Image Analysis Program Based on Hashcode Method Resulting in Errors - image-formats

Question

I am trying to write a program that will recognize an image on the screen, compare it against a resource library, and then calculate based on the result of the image source.
The first thing that I did was to create the capture screen function which looks like this:
private Bitmap Screenshot()
{
System.Drawing.Bitmap Table = new System.Drawing.Bitmap(88, 40, PixelFormat.Format32bppArgb);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(RouletteTable);
g.CopyFromScreen(1047, 44, 0, 0, Screen.PrimaryScreen.Bounds.Size);
return Table;
}
Then, I analyze this picture. The first method I used was to create two for loops and analyze both the bitmaps pixel by pixel. The problem with this method was time, it took a long time to complete 37 times. I looked around and found the convert to bytes and the convert to hash methods. This is the result:
public enum CompareResult
{
ciCompareOk,
ciPixelMismatch,
ciSizeMismatch
};
public CompareResult Compare(Bitmap bmp1, Bitmap bmp2)
{
CompareResult cr = CompareResult.ciCompareOk;
//Test to see if we have the same size of image
if (bmp1.Size != bmp2.Size)
{
cr = CompareResult.ciSizeMismatch;
}
else
{
//Convert each image to a byte array
System.Drawing.ImageConverter ic = new System.Drawing.ImageConverter();
byte[] btImage1 = new byte[1];
btImage1 = (byte[])ic.ConvertTo(bmp1, btImage1.GetType());
byte[] btImage2 = new byte[1];
btImage2 = (byte[])ic.ConvertTo(bmp2, btImage2.GetType());
//Compute a hash for each image
SHA256Managed shaM = new SHA256Managed();
byte[] hash1 = shaM.ComputeHash(btImage1);
byte[] hash2 = shaM.ComputeHash(btImage2);
for (int i = 0; i < hash1.Length && i < hash2.Length&& cr == CompareResult.ciCompareOk; i++)
{
if (hash1[i] != hash2[i])
cr = CompareResult.ciPixelMismatch;
}
}
return cr;
}
After I analyze the two bitmaps in this function, I call it in my main form with the following:
Bitmap Table = Screenshot();
CompareResult success0 = Compare(Properties.Resources.Result0, Table);
if (success0 == CompareResult.ciCompareOk)
{ double result = 0; Num.Text = result.ToString(); goto end; }
The problem I am getting is that once this has all been accomplished, I am always getting a cr value of ciPixelMismatch. I cannot get the images to match, even though the images are identical.
To give you a bit more background on the two bitmaps, they are approximately 88 by 40 pixels, and located at 1047, 44 on the screen. I wrote a part of the program to automatically take a picture of that area so I did not have to worry about the wrong location or size being captured:
Table.Save("table.bmp");
After I took the picture and saved it, I moved it from the bin folder in the project directly to the resource folder and ran the program again. Despite all of this, the result is still ciPixelMismatch. I believe the problem lies within the format that the pictures are being saved as. I believe that despite them being the same image, they are being analyzed in different formats, maybe one of the pictures contains a bit more information than the other which is causing the mismatch. Can somebody please help me solve this problem? I am just beginning with my c# programming, I am 5 days into the learning process, and I am really at a loss for this.
Yours sincerely,
Samuel