Image processing

[hunerajamshed]

hi all there.

im new in BYTES, this is my first post.
i m working on a project regarding image processing. i m working on face detection from video. i hv played the video captured from webcam on a picture box.I hv splitted it into frames it plays like original(means no problem) but as i attach or call some algorithm with it bofore display it becomes slower and plays like slow motion. What could b the problem.

thanks in advance.
hony,

[code green]

I would say your algorithm code is slowing it down.
It may be worth seeing if it can be optimised, otherwise multi-threading may be the answer

[hunerajamshed]

That could be a problem, but i dont think that the algorithm is such a complex anyhow, here is the algorithm which applies on each frame of video.

static ArrayList points = new ArrayList();
        static Int32 xx = 0, yy = 0;
        static int clrdpix;
        static int rect_width = clrdpix;
        static int clr_line_count = 0;
 
        public static Bitmap DetectSkin(Bitmap original, Bitmap modified)
        {
            Graphics g = Graphics.FromImage(original);
            clr_line_count = 0;     //Skin Colored Lines Count
            int strtpix = 0;        //Pixel from where rectangle begain to draw.
 
            for (Int32 y = 0; y < original.Height; y++)
            {
                clrdpix = 0;
 
                for (Int32 x = 0; x < original.Width; x++)
                {
                    Color c = modified.GetPixel(x, y);
 
                    double I = (Math.Log(c.R) + Math.Log(c.B) + Math.Log(c.G)) / 3;
                    double Rg = Math.Log(c.R) - Math.Log(c.G);
                    double By = Math.Log(c.B) - (Math.Log(c.G) + Math.Log(c.R)) / 2;
                    double hue = Math.Atan2(Rg, By) * (180 / Math.PI);
 
                    if (I <= 6 && (hue >= 100 && hue <= 255))
                    {
                        clrdpix++;
 
                        if (clr_line_count == 50 && clrdpix == 1)
                        {
                            strtpix = x;
                        }              
                     }
 
                    else
                    {
                        //modified.SetPixel(x, y, Color.Black);
                    }
 
 
                }
                if (clr_line_count == 50)
                {
                    xx = strtpix;
                    yy = y;
                    rect_width = original.Width - (original.Width - clrdpix) - 20;
                    //Console.WriteLine("Colored Pixel Value =" + clrdpix);
                    //Console.WriteLine("xx Value =" + strtpix);
                    //Console.WriteLine("yy Value =" + yy);
                }
                if(clrdpix>0)
                clr_line_count++;
            }
 
            return modified;
        }

[code green]

There may be howls of derision but I would improve this

for (Int32 x = 0; x < original.Width; x++) 

By storing Width in a variable to avoid multiple class calls

w = original.Width;
for (Int32 x = 0; x < w; x++) 

Same for height.

[hunerajamshed]

Thanks alot dear;
i got u.
but i m waiting for ur reply with more mistakes u caught from this code.

thanks again

[code green]

If somebody on this forum suggested code optimization to me,
I would eagerley rush off and study the subject.
I would not lie back and expect an expert to optimise the code for me