Which is faster pixel or byte array with image in comparison

Can get the byte array from the image like this..(from MSDN)

// Create a new bitmap.
Bitmap bmp = new Bitmap("Flower1.jpg");

// Lock the bitmap's bits.
Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
System.Drawing.Imaging.BitmapData bmpData =
    bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
    bmp.PixelFormat);

// Get the address of the first line.
IntPtr ptr = bmpData.Scan0;

// Declare an array to hold the bytes of the bitmap.
// This code is specific to a bitmap with 24 bits per pixels.
int bytes = bmp.Width * bmp.Height*3 ;
byte[] rgbValues = new byte[bytes];

// Copy the RGB values into the array.
System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);

Once get the array need to loop through the array and use the algorithm for comparison.

The simpler way for comparing images would be comparing the image histogram. There are ways in the frequency domain as well. Why because the same frame area taken in bright light and dim light has different pixel values, but more or less same histogram shape. For this simple fact comparing byte to byte (or pixel to pixel). There are many advance algorithms over there, some use the entropy content of the image. Though there many algorithms there is no hard and fast rules which one is better. So you need research trying those popular algorithms

You may use libraries like Accord.net or Aforge.net, they have already developed algorithms which may useful for you.

http://www.aforgenet.com/framework/[^]

http://accord-net.origo.ethz.ch/[^]