c++下Gdal将16bit的tif图像转8bit

【使用软件及版本】Gdal4.x（含proj等），vs2019

打包完的，到手即用。

头文件（仅罗列关键文件，其他基础自行添加）

#include "gdal_priv.h"
#include "gdal.h"
#include<algorithm>
class imageprocessing
{
public:
	int stretch_percent_16to8(const char* inFilename, const char* dstFilename);
};
           

可有可无文件，具体功能不太清楚

typedef unsigned __int16 uint16_t;
typedef unsigned unsigned char uint8_t;
           

cpp文件

int imageprocessing::stretch_percent_16to8(const char* inFilename, const char* dstFilename)
{
	GDALAllRegister();
	//为了支持中文路径
	CPLSetConfigOption("GDAL_FILENAME_IS_UTF8", "NO");
	int src_height = 0;
	int src_width = 0;
	GDALDataset* poIn = (GDALDataset*)GDALOpen(inFilename, GA_ReadOnly);   //打开影像
	//获取影像大小
	src_width = poIn->GetRasterXSize();
	src_height = poIn->GetRasterYSize();
	//获取影像波段数
	int InBands = poIn->GetRasterCount();
	//获取影像格式
	GDALDataType eDataType = poIn->GetRasterBand(1)->GetRasterDataType();
	//定义存储影像的空间参考数组
	double adfInGeoTransform[6] = { 0 };
	const char* pszWKT = NULL;
	//获取影像空间参考
	poIn->GetGeoTransform(adfInGeoTransform);
	pszWKT = poIn->GetProjectionRef();
	//创建文件
	GDALDriver* poDriver = (GDALDriver*)GDALGetDriverByName("GTiff");
	GDALDataset* poOutputDS = poDriver->Create(dstFilename, src_width, src_height, InBands, GDT_Byte, NULL);

	//设置拉伸后图像的空间参考以及地理坐标
	poOutputDS->SetGeoTransform(adfInGeoTransform);
	poOutputDS->SetProjection(pszWKT);
	//读取影像

	cout << "16位影像降到8位影像处理..." << endl;
	for (int iBand = 0; iBand < InBands; iBand++)
	{
		cout << "正在处理第 " << iBand + 1 << " 波段" << endl;
		//读取影像
		uint16_t* srcData = (uint16_t*)malloc(sizeof(uint16_t) * src_width * src_height * 1);
		memset(srcData, 0, sizeof(uint16_t) * 1 * src_width * src_height);
		int src_max = 0, src_min = 65500;
		//读取多光谱影像到缓存
		poIn->GetRasterBand(iBand + 1)->RasterIO(GF_Read, 0, 0, src_width, src_height, srcData + 0 * src_width * src_height, src_width, src_height, GDT_UInt16, 0, 0);
		//}
		//统计最大值
		for (int src_row = 0; src_row < src_height; src_row++)
		{
			for (int src_col = 0; src_col < src_width; src_col++)
			{
				uint16_t src_temVal = *(srcData + src_row * src_width + src_col);
				if (src_temVal > src_max)
					src_max = src_temVal;
				if (src_temVal < src_min)
					src_min = src_temVal;
			}
		}

		double* numb_pix = (double*)malloc(sizeof(double) * (src_max + 1));      //存像素值直方图，即每个像素值的个数
		memset(numb_pix, 0, sizeof(double) * (src_max + 1));
		//                 -------  统计像素值直方图  ------------         //

		for (int src_row = 0; src_row < src_height; src_row++)
		{
			for (int src_col = 0; src_col < src_width; src_col++)
			{
				uint16_t src_temVal = *(srcData + src_row * src_width + src_col);
				*(numb_pix + src_temVal) += 1;
			}
		}

		double* frequency_val = (double*)malloc(sizeof(double) * (src_max + 1));           //像素值出现的频率
		memset(frequency_val, 0.0, sizeof(double) * (src_max + 1));

		for (int val_i = 0; val_i <= src_max; val_i++)
		{
			*(frequency_val + val_i) = *(numb_pix + val_i) / double(src_width * src_height);
		}

		double* accumlt_frequency_val = (double*)malloc(sizeof(double) * (src_max + 1));   //像素出现的累计频率
		memset(accumlt_frequency_val, 0.0, sizeof(double) * (src_max + 1));

		for (int val_i = 0; val_i <= src_max; val_i++)
		{
			for (int val_j = 0; val_j < val_i; val_j++)
			{
				*(accumlt_frequency_val + val_i) += *(frequency_val + val_j);
			}
		}
		//统计像素两端截断值
		int minVal = 0, maxVal = 0;
		for (int val_i = 1; val_i < src_max; val_i++)
		{
			double acc_fre_temVal0 = *(frequency_val + 0);
			double acc_fre_temVal = *(accumlt_frequency_val + val_i);
			if ((acc_fre_temVal - acc_fre_temVal0) > 0.0015)
			{
				minVal = val_i;
				break;
			}
		}
		for (int val_i = src_max - 1; val_i > 0; val_i--)
		{
			double acc_fre_temVal0 = *(accumlt_frequency_val + src_max);
			double acc_fre_temVal = *(accumlt_frequency_val + val_i);
			if (acc_fre_temVal < (acc_fre_temVal0 - 0.00012))
			{
				maxVal = val_i;
				break;
			}
		}

		for (int src_row = 0; src_row < src_height; src_row++)
		{
			uint8_t* dstData = (uint8_t*)malloc(sizeof(uint8_t) * src_width);
			memset(dstData, 0, sizeof(uint8_t) * src_width);
			for (int src_col = 0; src_col < src_width; src_col++)
			{
				uint16_t src_temVal = *(srcData + src_row * src_width + src_col);
				double stre_temVal = (src_temVal - minVal) / double(maxVal - minVal);
				if (src_temVal < minVal)
				{
					*(dstData + src_col) = (src_temVal) * (20.0 / double(minVal));
				}
				else if (src_temVal > maxVal)
				{
					stre_temVal = (src_temVal - src_min) / double(src_max - src_min);
					*(dstData + src_col) = 254;
				}
				else
					*(dstData + src_col) = pow(stre_temVal, 0.7) * 250;

			}
			poOutputDS->GetRasterBand(iBand + 1)->RasterIO(GF_Write, 0, src_row, src_width, 1, dstData, src_width, 1, GDT_Byte, 0, 0);
			free(dstData);
		}

		free(numb_pix);
		free(frequency_val);
		free(accumlt_frequency_val);
		free(srcData);

	}
	GDALClose(poIn);
	GDALClose(poOutputDS);

	return 0;
}
           

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