Real Time I/O and bitmap video output

[Dr. Eutonium]

We are in the design stage of developing a measurement/control system for use with medical MRI scanners used for functional brain imaging.
The system must acquire a synchronization pulse from the scanner equipment as well as button presses from the patient. These signals are then
used to initiate and sequence the presentation of computer video graphics and audio stimuli. The system will also output digital control signals
to a pneumatic actuator for presenting tactile stimulation. Accurate timing to within 10 msec (approx. a video refresh frame) is required with no
"dropped" input signals. We want the system to run under Mac OSX. Clearly LabView and NI I/O cards can handle the digital I/O. However, how do
we handle control of the video and audio I/O? Are there any video and audio card manufacturers who produce software control libraries that are
compatible with the LabView system or that can be integrated with LabView code? We would like to make a purchasing decision for the development
platform as soon as possible (within the month at the latest). We would greatly appreciate help from NI engineers, sales people, or applications
developers who can suggest solutions. Thanks.

[Dan_Quinn]

Hi Dr. Eutonium,

Thanks for using our Discussion Forums! You're right in that NI DAQ devices can certainly handle all of the necessary synchronization that is needed in your application. The one bottleneck I see, however, is the Vision aspect of the application. The last hardware and driver support we offered for Mac was back on OS9 with a PCI-1408 board for Mac machines with PCI slots available. Unfortunately, we no longer manufacture the 1408 and there is no guarantee that the driver would work in OSX, just like there is no guarantee that a Windows 3.1 program would work in Windows 2000. Would it be possible for you to develop your application in a Windows environment? In such a case, it would be very easy to integrate timing signals through a PXI backplane, acquire your images, and send synchronization signals all through a single PXI chassis, or also through a Windows PC. Let us know if there is anything we can further advise you on.

Regards

Dan
National Instruments

[Dr. Eutonium]

Thanks for the info. The system I described is one of three pieces of a larger system, two of which will be running under Mac OSX, so for simplicity and cost minimization, we would like to use a single system. Fundamentally, the video output is going to be relatively simple, just a "page flipper" loaded either from a video card ram, system ram or, ideally, from disk if we can get high enough throughput. Consequently, we don't really need OpenGL or a high level system. I noticed another recent thread on this site that discussed something similar in a system that was capturing video frames with an input device and then displaying them on screen. (I'd get the thread ID but I don't know how to jump out of this editor to get it and get back. I'll try at the end once I've finished this message.) I'm not familiar enough with LabView to know if it was relevant or if it could run under Mac OSX. We'd really like to solve this problem since it is the last major design hurdle. Ultimately, we hope to offer the system comercially, so we like the idea of using NI boards since you guys are leaders in the field and are likely to offer stable solutions that (hopefully) will be upgradable over the years. Anyway, if you can offer any other thoughts about solving our problem let me know. And, thenks for the response.

[Dr. Eutonium]

The is the second of two responses to your email...
Just another thought. We had been thinking in terms of using LabView with some sort of video driver/libray under Mac OSX. If LabView doesn't have the capability, would it be possible to do something without LabView? In other words, does NI have linkable libraries of I/O routines/utilites that would allow us to access the I/O boards from a custom stand-alone program (assuming we can find a video board and library that we could also use). thanks again.

[Dan_Quinn]

Dr. Eutonium,

The problem here isn't actually with LabVIEW, but with the availability of the driver. What would probably work out quite well would be any image acquisition board that has a driver for Mac OSX. Once there is a driver, you can call the dll into LabVIEW and essentially create your own LabVIEW driver from there. The problem with NI boards right now is that we simply don't have a dll that can be used in Mac OSX, but only windows environments.

Regards

Dan
National Instruments