private void CalculateLuminanceValues(SixLabors.ImageSharp.Image image, byte[] bytes)
{
var luminance = image.CloneAs <L8>();
for (int i = 0; i < luminance.Height; i++)
{
var row = luminance.GetPixelRowSpan(i);
byte[] rawBytes = MemoryMarshal.AsBytes(row).ToArray();
var offset = i * (rawBytes.Length);
Buffer.BlockCopy(rawBytes, 0, bytes, offset, rawBytes.Length);
}
}