in range(3) if not u == 1 == v]

#Do the pixel comparisons
for u,v in offsets:
    census = (census << 1) | (src_bytes[v:v+h-2, u:u+w-2] >= cp)

#Convert transformed data to image
out_img = Image.fromarray(census)
out_img.show()
out_img.save(oname)

资源

产量

原始的全彩眼镜图像由Gilles Tran使用POV-Ray创建,属于公共领域.它可以在维基百科上找到.