Quality Magazine

Infrared Camera Goes Small

May 5, 2003
Designers of consumer electronics gear, it seems, are constantly developing ways to shrink a product's size without sacrificing features or capabilities found in the bigger model it is meant to replace. The same is true in many industrial electronics categories. A recent case in point comes from Indigo Systems Corp. (Santa Barbara, CA).

In April, Indigo introduced what it calls the world's smallest and lightest infrared, thermal imaging camera, the Omega. In fact, the company initially planned to call the camera UL3, which stands for ultralow size, ultralow weight and ultralow power. The camera, priced in single unit quantities at $10,000, weighs 3.5 ounces, is less than 4 cubic inches in size and consumes less than 1.5 watts of power.

"The smaller the size of the camera, the more applications one can easily use it in," says Bill Terre, director of miniature cameras for Indigo. "In the factory, an inspector can do preventative maintenance or process monitoring and not have to lug around a big camera. The inspector can carry this camera around all day."

Microbolometers
The Omega uses vanadium oxide (VOx) microbolometer detectors, which is the fundamental technology that enables the camera to be miniaturized. A microbolometer is essentially a sensitive thermometer whose electrical resistance varies with temperature. As the VOx array detects varying degrees of thermal radiation in a scene, "the material heats up, the resistance of the material changes and a picture is developed," Terre explains.

One key to the Omega's small size and low power consumption is a proprietary image optimization system that pre-processes image data and eliminates the need for temperature stabilization of the unit's detector array. This enables the Omega -- unlike most noncryogenically cooled infrared cameras -- to operate over a wide ambient temperature range, from -40 C to 55 C, without the need for a thermoelectric cooler. This saves on space, complexity and power consumption. By not having to wait for the thermal stabilization, the camera can generate an image in two seconds, compared to 15 to 20 seconds for systems that require thermoelectric cooler stabilization.

The Omega features a scene dynamic range management function that allows it to operate in two modes. In the normal mode, it operates at 150 C. If the camera detects hot scenes, it automatically switches into an extended temperature range mode allowing imaging of scenes up to 400 C. In addition, the hottest object in a scene can be colorized.

The camera incorporates on-focal plane signal processing, digital signal processing-based electronics, along with the VOx technology, which allows the camera to use higher f-number optics. With its standard f/1.6 lens, the camera has a sensitivity of 85 millikelvin (mK).

The camera has a 160- by 128-pixel focal plane array. That is somewhat smaller than larger systems, but is a tradeoff most companies are willing to accept because of the other features, says Terre.

"Many of the existing systems use a larger format focal plane," says Terre. "In that sense, we have given up some resolution, but the question is, 'Does the trade-off for portability and ease-of-use justify the reduction in the size of the focal plane?' In most cases, the answer is absolutely." Most applications don't require the resolution provided by the larger format systems, he says.

Digital and analog video
The Omega features analog and 14-bit digital outputs for direct support of machine vision and imaging applications. It captures images at real-time video rates of 30 frames per second for analog video (RS-170) or 25 frames per second for digital video (CCIR.)

The analog video output em-ploys the company's SmartScene video output technique to provide optimum picture quality. Smart-Scene converts the 14-bit digital image data into analog video, and the conversion algorithm is automatically adjusted, frame by frame, to maximize the contrast in darker (colder) parts of the frame, while avoiding "washout" of brighter (hotter) objects.

An attachment called the ThermoCorder allows the Omega to be used in conjunction with a Sony video camcorder. The camera sits on top of the camcorder and the operator can view the thermal imagery either through the eyepiece or on the flip-out LCD.

"With the flip of a switch you can view infrared or visible images," Terre relates. "An inspector can look at something in infrared and capture that data on tape, flip to the visible imagery and show the visible equivalent. In addition, he can do a voice recording annotating what he is seeing."

TECHNOLOGY CONTACT
For more information on the Omega infrared camera, contact:
Indigo Systems
5385 Hollister Ave., Suite 103
Santa Barbara, CA 93111
(805) 964-9797
FAX: (805) 964-7708
URL: www.indigosystems.com
E-mail: slaband@indigosystems.com

SPECS

  • The camera weighs 3.5 ounces, is less than 4 cubic inches and consumes less than 1.5 watts of power.
  • Time to first image is less than two seconds.
  • Operates at temperatures that range from -40 C to 55 C. In harsh conditions, environmental housing maybe needed.
  • The Omega provides analog video as well as optional 14-bit digital video output.