Camera captures images at record rate

01 Aug 2008

Researchers unveil a high-speed imaging system with an image quality, frame rate and frame count that they say is unprecedented.

A non-intensified multichannel camera system that can record image sequences at frame rates up to 200 MHz has been unveiled by a team from the US and Jordan. Given the general nature and wide applicability of their idea, the researchers have established a company called Spectrum Optical Solutions to develop and market a range of high-speed cameras (Measurement Science and Technology 19 085503).

“For applications where a maximum frame rate of 1 MHz is sufficient, the cost of this type of camera would be less than half the cost of currently available systems.”

"We have developed an ultra high-speed camera system that records microscopic images at higher resolutions than ever before," Ala Hijazi, a researcher at Hashemite University, Jordan, told optics.org. "Such a camera could be used with picosecond lasers to image highly reflective objects at gigahertz rates, something that has not been achieved to date."

Hijazi and his colleague Vis Madhavan from Wichita State University, US, were investigating high-speed machining of metals and found that commercially available systems were not able to capture the microscopic images they required. "This application necessitates frame rates from 100 kHz to 20 MHz," commented Hijazi.

To overcome this issue, Hijazi and Madhavan decided to make their own imaging system, which they say has many advantages compared with existing technologies.

"Our camera can record four-frame full-resolution image sequences at frame rates up to 200 MHz and eight-frame image sequences at frame rates up to 8 MHz," said Hijazi. "Our system can be configured in a variety of ways for different price/performance points. Initial costs are lower, as are operational and maintenance costs."

The resulting camera system relies on a concept called spectral shuttering. Here, short laser pulses of different wavelengths illuminate the object and wavelength selective elements route particular wavelengths to particular cameras.

The system combines four dual-frame cameras and four dual-cavity laser systems. The short illumination pulses are provided by four Q-switched Nd:YAG lasers emitting at 440, 532, 600 and 650 nm. The lasers emit 5 ns pulses with pulse energies of the order of 100 µJ to a few millijoules. The dual-frame cameras record two frames with very short inter-frame separation.

Spectrum Optical Systems is hoping to begin marketing these cameras in Q2 2009. "For applications where a maximum frame rate of 1 MHz is sufficient, the cost of this type of camera would be less than half the cost of currently available systems," concluded Hijazi. "There are no maintenance issues, such as in rotating-mirror and rotating-drum systems. For systems with a small number of frames, the cameras can be drop-in replacements for existing cameras, for instance in microscopes."