/// <summary>
/// Convert an float image to a squared integral image
/// </summary>
/// <remarks>
/// We skip the last line to keep the original size (better performance)
/// </remarks>
/// <param name="source">image source</param>
/// <param name="dest">image destination</param>
public void IntegralSquare(IImage2DByteA source, IImage2DUIntA dest)
{
if (source == null) throw new ArgumentNullException("source");
if (dest == null) throw new ArgumentNullException("dest");
if ((source.Width > dest.Width) || (source.Height > dest.Height)) throw new ArgumentException("Destination image (" + dest.Width + "x" + dest.Height + ") must have at least the source image width and height but is only " + source.Width + "x" + source.Height);
int height = source.Height;
int width = source.Width;
byte[] sBuf = source.HostBuffer;
uint[] dBuf = dest.HostBuffer;
for (int x = 0; x < width; x++) dest.HostBuffer[x] = 0; // zero first line
for (int y = 0, a = width * height; y < a; y += width) dest.HostBuffer[y] = 0; // zero first column
// for each line
int ySumIndex = 0;
int y1SumIndex;
int yIndex = 0;
for (int y = 1; y < height; y++)
{
y1SumIndex = ySumIndex;
ySumIndex += width;
// for each pixel
for (int x = 1; x < width; x++)
{
uint p = sBuf[yIndex + x - 1];
dBuf[ySumIndex + x] = p * p + dBuf[ySumIndex + x - 1] + dBuf[y1SumIndex + x] - dBuf[y1SumIndex + x - 1];
}
yIndex += width;
}
}
/// <summary>
/// Convert an float image to an integral image
/// </summary>
/// <remarks>
/// We skip the last line to keep the original size (better performance)
/// </remarks>
/// <param name="source">image source</param>
/// <param name="dest">image destination</param>
public void Integral(IImage2DByteA source, IImage2DUIntA dest)
{
if (source == null) throw new ArgumentNullException("source");
if (dest == null) throw new ArgumentNullException("dest");
if ((source.Width > dest.Width) || (source.Height > dest.Height)) throw new ArgumentException("Destination image (" + dest.Width + "x" + dest.Height + ") must have at least the source image width and height but is only " + source.Width + "x" + source.Height);
int heightS = source.Height;
int widthS = source.Width;
int heightD = dest.Height;
int widthD = dest.Width;
byte[] sBuf = source.HostBuffer;
uint[] dBuf = dest.HostBuffer;
for (int x = 0; x < widthD; x++) dest.HostBuffer[x] = 0; // zero first line
for (int y = 0, a = widthD * heightD; y < a; y += widthD) dest.HostBuffer[y] = 0; // zero first column
int y1IndexS = 0;
int yIndexD = widthD;
int y1IndexD = 0; // last
// for each line
for (int y = 1; y < heightS; y++)
{
// for each pixel
for (int x = 1; x < widthS; x++)
{
uint p = sBuf[y1IndexS + x - 1];
dBuf[yIndexD + x] = p + dBuf[yIndexD + x - 1] + dBuf[y1IndexD + x] - dBuf[y1IndexD + x - 1];
}
yIndexD += widthD;
y1IndexS += widthS;
y1IndexD += widthD;
}
}
/// <summary>
/// Free resources being used
/// </summary>
public void Dispose()
{
try { if (_ownIntegralImage) { _integralImage.Dispose(); _integralImage = null; } }
catch { }
try { if (_ownIntegral2Image) { _integral2Image.Dispose(); _integral2Image = null; } }
catch { }
try { if (_ownResultRectangles) { _resultRectangles.Dispose(); _resultRectangles = null; } }
catch { }
}
/// <summary>
/// Detects the presence of an object in a given window.
/// </summary>
protected bool Compute(HaarFeatureNode[] stageNodes,
int stagesCount,
int[] stageNodeCounts, float[] stageThresholds,
IImage2DUIntA integralImage,
IImage2DUIntA integral2Image,
float invArea,
int x, int y, int w, int h)
{
float mean = (float)integralImage.GetIntegralSum(x, y, w, h) * invArea;
float normFactor = (float)integral2Image.GetIntegralSum(x, y, w, h) * invArea
- (mean * mean);
normFactor = (normFactor >= 0) ? (float)Math.Sqrt(normFactor) : 1;
int pos = 0;
for (int j = 0; j < stagesCount; j++)
{
int count = stageNodeCounts[j];
float threshold = stageThresholds[j];
float value = 0;
for (int i = 0; i < count; i++)
{
// evaluate the node's feature
float sum = HaarExtensions.GetNodeSum(ref stageNodes[pos], integralImage, x, y);
// and increase the value accumulator
HaarFeatureNode node = stageNodes[pos++];
value += ((sum < node.Threshold * normFactor) ? node.LeftValue : node.RightValue);
}
if (value <= threshold) return false; // window has been rejected
}
return true;
}
/// <summary>
/// Gets the sum of a rectangular feature in an integral image.
/// </summary>
public static float GetSum(ref HaarRectangle rect, IImage2DUIntA integralImage, int x, int y)
{
return integralImage.GetIntegralSum(x + rect.ScaledX, y + rect.ScaledY, rect.ScaledWidth, rect.ScaledHeight) * rect.ScaledWeight;
}
/// <summary>
/// Gets the sum of the areas of the rectangular features in an integral image.
/// </summary>
public static float GetNodeSum(ref HaarFeatureNode node, IImage2DUIntA integralImage, int x, int y)
{
float sum;
sum = GetSum(ref node.Rect1, integralImage, x, y);
sum += GetSum(ref node.Rect2, integralImage, x, y);
if (node.RectCount == 3) sum += GetSum(ref node.Rect3, integralImage, x, y);
return sum;
}
