Electronic Design

Complete Camera Module Delivers Light-To-Byte Solution

A complete imaging subsystem, the PCM2112, can capture 1280- by 1024-pixel high-resolution color images and deliver a digital byte stream. The compact module that contains the high-resolution image sensor has a base footprint of just 26.3 by 25.5 mm and a height of 25.7 mm, including the lens and shutter assembly. Since the unit comes preassembled, the sensor is perfectly aligned to the optical axis of the lens, providing uniform focus.

The image capture rate at the full 1280- by 1024-pixel (10 bits/pixel) resolution is 9.3 frames/s. Designers, however, can sacrifice resolution to achieve higher rates. For example, 50 frames/s is possible with a resolution of 256 by 188 pixels. If the pixel depth is reduced to 8 bits, 50 frames/s can be attained for a 512- by 376-pixel image. A maximum of 102 frames/s can be achieved by reducing the resolution to a 256- by 188-pixel image (8 bits/pixel).

The integrated shutter is accurate to 1/200 of a second, suiting the camera for high-speed still-image-capture applications in addition to full-motion video. A high-quality five-element lens provides an f-stop of 3.0 and a 12-mm focal length. It has a depth of field from infinity to 1.5 m, along with a field of view of 44° (horizontal) and 36° (vertical). An optical filter also is incorporated in the lens barrel. This filter can suppress unwanted infrared light that could typically swamp out the desired image.

A 30-wire ribbon cable exiting from the camera module provides the 8- to 10-bit digital output and the various control signals and power connections. It also supplies all the power and signaling required by the module, including shutter control and on-the-fly programming that lets the user select between resolution, frame rate, and bit width.

The high-resolution image sensor incorporates patent-pending circuitry that eliminates fixed pattern noise and performs color balancing in the analog domain prior to digital conversion of the image. The sensor chip employs a scalable architecture that includes over a million 7.5-µm2 active-pixel photodiodes in a 0.75-in. optical format. Each pixel is capped by a color filter and a microlens.

The PCM2112 can be programmed to perform electronic zoom, pan, tilt, flip, and mirror operations. By pre-integrating all the components, the integrated module saves both time and money for designers who must quickly bring systems to market, too. No assembly is required, and no time-consuming optical alignment of the lens is needed. When powered by a 3.3-V supply, the module consumes less than 200 mW.

In lots of 1000 units, the PCM2112 costs $69.80 each. Samples will be available in the third quarter.

PixelCam Inc., 1500 E. Hamilton Ave., Suite 211, San Jose, CA 95008; (408) 558-8266; www.pixelcam.com.

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