Shrink an image by removing specified color from its boundaries.
Removes pixels with specified color from image boundaries making the image smaller in size.
The filter accepts 8 bpp grayscale and 24 bpp color images for processing.
Sample usage:
// create filter Shrink filter = new Shrink( Color.Black ); // apply the filter Bitmap newImage = filter.Apply( image ); Initial image:
Result image:
/// <summary>
/// Recognize hands gesture.
/// </summary>
///
/// <param name="imageData">Source image data to recognize hands gesture on.</param>
/// <param name="bodyImageOnly">Specifies if the passed image data contain only human's body or not.</param>
///
/// <returns>Returns gesture structure, which specifies position of both hands.</returns>
///
/// <remarks><para>The <b>bodyImageOnly</b>> parameter specifies if human's body occupies the
/// passes image from top to down and from left to rigth. If the value is set to <b>false</b>,
/// then humans' body may occupy only part of the image, what will require image shrinking.</para></remarks>
///
public Gesture Recognize( BitmapData imageData, bool bodyImageOnly )
{
// check source image format
if ( imageData.PixelFormat != PixelFormat.Format8bppIndexed )
{
throw new ArgumentException( "Source image can be binary (8 bpp indexed) only" );
}
// recognized gesture
Gesture gesture = new Gesture( HandPosition.NotRaised, HandPosition.NotRaised );
Bitmap bodyImage = null;
BitmapData bodyImageData = null;
if ( bodyImageOnly == false )
{
// use shrink filter to extract only body image
Shrink shrinkFilter = new Shrink( );
bodyImage = shrinkFilter.Apply( imageData );
// lock body image for further processing
bodyImageData = bodyImage.LockBits(
new Rectangle( 0, 0, bodyImage.Width, bodyImage.Height ),
ImageLockMode.ReadOnly, PixelFormat.Format8bppIndexed );
}
else
{
// use passed image as body image
bodyImageData = imageData;
}
int bodyWidth = bodyImageData.Width;
int bodyHeight = bodyImageData.Height;
// get statistics about horizontal pixels distribution
HorizontalIntensityStatistics his = new HorizontalIntensityStatistics( bodyImageData );
int[] hisValues = (int[]) his.Gray.Values.Clone( );
// build map of hands (0) and torso (1)
double torsoLimit = torsoCoefficient * bodyHeight;
for ( int i = 0; i < bodyWidth; i++ )
{
hisValues[i] = ( (double) hisValues[i] / 255 > torsoLimit ) ? 1 : 0;
}
// get hands' length
int leftHand = 0;
while ( ( hisValues[leftHand] == 0 ) && ( leftHand < bodyWidth ) )
leftHand++;
int rightHand = bodyWidth - 1;
while ( ( hisValues[rightHand] == 0 ) && ( rightHand > 0 ) )
rightHand--;
rightHand = bodyWidth - ( rightHand + 1 );
// get torso's width
int torsoWidth = bodyWidth - leftHand - rightHand;
// process left hand
if ( ( (double) leftHand / torsoWidth ) >= handsMinProportion )
{
// extract left hand's image
Crop cropFilter = new Crop( new Rectangle( 0, 0, leftHand, bodyHeight ) );
Bitmap leftHandImage = cropFilter.Apply( bodyImageData );
// get left hand's position
gesture.LeftHand = GetHandPosition( leftHandImage );
}
// process right hand
if ( ( (double) rightHand / torsoWidth ) >= handsMinProportion )
{
// extract right hand's image
Crop cropFilter = new Crop( new Rectangle( bodyWidth - rightHand, 0, rightHand, bodyHeight ) );
Bitmap rightHandImage = cropFilter.Apply( bodyImageData );
// get right hand's position
gesture.RightHand = GetHandPosition( rightHandImage );
}
if ( !bodyImageOnly )
{
// unlock body image and dispose it
bodyImage.UnlockBits( bodyImageData );
bodyImage.Dispose( );
}
return gesture;
}
