原文链接：https://stackoverflow.com/questions/40731433/understanding-tf-extract-image-patches-for-extracting-patches-from-an-image?newreg=2f7aa12c4b6d4870a979698318d457a4
tf.extract_image_patches: 提取图片中的一小块区域
表达式如下：
extract_image_patches(
images,
ksizes,
strides,
rates,
padding,
name=None
)ksize:滑动窗口的大小，长度必须大于四
strides:每块patch区域之间中心点之间的距离，必须是: [1, stride_rows, stride_cols, 1].
rates:在原始图像的一块patch中，隔多少像素点，取一个有效像素点，必须是[1, rate_rows, rate_cols, 1]
padding:有两个取值，“VALID”或者“SAME”，“VALID”表示所取的patch区域必须完全包含在原始图像中."SAME"表示
可以取超出原始图像的部分，这一部分进行0填充。
for example:
import tensorflow as tf
n = 10
# images is a 1 x 10 x 10 x 1 array that contains the numbers 1 through 100 in order
images = [[[[x * n + y + 1] for y in range(n)] for x in range(n)]]
# We generate four outputs as follows:
# 1. 3x3 patches with stride length 5
# 2. Same as above, but the rate is increased to 2
# 3. 4x4 patches with stride length 7; only one patch should be generated
# 4. Same as above, but with padding set to 'SAME'
with tf.Session() as sess:
print tf.extract_image_patches(images=images, ksizes=[1, 3, 3, 1], strides=[1, 5, 5, 1], rates=[1, 1, 1, 1], padding='VALID').eval(), '\n\n'
print tf.extract_image_patches(images=images, ksizes=[1, 3, 3, 1], strides=[1, 5, 5, 1], rates=[1, 2, 2, 1], padding='VALID').eval(), '\n\n'
print tf.extract_image_patches(images=images, ksizes=[1, 4, 4, 1], strides=[1, 7, 7, 1], rates=[1, 1, 1, 1], padding='VALID').eval(), '\n\n'
print tf.extract_image_patches(images=images, ksizes=[1, 4, 4, 1], strides=[1, 7, 7, 1], rates=[1, 1, 1, 1], padding='SAME').eval()Output:
[[[[ 1 2 3 11 12 13 21 22 23]
[ 6 7 8 16 17 18 26 27 28]]
[[51 52 53 61 62 63 71 72 73]
[56 57 58 66 67 68 76 77 78]]]]
[[[[ 1 3 5 21 23 25 41 43 45]
[ 6 8 10 26 28 30 46 48 50]]
[[ 51 53 55 71 73 75 91 93 95]
[ 56 58 60 76 78 80 96 98 100]]]]
[[[[ 1 2 3 4 11 12 13 14 21 22 23 24 31 32 33 34]]]]
[[[[ 1 2 3 4 11 12 13 14 21 22 23 24 31 32 33 34]
[ 8 9 10 0 18 19 20 0 28 29 30 0 38 39 40 0]]
[[ 71 72 73 74 81 82 83 84 91 92 93 94 0 0 0 0]
[ 78 79 80 0 88 89 90 0 98 99 100 0 0 0 0 0]]]]第一个输出可以看成是这样取值
* * * 4 5 * * * 9 10 * * * 14 15 * * * 19 20 * * * 24 25 * * * 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 * * * 54 55 * * * 59 60 * * * 64 65 * * * 69 70 * * * 74 75 * * * 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100