我正在尝试在 Cuda c 中制作影像过滤器，但我认为我不完全了解每个像素的执行绪分配是如何作业的。到目前为止，这是我的代码：imageFilter.cu

#include "cuda_runtime.h"
#include "device_launch_parameters.h"
#include "Filtering_Functions.h"

__global__ void Grayscale_image(int h, int w, unsigned char* Image) {
    int x = (blockIdx.x * blockDim.x)   threadIdx.x;
    int y = (blockIdx.y * blockDim.y)   threadIdx.y;
    unsigned int tid = threadIdx.y * blockDim.y   threadIdx.x;

    if (x > 0 && x < w - 1 && y > 0 && y < h - 1)
    {
        Image[tid] = 0.299 * Image[tid]   0.587 * Image[tid   1]   0.114 * Image[tid   2];
        Image[tid   1] = Image[tid];
        Image[tid   2] = Image[tid];
    }
}
void Image_Grayscale(unsigned char* Image, int Height, int Width) {
    unsigned char* Uploaded_Image = NULL;
    dim3 blocks(Width / 16, Height / 16);
    dim3 threads(16, 16);

    cudaMalloc((void**)&Uploaded_Image, Height * Width * 3);

    cudaMemcpy(Uploaded_Image, Image, Height * Width * 3, cudaMemcpyHostToDevice);
    
    Grayscale_image << <blocks, threads >> > (Height, Width, Uploaded_Image);

    cudaMemcpy(Image, Uploaded_Image, Height * Width * 3, cudaMemcpyDeviceToHost);

    cudaFree(Uploaded_Image);
}

过滤功能.h

#ifndef filtering_functions
#define filtering_functions
void Image_Grayscale(unsigned char* Image, int Height, int Width);
#endif

影像过滤.cpp

#include <iostream>
#include <stdio.h>
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgcodecs.hpp>
#include "Filtering_Functions.h"

using namespace std;
using namespace cv;

int main() {
    Mat Image = imread("Example.png");

    cout << "The uploaded image has Height: " << Image.rows << ", Width: " << Image.cols << endl;

    Image_Grayscale(Image.data, Image.rows, Image.cols);
    imwrite("Grayscale_Filter.png", Image);

    system("pause");
    return 0;
}

最后我没有看到任何变化。有人可以告诉我我做错了什么，或者至少我不明白什么？

uj5u.com热心网友回复：

Cuda 操作相对于主机处理器是异步的。我怀疑您正试图在 GPU 触及资料之前将资料写入磁盘。考虑cudaStreamSynchronize(0)在尝试检查结果之前打电话。

Cuda 流管理

uj5u.com热心网友回复：

您提供的代码无法编译 - 您Image2在此行中使用了未宣告的识别符号：

imwrite("Grayscale_Filter.png", Image2);

也许这就是问题？您是否在档案中写入其他内容？