public void ProcessFrame( UnmanagedImage videoFrame, UnmanagedImage motionFrame )
{
if ( motionFrame.PixelFormat != PixelFormat.Format8bppIndexed )
{
throw new InvalidImagePropertiesException( "Motion frame must be 8 bpp image." );
}
if ( ( videoFrame.PixelFormat != PixelFormat.Format8bppIndexed ) &&
( videoFrame.PixelFormat != PixelFormat.Format24bppRgb ) &&
( videoFrame.PixelFormat != PixelFormat.Format32bppRgb ) &&
( videoFrame.PixelFormat != PixelFormat.Format32bppArgb ) )
{
throw new UnsupportedImageFormatException( "Video frame must be 8 bpp grayscale image or 24/32 bpp color image." );
}
int width = videoFrame.Width;
int height = videoFrame.Height;
int pixelSize = Bitmap.GetPixelFormatSize( videoFrame.PixelFormat ) / 8;
if ( ( motionFrame.Width != width ) || ( motionFrame.Height != height ) )
return;
int cellWidth = width / gridWidth;
int cellHeight = height / gridHeight;
// temporary variables
int xCell, yCell;
unsafe
{
// process motion frame calculating amount of changed pixels
// in each grid's cell
byte* motion = (byte*) motionFrame.ImageData.ToPointer( );
int motionOffset = motionFrame.Stride - width;
for ( int y = 0; y < height; y++ )
{
// get current grid's row
yCell = y / cellHeight;
// correct row number if image was not divided by grid equally
if ( yCell >= gridHeight )
yCell = gridHeight - 1;
for ( int x = 0; x < width; x++, motion++ )
{
if ( *motion != 0 )
{
// get current grid's collumn
xCell = x / cellWidth;
// correct column number if image was not divided by grid equally
if ( xCell >= gridWidth )
xCell = gridWidth - 1;
motionGrid[yCell, xCell]++;
}
}
motion += motionOffset;
}
// update motion grid converting absolute number of changed
// pixel to relative for each cell
int gridHeightM1 = gridHeight - 1;
int gridWidthM1 = gridWidth - 1;
int lastRowHeight = height - cellHeight * gridHeightM1;
int lastColumnWidth = width - cellWidth * gridWidthM1;
for ( int y = 0; y < gridHeight; y++ )
{
int ch = ( y != gridHeightM1 ) ? cellHeight : lastRowHeight;
for ( int x = 0; x < gridWidth; x++ )
{
int cw = ( x != gridWidthM1 ) ? cellWidth : lastColumnWidth;
motionGrid[y, x] /= ( cw * ch );
}
}
if ( highlightMotionGrid )
{
// highlight motion grid - cells, which have enough motion
byte* src = (byte*) videoFrame.ImageData.ToPointer( );
int srcOffset = videoFrame.Stride - width * pixelSize;
if ( pixelSize == 1 )
{
// grayscale case
byte fillG = (byte) ( 0.2125 * highlightColor.R +
0.7154 * highlightColor.G +
0.0721 * highlightColor.B );
for ( int y = 0; y < height; y++ )
{
yCell = y / cellHeight;
if ( yCell >= gridHeight )
yCell = gridHeight - 1;
for ( int x = 0; x < width; x++, src++ )
{
xCell = x / cellWidth;
if ( xCell >= gridWidth )
xCell = gridWidth - 1;
if ( ( motionGrid[yCell, xCell] > motionAmountToHighlight ) && ( ( ( x + y ) & 1 ) == 0 ) )
{
*src = fillG;
}
}
src += srcOffset;
}
}
else
{
// color case
byte fillR = highlightColor.R;
byte fillG = highlightColor.G;
byte fillB = highlightColor.B;
for ( int y = 0; y < height; y++ )
{
yCell = y / cellHeight;
if ( yCell >= gridHeight )
yCell = gridHeight - 1;
for ( int x = 0; x < width; x++, src += pixelSize )
{
xCell = x / cellWidth;
if ( xCell >= gridWidth )
xCell = gridWidth - 1;
if ( ( motionGrid[yCell, xCell] > motionAmountToHighlight ) && ( ( ( x + y ) & 1 ) == 0 ) )
{
src[RGB.R] = fillR;
src[RGB.G] = fillG;
src[RGB.B] = fillB;
}
}
src += srcOffset;
}
}
}
}
}
