用C++代码和gdal库实现tif影像的匀光匀色程序

以下是一个简单的使用gdal库实现tif影像匀光匀色的C++代码示例。该程序读取输入tif影像文件，对其进行直方图均衡化处理，并输出匀光匀色后的tif影像文件。

#include "gdal_priv.h"
#include "cpl_conv.h" // for CPLMalloc()

int main(int argc, char* argv[])
{
    // Register all known GDAL drivers.
    GDALAllRegister();

    // Open input tif file.
    GDALDataset *poDataset;
    poDataset = (GDALDataset *) GDALOpen(argv[1], GA_ReadOnly );
    if( poDataset == NULL )
    {
        printf("Open failed.\n");
        exit(1);
    }

    // Get image width and height.
    int nXSize = poDataset->GetRasterXSize();
    int nYSize = poDataset->GetRasterYSize();

    // Get band count.
    int nBands = poDataset->GetRasterCount();

    // Allocate memory for input data.
    float *pData = (float *) CPLMalloc(sizeof(float) * nXSize * nYSize * nBands);

    // Read input data.
    poDataset->RasterIO(GF_Read, 0, 0, nXSize, nYSize, pData, nXSize, nYSize, GDT_Float32, nBands, NULL, 0, 0, 0);

    // Histogram equalization for each band.
    for(int i=0; i<nBands; i++)
    {
        GDALRasterBand *poBand = poDataset->GetRasterBand(i+1);

        // Get histogram.
        double adfHist[256];
        poBand->GetHistogram(0, 255, 256, adfHist, FALSE, FALSE, NULL, NULL);

        // Get cumulative histogram.
        double adfCumulativeHist[256];
        adfCumulativeHist[0] = adfHist[0];
        for(int j=1; j<256; j++)
        {
            adfCumulativeHist[j] = adfCumulativeHist[j-1] + adfHist[j];
        }

        // Normalize cumulative histogram.
        for(int j=0; j<256; j++)
        {
            adfCumulativeHist[j] = adfCumulativeHist[j] / (nXSize * nYSize);
        }

        // Equalize image.
        float fMin, fMax;
        poBand->ComputeRasterMinMax(TRUE, &fMin, &fMax);
        float fRange = fMax - fMin;
        for(int j=0; j<nXSize*nYSize; j++)
        {
            int nValue = (int) ((pData[j*nBands+i] - fMin) / fRange * 255);
            pData[j*nBands+i] = (float) adfCumulativeHist[nValue];
        }
    }

    // Create output tif file.
    GDALDriver *poDriver;
    poDriver = GetGDALDriverManager()->GetDriverByName("GTiff");
    if( poDriver == NULL )
    {
        printf("Create driver failed.\n");
        exit(1);
    }
    GDALDataset *poOutputDataset;
    poOutputDataset = poDriver->Create(argv[2], nXSize, nYSize, nBands, GDT_Float32, NULL);
    if( poOutputDataset == NULL )
    {
        printf("Create output dataset failed.\n");
        exit(1);
    }

    // Write output data.
    poOutputDataset->RasterIO(GF_Write, 0, 0, nXSize, nYSize, pData, nXSize, nYSize, GDT_Float32, nBands, NULL, 0, 0, 0);

    // Close datasets.
    GDALClose((GDALDatasetH) poDataset);
    GDALClose((GDALDatasetH) poOutputDataset);

    // Free memory.
    CPLFree(pData);

    return 0;
}

需要注意的是，该程序只支持单波段tif影像文件，如果需要处理多波段tif影像文件，需要对代码进行修改。