如何使用numpy拼接数组? [英] How to mosaic arrays using numpy?

问题描述

我有一个形状为(780,256,256)的numpy数组，代表图像的780个图块，我需要将其重新组装成原始图像，但无法弄清楚如何正确地对其重塑.

I have an numpy array of shape (780,256,256) representing 780 tiles of an image, which I need to reassemble into the original image, but can't figure out how to reshape this properly.

应将780个图块排列在26x30的网格中，因此最终结果的形状为(6656, 7680).图像按从左到右，从上到下的顺序排列.

The 780 tiles should be arranged in a grid 26x30 grid, so the end result has shape (6656, 7680). The tiles are in order as the image goes left to right, top to bottom.

我可以通过在数组上使用np.hstack在一行中获得切片，第一行可以使用row1 = np.hstack(array_of_tiles[0:30,:,:])正确地获得，但是我进行的任何重塑都不会保持切片结构.

I can get the tiles in a line by using np.hstack on the array, and the first row correctly using row1 = np.hstack(array_of_tiles[0:30,:,:]), but any reshaping I then do doesn't maintain the tile structure.

我可能可以使用QGIS将图块写到tif和马赛克上，但是直接使用numpy的正确方法是什么?

I can probably write out the tiles to tif and mosaic using QGIS but what is the correct way using numpy directly?

推荐答案

分步操作:

1)正确排列图块:

 tiles = array_of_tiles.reshape(26, 30, 256, 256)

2)将它们拼凑在一起:要制作一个相干图像，请将第二个图块的第一行像素(tiles [0、1、0 、:])连接到第一个图块的第一行像素的末尾(tiles [0，0，0，:])等.由此可见，必须交换两个中轴:

2) Piece them together: To make one coherent image the first row of pixels of the second tile (tiles[0, 1, 0, :]) be joined to the end of the first row of pixels of the first tile (tiles[0, 0, 0, :]) etc. From that we can see that the two middle axes must be swapped:

tiles = tiles.swapaxes(1, 2)  

3)移除多余的尺寸.像素的顺序现在是正确的，但是它们以4D结构进行布局.我们需要将其减少到2D:

3) Remove excess dimensions. The order of pixels is now correct but they are layed out in a 4D structure. We need reduce that to 2D:

img = tiles.reshape(6656, 7680)

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