Kim Nigel Matthews

Lensless imaging by compressive sensing

In this paper, we propose a lensless compressive imaging architecture. The architecture consists of two components, an aperture assembly and a sensor. No lens is used. The aperture assembly consists of a two dimensional array of aperture elements. The transmittance of each aperture element is independently controllable. The sensor is a single detection element. A compressive sensing matrix is implemented by adjusting the transmittance of the individual aperture elements according to the values of the sensing matrix. The proposed architecture is simple and reliable because no lens is used. The architecture can be used for capturing images of visible and other spectra such as infrared, or millimeter waves, in surveillance applications for detecting anomalies or extracting features such as speed of moving objects. Multiple sensors may be used with a single aperture assembly to capture multiview images simultaneously. A prototype was built by using a LCD panel and a photoelectric sensor for capturing images of visible spectrum.

A codec for HDTV

A high-quality digital video codec has been developed for the Zenith/AT&T HDTV system. It adaptively selects between two transmission modes with differing rates and robustness. The codec works on an image progressively scanned with 1575 scan lines every 1/30th of a second and achieves a compression ratio of approximately 50 to 1. The high compression ratio facilitates robust transmission of the compressed HDTV signal within an NTSC taboo channel. Transparent image quality is achieved using motion compensated transform coding coupled with a perceptual criterion to determine the quantization accuracy required for each transform coefficient. The codec has been designed to minimize complexity and memory in the receiver. >

A High Quality Digital HDTV Codec

A digital video codec has been developed for the Zenith/AT&T HDTV (high-definition TV) system for terrestrial broadcast over NTSC taboo channels. The codec works on an image progressively scanned with 1575 scan lines every 1/30th of a second and achieves a compression ratio of approximately 50 to 1. The transparent image quality is achieved using motion-compensated transform coding coupled with a perceptual criterion to determine the quantization accuracy required for each transform coefficient. The combination of a sophisticated encoded video format and advanced bit error protection techniques results in a highly robust reception and decoding of the compressed video signal. >

Public space behavior modeling with video and sensor analytics

We present a review of technologies relevant to public space surveillance and describe a pilot study to explore the challenges. The general purpose of this study is to capture and analyze behavior patterns and anomalies of people behavior in a public space. On the capture side, we explore a small array of networked cameras as well as an ultrasonic sensor array for measuring the height of walking persons. After capture, video and ultrasound signals are analyzed and statistics calculated for such measurements, including the duration and speed of the trajectory of each tracked person, and a persons height which is a useful biometric feature for tracking the person across multiple, non-overlapping camera views. These statistics are first analyzed offline to determine the expected patterns of measured values over many captured events. Based on the expected patterns, anomalies can be detected as outliers in real time. Since this is a broad-based pilot study, conclusions relate to the effectiveness of the capture modalities and approaches investigated. We discuss how we use these findings to guide our future work.

A high quality digital HDTV codec

A digital video codec has been developed for the Zenith/AT&T HDTV system for terrestrial broadcast over NTSC taboo channels. The codec works on an image progressively scanned with 1575 scan lines every 1/30th of a second and achieves a compression ratio of approximately 50 to 1. The transparent image quality is achieved using motion compensated transform coding coupled with a perceptual criterion to determine the quantization accuracy required for each transform coefficient. The combination of a sophisticated encoded video format and advanced bit error protection techniques results in a highly robust reception and decoding of the compression video signal.<<ETX>>