How to change the camera's exposure time in Labview and suggestions on purchasing cameras

[AlexZLee]

Hi,

I am using 2016 Labview 64 bit to run a microscope C mount camera to capture fluorescent images from a small device on an inverted fluorescence microscope. Basically, I am flowing low concentrations (~20-100 nMol) of flurocein solutions in the device and use a c mount microscope camera (GFP mode) to capture the image through Labview. 

There are no problems for the labview part to capture images. The only trouble is about the camera.

I used the Zeiss AxioCam MRm camera and it can capture such low concentrations of flurocein solutions but it is not compatible with Labview. I tried Chameleon PointGrey camera which has no problem with the Labview interface but can not detect low concentrations of flurocein solutions even though the exposure time/gain parameters are same to the Zeiss camera (the latter can show the image at same concentration of the solution). I guess the difference is the PointGrey camera's sensitivity is not as high as Zeiss. 

Then I tried IDS CP category camera and this camera works well with Labview and it meets the sensitivity requirements when using the software coming with the camera to change the frame rate to very low (1~4) and exposure time to very high (300ms~2000ms). But the problem is that under MAX, the frame rate is defaulted to be 15 and the corresponding maximum exposure time is 125 ms.

I wonder if someone knows how to change the camera's exposure time (or by changing the frame rate) in Labview or if you know some Labview compatible cameras which are as sensitive as Zeiss AxioMRm or IDS camera, please suggest! We have a budget around ~$1,500.

Thanks

but the problem is that this camera 

[Bob_Schor]

If the camera is not capable of executing a Grab at very low frame rates, you can "do it yourself" by doing, say, a Snap every 250-1000 msec (which works out to a frame rate of 4 down to 1 FPS).  It's a little more programming on your part, but there's plenty of time for it ...

Bob Schor

[AlexZLee]

Thanks Bob for your reply! I actually only need to increase the exposure time of the camera. Sometimes, the frame rate of the camera will limit the exposure time. I think what you suggest can make the frame rate "virtually" changed but the camera's property has not. Thus the exposure time limit won;t change. 

[AlexZLee]

Anyone has some suggestions please?

[Bob_Schor]

You ask about varying the Exposure time.  It really depends on the Camera specs.  Some video cameras allow you to vary the exposure (it can't be greater than the "frame time", of course).  If you have a camera that is compatible with IMAQ or IMAQdx, then you can investigate (a) does the Camera have a user-settable Exposure time, and (b) does the Camera's driver give you access to this parameter.

I have a colleague who is using some exotic camera, and I'm pretty sure he sets the exposure time.  I'll try to bug him tomorrow and get the details [I'm guessing that it will turn out to be a Property Node for the Camera].

Never mind -- I forgot that I've got a few cameras (including the WebCam on my laptop) available to me at home.  Configuring the Cameras with IMAQ/IMAQdx isn't so easy, but it is possible.  The first thing to do is to cobble together an "Attribute Browser".  Here's what you do:

• Drop an IMAQdx Open Camera, and wire a Session In constant.
• Connect a Camera, either through USB, TCP/IP, or whatever.
• Find the Camera's name in MAX (probably something like "cam0").
• Change the Session constant (little triangle) so it matches your Camera.
• Drop an IMAQdx Enumerate Attributes, connect to Open Camera using Error Line and Session Line.
• Wire an Indicator to Attribute Information.
• On the Front Panel, widen the Cluster to make the Attribute Name about 4-5 times wider.  Right-click the Array, choose "Visible Items", and turn on "Horizontal Scrollbar".
• Run this two-function VI.  This should populate the Array Indicator with a list of all of the Attributes that your Camera supports.
• Use the Horizontal Scroll Bar or the Array Index to look at the Attribute Names and see if any of them suggest Exposure Time.

On the two Cameras I can "see" (a Web Cam and an IP Cam), neither had an Attribute that suggested Exposure Control.

Hope some of this is useful for you.

Bob Schor

[AlexZLee]

Hi Bob,

Thanks! Did you get in touch with your colleague about the camera? I tried several cameras including several webcams in the method you suggest. None of them give me access to adjsut  the exposure time. I wonder if you know a certain brand of camera that could adjust the exposure time. I contacted a lot of vendors but none of theirs satisfys.

Thanks

[Bob_Schor]

Thanks for reminding me.  I went out-of-town for a few days, and when I returned, he was OOT, and once he returned, I forgot to ask!

So I called him, and he said "I don't think any of my cameras have variable exposure times".  Hmm.  So I went to his lab, fired up one of his LabVIEW programs that has his "Kitchen and Kitchen Sink" Front Panel (where everything is a separate control), and there was "Exposure time".  So I looked in MAX, and found the camera was an Allied Vision Technologies GC1380 (which I think he had mounted on a microscope).

This is a GigE camera that works with IMAQdx, and does seem to have some level of Exposure Control.

Bob Schor

[Alexander_Sobolev]

Strange that some cameras do not have exposure control.

Now we are working with simple usb web cams (logitech C525, Microsoft HD-3000), they all have some level of exposure control. If you simply show Property page (through Direct Show driver), it can set 16 levels of exposure (not time directly). 

When I was working with IMAQ for USB, it could call this camera property page, as far as I remember this functionality was transferrred to Imaqdx.

[Vince84]

I just wanted to add a bit of my experience: the Basler Ace cameras are really good and really easy to control using LabVIEW. I am currently using a Basler Ace A1920-40um (1920x1080, 40FPS @ max resolution), and the specs are awesome. I am using really fast exposures (60-80 us, I need a ton of light!!!), which is the opposite of what you need, but you can check the manuals for the max exposure time.

This one is around £400, but they have cheaper and more expensive options depending on your needs. The have a huge catalogue (USB3 and GigE):

http://www.baslerweb.com/en/products/cameras/area-scan-cameras/ace

I recommend them 100%, the manuals are easy to digest, controlling the camera is pretty straightforward and I haven't found anything that annoys me about it 😛

[Vince84 · Accepted solution]

Here you go: