A Brute-Force Duplicate Images Comparison

In this post a simple function is presented that runs a brute-force comparer to find whether two images/photos are exactly the same or not. It works well but not optimal.

using System.Drawing;

using System.Drawing.Imaging;

using System;

namespace Fabriclake.Imaging

{

internal class IntelliPhoto

{

/// <summary>

/// It runs a brute-force comparer to find whether two

/// images/photos are identical or not. It works well

/// but not optimal.

/// Author: G. R. Roosta

/// License: Free To Use (No Restriction)

/// </summary>

/// <param name="photo1">The first image/photo to compare</param>

/// <param name="photo2">The second image/photo to compare</param>

/// <returns>True if two images are identical</returns>

public static bool Identical(Bitmap photo1, Bitmap photo2)

{

int rows = photo1.Height;

int cols = photo1.Width;

if (photo2.Width != cols photo2.Height != rows)

return false;

BitmapData bmpData1 = photo1.LockBits(new Rectangle(0, 0, cols, rows), ImageLockMode.ReadWrite, photo1.PixelFormat);

BitmapData bmpData2 = photo2.LockBits(new Rectangle(0, 0, cols, rows), ImageLockMode.ReadWrite, photo2.PixelFormat);

int stride1 = bmpData1.Stride;

int stride2 = bmpData2.Stride;

IntPtr scan1 = bmpData1.Scan0;

IntPtr scan2 = bmpData2.Scan0;

unsafe

{

byte* p1 = (byte*)(void*)scan1;

byte* p2 = (byte*)(void*)scan2;

int cols3 = cols * 3;

int offs = stride1 - cols3;

for (int i = 0; i < rows; i++)

{

for (int j = 0; j < cols3; j++)

{

if (p1[0] != p2[0])

{

photo1.UnlockBits(bmpData1);

photo2.UnlockBits(bmpData2);

return false;

}

p1++;

p2++;

}

p1 += offs;

p2 += offs;

}

} // end unsafe

photo1.UnlockBits(bmpData1);

photo2.UnlockBits(bmpData2);

return true;

} // end of function

}

}