如何从具有给定角点的图像中裁剪面部分。 MATLAB [英] How to crop face section from an image with given corner points. MATLAB

问题描述

我想从图像裁剪脸部，但脸部图像不是直线/垂直对齐的。我有四个像素点来裁剪它..
问题是，
如果我将首先变换图像，之后不能使用像素点来裁剪面部部分。
或者在其他情况下我没有精确的边界框来直接使用imcrop裁剪图像，因为面部区域有些向左或向右倾斜。
四个像素点位于要裁剪的脸的前额，下巴和耳朵上。

I want to crop a face section from an image but face image is not straight/vertically aligned. I am having four pixel points to crop it.. Problem is that, If i will transform image first the pixel points cannot be used thereafter to crop the facial section out of it. Or in other case I am not having an exact bounding box to crop the image directly using imcrop as facial sections are somewhat tilted left or right. The four pixel points are at forehead , chin and ears of the face to be cropped.

推荐答案

你应该看看在 poly2mask 。此函数根据给定的x和y坐标生成蒙版图像：

You should look at poly2mask. This function produces a mask image from your given x and y coordinates:

BW = poly2mask(x,y,m,n);

其中 x 和 y 是您的坐标，生成的 BW 图片是 m by 名词。然后你可以使用这个 BW 图像来掩盖原始图像我做

where x and y are your coordinates, and the produced BW image is m by n. You can then use this BW image to mask your original image I by doing

I(~BW) = 0;

如果你真的想要裁剪，那么你可以获得边界框（通过 regionprops 功能或下面的代码）：

If you actually want to crop, then you could get the bounding box (either through the regionprops function or the code below):

x1 =  round(min(x));
y1 =  round(min(y));
x2 =  round(max(x));
y2 =  round(max(y));

然后在使用 BW 作为面具。

I2 = I(x1:x2,y1:y2);

希望有所帮助。

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