process image captured by the camera

[daisyszsy]

I got the image data from the camera like this:
byte[] imageArray=videoControl.getSnapshot(null)，

Then I read the pixels and processed the data:
readBarcode(imageArray);
public void readBarcode(byte[] array){
...
gray=(array[4*imageWidth*yPos+3]*11+
array[4*imageWidth*yPos+2]*59+
array[4*imageWidth*yPos+1]*30 )/100;
...
}

I ran the program on my mobile phone nokia 6120c and it return 'error 0' at the line 'gray=(array[4*imageWidth*yPos+3]*11+
array[4*imageWidth*yPos+2]*59+array[4*imageWidth*yPos+1]*30 )/100'

What`s wrong with it?

[grahamhughes]

I'd guess you're getting an IndexOutOfBoundsException. Are you sure the byte[] is as big as you think?

Graham.

[raj_J2ME]

Hi,
Try to put the code inside the try-catch block and as grahm suggested that please check that there is no exception,BTW what you are looking for and expect from the line gray = .....?

[daisyszsy]

I'd guess you're getting an IndexOutOfBoundsException. Are you sure the byte[] is as big as you think?

Graham.

It seems it`s an IndexOutOfBoundsException, but why?
I think the size of the imageArray is imageWidth*imageHeight*4 byte,isn`t it?

[grahamhughes]

Have you asked it how big it is?

[daisyszsy]

Have you asked it how big it is?

I have checked the size.

The screen size is 240*320. I set the video size like this:
videoControl.setDisplaySize(getWidth( )-10,getHeight( )-10);
The size of the canvas is 240*235, so the size of the video should be 230*225.

But when I created an image with the imageArray as following:
Image image=Image.createImage(imageArray, 0, imageArray.length);
I found that image.getWidth( ) and image.getHeight( ) return 320 and 240. The imageArray.length is approximately 170000 and it`s changing every time I captured an image.

I thought imageArray.length=image.getWidth( )*image.getHeight( )*4 and image.getWidth( )*image.getHeight( )=230*225. But it seems it`s wrong. Why`s that?

[grahamhughes]

The byte[] is not in a "raw" format. It is probably JPEG encoded data. You need to convert the data to an Image (as you have already), and work from the Image object.

You might find this example useful.

Graham.