Remove darkness in capturing image background in winform c#

Question

I have worked on image capture window application. When I have captured image by application in window tablet then image quality low and show darkness in captured image background. When I have captured image by tablet then image is good quality. What is missing/problem in my code? I have used code share by you...

private void cam_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
           Bitmap bitmap = (Bitmap)eventArgs.Frame.Clone();                     
           
         ImgContainer.Image = b;
            
            
        }
    private void btnKeep_Click(object sender, EventArgs e)
            {
    int width = 457;
                int height = 350;
    
                Image tmpimg = ImgContainer.Image;                
                System.Drawing.Bitmap b = new System.Drawing.Bitmap(ImgContainer.Image, width, height);
                System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(b);
                gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
                System.Drawing.Rectangle rectDestination = new System.Drawing.Rectangle(0, 0, width, height);
                System.Drawing.Imaging.ImageCodecInfo codec = System.Drawing.Imaging.ImageCodecInfo.GetImageEncoders()[1];
                System.Drawing.Imaging.EncoderParameters eParams = new System.Drawing.Imaging.EncoderParameters(1);
                eParams.Param[0] = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L);
                string ImagePath = Guid.NewGuid().ToString();
                string imagefullpath = System.AppDomain.CurrentDomain.BaseDirectory + "imageFolder\\" + ImagePath + ".jpg";                  
                b.Save(imagefullpath);
    }

Show you captured by application image ............

Show you captured by tablet ............

Please give me any idea and solution remove darkness captured by application (above image).

just a guess: tablet image size = `3264x1826`; you set `457x350` and get a low quality image — ASh, Feb 20 '16 at 08:09
I know, you are right but 3264x1826 is convert into 457x350 then quality not change only size change . — surendra Kandira, Feb 20 '16 at 08:33
Are you saying... You have your app running on a Window's tablet, and the difference is with image captured by tablet's own photo software VS your software on same tablet? Just it's not clear if you're using 2 different hardwares or not. Also why tag `Flash`? Did one of the photos use a flash? Is your real question, how to enable camera flash in your own app? Otherwise you have a correct answer below. Either accept it or edit your question to be more clear on facts & goals. — VC.One, Feb 20 '16 at 15:11

score 1 · Answer 1 · edited May 23 '17 at 12:19

You can use a DrawImage with an ImageAttributes instance to change the gamma. I found 0.5f to work:

Here is a function that applies a gamma value to a bitmap and returns a modified bitmap. It is up to you to ..:

make sure you don't leak resources
make sure to apply the gamma always to the original and not repeatedly to the same bitmap when giving the user a trackbar to find a good value..

The function:

public static Bitmap ApplyGamma(Bitmap bmp0, float gamma)
{
    Bitmap bmp1 = new Bitmap(bmp0.Width, bmp0.Height);
    using (Graphics g = Graphics.FromImage(bmp1))
    {
        ImageAttributes attributes = new ImageAttributes();
        attributes.SetGamma(gamma, ColorAdjustType.Bitmap);
        g.DrawImage(bmp0, new Rectangle(0, 0, bmp0.Width, bmp0.Height),
                    0, 0, bmp0.Width, bmp0.Height, GraphicsUnit.Pixel, attributes);
    }
    return bmp1;
}

The calling code I used:

Image img = Image.FromFile(yourImage);            // some image to use
float gamma = (float)(trackBar1.Value / 10f);     // a trackbar to test
Text = "Gamma = " + gamma;                        // a control display
pictureBox1.Image = ApplyGamma((Bitmap)img, gamma);

If you also want to change contrast and/or brightness you can use a ColorMatrix. See here for an example!

Remove darkness in capturing image background in winform c#

1 Answers1