Stereo Introduction
Stereo Technology
Selection Guide
Applications Guide
Products
STOC
STH-DCSG
STH-MDCS3
STH-DCSG-VAR
STH-DCSG-VARX
STH-MDCS3-VAR
STH-MDCS3-VARX
Small Vision System
Manuals
Downloads

Stereo Applications Guide

To choose the right stereo device for your application, it helps to know about the characteristics of our stereo devices. This page is a summary of the information you will need to make an informed choice on a device, with links to more.

For an quick product comparison, see the Stereo Products Comparison.

Stereo Computation

Computing 3D stereo results is computationally expensive. Videre uses SRI International's best-of-class algorithms for efficient computation. The computations can be performed on a PC, or on-camera, with Videre's new Stereo-on-a-Chip (STOC) board. The STOC uses a fraction of the power of a PC, yet produces the same result. Since the STOC frees up the PC for other work, it is recommended where realtime performance and/or low power are important.

More information:

Stereo-on-a-Chip
Small Vision System (PC-based stereo)
Some sample images and 3D reconstructions from our Stereo Cameras:

Stereo Baseline and Optics

The baseline is the distance between the two cameras. Smaller baselines work well for close objects, larger baselines give better depth precision for far-away objects:

Product	Baseline	Object Distance	Application
STOC-6cm STH-DCSG-6cm STH-DCSG-VAR STH-MDCS3-VAR	6 cm 5-20 cm	Close Work	Head Tracking Gesture Recognition
STOC-9cm STH-DCSG-9cm STH-MDCS3-9cm STOC-15cm STH-DCSG-15cm STH-DCSG-VAR STH-MDCS3-VAR	9 cm 15 cm 5-20 cm	Moderate Distrance (15-20 m)	People Tracking Obstacle Detection and Avoidance
STOC-30cm STH-DCSG-30cm STH-DCSG-VARX STH-MDCS-VARX	30 cm 18-60 cm	Long Distance	Outdoor Scene Reconstruction Vehicle Obstacle Detection

The baseline and the lens field of view interact to determine the basic characteristics of the stereo device. You can use the Stereo Worksheet to help determine the best baseline and lenses for your application.

Videre makes both fixed and variable baseline devices. The fixed baseline devices are recommended for most applications, since they are pre-calibrated and maintain their calibration. Calibration compensates for any lens distortion and mechanical misalignment of the cameras. All Videre products can also be easily calibrated in the field, should it be needed.

Variable baseline devices allow the most flexibility in prototyping. The standard device is adjustable from 5 - 20 cm, the extended range device from 18 - 60 cm. The STOC is not available as a variable-baseline device.

More information: Stereo Worksheet

Resolution and Shutter

Videre's cameras use CMOS imagers, with a resolution of 1280x960 (STH-MDCS devices) or 640x480 (STH-DCSG and STOC devices). For realtime applications and higher frame rates, the smaller resolution is appropriate. For applications that need higher resolution, the megapixel devices are better.

The DCSG/STOC devices have a global shutter, which means that all pixels are exposed at exactly the same time. For capturing rapid motion, or when the stereo device itself is moving, global shutter is required. The MDCS devices have a rolling shutter, which means that each line of the image is exposed at a slightly different time. These devices are good when the cameras are stationary.

More information: Global Shutter Video

Color, Monochrome and Infrared

If your application doesn't need color, then monochrome devices are best, because they have better effective resolution than the corresponding color device. Videre cameras are also sensitive in the near infrared band, for specialized applications.

More information: Color and Infrared Properties