回复： Re : How to set exposure time using IMAQdx?

[courage]

I'm having trouble using IMAQdx to control a camera, I've read the IMAQdx user Manual and I'm able to open the camera and alter some attributes like brightness,contrast and Gamma etc. However,I don't have access to some attributes like exposure time and frame rate, these don't even show up in the Enumerate attributes.vi ,there's also a problem with the one that show up-white balance,it remains the default value and change it causes the vi terminated.

I'm pretty sure that the exposure time and all the other attributes can be altered because there's a C based software can alter all this.So I want to know if these attributes can be populated and altered in IMAQdx,if not is there any other methods to accomplish this?

And can someone tell me how the IMAQdx driver works?

And BTW,my camera is DirectShow compliant.

All reply are greatly appreciated!

[toto69]

Hi

First, go to MAX (measurement and automation explorer). It will expose all the attributes of your camera. Just check that you are in expert mode (by clicking on the "Show all" button)

All the accessible parameters are shown here. If you do not see some exposure or shutter parameters, you won't be able to control your camera exposure time... It's often the case with webcams.

Then if you can access exposure time in max, you can do so in labview with an IMAQdx property node.

Just check the labview examples that comes with the installer of the VAS.

Regards

[mwenger]

To elaborate a little bit more. Yes all the access parameters can be found in MAX and sometimes it is a hit and miss depending on what camera you have to set the parameters.  I have not had to use that particular parameter but you can see below how I had set it up. I had created a vi that reads all the attributes available to me just for reference.  This was from a Basler Scout SCA640-70GM.  I hope this helps.

[courage]

I have used the MAX to open my camera long time ago and the exposure time doesn't show up. According to what you've said,this means I can't control the exposure time of my camera in LabVIEW. For the record, the camera I'm using is not a webcam and it comes with SDK Toolkit and the exposure time can be altered in the program that our company compiled. So can Call Library Function Node be able to change the exposure time?

[courage]

I've used this method and it doesn't work for the exposure time attribute,when I runs the VI labview pops out a window says that "camera doesn't support this attribute".So this is a dead end ,do you know any other method may accomplish this?

[toto69]

Hi

Use the IMAQdxEnumerateAttributes2 function to list the string of attributes availables. 

Once you have the full list you can get the data type of each attributes. 

I know there's an example for this, search the LabVIEW help.

Regards

[courage]

You mean the Grab and Attributes Setup.vi. I've used this VI to control my camera,it can alter some attributes but exposure time,so do you have any other suggestion that may slove this please let me know!

[mwenger]

I remember I had some similar other problems.  Ironically what resolved it was installing the Basler camera software and changing my mode to Guru.  I noticed that amount of selectable information increased dramatically in MAX as well.  But I'm not completely sure this is still the case for yours.  Yes I used the Camera Attributes.vi, there were some unique identifiers that were not listed in there but I was able to still use them on a trial by name basis.  Basically I had to guess what the input attribute was.  most of the names are in direct correlation so it wasn't extremely difficult

[BlueCheese]

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@mwenger wrote:

I remember I had some similar other problems.  Ironically what resolved it was installing the Basler camera software and changing my mode to Guru.  I noticed that amount of selectable information increased dramatically in MAX as well.  But I'm not completely sure this is still the case for yours.  Yes I used the Camera Attributes.vi, there were some unique identifiers that were not listed in there but I was able to still use them on a trial by name basis.  Basically I had to guess what the input attribute was.  most of the names are in direct correlation so it wasn't extremely difficult

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The "Guru" visibility level (defined by the GenICam standard) directly maps to the "Advanced" setting in MAX, which is actually what the default visibility level is in IMAQdx.

One thing to note is that features can have both their normal names as well as a "display name." The display name is what is shown in MAX by default, but all programatic access is via the actual names. You can tell MAX to show either.

Eric

[courage]

What exactly is 'Guru' and how can I have access to it. In mwenger's reply he mentioned this,but after I installed the camera's software I still can't find how to change 'Guru',so does it suggest that my camera is running in 'Guru' mode or I just don't have the access to this mode? Please let me know.