c++ 如何把RGB图像转换成HSV图像？

CV_<bit_depth>(S|U|F)C<number_of_channels>

1--bit_depth---比特数---代表8bite,16bites,32bites,64bites---举个例子吧--比如说,如
        如果你现在创建了一个存储--灰度图片的Mat对象,这个图像的大小为宽100,高100,那么,现在这张
        灰度图片中有10000个像素点，它每一个像素点在内存空间所占的空间大小是8bite,8位--所以它对
        应的就是CV_8
     2--S|U|F--S--代表---signed int---有符号整形
               U--代表--unsigned int--无符号整形
               F--代表--float---------单精度浮点型
     3--C<number_of_channels>----代表---一张图片的通道数,比如:
         1--灰度图片--grayImg---是--单通道图像
         2--RGB彩色图像---------是--3通道图像
         3--带Alph通道的RGB图像--是--4通道图像

//【1】CV_8UC1---则可以创建----8位无符号的单通道---灰度图片------grayImg
#define CV_8UC1 CV_MAKETYPE(CV_8U,1)
#define CV_8UC2 CV_MAKETYPE(CV_8U,2)
//【2】CV_8UC3---则可以创建----8位无符号的三通道---RGB彩色图像---colorImg
#define CV_8UC3 CV_MAKETYPE(CV_8U,3)
//【3】CV_8UC4--则可以创建-----8位无符号的四通道---带透明色的RGB图像
#define CV_8UC4 CV_MAKETYPE(CV_8U,4)

struct RGB2HSV_b
{
    typedef uchar channel_type;

    RGB2HSV_b(int _srccn, int _blueIdx, int _hrange)
    : srccn(_srccn), blueIdx(_blueIdx), hrange(_hrange)
    {
        CV_Assert( hrange == 180 || hrange == 256 );
    }

    void operator()(const uchar* src, uchar* dst, int n) const
    {
        int i, bidx = blueIdx, scn = srccn;
        const int hsv_shift = 12;

        static int sdiv_table[256];
        static int hdiv_table180[256];
        static int hdiv_table256[256];
        static volatile bool initialized = false;

        int hr = hrange;
        const int* hdiv_table = hr == 180 ? hdiv_table180 : hdiv_table256;
        n *= 3;

        if( !initialized )
        {
            sdiv_table[0] = hdiv_table180[0] = hdiv_table256[0] = 0;
            for( i = 1; i < 256; i++ )
            {
                sdiv_table[i] = saturate_cast<int>((255 << hsv_shift)/(1.*i));
                hdiv_table180[i] = saturate_cast<int>((180 << hsv_shift)/(6.*i));
                hdiv_table256[i] = saturate_cast<int>((256 << hsv_shift)/(6.*i));
            }
            initialized = true;
        }

        for( i = 0; i < n; i += 3, src += scn )
        {
            int b = src[bidx], g = src[1], r = src[bidx^2];
            int h, s, v = b;
            int vmin = b;
            int vr, vg;

            CV_CALC_MAX_8U( v, g );
            CV_CALC_MAX_8U( v, r );
            CV_CALC_MIN_8U( vmin, g );
            CV_CALC_MIN_8U( vmin, r );

            uchar diff = saturate_cast<uchar>(v - vmin);
            vr = v == r ? -1 : 0;
            vg = v == g ? -1 : 0;

            s = (diff * sdiv_table[v] + (1 << (hsv_shift-1))) >> hsv_shift;
            h = (vr & (g - b)) +
                (~vr & ((vg & (b - r + 2 * diff)) + ((~vg) & (r - g + 4 * diff))));
            h = (h * hdiv_table[diff] + (1 << (hsv_shift-1))) >> hsv_shift;
            h += h < 0 ? hr : 0;

            dst[i] = saturate_cast<uchar>(h);
            dst[i+1] = (uchar)s;
            dst[i+2] = (uchar)v;
        }
    }

    int srccn, blueIdx, hrange;
};

struct RGB2HSV_f
{
    typedef float channel_type;

    RGB2HSV_f(int _srccn, int _blueIdx, float _hrange)
    : srccn(_srccn), blueIdx(_blueIdx), hrange(_hrange) {}

    void operator()(const float* src, float* dst, int n) const
    {
        int i, bidx = blueIdx, scn = srccn;
        float hscale = hrange*(1.f/360.f);
        n *= 3;

        for( i = 0; i < n; i += 3, src += scn )
        {
            float b = src[bidx], g = src[1], r = src[bidx^2];
            float h, s, v;

            float vmin, diff;

            v = vmin = r;
            if( v < g ) v = g;
            if( v < b ) v = b;
            if( vmin > g ) vmin = g;
            if( vmin > b ) vmin = b;

            diff = v - vmin;
            s = diff/(float)(fabs(v) + FLT_EPSILON);
            diff = (float)(60./(diff + FLT_EPSILON));
            if( v == r )
                h = (g - b)*diff;
            else if( v == g )
                h = (b - r)*diff + 120.f;
            else
                h = (r - g)*diff + 240.f;

            if( h < 0 ) h += 360.f;

            dst[i] = h*hscale;
            dst[i+1] = s;
            dst[i+2] = v;
        }
    }

    int srccn, blueIdx;
    float hrange;
};

#define FLT_EPSILON      1.192092896e-07F        // smallest such that 1.0+FLT_EPSILON != 1.0
/* helper tables */
extern const uchar icvSaturate8u_cv[];
#define CV_FAST_CAST_8U(t)  ( (-256 <= (t) && (t) <= 512) ? icvSaturate8u_cv[(t)+256] : 0 )
#define CV_CALC_MIN_8U(a,b) (a) -= CV_FAST_CAST_8U((a) - (b))
#define CV_CALC_MAX_8U(a,b) (a) += CV_FAST_CAST_8U((b) - (a))