public static bool Compare()

in Sources/Imaging/Microsoft.Psi.Imaging/ImageExtensions.cs [371:488]
98 lines of code
17 McCabe index (conditional complexity)

        public static bool Compare(this ImageBase image1, ImageBase image2, double tolerance, double percentOutliersAllowed, ref ImageError errorMetrics)
        {
            if (image1.GetType() != image2.GetType() ||
                image1.PixelFormat != image2.PixelFormat ||
                image1.Width != image2.Width ||
                image1.Height != image2.Height)
            {
                return false;
            }

            errorMetrics.MaxError = 0.0f;
            errorMetrics.AvgError = 0.0f;
            errorMetrics.NumberOutliers = 0;
            double dist = 0.0f;
            unsafe
            {
                int bytesPerPixel1 = image1.BitsPerPixel / 8;
                int bytesPerPixel2 = image2.BitsPerPixel / 8;

                byte* row1 = (byte*)image1.ImageData.ToPointer();
                byte* row2 = (byte*)image2.ImageData.ToPointer();
                for (int y = 0; y < image1.Height; y++)
                {
                    byte* col1 = row1;
                    byte* col2 = row2;
                    for (int x = 0; x < image1.Width; x++)
                    {
                        switch (image1.PixelFormat)
                        {
                            case PixelFormat.BGRA_32bpp:
                                {
                                    int db = col1[0] - col2[0];
                                    int dg = col1[1] - col2[1];
                                    int dr = col1[2] - col2[2];
                                    int da = col1[3] - col2[3];
                                    dist = (double)(db * db + dg * dg + dr * dr + da * da);
                                }

                                break;

                            case PixelFormat.BGRX_32bpp:
                            case PixelFormat.BGR_24bpp:
                                {
                                    int db = col1[0] - col2[0];
                                    int dg = col1[1] - col2[1];
                                    int dr = col1[2] - col2[2];
                                    dist = (double)(db * db + dg * dg + dr * dr);
                                }

                                break;

                            case PixelFormat.Gray_16bpp:
                                {
                                    int d = ((ushort*)col1)[0] - ((ushort*)col2)[0];
                                    dist = (double)(d * d);
                                }

                                break;

                            case PixelFormat.Gray_8bpp:
                                {
                                    int d = col1[0] - col2[0];
                                    dist = (double)(d * d);
                                }

                                break;

                            case PixelFormat.RGB_24bpp:
                                {
                                    int dr = col1[0] - col2[0];
                                    int dg = col1[1] - col2[1];
                                    int db = col1[2] - col2[2];
                                    dist = (double)(dr * dr + dg * dg + db * db);
                                }

                                break;

                            case PixelFormat.RGBA_64bpp:
                                {
                                    int dr = ((ushort*)col1)[0] - ((ushort*)col2)[0];
                                    int dg = ((ushort*)col1)[1] - ((ushort*)col2)[1];
                                    int db = ((ushort*)col1)[2] - ((ushort*)col2)[2];
                                    int da = ((ushort*)col1)[3] - ((ushort*)col2)[3];
                                    dist = (double)(dr * dr + dg * dg + db * db + da * da);
                                }

                                break;

                            case PixelFormat.Undefined:
                            default:
                                throw new ArgumentException("Unsupported image format");
                        }

                        if (dist > errorMetrics.MaxError)
                        {
                            errorMetrics.MaxError = dist;
                        }

                        errorMetrics.AvgError += dist;
                        if (dist > tolerance * tolerance)
                        {
                            errorMetrics.NumberOutliers++;
                        }

                        col1 += bytesPerPixel1;
                        col2 += bytesPerPixel2;
                    }

                    row1 += image1.Stride;
                    row2 += image2.Stride;
                }
            }

            errorMetrics.AvgError /= (double)(image1.Width * image1.Height);
            errorMetrics.MaxError = Math.Sqrt(errorMetrics.MaxError);

            return errorMetrics.NumberOutliers <= percentOutliersAllowed * image1.Width * image1.Height;
        }