与previous 1 numpy的阵列上比较当前像素值 [英] Compare current pixel value with the previous one on numpy array

问题描述

有可能实现在numpy的阵列这个图像过滤过程？我需要检查previous列和previous行的像素是differente当前像素。

Is possible to implement this image filtering process in numpy array ? I need to check if the pixel in the previous column and previous row is differente of the current pixel.

width, height = orig_bin.size
pixels = orig_bin.load()

delta = 50
begin = 10
min_w = 30
max_w = 260
min_h = 10
max_h = 40

w_range = range(begin, width - min_w - delta)
h_range = range(begin, height - min_h - delta)

is_changing = False
for x in w_range:
    for y in h_range:
        change_pixel = False
        current_pixel = pixels[x,y]
        if current_pixel != pixels[x, y+1]:
            change_pixel = True

        if current_pixel != pixels[x+1, y]:
            change_pixel = True

        if change_pixel:
            pixels[x,y] = (0,0,0)
        else:
            pixels[x,y] = (255,255,255)

最好的问候，
埃米利奥

Best regards, Emilio

推荐答案

下面是一个方法。以一个例如图片：

Here's one approach. Take an example image:

您没有说您的 orig_bin 是从哪里来的，所以我使用的 scipy.misc.imread ：

You didn't say where your orig_bin came from, so I've used scipy.misc.imread:

from scipy.misc import imread, imsave
img = imread('input.png')

首先，创建是从上面的像素不同像素面具（这里使用一个想法从毕波多黎各的回答 ）：

up   = (img[1:,1:] != img[:-1,1:]).any(axis=2)

注意 imread 载荷行优先顺序排列的图像，所以第一numpy的轴是垂直轴。请参见<一个href=\"http://docs.scipy.org/doc/numpy/reference/internals.html#multidimensional-array-indexing-order-issues\"相对=nofollow>多维数组索引顺序问题解释了。

Note that imread loads images in row-major order, so the first NumPy axis is the vertical axis. See "Multidimensional Array Indexing Order Issues" for an explanation.

类似地，创建一个掩模是从像素向左不同像素：

Similarly, create a mask for pixels that are different from the pixel to the left:

left = (img[1:,1:] != img[1:,:-1]).any(axis=2)

结合这些能为那些对以上任一像素或左不同像素的面具：

Combine these to get a mask for pixels that are different to either the pixel above or left:

mask = numpy.zeros(img.shape[:2], dtype=bool)
mask[1:,1:] = left | up

创建一个大小合适的黑色输出图像;然后将面膜白：

Create a black output image of the right size; then set the mask to white:

output = numpy.zeros(img.shape)
output[mask] = (255, 255, 255)
imsave('output.png', output)

和这里的结果是：

或者，如果你想的颜色是圆的其他方式，反转面膜：

or if you want the colours to be the other way round, invert the mask:

output[~mask] = (255, 255, 255)

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