Image processing problem...

[S K Y]

how can i change the contrast of the image at the same time changing brightness. my brightness can change. its working fine i want to change the contrast at the same time....can i use this method too ???

    Bitmap image = new Bitmap("d:\\\\14.jpg");
                Bitmap bm = new Bitmap(image, 350, 300);
                
                System.Drawing.Bitmap TempBitmap = bm;
                float FinalValue = 0.5f;
                System.Drawing.Bitmap NewBitmap = new System.Drawing.Bitmap(TempBitmap.Width, TempBitmap.Height);
                System.Drawing.Graphics NewGraphics = System.Drawing.Graphics.FromImage(NewBitmap);
                float\[\]\[\] FloatColorMatrix ={
                new float\[\] {1, 0, 0, 0, 0},
                new float\[\] {0, 1, 0, 0, 0},
                new float\[\] {0, 0, 1, 0, 0},
                new float\[\] {0, 0, 0, 1, 0},
                new float\[\] {FinalValue, FinalValue, FinalValue, 1, 1}
            };

                System.Drawing.Imaging.ColorMatrix NewColorMatrix = new System.Drawing.Imaging.ColorMatrix(FloatColorMatrix);
                System.Drawing.Imaging.ImageAttributes Attributes = new System.Drawing.Imaging.ImageAttributes();
                Attributes.SetColorMatrix(NewColorMatrix);
                NewGraphics.DrawImage(TempBitmap, new System.Drawing.Rectangle(0, 0, TempBitmap.Width, TempBitmap.Height), 0, 0, TempBitmap.Width, TempBitmap.Height, System.Drawing.GraphicsUnit.Pixel, Attributes);
                Attributes.Dispose();
                NewGraphics.Dispose();
                
               picDecode.Image = NewBitmap;

A S E L A

[Christian Graus]

You can add the contrast and brightness matrices, I guess, or you can apply one, then the other.

Christian Graus Driven to the arms of OSX by Vista. "! i don't exactly like or do programming and it only gives me a headache." - spotted in VB forums. I can do things with my brain that I can't even google. I can flex the front part of my brain instantly anytime I want. It can be exhausting and it even causes me vision problems for some reason. - CaptainSeeSharp

[S K Y]

i could do it....but i got a big problem. as i told im doing a QR barcode reader by using webcam. my web cam pictures are too dark so i have to process image before i send it to decode. some times after process i code decode.but when the envirentmant change it couldn't decode. that mean when change brightness and contrast in enviranmetn i couldn't decode. is there any solution....may be auto brightness and contrast detect or some thing else....???

A S E L A

[Luc Pattyn]

Hi, I think you want a non-linear transformation, ideally something that maps all colors to either black or white. Maybe ImageAttributes.SetThreshold could help you out, provided you give it a good value, at best it would depend on the average brightness of your image, :)

Luc Pattyn [Forum Guidelines] [My Articles]

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