NI-IMAQdx camera attributes don't update

[andymars]

I am trying to control the illumination of an image captured by a generic USB camera module, by varying the intensity of an LED array. My intention is to adjust the intensity of the LED array (managed by a microcontroller communicating with LabVIEW over USB) based on the camera's reported exposure.

The problem I am having is that when the camera is in auto mode for exposure (the default), the value read from the camera (using IMAQ-dx property with the appropriate active attribute) does not update. This is also the case in NI-MAX, even after refreshing the attributes.

But when I switch it to manual exposure mode I can easily write a new exposure value and read that value back.

Is this just an issue with the Camera or is there something else I can do in LabVIEW to read the attribute value in auto mode.

[Enrique.Noe]

 This snippet can help you to set properties to your camera before acquision, you can read the actual camera attributes and look if are writtable or readable or both, in my experience not all camera have the same attributes, so it depends on your camera if it is possible to set the configuration you need.

[Sairam@99]

Hi Enrique,

I have one question here I like to change the camera attribute in which I need to change the image adjust mode into manual to set the lower and upper limits to scale the image using LabView l. The camera I am using in this is Flir A400 can you please help or can you direct me to read how to do it. 

Thanks 

Sanjith