Dr. Feng Xiao Profile

Dr. Feng Xiao

Manager of Algorithms at Vimicro Corp

SPIE Involvement:

Author

Proceedings Article | 17 March 2011 Paper

CMOS digital intra-oral sensor for x-ray radiography

Xinqiao Liu, Andrew Byczko, Marcus Choi, Lap Chung, Hung Do, Boyd Fowler, Radu Ispasoiu, Kumar Joshi, Todd Miller, Alex Nagy, David Reaves, Brian Rodricks, Doug Teeter, George Wang, Feng Xiao

Proceedings Volume 7961, 79614M (2011) https://doi.org/10.1117/12.878722

KEYWORDS: Sensors, CMOS sensors, X-rays, Imaging systems, Image sensors, X-ray imaging, Radiography, Quantum efficiency, Telecommunications, Cameras

Read Abstract +

Proceedings Article | 19 January 2009 Paper

Mobile imaging: the big challenge of the small pixel

Feng Xiao, Joyce Farrell, Peter Catrysse, Brian Wandell

Proceedings Volume 7250, 72500K (2009) https://doi.org/10.1117/12.806616

KEYWORDS: Cameras, Imaging systems, Sensors, Zoom lenses, Image quality, Spatial resolution, Signal to noise ratio, Modulation transfer functions, Diffraction, Image sensors

Read Abstract +

Proceedings Article | 20 February 2007 Paper

Camera motion and mobile imaging

Feng Xiao, John Pincenti, George John, Kevin Johnson

Proceedings Volume 6502, 650204 (2007) https://doi.org/10.1117/12.706974

KEYWORDS: Cameras, Digital cameras, Motion models, Photography, Digital photography, Imaging systems, Motion estimation, Digital imaging, Signal to noise ratio, Sensors

Read Abstract +

Due to the demanding size and cost constraints of camera phones, the mobile imaging industry needs to address several key challenges in order to achieve the quality of a digital still camera. Minimizing camera-motion introduced image blur is one of them. Film photographers have long used a rule-of-thumb that a hand held 35mm format film camera should have an exposure in seconds that is not longer than the inverse of the focal length in millimeters. Due to the lack of scientific studies on camera-motion, it is still an open question how to generalize this rule-of-thumb to digital still cameras as well as camera phones. In this paper, we first propose a generalized rule-of-thumb with the original rule-of-thumb as a special case when camera-motion can be approximated by a linear motion at 1.667 °/sec. We then use a gyroscope-based system to measure camera-motion patterns for two camera phones (one held with one hand and the other held in two hands) and one digital still camera. The results show that effective camera-motion function can be approximated very well by a linear function for exposure durations less than 100ms. While the effective camera-motion speed for camera phones (5.95 °/sec and 4.39 °/sec respectively) is significantly higher than that of digital still cameras (2.18 °/sec), it was found that holding a camera phone with two hands while taking pictures does reduce the amount of camera motion. It was also found that camera-motion not only varies significantly across subjects but also across captures for the same subject. Since camera phones have significantly higher motion and longer exposure durations than 35mm format film cameras and most digital still cameras, it is expected that many of the pictures taken by camera phones today will not meet the sharpness criteria used in 35mm film print. The mobile imaging industry is aggressively pursuing a smaller and smaller pixel size in order to meet the digital still camera's performance in terms of total pixels while retaining the small size needed for the mobile industry. This makes it increasingly more important to address the camera-motion challenge associated with smaller pixel size.

Proceedings Article | 10 February 2006 Paper

Resolution and light sensitivity tradeoff with pixel size

Joyce Farrell, Feng Xiao, Sam Kavusi

Proceedings Volume 6069, 60690N (2006) https://doi.org/10.1117/12.646805

KEYWORDS: Image sensors, Sensors, Signal to noise ratio, Optical sensors, Color imaging, Spatial resolution, Modulation transfer functions, Imaging systems, Image resolution, Image processing

Read Abstract +

Proceedings Article | 23 February 2005 Paper

Color processing in camera phones: How good does it need to be?

Feng Xiao, Xuemei Zhang, Boyd Fowler

Proceedings Volume 5678, (2005) https://doi.org/10.1117/12.596646

KEYWORDS: Cameras, Manufacturing, RGB color model, Colorimetry, Digital cameras, Color reproduction, Image quality, Sensors, Visual process modeling, Data analysis

Read Abstract +

Proceedings Article | 23 February 2005 Paper

Psychophysical thresholds and digital camera sensitivity: the thousand-photon limit

Feng Xiao, Joyce Farrell, Brian Wandell

Proceedings Volume 5678, (2005) https://doi.org/10.1117/12.587468

KEYWORDS: Signal to noise ratio, LCDs, Digital Light Processing, Visibility, Image quality, Image processing, Cameras, High dynamic range imaging, Digital cameras, Sensors

Read Abstract +

Proceedings Article | 18 December 2003 Paper

A simulation tool for evaluating digital camera image quality

Joyce Farrell, Feng Xiao, Peter Catrysse, Brian Wandell

Proceedings Volume 5294, (2003) https://doi.org/10.1117/12.537474

KEYWORDS: Sensors, Image sensors, Image quality, Image processing, Device simulation, RGB color model, Digital cameras, Imaging systems, Optical filters, Cadmium sulfide

Read Abstract +

Proceedings Article | 16 May 2003 Paper

Preferred color spaces for white balancing

Feng Xiao, Joyce Farrell, Jeffrey DiCarlo, Brian Wandell

Proceedings Volume 5017, (2003) https://doi.org/10.1117/12.478482

KEYWORDS: RGB color model, Sensors, Cameras, Space sensors, Calibration, Visualization, Tungsten, Light sources and illumination, Digital photography, Photography

Read Abstract +

Proceedings Article | 15 May 2001 Paper

Image analysis using modulated light sources

Feng Xiao, Jeffrey DiCarlo, Peter Catrysse, Brian Wandell

Proceedings Volume 4306, (2001) https://doi.org/10.1117/12.426961

KEYWORDS: Modulation, Sensors, Light sources, Error analysis, Image sensors, Light emitting diodes, Imaging systems, Cameras, Color imaging, Blue light emitting diodes

Read Abstract +