Real-time IMAQ Vision image analysis

[Naveen S]

I am using the IMAQ Vision for Measurement Studio for a particle trapping application that requires the position of a particle to be tracked as fast as possible (more than 500 fps). I am acquiring the images from an Andor iXon CCD camera with a 500 to 4000 fps frame rate (depending on image size). However, to use the ArrayToImage function takes at least 1.5 milliseconds and I would appreciate any suggestions about how to speed up this process.

Thanks,

Naveen

[Christopher W]

Why are you using the ArrayToImage function? Are you doing your image processing on array of data? You could use the Vision Development Module for your image processing which would be faster than performing processing on an array of data.  You still may run into problems with processing speed though since your frame rate is so high.  Do you have the Vision Development Module or just the Vision Acquistion Software?

You can download an evaluation copy of the Vision Development Module here:

https://www.ni.com/en/support/downloads/software-products/download.vision-development-module.html

Basically, the Vision Development Module will give you fastest processing but it may still not be fast enough.

Christopher W.

[Naveen S]

Hi Christopher,

Thank you for the advice. I'm sorry about the delay in my reply. I did download the latest version of the Vision Development Module, but had some difficulties upgrading from the IMAQ Vision for Measurement Studio that I was using previously.

To clarify my application, I am using the software provided by the camera manufacturer (Andor) in order to acquire the image data as a two-dimensional array. I then use the ArrayToImage function to convert that data to a National Instruments Image object, so that I can use NI image processing functions. Right now I'm looking for a way to speed up the array-to-image conversion, such as by transfering the data from the camera directly to the Image object instead of the 2D array. If you have any other suggestions, I would greatly appreciate it.

Thanks,

Naveen

[Christopher W]

Hello Naveen,

What kind of camera are you using? If you could use our IMAQ driver to get the image data it would be much faster because you would not need to convert it from an array, it would already be the image data type.  You do need to use one of our frame grabbers to do this unless its a 1394 camera or a gigE camera. Are you using a frame grabber?

Christopher W.

[Naveen S]

Hi Christopher, 

The Andor iXon CCD camera that I am using has a proprietary 36-way connector to the detector head. I checked the Andor website and it seems that drivers are only available for LabView, but not NI Vision (see http://www.andor.com/products/software/index.asp?app=393). Right now I'm using commands in the Andor Software Development Kit, a dynamic link library, to transfer the data from the camera to the computer. The command that I'm using right now transfers the image data from a circular buffer to a user-defined array specified by a pointer.

Naveen

[Christopher W]

Hi Naveen,

Since your camera is proprietary and you have to use their driver to get the data into LabVIEW there isn't really anything we can do.  The only ways to convert data to image data is to use the array to image function or to save the image data to a file and then open it.  The array to image function is your only option since obviously saving it to a file would not work.  Perhaps you could use a ring buffer so that you could have your processing lag the acquisition. If you really need it to be real time you may be out of luck with such a high frame rate.

Christopher W.

[Naveen S]

Hi Christopher,

I greatly appreciate all of your help with my questions about real-time image processing. I will continue to explore the features of the Vision Development Module to see if they can help with my application.

Thanks,

Naveen

[gvsoni]

hi Naveen

I am trying out something similar. I am trying to see single molecule fluorescence by fast acquisition from the andor ixon. you said you could reach 500 fps....can you tell me at what frame size and binning are you working at? that number [500-4000fps] sounds awe-fully fast ! I am acquiring using labview...512x256 ar 2x2 binning and cant seem to do better than 100fps. I record my data to a file and then do an offline analysis of the movies.

I hope we can discuss this.

[Naveen S]

Hello,

I'm glad to hear that someone else is doing single molecule studies with the Andor iXon camera. In my application, I'm using the NI-IMAQ controls for Visual Basic 6.0, instead of LabView. In order to speed up the processing, I observe a small region of interest that is typically 32x32 pixels, which currently leads to ~300 fps. In addition, I save the data to a large array in memory and transfer the data a file only after the acquisition is complete (~10 to 60 seconds).

That seems to be about the maximum possible using Visual Basic, but a C program operating in Linux could be significantly faster. There is also a LabView Real Time module that could improve the performance. I would be interested in any other ideas you may have for speeding up the image processing.

Naveen

[IgG]

Hi, Naveen and ggvsoni::

so glad I found a person who is doing particle tracking with high speed camera.
right now i'm doing the same thing.  I also want to get over 1000fps frame rates.
I'm using NI PCIe 1427 cameralink frame grabber and labview 8.2,
but right now i got a very big problem which i've struggling for several months.
right now I always lost many frames from camera to PC, evenghout i'm working on ROI 100*10, 10 bits , 2000fps condition.
i don't know what's really limit my speed, the PCIe 1427 should be able to handle this amount of data.

really want to discuss with you guys, and listen to your suggestions.

looking forward to your replies.

best regards,

jack

Message Edited by weichengatech on 06-09-2007 11:33 AM