Images of varying intensity while using "continuous acquisition" in vision acquisition express.

[Lab_View_User]

From a parent VI, I call a sub VI three times. The sub VI captures 3 images
every time using vision acquisition express. I can see a difference in
intensity between the images within a single call as well as in images between
calls. I did not change the camera attributes during the entire process. I am
attaching the images here. I am using a constant light
source in a dark room, so we can eliminate the room’s ceiling light flicker
interfering with the shutter speed.

[BruceAmmons]

Perhaps the light source fluctuates with the line voltage as well, or at some other frequency.  What kind of light is it?  How is it powered?

Bruce

[Lab_View_User]

Hi Bruce,

     Thanks for responding. I am pretty sure the light source (fiber optic source plugged into a conventional wall outlet) is not the problem, because I am getting same intensity images when I use a third party software to capture multiple images. I am attaching the sub VI here.

[Prickly_Pear]

One problem with this code that I forsee is that you are using the IMAQ Dispose VI partway through the code. This dispose VI will destroy the reference and free up the memory location that was reserved for the image. You should use this VI only after you are finished with using all of the images and after you have written them to file. Are you even able to see any images on the front panel?

Also, you should consider writing your image to the hard drive using the IMAQ Write File 2 VI.

Jeremy P.

[BruceAmmons]

What is your exposure time (shutter speed)?  What kind of light bulb does the fiber optic source have?  Does it use a constant current source or a simple incandescent light bulb?

I still think it could be the light.

Bruce