从numpy数组获取指针以将图像发送到C ++ [英] Get pointer from numpy array to send image to C++

问题描述

我正在做一个项目，必须处理 Python 和 C ++ 之间的图像.为了将图像从C ++发送到Python，我在图像的第一个像素上发送了一个指针(是OpenCV库中的Mat对象)，在Python中有两个for循环，我使用了该指针来创建2D numpy数组.

I am working on a project on which I have to deal with images between Python and C++. In order to send an image from C++ to Python, I send a pointer on the first pixel of my image (being a Mat object from OpenCV library) and in Python with two for loops I used this pointer to create a 2D numpy array.

但是我不能以另一种方式做同样的事情:获取numpy 2D数组(图像)的第一个像素的内存地址，并将其传递给C ++.

But I don't succeed to do the same in the other way : get the memory address of the first pixel of the numpy 2D array (an image) and pass it to the C++.

假设x是我的图像(二维numpy数组)，我尝试了以下解决方案:

Assume x is my image (2D numpy array), I tried solution like :

• x.__array_interface__['data'][0]，但这给出一个整数，而不是地址
• x.data每次调用它都会赋予不同的值，因为它给了我一个临时缓冲区的地址，而不是图像本身

• x.__array_interface__['data'][0] but this give an integer, not an address
• x.data which give different values each time I call it because it gives me the address of a temporary buffer, not the image itself

在此先感谢您的任何建议/帮助.

Thank you in advance for any advice/help.

推荐答案

我发现了一种简单"的方法:

I found a "simple" way to do that:

在 C ++ 中，该函数必须将void * ptr作为参数，这样，我可以使用从Python发送来的指针创建Mat对象:

In C++, the function has to take as argument a void * ptr, and like this I can create a Mat object using the pointer sent from Python :

void myCfunction(void* ptr){
    Mat matrix = Mat(sizes, CV_8UC1, (uchar*)ptr);
}

然后，在 Python 中，使用__array_interface__获取内存地址(以int类型，很奇怪):

And, in Python, use __array_interface__ to get the memory address (in int type, weird) :

mydll.myFunction(myNumpyArray.__array_interface__['data'][0], ...)

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