利用FreeImage将gif图像转为opencv中的Mat

来源：互联网发布：ecshop php 5.6 编辑：程序博客网时间：2024/05/21 11:20

原文：http://www.cnblogs.com/monkeyhey/p/3927857.html

网上有将gif转为iplimg的版本，只是用惯了C++的接口，所以就写了个转Mat的版本，代码比较简单

一、读文件

 1     int MatFun::gif2Mat(char* data, size_t dataSize, vector<Mat>& gifImgs, Mat& singleImg) 2     { 3         /* initialise 4         ->open memory 5         ->getImageType 6         ->load bitmaps 7         ->bitmaps to Mat 8         ->free all resource 9         */10         // condition1: data is not null11         if (NULL == data || dataSize == 0)12             return -1;13         FreeImage_Initialise();14         FIMEMORY* memory = FreeImage_OpenMemory((BYTE*)data, dataSize);15         if (NULL==memory)16         {17             FreeImage_DeInitialise();   //condition 2: memory is not null 18         }19 20         FREE_IMAGE_FORMAT fif = FreeImage_GetFileTypeFromMemory(memory);21         if (FIF_UNKNOWN == fif)    //condition 3: type of image should be know22         {23             fprintf(stderr, "unknown type of image");24             if (NULL != memory) FreeImage_CloseMemory(memory);25             FreeImage_DeInitialise();26             return -1;27         }28         else if (FIF_GIF != fif)  //condition 4: type of image should be GIF29         {30             if (NULL != memory) FreeImage_CloseMemory(memory);31             FreeImage_DeInitialise();32             return 0;33         }34 35         FIMULTIBITMAP * fiBmp = FreeImage_LoadMultiBitmapFromMemory(fif, memory, GIF_DEFAULT);36         if (NULL==fiBmp)37         {38             if (NULL != memory) FreeImage_CloseMemory(memory);   //condition 5: bitmaps is not null39             FreeImage_DeInitialise();40             return -1;41         }42 43         int num = FreeImage_GetPageCount(fiBmp);44 45         for (int i = 0; i < num; i++)46         {47             if (i==0 || i==2)48             {49                 FIBITMAP *mfibmp = FreeImage_LockPage(fiBmp, i);50                 if (mfibmp)     51                 {52                     Mat dst = bitMap2Mat(mfibmp, fif);53                     FreeImage_UnlockPage(fiBmp, mfibmp, false);54                     if (dst.empty())55                     {56                         if (NULL != memory) FreeImage_CloseMemory(memory);57                         if (NULL != fiBmp) FreeImage_CloseMultiBitmap(fiBmp, GIF_DEFAULT);58                         FreeImage_DeInitialise();59                         return -1;60                     }61                     gifImgs.push_back(dst);62                     dst.release();63                 }64             }65         }66 67         if (NULL != memory)68             FreeImage_CloseMemory(memory);69         if (NULL != fiBmp)70             FreeImage_CloseMultiBitmap(fiBmp);71         FreeImage_DeInitialise();72 73         return 0;74     }

这部分其实功能很简单，代码里面大部分都是检查，实际执行就初始化、打开内存、内存中读bitmap这几步。

二、gif转Mat

    Mat MatFun::bitMap2Mat(FIBITMAP* fiBmp, const FREE_IMAGE_FORMAT &fif)    {        if (NULL == fiBmp || FIF_GIF != fif)            return Mat();        int width = FreeImage_GetWidth(fiBmp);        int height = FreeImage_GetHeight(fiBmp);        BYTE intensity;        BYTE* pIntensity = &intensity;        if(FreeImage_GetBPP(fiBmp) !=8)            fiBmp = FreeImage_ConvertTo8Bits(fiBmp); //必须转化为8bit        RGBQUAD* pixels = new RGBQUAD;         pixels = FreeImage_GetPalette(fiBmp);        Mat img=Mat::zeros(height, width, CV_8UC3);        uchar* p;        for (int i = 0; i < height; i++)        {            p = img.ptr<uchar>(i);            for (int j = 0; j < width; j++)            {                FreeImage_GetPixelIndex(fiBmp, j, i, pIntensity);                                p[3 * j] = pixels[intensity].rgbBlue;                p[3 * j + 1] = pixels[intensity].rgbGreen;                p[3 * j + 2] = pixels[intensity].rgbRed;            }        }        return img;    }

具体的将byte像素转化为mat里面的像素值即可，注意rgb图像的Mat里是一个像素包含三通道的值，知道这点，代码就很好理解了。

#include <FreeImage.h>#include <opencv2\opencv.hpp>using namespace cv;void FI2MAT(FIBITMAP* src, Mat& dst){    //FIT_BITMAP    //standard image : 1 - , 4 - , 8 - , 16 - , 24 - , 32 - bit    //FIT_UINT16    //array of unsigned short : unsigned 16 - bit    //FIT_INT16     //array of short : signed 16 - bit    //FIT_UINT32    //array of unsigned long : unsigned 32 - bit    //FIT_INT32     //array of long : signed 32 - bit    //FIT_FLOAT     //array of float : 32 - bit IEEE floating point    //FIT_DOUBLE    //array of double : 64 - bit IEEE floating point    //FIT_COMPLEX   //array of FICOMPLEX : 2 x 64 - bit IEEE floating point    //FIT_RGB16     //48 - bit RGB image : 3 x 16 - bit    //FIT_RGBA16    //64 - bit RGBA image : 4 x 16 - bit    //FIT_RGBF      //96 - bit RGB float image : 3 x 32 - bit IEEE floating point    //FIT_RGBAF     //128 - bit RGBA float image : 4 x 32 - bit IEEE floating point    int bpp = FreeImage_GetBPP(src);    FREE_IMAGE_TYPE fit = FreeImage_GetImageType(src);    int cv_type = -1;    int cv_cvt = -1;    switch (fit)    {    case FIT_UINT16: cv_type = DataType<ushort>::type; break;    case FIT_INT16: cv_type = DataType<short>::type; break;    case FIT_UINT32: cv_type = DataType<unsigned>::type; break;    case FIT_INT32: cv_type = DataType<int>::type; break;    case FIT_FLOAT: cv_type = DataType<float>::type; break;    case FIT_DOUBLE: cv_type = DataType<double>::type; break;    case FIT_COMPLEX: cv_type = DataType<Complex<double>>::type; break;    case FIT_RGB16: cv_type = DataType<Vec<ushort, 3>>::type; cv_cvt = COLOR_RGB2BGR; break;    case FIT_RGBA16: cv_type = DataType<Vec<ushort, 4>>::type; cv_cvt = COLOR_RGBA2BGRA; break;    case FIT_RGBF: cv_type = DataType<Vec<float, 3>>::type; cv_cvt = COLOR_RGB2BGR; break;    case FIT_RGBAF: cv_type = DataType<Vec<float, 4>>::type; cv_cvt = COLOR_RGBA2BGRA; break;    case FIT_BITMAP:        switch (bpp) {        case 8: cv_type = DataType<Vec<uchar, 1>>::type; break;        case 16: cv_type = DataType<Vec<uchar, 2>>::type; break;        case 24: cv_type = DataType<Vec<uchar, 3>>::type; break;        case 32: cv_type = DataType<Vec<uchar, 4>>::type; break;        default:            // 1, 4 // Unsupported natively            cv_type = -1;        }        break;    default:        // FIT_UNKNOWN // unknown type        dst = Mat(); // return empty Mat        return;    }    int width = FreeImage_GetWidth(src);    int height = FreeImage_GetHeight(src);    int step = FreeImage_GetPitch(src);    if (cv_type >= 0) {        dst = Mat(height, width, cv_type, FreeImage_GetBits(src), step);        if (cv_cvt > 0)        {            cvtColor(dst, dst, cv_cvt);        }    }    else {        vector<uchar> lut;        int n = pow(2, bpp);        for (int i = 0; i < n; ++i)        {            lut.push_back(static_cast<uchar>((255 / (n - 1))*i));        }        FIBITMAP* palletized = FreeImage_ConvertTo8Bits(src);        BYTE* data = FreeImage_GetBits(src);        for (int r = 0; r < height; ++r) {            for (int c = 0; c < width; ++c) {                dst.at<uchar>(r, c) = saturate_cast<uchar>(lut[data[r*step + c]]);            }        }    }    flip(dst, dst, 0);}int main(){    FreeImage_Initialise();    FREE_IMAGE_FORMAT format = FreeImage_GetFileType("path_to_image", 0);    FIBITMAP* fi_image = FreeImage_Load(format, "path_to_image");    Mat cv_img;    FI2MAT(fi_image, cv_img);    return 0;}

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