Low-light-level images are currently acquired by two methods: coupling an image intensifier to a camera or using a sensor to integrate an image over a period of time. If the image is extremely dim and moving, then a low-light-level camera based around an image intensifier may be the best choice. However, if the image is stationary and the light level is reasonably high, then image integration using a cooled CCD camera may be the better choice. In this month's column we take a look at cooled CCD cameras, the types of sensors and software available, and some applications of these devices.
Very chilling
www.cryocam.com/
For low-light-level imaging applications, Micro Luminetics (Los Angeles, CA) manufactures the Cryocam series of slow-scan, digital, cooled CCD cameras. On the company's Web site, you'll find a description of several configurations of the camera that support a variety of scientific-grade CCDs. These include large format, high resolution, and front- and back-illuminated devices. Available with a 12- or 16-bit ADC, the Cryocam uses a thermoelectric cooler to chill the CCD to -70°C without liquids. Features, CCD specifications, PC-based software, and a gallery of Cyrocam images can also be found on this site.
Intensified imaging
www.cookecorp.com/
Winner of the 1999 Laser Focus World Commercial Technology Achievement Award, the DiCam-PRO featured on the Website of the Cooke Corp (Auburn Hills, MI) is an intensified imaging system capable of exposure times down to 1.5 nanoseconds. As well, the site features the company's SensiCam, a 12-bit cooled CCD camera system and the Axon Imaging Workbench 2, software for ion concentration imaging. An array of on-line articles help readers understand how these camera systems are used in bio-photonics, biomedical imaging, print head analysis and Problems and quantitative fluorescence microscopy.
Back illumination
www.pv-inc.com/
Located in Tigard, OR, PixelVision manufactures CCD-based digital imaging systems for the scientific, medical, industrial, and surveillance markets. This Web site illuminates the company's standard CCD and imaging electronics products, custom CCD designs, and system and subsystem manufacturing services. There are product descriptions, applications, and links to other relevant sites and tutorials.
Selecting CCDs
www.prinst.com/
Imaging systems for scientific applications using back-illuminated arrays are highlighted on the Web site of RS Princeton Instruments (Trenton, NJ). This comprehensive site also offers white papers describing the advantages of slow-scan CCD cameras and the selection of CCD arrays. In addition to data sheets on the company's PentaMAX and small, cooled CCD camera products, you'll find descriptions of frame-transfer cameras and notes on the limitations of CCD arrays.
Cool for OEMs
www.patelec.com/
Using a 658 x 496 frame-transfer CCD, the Pegasus camera from Patterson Electronics (Tustin, CA) operates at -30°C, using a thermoelectric cooler to reduce dark current noise and allow long integration times. Supporting subarray readout and on-chip vertical and horizontal binning, the camera, along with the 1k x 1k PegasusXL frame-transfer CCD camera, is described on this Web site. Systems engineering services, custom interfaces, sample images, and demonstration software are also highlighted.
Precision imaging
www.astrocam.co.uk/
Life Science Resources (Cambridge, England) offers a range of digital, cooled CCD cameras, including the company's UltraPix cooled CCD cameras. On this Web site, you'll find up-to-date information on the 2000 series cooled, interline, digital CCD cameras and descriptions of low-light-level applications and software supplied with the cameras.
Scientific imaging
www.specinst.com/
Specializing in CCD-based analytical instrumentation and detector systems, Spectral Instruments (Tucson, AZ) has developed a number of cooled-CCD-camera systems that are highlighted on this Web site. Permitting readout modes, including subarrays, binning, and TDI, the cameras use linear and area scientific silicon CCD sensors at data rates from 5 kHz to 5 MHz. The 500 series cameras are thermoelectrically cooled with 12-bit digitization at 5 MHz or 14-bit digitization at 1 MHz, and the 600 series cameras are liquid-nitrogen cooled with 16-bit digitization from 20- to 200-kHz pixel rates.
