[置顶] opencv一些函数的底层代码

cvWaitKey()的实现

 int  cvWaitKey( int delay )
{
    int time0 = GetTickCount();

    for(;;)
    {
        CvWindow* window;
        MSG message;
        int is_processed = 0;

        if( (delay > 0 && abs((int)(GetTickCount() - time0)) >= delay) ||

hg_windows == 0 )
            return -1;

        if( delay <= 0 )
            GetMessage(&message, 0, 0, 0);
        else if( PeekMessage(&message, 0, 0, 0, PM_REMOVE) == FALSE )
        {
            Sleep(1);
            continue;
        }

        for( window = hg_windows; window != 0 && is_processed == 0; window =

window->next )
        {
            if( window->hwnd == message.hwnd || window->frame == message.hwnd )
            {
                is_processed = 1;
                switch(message.message)
                {
                case WM_DESTROY:
                case WM_CHAR:
                    DispatchMessage(&message);
                    return (int)message.wParam;

                case WM_KEYDOWN:
                    TranslateMessage(&message);
                default:
                    DispatchMessage(&message);
                    is_processed = 1;
                    break;
                }
            }
        }

        if( !is_processed )
        {
            TranslateMessage(&message);
            DispatchMessage(&message);
        }
    }
}
/**********************************************************/
cvReleaseMat的实现
void cvReleaseMat( CvMat** array )
{
    CV_FUNCNAME( "cvReleaseMat" );
   
    __BEGIN__;

    if( !array )
        CV_ERROR_FROM_CODE( CV_HeaderIsNull );

    if( *array )
    {
        CvMat* arr = *array;
       
        if( !CV_IS_MAT_HDR(arr) && !CV_IS_MATND_HDR(arr) )
            CV_ERROR_FROM_CODE( CV_StsBadFlag );

        *array = 0;

        cvDecRefData( arr );
        cvFree( &arr );
    }

    __END__;
}

/**********************************************************/
cvFree的实现
#define cvFree(ptr) (cvFree_(*(ptr)), *(ptr)=0)
void  cvFree_( void* ptr )
{
    CV_FUNCNAME( "cvFree_" );

    __BEGIN__;

    if( ptr )
    {
        CVStatus status = p_cvFree( ptr, p_cvAllocUserData );
        if( status < 0 )
            CV_ERROR( status, "Deallocation error" );
    }

    __END__;
}
*ptr==NULL;

/**********************************************************/
cvReleaseMemStorage的实现
void
cvReleaseMemStorage( CvMemStorage** storage )
{
    CvMemStorage *st;
    CV_FUNCNAME( "cvReleaseMemStorage" );

    __BEGIN__;

    if( !storage )
        CV_ERROR( CV_StsNullPtr, "" );

    st = *storage;
    *storage = 0;

    if( st )
    {
        CV_CALL( icvDestroyMemStorage( st ));
        cvFree( &st );
    }

    __END__;
}

typedef struct CvMemStorage
{
    int signature;
    CvMemBlock* bottom;/* first allocated block */
    CvMemBlock* top;   /* current memory block - top of the stack */
    struct  CvMemStorage* parent; /* borrows new blocks from */
    int block_size;  /* block size */
    int free_space;  /* free space in the current block */
}
CvMemStorage;

typedef struct CvMemBlock
{
    struct CvMemBlock*  prev;
    struct CvMemBlock*  next;
}
CvMemBlock;

/**********************************************************/
cvSeqPush的实现
char* cvSeqPush( CvSeq *seq, void *element )
{
    char *ptr = 0;
    size_t elem_size;

    CV_FUNCNAME( "cvSeqPush" );// means static char cvFuncName[] = Name

    __BEGIN__;

    if( !seq )
        CV_ERROR( CV_StsNullPtr, "" );

    elem_size = seq->elem_size;
    ptr = seq->ptr;

    if( ptr >= seq->block_max )
    {
        CV_CALL( icvGrowSeq( seq, 0 ));

        ptr = seq->ptr;
        assert( ptr + elem_size <= seq->block_max /*&& ptr == seq->block_min */

 );
    }

    if( element )
        CV_MEMCPY_AUTO( ptr, element, elem_size );
    seq->first->prev->count++;
    seq->total++;
    seq->ptr = ptr + elem_size;

    __END__;

    return ptr;
}

 #define CV_FUNCNAME( Name )  \
    static char cvFuncName[] = Name

#define CV_MEMCPY_AUTO( dst, src, len )                                        

    \
{                                                                              

    \
    size_t _icv_memcpy_i_, _icv_memcpy_len_ = (len);                           

    \
    char* _icv_memcpy_dst_ = (char*)(dst);                                     

    \
    const char* _icv_memcpy_src_ = (const char*)(src);                         

    \
    if( (_icv_memcpy_len_ & (sizeof(int)-1)) == 0 )                            

    \
    {                                                                          

    \
        assert( ((size_t)_icv_memcpy_src_&(sizeof(int)-1)) == 0 &&             

    \
                ((size_t)_icv_memcpy_dst_&(sizeof(int)-1)) == 0 );             

    \
        for( _icv_memcpy_i_ = 0; _icv_memcpy_i_ < _icv_memcpy_len_;            

    \
            _icv_memcpy_i_+=sizeof(int) )                                      

    \
        {                                                                      

    \
            *(int*)(_icv_memcpy_dst_+_icv_memcpy_i_) =                         

    \
            *(const int*)(_icv_memcpy_src_+_icv_memcpy_i_);                    

    \
        }                                                                      

    \
    }                                                                          

    \
    else                                                                       

    \
    {                                                                          

    \
        for(_icv_memcpy_i_ = 0; _icv_memcpy_i_ < _icv_memcpy_len_;

_icv_memcpy_i_++)\
            _icv_memcpy_dst_[_icv_memcpy_i_] = _icv_memcpy_src_

[_icv_memcpy_i_];    \
    }                                                                          

    \
}

 

/**********************************************************/
cvGetSeqElem的底层实现
char*
cvGetSeqElem( const CvSeq *seq, int index )
{
    CvSeqBlock *block;
    int count, total = seq->total;

    if( (unsigned)index >= (unsigned)total )
    {
        index += index < 0 ? total : 0;
        index -= index >= total ? total : 0;
        if( (unsigned)index >= (unsigned)total )
            return 0;
    }

    block = seq->first;
    if( index + index <= total )
    {
        while( index >= (count = block->count) )
        {
            block = block->next;
            index -= count;
        }
    }
    else
    {
        do
        {
            block = block->prev;
            total -= block->count;
        }
        while( index < total );
        index -= total;
    }

    return block->data + index * seq->elem_size;
}

typedef struct CvSeqBlock
{
    struct CvSeqBlock*  prev; /* previous sequence block */
    struct CvSeqBlock*  next; /* next sequence block */
    int    start_index;       /* index of the first element in the block +
                                 sequence->first->start_index */
    int    count;             /* number of elements in the block */
    char*  data;              /* pointer to the first element of the block */
}
CvSeqBlock;

/**********************************************************/
cvAlloc的实现代码
 void*  cvAlloc( size_t size )
{
    void* ptr = 0;
   
    CV_FUNCNAME( "cvAlloc" );

    __BEGIN__;

    if( (size_t)size > CV_MAX_ALLOC_SIZE )
        CV_ERROR( CV_StsOutOfRange,
                  "Negative or too large argument of cvAlloc function" );

    ptr = p_cvAlloc( size, p_cvAllocUserData );
    if( !ptr )
        CV_ERROR( CV_StsNoMem, "Out of memory" );

    __END__;

    return ptr;
}

#define  CV_MAX_ALLOC_SIZE    (((size_t)1 << (sizeof(size_t)*8-2)))

/**********************************************************/
cvCreateMat的实现

 

/**********************************************************/
 cvIntegral的实现
/* D:\Program Files\OpenCV\cv\src\cvsumpixels.cpp */
 void
cvIntegral( const CvArr* image, CvArr* sumImage,
            CvArr* sumSqImage, CvArr* tiltedSumImage )
{
    static CvFuncTable tab_c1, tab_cn;
    static int inittab = 0;
   
    CV_FUNCNAME( "cvIntegralImage" );

    __BEGIN__;

    CvMat src_stub, *src = (CvMat*)image;
    CvMat sum_stub, *sum = (CvMat*)sumImage;
    CvMat sqsum_stub, *sqsum = (CvMat*)sumSqImage;
    CvMat tilted_stub, *tilted = (CvMat*)tiltedSumImage;
    int coi0 = 0, coi1 = 0, coi2 = 0, coi3 = 0;
    int depth, cn;
    int src_step, sum_step, sqsum_step, tilted_step;
    CvIntegralImageFuncC1 func_c1 = 0;
    CvIntegralImageFuncCn func_cn = 0;
    CvSize size;

    if( !inittab )
    {
        icvInitIntegralImageTable( &tab_c1, &tab_cn );
        inittab = 1;
    }

    CV_CALL( src = cvGetMat( src, &src_stub, &coi0 ));
    CV_CALL( sum = cvGetMat( sum, &sum_stub, &coi1 ));
   
    if( sum->width != src->width + 1 ||
        sum->height != src->height + 1 )
        CV_ERROR( CV_StsUnmatchedSizes, "" );

    if( CV_MAT_DEPTH( sum->type ) != CV_64F &&
        (CV_MAT_DEPTH( src->type ) != CV_8U ||
         CV_MAT_DEPTH( sum->type ) != CV_32S ) ||
        !CV_ARE_CNS_EQ( src, sum ))
        CV_ERROR( CV_StsUnsupportedFormat,
        "Sum array must have 64f type (or 32s type in case of 8u source array)

"
        "and the same number of channels as the source array" );

    if( sqsum )
    {
        CV_CALL( sqsum = cvGetMat( sqsum, &sqsum_stub, &coi2 ));
        if( !CV_ARE_SIZES_EQ( sum, sqsum ) )
            CV_ERROR( CV_StsUnmatchedSizes, "" );
        if( CV_MAT_DEPTH( sqsum->type ) != CV_64F || !CV_ARE_CNS_EQ( src, sqsum

))
            CV_ERROR( CV_StsUnsupportedFormat,
                      "Squares sum array must be 64f "
                      "and the same number of channels as the source array" );
    }

    if( tilted )
    {
        if( !sqsum )
            CV_ERROR( CV_StsNullPtr,
            "Squared sum array must be passed if tilted sum array is passed" );

        CV_CALL( tilted = cvGetMat( tilted, &tilted_stub, &coi3 ));
        if( !CV_ARE_SIZES_EQ( sum, tilted ) )
            CV_ERROR( CV_StsUnmatchedSizes, "" );
        if( !CV_ARE_TYPES_EQ( sum, tilted ) )
            CV_ERROR( CV_StsUnmatchedFormats,
                      "Sum and tilted sum must have the same types" );
        if( CV_MAT_CN(tilted->type) != 1 )
            CV_ERROR( CV_StsNotImplemented,
                      "Tilted sum can not be computed for multi-channel arrays"

);
    }

    if( coi0 || coi1 || coi2 || coi3 )
        CV_ERROR( CV_BadCOI, "COI is not supported by the function" );

    depth = CV_MAT_DEPTH(src->type);
    cn = CV_MAT_CN(src->type);

    if( CV_MAT_DEPTH( sum->type ) == CV_32S )
    {
        func_c1 = (CvIntegralImageFuncC1)icvIntegralImage_8u32s_C1R;
        func_cn = (CvIntegralImageFuncCn)icvIntegralImage_8u32s_CnR;
    }
    else
    {
        func_c1 = (CvIntegralImageFuncC1)tab_c1.fn_2d[depth];
        func_cn = (CvIntegralImageFuncCn)tab_cn.fn_2d[depth];
        if( !func_c1 && !func_cn )
            CV_ERROR( CV_StsUnsupportedFormat, "This source image format is

unsupported" );
    }

    size = cvGetMatSize(src);
    src_step = src->step ? src->step : CV_STUB_STEP;
    sum_step = sum->step ? sum->step : CV_STUB_STEP;
    sqsum_step = !sqsum ? 0 : sqsum->step ? sqsum->step : CV_STUB_STEP;
    tilted_step = !tilted ? 0 : tilted->step ? tilted->step : CV_STUB_STEP;

    if( cn == 1 )
    {
        if( depth == CV_8U && !tilted && CV_MAT_DEPTH(sum->type) == CV_32S )
        {
            if( !sqsum && icvIntegral_8u32s_C1R_p &&
                icvIntegral_8u32s_C1R_p( src->data.ptr, src_step,
                            sum->data.i, sum_step, size, 0 ) >= 0 )
                EXIT;
           
            if( sqsum && icvSqrIntegral_8u32s64f_C1R_p &&
                icvSqrIntegral_8u32s64f_C1R_p( src->data.ptr, src_step, sum-

>data.i,
                            sum_step, sqsum->data.db, sqsum_step, size, 0, 0 )

>= 0 )
                EXIT;
        }

        IPPI_CALL( func_c1( src->data.ptr, src_step, sum->data.ptr, sum_step,
                        sqsum ? sqsum->data.ptr : 0, sqsum_step,
                        tilted ? tilted->data.ptr : 0, tilted_step, size ));
    }
    else
    {
        IPPI_CALL( func_cn( src->data.ptr, src_step, sum->data.ptr, sum_step,
                        sqsum ? sqsum->data.ptr : 0, sqsum_step, size, cn ));
    }

    __END__;
}

typedef struct CvFuncTable
{
    void*   fn_2d[CV_DEPTH_MAX];
}
CvFuncTable;

#define CV_CN_SHIFT   3
#define CV_DEPTH_MAX  (1 << CV_CN_SHIFT)
/**********************************************************/
cvCanny 算法实现

 void cvCanny( const void* srcarr, void* dstarr,
         double low_thresh, double high_thresh, int aperture_size )
{
    static const int sec_tab[] = { 1, 3, 0, 0, 2, 2, 2, 2 };
    CvMat *dx = 0, *dy = 0;
    void *buffer = 0;
    uchar **stack_top, **stack_bottom = 0;

    CV_FUNCNAME( "cvCanny" );

    __BEGIN__;

    CvMat srcstub, *src = (CvMat*)srcarr;
    CvMat dststub, *dst = (CvMat*)dstarr;
    CvSize size;
    int flags = aperture_size;
    int low, high;
    int* mag_buf[3];
    uchar* map;
    int mapstep, maxsize;
    int i, j;
    CvMat mag_row;

    CV_CALL( src = cvGetMat( src, &srcstub ));
    CV_CALL( dst = cvGetMat( dst, &dststub ));

    if( CV_MAT_TYPE( src->type ) != CV_8UC1 ||
        CV_MAT_TYPE( dst->type ) != CV_8UC1 )
        CV_ERROR( CV_StsUnsupportedFormat, "" );

    if( !CV_ARE_SIZES_EQ( src, dst ))
        CV_ERROR( CV_StsUnmatchedSizes, "" );

    if( low_thresh > high_thresh )
    {
        double t;
        CV_SWAP( low_thresh, high_thresh, t );
    }

    aperture_size &= INT_MAX;
    if( (aperture_size & 1) == 0 || aperture_size < 3 || aperture_size > 7 )
        CV_ERROR( CV_StsBadFlag, "" );

    size = cvGetMatSize( src );

    dx = cvCreateMat( size.height, size.width, CV_16SC1 );
    dy = cvCreateMat( size.height, size.width, CV_16SC1 );
    cvSobel( src, dx, 1, 0, aperture_size );
    cvSobel( src, dy, 0, 1, aperture_size );

    if( icvCannyGetSize_p && icvCanny_16s8u_C1R_p && !(flags &

CV_CANNY_L2_GRADIENT) )
    {
        int buf_size=  0;
        IPPI_CALL( icvCannyGetSize_p( size, &buf_size ));
        CV_CALL( buffer = cvAlloc( buf_size ));
        IPPI_CALL( icvCanny_16s8u_C1R_p( (short*)dx->data.ptr, dx->step,
                                     (short*)dy->data.ptr, dy->step,
                                     dst->data.ptr, dst->step,
                                     size, (float)low_thresh,
                                     (float)high_thresh, buffer ));
        EXIT;
    }

    if( flags & CV_CANNY_L2_GRADIENT )
    {
        Cv32suf ul, uh;
        ul.f = (float)low_thresh;
        uh.f = (float)high_thresh;

        low = ul.i;
        high = uh.i;
    }
    else
    {
        low = cvFloor( low_thresh );
        high = cvFloor( high_thresh );
    }

    CV_CALL( buffer = cvAlloc( (size.width+2)*(size.height+2) +
                                (size.width+2)*3*sizeof(int)) );

    mag_buf[0] = (int*)buffer;
    mag_buf[1] = mag_buf[0] + size.width + 2;
    mag_buf[2] = mag_buf[1] + size.width + 2;
    map = (uchar*)(mag_buf[2] + size.width + 2);
    mapstep = size.width + 2;

    maxsize = MAX( 1 << 10, size.width*size.height/10 );
    CV_CALL( stack_top = stack_bottom = (uchar**)cvAlloc( maxsize*sizeof

(stack_top[0]) ));

    memset( mag_buf[0], 0, (size.width+2)*sizeof(int) );
    memset( map, 1, mapstep );
    memset( map + mapstep*(size.height + 1), 1, mapstep );

    /* sector numbers
       (Top-Left Origin)

        1   2   3
         *  *  *
          * * * 
        0*******0
          * * * 
         *  *  *
        3   2   1
    */

    #define CANNY_PUSH(d)    *(d) = (uchar)2, *stack_top++ = (d)
    #define CANNY_POP(d)     (d) = *--stack_top

    mag_row = cvMat( 1, size.width, CV_32F );

    // calculate magnitude and angle of gradient, perform non-maxima

supression.
    // fill the map with one of the following values:
    //   0 - the pixel might belong to an edge
    //   1 - the pixel can not belong to an edge
    //   2 - the pixel does belong to an edge
    for( i = 0; i <= size.height; i++ )
    {
        int* _mag = mag_buf[(i > 0) + 1] + 1;
        float* _magf = (float*)_mag;
        const short* _dx = (short*)(dx->data.ptr + dx->step*i);
        const short* _dy = (short*)(dy->data.ptr + dy->step*i);
        uchar* _map;
        int x, y;
        int magstep1, magstep2;
        int prev_flag = 0;

        if( i < size.height )
        {
            _mag[-1] = _mag[size.width] = 0;

            if( !(flags & CV_CANNY_L2_GRADIENT) )
                for( j = 0; j < size.width; j++ )
                    _mag[j] = abs(_dx[j]) + abs(_dy[j]);
            else if( icvFilterSobelVert_8u16s_C1R_p != 0 ) // check for IPP
            {
                // use vectorized sqrt
                mag_row.data.fl = _magf;
                for( j = 0; j < size.width; j++ )
                {
                    x = _dx[j]; y = _dy[j];
                    _magf[j] = (float)((double)x*x + (double)y*y);
                }
                cvPow( &mag_row, &mag_row, 0.5 );
            }
            else
            {
                for( j = 0; j < size.width; j++ )
                {
                    x = _dx[j]; y = _dy[j];
                    _magf[j] = (float)sqrt((double)x*x + (double)y*y);
                }
            }
        }
        else
            memset( _mag-1, 0, (size.width + 2)*sizeof(int) );

        // at the very beginning we do not have a complete ring
        // buffer of 3 magnitude rows for non-maxima suppression
        if( i == 0 )
            continue;

        _map = map + mapstep*i + 1;
        _map[-1] = _map[size.width] = 1;
       
        _mag = mag_buf[1] + 1; // take the central row
        _dx = (short*)(dx->data.ptr + dx->step*(i-1));
        _dy = (short*)(dy->data.ptr + dy->step*(i-1));
       
        magstep1 = (int)(mag_buf[2] - mag_buf[1]);
        magstep2 = (int)(mag_buf[0] - mag_buf[1]);

        if( (stack_top - stack_bottom) + size.width > maxsize )
        {
            uchar** new_stack_bottom;
            maxsize = MAX( maxsize * 3/2, maxsize + size.width );
            CV_CALL( new_stack_bottom = (uchar**)cvAlloc( maxsize * sizeof

(stack_top[0])) );
            memcpy( new_stack_bottom, stack_bottom, (stack_top - stack_bottom)

*sizeof(stack_top[0]) );
            stack_top = new_stack_bottom + (stack_top - stack_bottom);
            cvFree( &stack_bottom );
            stack_bottom = new_stack_bottom;
        }

        for( j = 0; j < size.width; j++ )
        {
            #define CANNY_SHIFT 15
            #define TG22  (int)(0.4142135623730950488016887242097*

(1<<CANNY_SHIFT) + 0.5)

            x = _dx[j];
            y = _dy[j];
            int s = x ^ y;
            int m = _mag[j];

            x = abs(x);
            y = abs(y);
            if( m > low )
            {
                int tg22x = x * TG22;
                int tg67x = tg22x + ((x + x) << CANNY_SHIFT);

                y <<= CANNY_SHIFT;

                if( y < tg22x )
                {
                    if( m > _mag[j-1] && m >= _mag[j+1] )
                    {
                        if( m > high && !prev_flag && _map[j-mapstep] != 2 )
                        {
                            CANNY_PUSH( _map + j );
                            prev_flag = 1;
                        }
                        else
                            _map[j] = (uchar)0;
                        continue;
                    }
                }
                else if( y > tg67x )
                {
                    if( m > _mag[j+magstep2] && m >= _mag[j+magstep1] )
                    {
                        if( m > high && !prev_flag && _map[j-mapstep] != 2 )
                        {
                            CANNY_PUSH( _map + j );
                            prev_flag = 1;
                        }
                        else
                            _map[j] = (uchar)0;
                        continue;
                    }
                }
                else
                {
                    s = s < 0 ? -1 : 1;
                    if( m > _mag[j+magstep2-s] && m > _mag[j+magstep1+s] )
                    {
                        if( m > high && !prev_flag && _map[j-mapstep] != 2 )
                        {
                            CANNY_PUSH( _map + j );
                            prev_flag = 1;
                        }
                        else
                            _map[j] = (uchar)0;
                        continue;
                    }
                }
            }
            prev_flag = 0;
            _map[j] = (uchar)1;
        }

        // scroll the ring buffer
        _mag = mag_buf[0];
        mag_buf[0] = mag_buf[1];
        mag_buf[1] = mag_buf[2];
        mag_buf[2] = _mag;
    }

    // now track the edges (hysteresis thresholding)
    while( stack_top > stack_bottom )
    {
        uchar* m;
        if( (stack_top - stack_bottom) + 8 > maxsize )
        {
            uchar** new_stack_bottom;
            maxsize = MAX( maxsize * 3/2, maxsize + 8 );
            CV_CALL( new_stack_bottom = (uchar**)cvAlloc( maxsize * sizeof

(stack_top[0])) );
            memcpy( new_stack_bottom, stack_bottom, (stack_top - stack_bottom)

*sizeof(stack_top[0]) );
            stack_top = new_stack_bottom + (stack_top - stack_bottom);
            cvFree( &stack_bottom );
            stack_bottom = new_stack_bottom;
        }

        CANNY_POP(m);
   
        if( !m[-1] )
            CANNY_PUSH( m - 1 );
        if( !m[1] )
            CANNY_PUSH( m + 1 );
        if( !m[-mapstep-1] )
            CANNY_PUSH( m - mapstep - 1 );
        if( !m[-mapstep] )
            CANNY_PUSH( m - mapstep );
        if( !m[-mapstep+1] )
            CANNY_PUSH( m - mapstep + 1 );
        if( !m[mapstep-1] )
            CANNY_PUSH( m + mapstep - 1 );
        if( !m[mapstep] )
            CANNY_PUSH( m + mapstep );
        if( !m[mapstep+1] )
            CANNY_PUSH( m + mapstep + 1 );
    }

    // the final pass, form the final image
    for( i = 0; i < size.height; i++ )
    {
        const uchar* _map = map + mapstep*(i+1) + 1;
        uchar* _dst = dst->data.ptr + dst->step*i;
       
        for( j = 0; j < size.width; j++ )
            _dst[j] = (uchar)-(_map[j] >> 1);
    }

    __END__;

    cvReleaseMat( &dx );
    cvReleaseMat( &dy );
    cvFree( &buffer );
    cvFree( &stack_bottom );
}