Andre Yakovleff

An insect vision-based motion detection chip

The architectural and circuit design aspects of a mixed analog/digital very large scale integration (VLSI) motion detection chip based on models of the insect visual system are described. The chip comprises two one-dimensional 64-cell arrays as well as front-end analog circuitry for early visual processing and digital control circuits. Each analog processing cell comprises a photodetector, circuits for spatial averaging and multiplicative noise cancellation, differentiation, and thresholding. The operation and configuration of the analog cells is controlled by digital circuits, thus implementing a reconfigurable architecture which facilitates the evaluation of several newly designed analog circuits. The chip has been designed and fabricated in a 1.2-/spl mu/m CMOS process and occupies an area of 2/spl times/2 mm/sup 2/.

An analog implementation of early visual processing in insects

An analog VLSI implementation which mimics the early visual processing stages in insects is described. The system is composed of sixty parallel channels of integrated photodetectors and processing elements. It serves as the front end processor for a motion detection chip. The photodetection circuitry includes p-well junction diodes on a 2 mu m CMOS process and a logarithmic compression to increase the dynamic range of the system. The processing elements consist of an analog differentiator behind each photodetector. The differentiators are low frequency and have been designed using subthreshold design methods.<<ETX>>

A 90-nm CMOS Low-Power GSM/EDGE Multimedia-Enhanced Baseband Processor With 380-MHz ARM926 Core and Mixed-Signal Extensions

To meet the widely varying speed and power requirements of multifunctional mobile devices, an appropriate combination of technology features, circuit-level low-power techniques, and system architecture is implemented in a GSM/Edge baseband processor with multimedia and mixed-signal extensions. Power reduction techniques and performance requirements are derived from an analysis of relevant use cases and applications. The 44 mm2 baseband processor is fabricated in a 90-nm low-power CMOS technology with triple-well option and dual-gate oxide core devices. The ARM926 core achieves a maximum clock frequency of 380 MHz at 1.4-V supply due to the usage of thin oxide (1.6 nm) devices. Power dissipation can be adapted to the performance requirements by means of combined voltage and frequency scaling to reduce active power consumption in medium-performance mode by 68%. To reduce leakage currents during standby mode, large SRAM blocks, nFET sleep transistors, and circuit components with relaxed performance requirements are implemented using devices with 2.2-nm gate oxide thickness

Motion Perception Using Analog VLSI

Motion perception is arguably a fundamental mechanism used by natural species to accomplish a number of tasks, such as navigating freely in an unknown environment. Traditional motion perception methods tend to be computationally intensive, requiring powerful computers and large memories. However, by copying biological mechanisms, such as elementary motion discrimination at the early stages of the visual processing paths, it should be possible to build small and efficient motion perception systems. This paper describes the manner in which a simple motion perception model based on the insect visual system has been implemented using mixed analog/digital VLSI. The device has been fabricated in a 2 micron double metal, double polysilicon process, and comprises 61 photo-detectors, and associated analog and digital circuitry. While not entirely successful in that component mismatches hamper the detection of dark-to-bright changes in contrast, the results clearly show the feasibility of using such a device in autonomous control systems.

Obstacle avoidance and motion-induced navigation

In nature, the visual detection of motion appears to be used in a variety of tasks, ranging from collision avoidance to posture maintenance. Many insects seem to rely primarily on information provided by an array of elementary movement detectors in order to navigate. Moreover, experimental evidence suggests that motion information is interpreted at an early stage of the insect visual system, and may be closely linked to motor control. A motion detector, whose design is based on some of the characteristics of the insect visual system, has been implemented on a single VLSI chip. This paper shows the manner in which motion information, provided by the chip in real-time, may be utilised by the control system of an autonomous vehicle in low-level perceptual tasks.

A micro-sensor based on insect vision

A major problem faced by artificial vision systems is the computational bottleneck. The problem can be addressed by incorporating preliminary parallel signal processing in the sensor itself, thereby alleviating subsequent processing requirements. The authors describe a vision system implemented in analog and digital VLSI incorporating sensors and a processing unit. It extracts information such as range, depth and motion of objects in the visual environment. Advantages are its small size and its wide dynamic range which make it very suitable for real-life applications, particularly in robotics.

Two-dimensional motion detector based on insect vision

Implementing motion detection algorithms using analog VLSI techniques has proven to be a challenging task due to several obstacles, including the limitations of analog VLSI, the algorithmic limitations brought forward by complex motion detection schemes, and the effect of various types of noise. Insect vision has been an inspiring model for motion detectors, as insects heavily rely on motion detection for navigation, and the natural complexity of their neuro-visual circuitry is also less than that of vertebrates. In an effort to implement the so called template model of insect vision, a comparative study of various analog differentiators was undertaken by implementing different candidates on a test chip. Based on the results, a 64 by 4 motion detector has been designed and fabricated. The chip is designed in a 0.8 micrometer 3M-1P CMOS process, and the 2-D array occupies an area of 1.5 multiplied by 3.1 mm2. Each cell comprises a bipolar-mode photodetector, an adaptive amplifier, the improved analog differentiator, and thresholding circuits.

Biologically inspired obstacle avoidance: a technology-independent paradigm

With regard to obstacle avoidance, a paradigm shift from technology centered solutions to technology independent solutions is taking place. This trend also gives rise to a shift from function specific solutions to multifunctional solutions. A number of existing approaches are reviewed and a case study of a biologically inspired insect vision model is used to illustrate the new paradigm. The insect vision model leads to the realization of a sensor that is low in complexity, high in compactness, multifunctional and technology independent. Technology independence means that any front end technology, resulting in either optical, infrared or mm wave detection, for example, can be used with the model. Each technology option can be used separately or together with simple data fusion. Multifunctionality implies that the same system can detect obstacles, perform tracking, estimate time-to-impact, estimate bearing, etc. and is thus non-function specific. Progress with the latest VLSI realization of the insect vision sensor is reviewed and gallium arsenide is proposed as the future medium that will support a multifunctional and multitechnology fusion of optical, infrared, millimeter wave, etc. approaches. Applications are far reaching and include autonomous robot guidance, automobile anti-collision warning, IVHS, driver alertness warning, aids for the blind, continuous process monitoring/web inspection and automated welding, for example.

NAC: A Building Block for Neural Architectures

Abstract Artificial Neural Systems have very high computational requirements. This is a limiting factor in the hardware implementation of real-time systems employing this paradigm. Many of the applications are implemented with a large number of simple processing elements interconnected in parallel. This paper describes the Neural Accelerator Chip, NAC, and some applications. The NAC is a linear systolic array architecture comprising sixteen processing elements. Applications include motion analysis and range estimation on a real-time video signal.

From sensing to perceiving: an overview of the bugeye project

To navigate in an unknown environment, many natural species appear to rely primarily on motion information. Accordingly, the visual system of insects, arguably one of the simplest, is geared towards the detection of motion, which is implemented in mechanisms present at an early stage of visual processing. The interpretation of motion information may then produce percepts which are useful to navigation, such as the warning of an impending collision and the estimation of the distance to potential obstacles through egomotion. The original objective of the badge project was to demonstrate the feasibility of copying motion perception mechanisms onto a mixed mode analog/digital VLSI device. The initial success of the project led to other devices being designed with a view to improving the performance and stability of the analog circuitry. In retrospect, the original concepts appear to remain the most robust, which suggests that the most effective approach would consist of focusing on the simple but fundamental characteristics, and is supported by electrophysiological evidence.