How to convert an image to binary format

[Wan81]

Hi!

I am currentyl trying to convert an 8 bit image to a binary image using IMAQ. However, it seems that 8 bits is the lowest it can go. How can I achieve the conversion? Please help..

Thanks

[GerdW]

Hi Wan,

8-bit is binary too

Do you want a black/white picture (or: 1-bit color resolution)? There surely are some threshold functions in IMAQ (or: brightness/contrast controls) to calc your picture!

[Wan81]

Hi..

Thanks a lot. I actually want a 1 bit to represent each pixel in order to save as much space as possible. Can help suggest some VIs from IMAQ or any normal labview VIs?

Thanks In advance.

[VGA_CD-ROM]

Hi Wan81,
If you are trying save disk space by writing your image out to a 1-bit file, I think the best way to do this would be to convert your image into an array of booleans, and then use the Flatten Pixmap VI to construct a pixmap of your image (with settings for no transparency, 1-bit depth, etc.) You could then use this pixmap with Write to BMP to write out a 1-bit image. See the LabVIEW help on the Graphics Formats VIs for more information.

To do the conversion into booleans, I would recommend thresholding your image into 0's and 1's, and then using two nested For Loops to build a corresponding 2-D boolean array based on whether the value at each pixel is 0 or 1.

If you are trying to save RAM by working with the image in memory as a 1-bit IMAQ image, then this unfortunately won't be possible. The normal IMAQ functions require at minimum an 8-bit image depth, such as Grayscale U8.

Message Edited by VGA CD-ROM on 04-22-2008 11:38 AM

[GerdW]

Hi Wan & Vijay,

to save disk space I would use WriteToPNG instead of WriteToBMP

[VGA_CD-ROM]

Hi GerdW,
That's a good point. I forgot that the PNG format does in fact support 1-bit color depth. Looking at the help confirms that the Write to PNG VI supports it as well.

[Wan81]

Hi Vijay and GerardW,

Thanks for the tips. Really appreciate it. I will give it a try in my lab later.

Best Regards

Ridwan