コード例 #1
0
        /// <summary>
        /// Calculate the gradient of a given pixel.
        /// </summary>
        /// <param name="x">x coordinate of pixel, must be between 1..cols-1</param>
        /// <param name="y">y coordinate of pixel, must be between 1..rows-1</param>
        /// <returns>The gradient of the given pixel, considering x and y directions.</returns>
        public byte GetPixelGradient(int x, int y)
        {
            int  GXxy = 0;           //the y portion
            int  GYxy = 0;           //the x portion
            byte Gxy  = 0;           //final value

            if (directBitmapReader == null)
            {
                directBitmapReader = new DirectBitmapReader(grayBitmap.Bitmap);
            }

            GXxy = ((directBitmapReader.GetGrayPixel(x + 1, y + 1)) - (directBitmapReader.GetGrayPixel(x - 1, y + 1)));
            GXxy = GXxy + (2 * ((directBitmapReader.GetGrayPixel(x + 1, y)) - (directBitmapReader.GetGrayPixel(x - 1, y))));
            GXxy = GXxy + ((directBitmapReader.GetGrayPixel(x + 1, y - 1)) - (directBitmapReader.GetGrayPixel(x - 1, y - 1)));
            GXxy = GXxy / 4;

            GYxy = ((directBitmapReader.GetGrayPixel(x + 1, y + 1)) - (directBitmapReader.GetGrayPixel(x + 1, y - 1)));
            GYxy = GYxy + (2 * ((directBitmapReader.GetGrayPixel(x, y + 1)) - (directBitmapReader.GetGrayPixel(x, y - 1))));
            GYxy = GYxy + ((directBitmapReader.GetGrayPixel(x - 1, y + 1)) - (directBitmapReader.GetGrayPixel(x - 1, y - 1)));
            GYxy = GYxy / 4;

            /* This is how we did this in CS 450, it's faster than doing
             * a square root, but not quite as accurate, hence the clamping.
             * It does bring out more edges, but I don't know if that is
             * good or not - Ryan
             * Gxy = (Math.Abs(GXxy) + Math.Abs(GYxy));
             * Gxy = Math.Max(0, Gxy);
             * Gxy = Math.Min(imgMaxGray, Gxy);
             */

            Gxy = (byte)Math.Sqrt((double)(GXxy * GXxy) + (double)(GYxy * GYxy));
            return(Gxy);
        }
コード例 #2
0
 /// <summary>
 /// Calculates the gradient for each pixel in this image then returns a bitmap
 /// in which the color corresponds to the gradient.
 /// </summary>
 /// <returns></returns>
 public virtual void GenerateGradientBitmap(ProgressCallback callback)
 {
     Reset();
     directBitmapReader = new DirectBitmapReader(grayBitmap.Bitmap);
     bitmap             = new Bitmap(grayBitmap.Bitmap.Width, grayBitmap.Bitmap.Height);
     using (DirectBitmapWriter dbw = new DirectBitmapWriter(bitmap))
     {
         for (int i = 1; i < Bitmap.Height - 1; i++)
         {
             if (callback != null)
             {
                 callback(i * 100 / (Bitmap.Height - 2));
             }
             for (int j = 1; j < Bitmap.Width - 1; j++)
             {
                 byte grad = GetPixelGradient(j, i);
                 dbw.SetGrayPixel(j, i, grad);
                 if (grad > maximumGradientValue)
                 {
                     maximumGradientValue = grad;
                 }
             }
         }
     }
 }
コード例 #3
0
 public virtual void Reset()
 {
     maximumGradientValue = -1;
     if (bitmap != null)
     {
         bitmap.Dispose();
         bitmap = null;
     }
     directBitmapReader = null;
 }
コード例 #4
0
        /// <summary>
        /// Calculates the gradient for each pixel in this image then returns a bitmap 
        /// in which the color corresponds to the gradient.
        /// </summary>
        /// <returns></returns>
        public virtual void GenerateGradientBitmap(ProgressCallback callback)
        {
            Reset();
            directBitmapReader = new DirectBitmapReader(grayBitmap.Bitmap);
            bitmap = new Bitmap(grayBitmap.Bitmap.Width, grayBitmap.Bitmap.Height);
            using (DirectBitmapWriter dbw = new DirectBitmapWriter(bitmap))
            {

                for (int i = 1; i < Bitmap.Height - 1; i++)
                {
                    if (callback != null) callback(i * 100 / (Bitmap.Height - 2));
                    for (int j = 1; j < Bitmap.Width - 1; j++)
                    {
                        byte grad = GetPixelGradient(j, i);
                        dbw.SetGrayPixel(j, i, grad);
                        if (grad > maximumGradientValue) maximumGradientValue = grad;
                    }
                }
            }
        }
コード例 #5
0
 public virtual void Reset()
 {
     maximumGradientValue = -1;
     if (bitmap != null)
     {
         bitmap.Dispose();
         bitmap = null;
     }
     directBitmapReader = null;
 }
コード例 #6
0
        /// <summary>
        /// Calculate the gradient of a given pixel.
        /// </summary>
        /// <param name="x">x coordinate of pixel, must be between 1..cols-1</param>
        /// <param name="y">y coordinate of pixel, must be between 1..rows-1</param>
        /// <returns>The gradient of the given pixel, considering x and y directions.</returns>
        public byte GetPixelGradient(int x, int y)
        {
            int GXxy = 0;//the y portion
            int GYxy = 0;//the x portion
            byte Gxy = 0;//final value

            if (directBitmapReader == null)
                directBitmapReader = new DirectBitmapReader(grayBitmap.Bitmap);

            GXxy = ((directBitmapReader.GetGrayPixel(x + 1, y + 1)) - (directBitmapReader.GetGrayPixel(x - 1, y + 1)));
            GXxy = GXxy + (2 * ((directBitmapReader.GetGrayPixel(x + 1, y)) - (directBitmapReader.GetGrayPixel(x - 1, y))));
            GXxy = GXxy + ((directBitmapReader.GetGrayPixel(x + 1, y - 1)) - (directBitmapReader.GetGrayPixel(x - 1, y - 1)));
            GXxy = GXxy / 4;

            GYxy = ((directBitmapReader.GetGrayPixel(x + 1, y + 1)) - (directBitmapReader.GetGrayPixel(x + 1, y - 1)));
            GYxy = GYxy + (2 * ((directBitmapReader.GetGrayPixel(x, y + 1)) - (directBitmapReader.GetGrayPixel(x, y - 1))));
            GYxy = GYxy + ((directBitmapReader.GetGrayPixel(x - 1, y + 1)) - (directBitmapReader.GetGrayPixel(x - 1, y - 1)));
            GYxy = GYxy / 4;

            /* This is how we did this in CS 450, it's faster than doing
             a square root, but not quite as accurate, hence the clamping.
             It does bring out more edges, but I don't know if that is
             good or not - Ryan
            Gxy = (Math.Abs(GXxy) + Math.Abs(GYxy));
            Gxy = Math.Max(0, Gxy);
            Gxy = Math.Min(imgMaxGray, Gxy);
            */

            Gxy = (byte)Math.Sqrt((double)(GXxy * GXxy) + (double)(GYxy * GYxy));
            return Gxy;
        }