如何使用Opencv 2.4将python numpy数组转换为RGB图像? [英] How to convert a python numpy array to an RGB image with Opencv 2.4?

问题描述

我已经搜索了类似的问题，但是没有发现任何有用的信息，因为大多数解决方案都使用旧版本的OpenCV.

I have searched for similar questions, but haven't found anything helpful as most solutions use older versions of OpenCV.

我有一个3D numpy数组，我想使用OpenCV(cv2)将其显示和/或保存为BGR图像.

I have a 3D numpy array, and I would like to display and/or save it as a BGR image using OpenCV (cv2).

作为一个简短的例子，假设我有:

As a short example, suppose I had:

import numpy, cv2
b = numpy.zeros([5,5,3])

b[:,:,0] = numpy.ones([5,5])*64
b[:,:,1] = numpy.ones([5,5])*128
b[:,:,2] = numpy.ones([5,5])*192

我想做的就是将b保存并显示为类似于以下内容的彩色图像:

What I would like to do is save and display b as a color image similar to:

cv2.imwrite('color_img.jpg', b)
cv2.imshow('Color image', b)
cv2.waitKey(0)
cv2.destroyAllWindows()

这不起作用，大概是因为b的数据类型不正确，但是经过大量搜索之后，我不知道如何将其更改为正确的数据.如果您可以提供任何指针，将不胜感激！

This doesn't work, presumably because the data type of b isn't correct, but after substantial searching, I can't figure out how to change it to the correct one. If you can offer any pointers, it would be greatly appreciated!

推荐答案

您不需要将NumPy数组转换为Mat，因为OpenCV cv2模块可以接受NumPy数组. 您唯一需要关心的是{0,1}映射到{0,255}，并且NumPy数组中任何大于1的值都等于255.因此，应在代码中除以255，如下所示

You don't need to convert NumPy array to Mat because OpenCV cv2 module can accept NumPyarray. The only thing you need to care for is that {0,1} is mapped to {0,255} and any value bigger than 1 in NumPy array is equal to 255. So you should divide by 255 in your code, as shown below.

img = numpy.zeros([5,5,3])

img[:,:,0] = numpy.ones([5,5])*64/255.0
img[:,:,1] = numpy.ones([5,5])*128/255.0
img[:,:,2] = numpy.ones([5,5])*192/255.0

cv2.imwrite('color_img.jpg', img)
cv2.imshow("image", img)
cv2.waitKey()

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