A novel ultra-high speed camera for digital image processing applications

Abstract

Multi-channel gated-intensified cameras are commonly used for capturing images at ultra-high frame rates. The use of image intensifiers reduces the image resolution and increases the error in applications requiring high-quality images, such as digital image correlation. We report the development of a new type of non-intensified multi-channel camera system that permits recording of image sequences at ultra-high frame rates at the native resolution afforded by the imaging optics and the cameras used. This camera system is based upon the concept of using a sequence of short-duration light pulses of different wavelengths for illumination and using wavelength selective elements in the imaging system to route each particular wavelength of light to a particular camera. As such, the duration of the light pulses controls the exposure time and the timing of the light pulses controls the interframe time. A prototype camera system built according to this concept comprises four dual-frame cameras synchronized with four dual-cavity pulsed lasers producing 5 ns pulses in four different wavelengths. The prototype is capable of recording 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. This system is built around a stereo microscope to capture stereoscopic image sequences usable for 3D digital image correlation. The camera system is used for imaging the chip-workpiece interface area during high speed machining, and the images are used to map the strain rate in the primary shear zone.

Sub-Millimeter Measurement of Finite Strains at Cutting Tool Tip Vicinity

“…The work of [37] proposes the use of a 12X video-microscope for a pixel size of 4.9µm at 25000 f ps. Finally, [21] proposes to use 4 standard CCD sensors triggered successively in order to obtain 4 images with an inter-frame time of 0.001ms (equivalent to 1M f ps) at very high magnification (pixel size: 0.27µm). However, monitoring the chip formation process require a complete sequence of images.…”

“…The use of Digital Image Correlation (DIC) has also been reported to analyze the cutting zone. [21] have developed a complex dedicated device composed of four non-intensified digital cameras set in dual frame mode to perform a 4 images acquisition at 1M Hz.…”

Kinematic Field Measurements During Orthogonal Cutting Tests via DIC with Double-frame Camera and Pulsed Laser Lighting

“…These observations were first conducted with low frame rates of 100 to 1000 fps [5,10], and then with frame rates of up to 100 kHz [11][12][13][14][15] using highspeed cameras. Classical high-speed cameras are primarily limited by exposure time, which is typically higher than 1 μs.…”

Recent advances in digital particle image velocimetry methods for flow motion analysis

“…Cameras working above this range (1 MHz) are referred to as ultrahigh speed cameras. Recently, in [24], a camera with frame rates up to 200 MHz has been introduced.…”