/// <summary>
/// Build descriptor vector for each interest point in the supplied list
/// </summary>
/// <param name="img"></param>
/// <param name="ipts"></param>
/// <param name="upright"></param>
public void DescribeInterestPoints(List <IPoint2> ipts, bool upright, bool extended, IntegralImage img)
{
if (ipts.Count == 0)
{
return;
}
this.img = img;
foreach (IPoint2 ip in ipts)
{
// determine descriptor size
if (extended)
{
ip.descriptorLength = 128;
}
else
{
ip.descriptorLength = 64;
}
// if we want rotation invariance get the orientation
if (!upright)
{
GetOrientation(ip);
}
// Extract SURF descriptor
GetDescriptor(ip, upright, extended);
}
}
/// <summary>
/// Constructor with parameters
/// </summary>
/// <param name="thresh"></param>
/// <param name="octaves"></param>
/// <param name="init_sample"></param>
/// <param name="img"></param>
public FastHessian(float thresh, int octaves, int init_sample, IntegralImage img)
{
this.thresh = thresh;
this.octaves = octaves;
this.init_sample = init_sample;
this.img = img;
}
public static IntegralImage FromImage(Bitmap image)
{
IntegralImage pic = new IntegralImage(image.Width, image.Height);
float rowsum = 0;
/* for (int y = 0; y < image.Height; y++)
* {
* rowsum = 0;
* for (int x = 0; x < image.Width; x++)
* {
* Color c = image.GetPixel(x, y);
* rowsum += (cR * c.R + cG * c.G + cB * c.B) / 255f;
*
* // integral image is rowsum + value above
* if(y==0)
* pic[0, x] = rowsum;
* else
* pic[y, x] = rowsum + pic[y - 1, x];
* }
* }*/
BitmapData dataIn = image.LockBits(new Rectangle(0, 0, image.Width, image.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
unsafe
{
byte *pIn = (byte *)(dataIn.Scan0.ToPointer());
for (int y = 0; y < dataIn.Height; y++)
{
rowsum = 0;
for (int x = 0; x < dataIn.Width; x++)
{
int cb = (byte)(pIn[0]);
int cg = (byte)(pIn[1]);
int cr = (byte)(pIn[2]);
// 0 1 2代表的次序是B G R
rowsum += (cR * cr + cG * cg + cB * cb) / 255f;
// integral image is rowsum + value above
if (y == 0)
{
pic[0, x] = rowsum;
}
else
{
pic[y, x] = rowsum + pic[y - 1, x];
}
pIn += 3;
}
pIn += dataIn.Stride - dataIn.Width * 3;
}
}
image.UnlockBits(dataIn);
return(pic);
}
List <IPoint2> GetFtPntList(Bitmap bitImg, float thread)
{
List <IPoint2> ipts1 = new List <IPoint2>();//图片1的特征点
//--------------------------------------------------
// Create Integral Image
IntegralImage iimg = IntegralImage.FromImage(bitImg);
// Extract the interest points
ipts1 = FastHessian.getIpoints(thread, //此值越小，特征点越多
5, 2, iimg);
// Describe the interest points
SurfDescriptor.DecribeInterestPoints(ipts1, false, //是否表示方向
false, //false为64，true为128
iimg);
iimg.Dispose();
iimg = null;
return(ipts1);
}
/// <summary>
/// Static one-call do it all function
/// </summary>
/// <param name="img"></param>
/// <param name="ipts"></param>
/// <param name="extended"></param>
/// <param name="upright"></param>
public static void DecribeInterestPoints(List <IPoint2> ipts, bool upright, bool extended, IntegralImage img)
{
SurfDescriptor des = new SurfDescriptor();
des.DescribeInterestPoints(ipts, upright, extended, img);
}
/// <summary>
/// Static one-call do it all method
/// </summary>
/// <param name="thresh"></param>
/// <param name="octaves"></param>
/// <param name="init_sample"></param>
/// <param name="img"></param>
/// <returns></returns>
public static List<IPoint2> getIpoints(float thresh, int octaves, int init_sample, IntegralImage img)
{
FastHessian fh = new FastHessian(thresh, octaves, init_sample, img);
return fh.getIpoints();
}
