示例#1
0
        /// <summary>
        /// Convert from RGB to YCbCr color space (Rec 601-1 specification).
        /// </summary>
        ///
        /// <param name="rgb">Source color in <b>RGB</b> color space.</param>
        ///
        /// <returns>Returns <see cref="YCbCr"/> instance, which represents converted color value.</returns>
        ///
        public static YCbCr FromRGB(RGB rgb)
        {
            YCbCr ycbcr = new YCbCr( );

            FromRGB(rgb, ycbcr);
            return(ycbcr);
        }
示例#2
0
        /// <summary>
        /// Convert from RGB to YCbCr color space (Rec 601-1 specification).
        /// </summary>
        ///
        /// <param name="rgb">Source color in <b>RGB</b> color space.</param>
        /// <param name="ycbcr">Destination color in <b>YCbCr</b> color space.</param>
        ///
        public static void FromRGB(RGB rgb, YCbCr ycbcr)
        {
            float r = (float)rgb.Red / 255;
            float g = (float)rgb.Green / 255;
            float b = (float)rgb.Blue / 255;

            ycbcr.Y  = (float)(0.2989 * r + 0.5866 * g + 0.1145 * b);
            ycbcr.Cb = (float)(-0.1687 * r - 0.3313 * g + 0.5000 * b);
            ycbcr.Cr = (float)(0.5000 * r - 0.4184 * g - 0.0816 * b);
        }
示例#3
0
        /// <summary>
        /// Convert from YCbCr to RGB color space.
        /// </summary>
        ///
        /// <param name="ycbcr">Source color in <b>YCbCr</b> color space.</param>
        /// <param name="rgb">Destination color in <b>RGB</b> color spacs.</param>
        ///
        public static void ToRGB(YCbCr ycbcr, RGB rgb)
        {
            // don't warry about zeros. compiler will remove them
            float r = Math.Max(0.0f, Math.Min(1.0f, (float)(ycbcr.Y + 0.0000 * ycbcr.Cb + 1.4022 * ycbcr.Cr)));
            float g = Math.Max(0.0f, Math.Min(1.0f, (float)(ycbcr.Y - 0.3456 * ycbcr.Cb - 0.7145 * ycbcr.Cr)));
            float b = Math.Max(0.0f, Math.Min(1.0f, (float)(ycbcr.Y + 1.7710 * ycbcr.Cb + 0.0000 * ycbcr.Cr)));

            rgb.Red   = (byte)(r * 255);
            rgb.Green = (byte)(g * 255);
            rgb.Blue  = (byte)(b * 255);
            rgb.Alpha = 255;
        }
示例#4
0
        // Gather statistics for the specified image
        private unsafe void ProcessImage(UnmanagedImage image, byte *mask, int maskLineSize)
        {
            // get image dimension
            int width  = image.Width;
            int height = image.Height;

            pixels = pixelsWithoutBlack = 0;

            int[] yhisto  = new int[256];
            int[] cbhisto = new int[256];
            int[] crhisto = new int[256];

            int[] yhistoWB  = new int[256];
            int[] cbhistoWB = new int[256];
            int[] crhistoWB = new int[256];

            RGB   rgb   = new RGB( );
            YCbCr ycbcr = new YCbCr( );

            int pixelSize  = (image.PixelFormat == PixelFormat.Format24bppRgb) ? 3 : 4;
            int offset     = image.Stride - width * pixelSize;
            int maskOffset = maskLineSize - width;

            // do the job
            byte *p = (byte *)image.ImageData.ToPointer( );

            if (mask == null)
            {
                // for each line
                for (int y = 0; y < height; y++)
                {
                    // for each pixel
                    for (int x = 0; x < width; x++, p += pixelSize)
                    {
                        rgb.Red   = p[RGB.R];
                        rgb.Green = p[RGB.G];
                        rgb.Blue  = p[RGB.B];

                        // convert to YCbCr color space
                        AForgeCore.Imaging.YCbCr.FromRGB(rgb, ycbcr);

                        yhisto[(int)(ycbcr.Y * 255)]++;
                        cbhisto[(int)((ycbcr.Cb + 0.5) * 255)]++;
                        crhisto[(int)((ycbcr.Cr + 0.5) * 255)]++;

                        pixels++;

                        if ((ycbcr.Y != 0.0) || (ycbcr.Cb != 0.0) || (ycbcr.Cr != 0.0))
                        {
                            yhistoWB[(int)(ycbcr.Y * 255)]++;
                            cbhistoWB[(int)((ycbcr.Cb + 0.5) * 255)]++;
                            crhistoWB[(int)((ycbcr.Cr + 0.5) * 255)]++;

                            pixelsWithoutBlack++;
                        }
                    }
                    p += offset;
                }
            }
            else
            {
                // for each line
                for (int y = 0; y < height; y++)
                {
                    // for each pixel
                    for (int x = 0; x < width; x++, p += pixelSize, mask++)
                    {
                        if (*mask == 0)
                        {
                            continue;
                        }

                        rgb.Red   = p[RGB.R];
                        rgb.Green = p[RGB.G];
                        rgb.Blue  = p[RGB.B];

                        // convert to YCbCr color space
                        AForgeCore.Imaging.YCbCr.FromRGB(rgb, ycbcr);

                        yhisto[(int)(ycbcr.Y * 255)]++;
                        cbhisto[(int)((ycbcr.Cb + 0.5) * 255)]++;
                        crhisto[(int)((ycbcr.Cr + 0.5) * 255)]++;

                        pixels++;

                        if ((ycbcr.Y != 0.0) || (ycbcr.Cb != 0.0) || (ycbcr.Cr != 0.0))
                        {
                            yhistoWB[(int)(ycbcr.Y * 255)]++;
                            cbhistoWB[(int)((ycbcr.Cb + 0.5) * 255)]++;
                            crhistoWB[(int)((ycbcr.Cr + 0.5) * 255)]++;

                            pixelsWithoutBlack++;
                        }
                    }
                    p    += offset;
                    mask += maskOffset;
                }
            }

            // create histograms
            yHistogram  = new ContinuousHistogram(yhisto, new Range(0.0f, 1.0f));
            cbHistogram = new ContinuousHistogram(cbhisto, new Range(-0.5f, 0.5f));
            crHistogram = new ContinuousHistogram(crhisto, new Range(-0.5f, 0.5f));

            yHistogramWithoutBlack  = new ContinuousHistogram(yhistoWB, new Range(0.0f, 1.0f));
            cbHistogramWithoutBlack = new ContinuousHistogram(cbhistoWB, new Range(-0.5f, 0.5f));
            crHistogramWithoutBlack = new ContinuousHistogram(crhistoWB, new Range(-0.5f, 0.5f));
        }