Image Display blinking and always missing images.

[jingli]

I have labview 7.1 express and vision 7. I have made a VI for tracking a moving object. In the VI a while loop was used and the image was acquired through a camera and linked to a pci1409. After the IMAQ Grab Acquire.vi, the image was transmitted to both Image Display for display and to a serial process of IMAQ Set Simple Calibration.vi, IMAQ Threshold.vi,IMAQ RemoveParticle.vi and IMAQ Centroid.vi etc for image process. the problem is that in most of the time there were no images in Image Display,but sometimes there were and were blinking. But when a probe was insert between the IMAQ Grab Acquire.vi and the Image Display, the images were quite well. This problem was not shown in LabVIEW6.1 when I transmmited an image from Im
age Grab Acquire.vi to both IMAQ ImageToArray for display and to the same serial process of Calibration,Threshold,RemoveParticle and Centroid.
I tried several times buy failed. Would you like to help me? thank you very much.
Jing

[ColinAE]

Hello jingli.

It sounds like you are having some strange behavior with your image display in LabVIEW. The probe that you are using between the IMAQ Grab Acquire and the image display should be essentially identical to the image display itself, so this behavior is very strange.

My suggestion is to remove the display from the front panel and replace it with a new one. Also, verify that the palette setting (right click on the display and go to Palette) is correct for your image type.

One thing to remember is that the image display will display the image that you wire into it, including any modifications that you make to the image later on in your program. For example, if you wire up an image from the Grab Acquire, then wire it to the image, and then convert the
image to binary without wiring a new Image Dst, then the image display will reflect the new binary image even though there is no data dependency. You might also try running the display in 'Snapshot' mode by right clicking on the display. This can remedy the previous problem.

In general, just be sure to do an IMAQ Create for new copies of images (i.e. IMAQ Threshold, etc.)

I hope this helps you out.
Regards,
Colin C.
Applications Engineering