I have 16-bit grayscale images. I want to annotate these images nondestructively and be able to later edit the annotations. How do I do this.

[bkse]

I have 16-bit grayscale images. I want to annotate these images nondestructively and be able to later edit the annotations. How do I do this.

[dmp]

Use the IMAQ Overlay Text VI. Overlays are nondestructive, which means that they do not overwrite the underlying pixel values. You can save overlay information with an image by using the IMAQ Write Image And Vision Info VI. Likewise, you can use the IMAQ Read Image And Vision Info VI to read the image file and its overlay information back into LabVIEW.

You cannot, however, edit the overlay text once it is placed on the image. Your best option is to remove the previous overlay using the IMAQ Clear Overlay VI, and then place a new overlay using the IMAQ Overlay Text VI again.

Best wishes with your application!

Dawna P.
Applications Engineer
National Instruments

[bkse]

I am using VB6.0. However, I understand your answer. I was hoping to be able to edit rather than clear and re-write to the overlay. If you have suggeations as to how to do that, please reply.

Thanks,
bkse

[zou]

You can try LabVIEW picture control functions. Picture control will add text to the end of your image data. It's not too hard to separate image from text, and append new text to picture control. However, picture control doesn't support 16 bit image, you've to convert 16 bit gray (not supported by MS Window) to 8 bit gray (256 gray levels), 24 bit color first.

Or you can create a Window Metafile (EMF). EMF appends text to the end of image data, just like LabVIEW picture control does. EMF support 16 bit images.

George Zou
http://gtoolbox.yeah.net

[bkse]

Thanks for the information. I'm in the process of trying what you suggested with TIFF image files.