1. 简介

NVIDIA Performance Primitives library (NPP)是一系列为加速进程的库函数，NPP的原始目标是针对图像和视频进程，而现在以被开发工程师应用于其它很多领域，包括信号处理。与同级别的纯CPU 函数相比，这些函数最高可实现5 - 10倍性能提升。利用NPP，开发者能够利用 (CUDA4.1中)2000多个图像处理与信号处理基元，在数小时之内即可实现应用程序的大幅性能提升。

无论用GPU加速的版本代替CPU基元还是将NPP基元与现有的GPU加速流水线相结合，NPP都能够实现极高的性能，同时可缩短开发时间。

2. 例子

这里用npp做一个图片resize

main.cpp

#include <stdlib.h>
#include <stdio.h>
#include <opencv/cv.h>
#include <opencv/highgui.h>
#include <opencv2/opencv.hpp>

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

#include "npp.h"

using namespace cv;
 
int main()
{
    Mat image = imread("../lena_1.jpg");
    imshow("src",image);

    int outwidth = 1024;
    int outheight = 720;
    int outsize = outwidth * outheight * sizeof(uchar3);
    
    int inwidth = image.cols;
    int inheight = image.rows;
    int memSize = inwidth * inheight * sizeof(uchar3);

    NppiSize srcsize = {inwidth, inheight};
    NppiRect srcroi  = {0, 0, inwidth, inheight};
    NppiSize dstsize = {outwidth, outheight};
    NppiRect dstroi  = {0, 0, outwidth, outheight}; 

    uchar3* d_src = NULL;
    uchar3* d_dst = NULL;
    cudaMalloc((void**)&d_src, memSize);
    cudaMalloc((void**)&d_dst, outsize);
    cudaMemcpy(d_src, image.data, memSize, cudaMemcpyHostToDevice);
    
    // nvidia npp 图像处理
    nppiResize_8u_C3R( (Npp8u*)d_src, inwidth * 3, srcsize, srcroi, 
                       (Npp8u*)d_dst, outwidth * 3, dstsize, dstroi,
                       NPPI_INTER_LINEAR );
    
    Mat newimage(outheight, outwidth, CV_8UC3);
    
    cudaMemcpy(newimage.data, d_dst, outsize, cudaMemcpyDeviceToHost);
    imshow("gpu", newimage);
    waitKey(0);
    
    cudaFree(d_src);
    cudaFree(d_dst);
    return 0;
}


cmakelists.txt

cmake_minimum_required(VERSION 2.8.0)
project(demo)

set(CMAKE_BUILD_TYPE Debug)
# OPENCV
find_package(OpenCV REQUIRED)

include_directories(${OpenCV_INCLUDE_DIRS})

find_package(CUDA REQUIRED)

CUDA_ADD_EXECUTABLE(demo main.cpp)
target_link_libraries(demo ${OpenCV_LIBS} 
                    libnppig.so   # resize 函数
                    )


3. 结果

【nvidia npp】——图像resize_#include