How to reduce noise from image (jpg or Png) in Asp.net C#

Hello,

You can use the code above.

Parameters: Image as bitmap, level of noise and radius of noise.

public static Bitmap NoiseReduction(Bitmap original, int level, int radius)
        {
            int width = original.Width;
            int height = original.Height;

            Bitmap source = null;

            source = original.PixelFormat != PixelFormat.Format8bppIndexed
                ? BitmapManipulator.ConvertToGrayScale8bpp(original, false)
                : original;


            Bitmap destination = BitmapManipulator.CreateGrayscaleImage(width, height);

            BitmapData srcData = source.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadOnly,
                source.PixelFormat);
            BitmapData dstData = destination.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly,
                destination.PixelFormat);

            int stride = srcData.Stride;
            byte pxVal;
            int matrixWidth = (radius*2 + 1)*(radius*2 + 1);
            var pxM = new byte[matrixWidth];
            int meanIndex = (matrixWidth - 1)/2;
            unsafe
            {
                var srcScan0 = (byte*) srcData.Scan0;
                var dstScan0 = (byte*) dstData.Scan0;

                for (int l = 0; l < level; l++)
                {
                    for (int y = radius; y < height - radius; y++)
                    {
                        byte* srcRow = srcScan0 + (y*stride);
                        byte* dstRow = dstScan0 + (y*stride);
                        for (int x = radius; x < width - radius; x++)
                        {
                            pxVal = srcRow[x];
                            int mIndex = 0;
                            for (int k = y - radius; k < y + radius + 1; k++)
                            {
                                byte* srcRowMatrix = srcScan0 + (k*stride);
                                for (int j = x - radius; j < x + radius + 1; j++)
                                {
                                    pxM[mIndex++] = srcRowMatrix[j];
                                }
                            }
                            Array.Sort(pxM);
                            dstRow[x] = pxM[meanIndex];
                        }
                    }
                }
            }

            destination.UnlockBits(dstData);
            source.UnlockBits(srcData);

            // Dispose of fastOriginal if not originally supplied bitmap
            if (source != original)
                source.Dispose();

            // Return
            return destination;
        }

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João Sousa (MCTS) Senior Software Engineer

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