Image Analysis Program Based on Hashcode Method Resulting in Errors

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

Image Analysis Program Based on Hashcode Method Resulting in Errors

0 Answers0