Optimal use of dynamic range of a white light video measurement system

✍ Scribed by C Quan; C.J Tay; T Wu; S.H Wang; H.M Shang

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 571 KB
• Volume: 237
• Category: Article
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2004.03.090

✦ Synopsis

This paper describes a method to make optimal use of the dynamic range of a white light video measurement system. Since the exposure period of a CCD camera is reduced with high frame rate, dynamic measurement with a short exposure is intrinsically light intensity starved. Thus insufficiency in light intensity may introduce underexposure problem and leads to poor image quality. To overcome this problem, we have developed a simple method which enhances the light intensity detected by a high-speed camera using a white light source (WLS). As an example, we have implemented the system for vibration measurement using a liquid crystal display (LCD) projector and a high-speed camera. By incorporating the WLS, the measurement speed of the camera is effectively increased by a factor of 6. Discrepancy in the measured vibration amplitude is less than 2%. This experimental study shows a clear demonstration of the limitations of the performance of a CCD camera and the importance of matching the intensity of the image to be analyzed to the characteristics of the detector.