pybind11—opencv图像处理(numpy数据交换)

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C++

main.cpp

#include<iostream>
#include<vector>
#include<opencv2/opencv.hpp>
#include<pybind11/pybind11.h>
#include<pybind11/numpy.h>
#include<pybind11/stl.h>
#include"mat_warper.h"

namespace py = pybind11;

py::array_t<unsigned char> test_rgb_to_gray(py::array_t<unsigned char>& input) {

    cv::Mat img_rgb = numpy_uint8_3c_to_cv_mat(input);
    cv::Mat dst;
    cv::cvtColor(img_rgb, dst, cv::COLOR_RGB2GRAY);
    return cv_mat_uint8_1c_to_numpy(dst);

}

py::array_t<unsigned char> test_gray_canny(py::array_t<unsigned char>& input) {
    cv::Mat src = numpy_uint8_1c_to_cv_mat(input);
    cv::Mat dst;
    cv::Canny(src, dst, 30, 60);
    return cv_mat_uint8_1c_to_numpy(dst);
}


/*
@return Python list
*/
py::list test_pyramid_image(py::array_t<unsigned char>& input) {
    cv::Mat src = numpy_uint8_1c_to_cv_mat(input);
    std::vector<cv::Mat> dst;

    cv::buildPyramid(src, dst, 4);

    py::list out;
    for (int i = 0; i < dst.size(); i++)
    {
        out.append<py::array_t<unsigned char>>(cv_mat_uint8_1c_to_numpy(dst.at(i)));
    }
    
    return out;
}

PYBIND11_MODULE(cv_demo1, m) {
    
    m.doc() = "Simple opencv demo";

    m.def("test_rgb_to_gray", &test_rgb_to_gray);
    m.def("test_gray_canny", &test_gray_canny);
    m.def("test_pyramid_image", &test_pyramid_image);

}

mat_warper.h

#ifndef MAT_WARPER_H_

#include<opencv2/opencv.hpp>
#include<pybind11/pybind11.h>
#include<pybind11/numpy.h>

namespace py = pybind11;

cv::Mat numpy_uint8_1c_to_cv_mat(py::array_t<unsigned char>& input);

cv::Mat numpy_uint8_3c_to_cv_mat(py::array_t<unsigned char>& input);

py::array_t<unsigned char> cv_mat_uint8_1c_to_numpy(cv::Mat & input);

py::array_t<unsigned char> cv_mat_uint8_3c_to_numpy(cv::Mat & input);

#endif // !MAT_WARPER_H_

mat_warper.cpp

#include"mat_warper.h"
#include <pybind11/numpy.h>

/*
Python->C++ Mat
*/


cv::Mat numpy_uint8_1c_to_cv_mat(py::array_t<unsigned char>& input) {

    if (input.ndim() != 2)
        throw std::runtime_error("1-channel image must be 2 dims ");

    py::buffer_info buf = input.request();

    cv::Mat mat(buf.shape[0], buf.shape[1], CV_8UC1, (unsigned char*)buf.ptr);
    
    return mat;
}


cv::Mat numpy_uint8_3c_to_cv_mat(py::array_t<unsigned char>& input) {

    if (input.ndim() != 3)
        throw std::runtime_error("3-channel image must be 3 dims ");

    py::buffer_info buf = input.request();

    cv::Mat mat(buf.shape[0], buf.shape[1], CV_8UC3, (unsigned char*)buf.ptr);

    return mat;
}


/*
C++ Mat ->numpy
*/
py::array_t<unsigned char> cv_mat_uint8_1c_to_numpy(cv::Mat& input) {

    py::array_t<unsigned char> dst = py::array_t<unsigned char>({ input.rows,input.cols }, input.data);
    return dst;
}

py::array_t<unsigned char> cv_mat_uint8_3c_to_numpy(cv::Mat& input) {

    py::array_t<unsigned char> dst = py::array_t<unsigned char>({ input.rows,input.cols,3}, input.data);
    return dst;
}



//PYBIND11_MODULE(cv_mat_warper, m) {
//
//  m.doc() = "OpenCV Mat -> Numpy.ndarray warper";
//
//  m.def("numpy_uint8_1c_to_cv_mat", &numpy_uint8_1c_to_cv_mat);
//  m.def("numpy_uint8_1c_to_cv_mat", &numpy_uint8_1c_to_cv_mat);
//
//
//}

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python中测试

python代码

import cv2
import matplotlib.pyplot as plt
import demo11.cv_demo1 as cv_demo1
import numpy as np


image_rgb = cv2.imread('F:\\lena\\lena_rgb.jpg', cv2.IMREAD_UNCHANGED)
image_gray = cv2.imread('F:\\lena\\lena_gray.jpg', cv2.IMREAD_UNCHANGED)

var1 = cv_demo1.test_rgb_to_gray(image_rgb)
print(var1.shape)
plt.figure('rgb-gray')
plt.imshow(var1, cmap=plt.gray())

var2 = cv_demo1.test_gray_canny(image_gray)
plt.figure('canny')
plt.imshow(var2, cmap=plt.gray())

var3 = cv_demo1.test_pyramid_image(image_gray)
var3 = var3[1:]
plt.figure('pyramid_demo')
for i, image in enumerate(var3, 1):
    plt.subplot(2, 2, i)
    plt.axis('off')
    plt.imshow(image, cmap=plt.gray())

plt.show()

测试图像:
RGB图像

rgb.jpg

GRAY灰度图像

lena_gray.jpg

结果

• RGB转GRAY

  
  image.png

• 灰度图像Canny边缘检测

  
  image.png

• 图像金字塔

  
  image.png