cuda(0)
自从进入电气工程，阴差阳错的学习了cuda，在学习的过程中初步了解并行计算的一些思路，
由于我的电脑空间有限，所以我准备记录平时的一些cuda编程的练习，放到博客园上这样方便我
以后的学习，这样也可以为博客园的成长尽一下绵薄之力。接下来进入正题:
图像灰度转换cuda实现：
1 #include "cuda_runtime.h" 2 #include "device_launch_parameters.h" 3 #include <stdio.h> 4 #include<iostream> 5 6 #include <iostream> 7 #include <opencv2/core/core.hpp> 8 #include <opencv2/highgui/highgui.hpp> 9 10 #define CHANNELS 3 11 12 __global__ void colorToGreyScaleConversion(unsigned char *pout, unsigned char *pin, int width, int height) { 13 int Col = blockIdx.x*blockDim.x + threadIdx.x; 14 int Row = blockIdx.y*blockDim.y + threadIdx.y; 15 16 if (Col < width && Row < height) { 17 int greyoffset = Row * width + Col; 18 int rgbOffset = greyoffset * CHANNELS; 19 20 unsigned char r = pin[rgbOffset]; 21 unsigned char g = pin[rgbOffset + 1]; 22 unsigned char b = pin[rgbOffset + 2]; 23 24 pout[greyoffset] = 0.21f*r + 0.71f*g + 0.07f*b; 25 } 26 } 27 28 using namespace cv; 29 int main(void) { 30 31 // 读入一张图片（缩小图） 32 Mat img = imread("E:\\opencv\\lena512color.tiff"); 33 // 创建一个名为 "图片"窗口 34 namedWindow("lena"); 35 // 在窗口中显示图片 36 imshow("lena", img); 37 // 等待6000 ms后窗口自动关闭 38 waitKey(6000); 39 40 const int imgheight = img.rows; 41 const int imgwidth = img.cols; 42 const int imgchannel = img.channels(); 43 44 Mat grayImage(imgheight, imgwidth, CV_8UC1, Scalar(0)); 45 46 unsigned char *dev_pin; 47 unsigned char *dev_pout; 48 49 cudaMalloc((void**)&dev_pin, imgheight*imgwidth*imgchannel* sizeof(unsigned char)); 50 cudaMalloc((void**)&dev_pout, imgheight*imgwidth*sizeof(unsigned char)); 51 52 cudaMemcpy(dev_pin, img.data, imgheight*imgwidth*imgchannel * sizeof(unsigned char), cudaMemcpyHostToDevice); 53 54 55 dim3 BlockDim(16, 16); 56 dim3 GridDim((imgwidth - 1) / BlockDim.x + 1, (imgheight - 1) / BlockDim.y + 1); 57 colorToGreyScaleConversion << <GridDim, BlockDim >> > (dev_pout, dev_pin, imgwidth, imgheight); 58 59 cudaMemcpy(grayImage.data, dev_pout, imgheight*imgwidth*sizeof(unsigned char), cudaMemcpyDeviceToHost); 60 61 cudaFree(dev_pin); 62 cudaFree(dev_pout); 63 imshow("grayImage", grayImage); 64 waitKey(3000); 65 return 0; 66 }
值得注意的是：我是在vs2017平台上实现的，在编程的时候调用了openCV的库函数，读者需要自行配置该环境，为了不让
大家在配置环境时耗费太长时间，我附上CSDN上一位大神的配置教程链接：https://blog.csdn.net/qq_41175905/article/details/80560429
转换前如下图：
转换后如下图：
另外读者也可用Matlab, openCV等库函数实现，比较发现，cuda并行计算的时间要快一些。
