How to get white pixel from image box?

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Hai guys..
I'm a beginner in C# language..
I have a project to classification fruits based on size..
This is my step :
1. Capture image from webcam.
2. Convert image to gray scale.
3. Convert image to binary image.
4. Counting white pixel to getting the object size.

But now, i get stuck on step 4..
I can't count white pixel from image box,
My project using C# and emguCV as a library,
Anybody can solve my problem? How to count white pixel from image box?
Thanks,,
(Sorry for my bad English :D)

[Edit - Keith Barrow] - Added formatted code from comment

This the code to convert image capture to binary image :

C#

Image<gray,> imgTarget = hueFilter.And(saturationFilter).And(valueFilter);
           imgTarget._Erode(1);
           imgTarget._Dilate(1);
           Image<gray,> bin = imgTarget.ThresholdBinary(new Gray(80), new Gray(255));
           imageBox3.Image = bin.Resize(320, 240, Emgu.CV.CvEnum.INTER.CV_INTER_LINEAR, true);
           imgTarget.Dispose();
           channels[0].Dispose();
           channels[1].Dispose();
           channels[2].Dispose();

But i was try to count the white pixel value using this code :

C#

Image<gray,> binary = new Image<gray,>(320, 240);
imageBox3.Image = binary;

for (int i = 0; i < binary.Rows; i++)
{
    for (int j = 0; j < binary.Cols; j++)
    {

        binary.Data[i, j, 0] = 255;


        byte white = binary.Data[i, j, 0];




        lblWhite.Text = white + " white pixels";
    }

And when i run this project the "lblWhite getting value = 255" , but it did't count the white pixel..
Can you tell me what's the problem?

Posted 1-Nov-12 6:13am

zaenal arifin

Updated 1-Nov-12 7:13am

Keith Barrow

v2

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Comments

Richard C Bishop 1-Nov-12 12:16pm

First of all, your English is 100x better than most non-English speakers on this site. Second, can you post the code you have so far so that others can see what you are trying to do?

zaenal arifin 1-Nov-12 12:47pm

Thank you @richcb for your suggest..
This the code to convert image capture to binary image :

Image<gray, byte=""> imgTarget = hueFilter.And(saturationFilter).And(valueFilter);
imgTarget._Erode(1);
imgTarget._Dilate(1);
Image<gray, byte=""> bin = imgTarget.ThresholdBinary(new Gray(80), new Gray(255));
imageBox3.Image = bin.Resize(320, 240, Emgu.CV.CvEnum.INTER.CV_INTER_LINEAR, true);
imgTarget.Dispose();
channels[0].Dispose();
channels[1].Dispose();
channels[2].Dispose();

But i was try to count the white pixel value using this code :

Image<gray, byte=""> binary = new Image<gray, byte="">(320, 240);
imageBox3.Image = binary;

for (int i = 0; i < binary.Rows; i++)
{
for (int j = 0; j < binary.Cols; j++)
{

binary.Data[i, j, 0] = 255;

byte white = binary.Data[i, j, 0];

lblWhite.Text = white + " white pixels";
}

And when i run this project the "lblWhite getting value = 255" , but it did't count the white pixel..
Can you tell me what's the problem?

Keith Barrow 1-Nov-12 13:16pm

Hi, I've edited your question and put you code in it, with formatting. That way everyone looking at the question will see it and the formatting makes it more readable.
What I'd do in this situation is to edit the original question (as I have done) and reply to the comment saying I've done this.

Sergey Alexandrovich Kryukov 1-Nov-12 12:52pm

First of all, why would be use PictureBox for this? It's pointless...
--SA

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Keith Barrow · Accepted Answer · 2012-11-01T07:37:00

Hi, first off the image dilate and erode methods use a 3x3 grid of pixels this will effect your results, but I assume this is deliberate.
I'd start off using a 3x3 white image to start with, and comment the erode, dilate, threshold and re-size operations. That way you have baseline to check the rest of your code.

ImageBox doesn't make much sense to me: you'd be better off just using binary.

You don't have comparison anywhere, I'd expect you to compare the current pixel in your loop with a white one, or compare the brightness value with 255.

[edit]
the contents of loop is wrong for counting the white pixels, you have two preoblems:

C#

binary.Data[i, j, 0] = 255; //This sets the pixel to white (I assume)

then

C#

byte white = binary.Data[i, j, 0];

Gets the value of the pixel, which you've just set to white (255).

I think you need something more like:

C#

int count = 0;
for (int i = 0; i < binary.Rows; i++)
{
    for (int j = 0; j < binary.Cols; j++)
    {
         if(binary.Data[i, j, 0] == 255)
             count++;
         lblWhite.Text = string.Format("{0} white pixels", count);
    }
}

One thing I've found is that looping the pixels in any reasonably sized image is slow, but you should only optimise one your basic algorithm is working.