Image acquisition: Number of frames saved too low

[Costa111]

I am using a VI to save a number of frames using the Imaq board. Currently, the maximum number of frames I can save each time is 360. How can I increase that? (I need at least 2100 frames saved each time)

[mikeporter]

What happens when you increase the value of the front panel control labeled "Number of Images"?

Mike...

[Kyle_V]

The limit for the number of frames in a sequence is only limited by your computer's system memory. With that said, there is a Maximum number of Buffers parameter that you must set in MAX. It's under the Tools>>NI-IMAQ menu and I believe it defaults to 50. You can set this number to whatever you want (mine is set to 1000, even though I don't have that much system memory).

Once you've set the value, then it's just a matter of having enough RAM. Another factor that you may have to consider is time. If you're trying to save images in real-time (30 frames per second for example), then this code will probably go too slowly. Converting an image into a 2D array, then flattening it into a pixmap before saving it to disk can take time. What kind of saving rate are
you trying to achieve? What's the data rate?

One way to just trouble shoot the frames issue is to not bother saving to disk just yet. Instead, run the HL Sequence example that ships with NI-IMAQ.

Good Luck!

Kyle V

[Costa111]

Dear Kyle V.
The data rate is 30 frames/second.
I want a saving rate of 30 frames/second or closer.
Alex Costa

[Kyle_V]

Hello Costa111. The bottleneck here will be your harddrive. On my simple Dell machine, I can stream data to disk at a rate of about 8 MB/s. If you have an image that is 640x480 and each pixel is 8 bits, then each image is about 300 KB. So on my computer, I can save about 26 frames per second to disk.

There are a few ways to speed this up. The simplest way is to just get a better harddrive. Even better solutions (including software optimization) are available from Graftek Imaging (www.graftek.com).

Kyle V

[Costa111]

Dear friends,
Let me be more clear. I need a practical way of doing this: I want save a greater amount of frames, i.e. around 2100, in a continuous way (I am streaming this
frames from an video camera to the IMAQ board). How can I accomplish this in a satisfactory way? (By now the maximum amount of frames I can save is 360 frames)
Thanks in advance for the help.