Multiple Camera Acquisition

The Multiple Camera Acquisition VI demonstrates three different ways to acquire images from multiple cameras.

The first acquisition mode (0) acquires images from two cameras that are connected to two separate frame grabbers where neither the cameras nor the frame grabbers are synchronized. The IMAQ Start VI is called almost simultaneously for both acquisitions, meaning that the next available frames from both cameras will be displayed. This mode acquires images at a rate of 30 fps per interface since the cameras are connected to separate framegrabbers.

The second acquisition mode (1) acquires images from two cameras that are connected to a single framegrabber. This mode requires either an IMAQ 1408 or IMAQ 1409 device. The cameras are synchronized, which means both cameras send images at the same time. The HL Ring Buffer Config VI reserves a buffer for each camera and stores the images accordingly. Set the frame grabber slave acquisition mode to CSYNC External and assign it the source to be one of the channels. This mode results in a total acquisition rate of 30 fps, or 15 fps per camera.

The third acquisition mode (2) acquires images from two non-synchronized cameras that are connected to the same frame grabber. This mode requires either an IMAQ 1408 or IMAQ 1409 device. This VI acquires an image from the first camera as soon as it is available and waits for the beginning of the next available frame on the second channel. Once the second image is captured, the VI returns to the first channel. This continues until you stop the VI. This mode results in the lowest frame rate of all the modes because the framegrabber must relock before each new acquisition.

Requirements

Filename: multiple_camera_acquisition.llb

Software Requirements

Application Software: LabVIEW Full Development System 7.0
Language(s): LabVIEW

Hardware Requirements

Hardware Group: Vision (IMAQ)
Driver: NI-IMAQ 2.5.1

Reader Comments | Submit a comment »

Does not work with NI1407 & NI1409 (two cameras with two boards)
I am trying to use 2 cards to perform asynchronous acquisition from 2 cameras at nearly full frame rate. The example program does not work when selecting mode: "Acquire from two cameras (one on each frame grabber). This mode requires two frame grabbers." The video from the NI1409 comes through OK, but the NI1407 freezes. This was not helpful at all.
- Carlton Brooks, Sandia National Labs. cfbrook@sandia.gov - Sep 13, 2005