Yan-Chay Li

Multiple-frequency continuous wave ultrasonic system for accurate distance measurement

A highly accurate multiple-frequency continuous wave ultrasonic range-measuring system for use in air is described. The proposed system uses a method heretofore applied to radio frequency distance measurement but not to air-based ultrasonic systems. The method presented here is based upon the comparative phase shifts generated by three continuous ultrasonic waves of different but closely spaced frequencies. In the test embodiment to confirm concept feasibility, two low cost 40 kHz ultrasonic transducers are set face to face and used to transmit and receive ultrasound. Individual frequencies are transmitted serially, each generating its own phase shift. For any given frequency, the transmitter/receiver distance modulates the phase shift between the transmitted and received signals. Comparison of the phase shifts allows a highly accurate evaluation of target distance. A single-chip microcomputer-based multiple-frequency continuous wave generator and phase detector was designed to record and compute the phas...

The Implementation of a Stand-alone Video Tracking and Analysis System for Animal Behavior Measurement in Morris Water Maze

In this paper, a digital image tracking and analysis system based on FPGA is presented. The goal of this research is to build an animal tracking system with a new algorithm for Morris water maze experiment application. Our tracking algorithm can track animal motion and is insensitive to environment brightness change. The system can process the high-resolution image up to 700times480 pixels in real-time speed. We can analyze tiny animal behavior change precisely. This system is very compact and is portable. Compared with other similar device, our system is a standalone operation without the need of a personal computer

A new ultrasonic method for measuring minute motion activities on rats

A new ultrasonic method is presented for measuring the minute motion activities of rats. A pair of low-cost 40 kHz ultrasonic transducers are used to transmit ultrasound toward a rat and receive the ultrasound reflected from the rat. The relative motion of the rat modulates the phase difference between the transmitted and received ultrasound signals. An 8-bit digital phase meter was designed to record the phase difference signal which was used to reconstruct the relative motion waveform of the rat in an 8751 single-chip microcomputer. The reconstructed data are then sent to a PC-AT microcomputer for further processing. This method employs a spectrum analysis for the reconstructed data and can measure three minute motion activities including locomotor activity (LMA), tremor and myoclonia. Finally, the method has been tested with real animal experiments. The main advantages of this new method are that it is non-invasive, non-contact, low cost and high precision. This new method could also be profitably employed for other behavioral studies and offer potential for research in basic medicine.

Temperature measurement system based on ultrasonic phase-shift method

The purpose of this study describes an ultrasonic system which can measure air temperature based on the variations of sound speed in the air. Changes of the sound speed are in turn determined by detecting the phase-shift variations of a 40 kHz continuous ultrasonic wave. Phase angle differences between transmitted and received signals are determined by a FPGA digital phase detector and then analyzed in an 89C51 single-chip microcontroller. Theoretical accuracy of measurement is within 0.05 L at an inter-transducer distance of 10 cm. Temperature variations are measured within 10 ins. The main advantages of the temperature measurement system are high resolution, rapid temperature measurement, noncontact measurement and easy implementation.

Video tracking algorithm of long-term experiment using stand-alone recording system

Many medical and behavioral applications require the ability to monitor and quantify the behavior of small animals. In general these animals are confined in small cages. Often these situations involve very large numbers of cages. Modern research facilities commonly monitor simultaneously thousands of animals over long periods of time. However, conventional systems require one personal computer per monitoring platform, which is too complex, expensive, and increases power consumption for large laboratory applications. This paper presents a simplified video tracking algorithm for long-term recording using a stand-alone system. The feature of the presented tracking algorithm revealed that computation speed is very fast data storage requirements are small, and hardware requirements are minimal. The stand-alone system automatically performs tracking and saving acquired data to a secure digital card. The proposed system is designed for video collected at a 640 x 480 pixel with 16 bit color resolution. The tracking result is updated every 30 frames/s. Only the locomotive data are stored. Therefore, the data storage requirements could be minimized. In addition, detection via the designed algorithm uses the Cb and Cr values of a colored marker affixed to the target to define the tracked position and allows multiobject tracking against complex backgrounds. Preliminary experiment showed that such tracking information stored by the portable and stand-alone system could provide comprehensive information on the animals activity.

Stand-Alone Video-Based Animal Tracking System for Noiseless Application

Abstract The acoustic environment is an important variable in studies with animal behavior and psychology. Noise represents an important factor in laboratory settings. Noise of moderate intensity is produced by air conditioning devices and experimental equipment. Traditional automated video tracking systems require one personal computer per monitoring platform, which are noisy and inconvenient for large laboratory applications. This paper presents a stand-alone system for this function (noise-control environment/noiseless application). A novel system combination of FPGA and MCU simultaneously and automatically perform tracking and saving acquired data to an SD card. A fast and efficient tracking algorithm is designed and implemented. Detection via the designed algorithm uses the Y (luminance component), Cb (blue-difference chrominance component) and Cr (red-difference chrominance component) value of a colored marker affixed to the target to define the tracked position and allows multi-object tracking against complex backgrounds. The tracking result is updated every 30 frames/second and only the locomotive data are stored. The proposed system can track animals locomotion totally noiseless operating.

The Study of a Handheld Digital Microscope for Biomedical Applications

In recent years, biotechnology is a highly developed and popular research topic. Microorganism behavior measurement is an important method for biotechnology experiment. Microscope is often used to measure microorganism behavior. The disadvantages of using the tradition microscope are expensive, heavy when the magnification is too large its not easy to tracking microorganism. In this research, we focus on the development of a low-cost and convenient hand-held digital microscope platform. Based on digital microscope technology, we can observe and record any tiny objects behavior and movement, like Paramecium behavior etc. The platform is not only low-cost, easy to operation, but it can also connect to a computer for further data processing and analysis it let the digital microscope can be used in many applications.

A new method for temperature measurement in an infant incubator [using speed of sound]

In this study, we introduce a new measurement system to measure the temperature by using the speed of sound. This method based on the relationship between the speed of sound and temperature. Temperature was quantified by the speed of the sound. The distance between the receiver and the transmitter of ultrasound is positively associated with the resolution of the temperature. This method can provide a quick and precise monitoring for the temperature in an infant incubator.

The development of a low cost animal behavior measurement system

In this paper, we introduce a low-cost system for animal behavior measurement. This system includes four animal experiment cages, each cage being attached to a very sensitive vibration sensor. The output signal of each vibration sensor is connected to a four-channel data acquisition system. The vibration sensor we adopt here is modified from a low cost piezoelectric buzzer. The self-made data acquisition system has four 24 bit A/D converters controlled by a signal-chip microprocessor. The microprocessor then sends this vibration information into a PC computer from a RS-232 port for animal behavior analysis.

Development of a multitarget tracking system for paramecia

This investigation develops a multitarget tracking system for the motile protozoa, paramecium. The system can recognize, track, and record the orbit of swimming paramecia within a 4 mm diameter of a circular experimental pool. The proposed system is implemented using an optical microscope, a charge-coupled device camera, and a software tool, Laboratory Virtual Instrumentation Engineering Workbench (LABVIEW). An algorithm for processing the images and analyzing the traces of the paramecia is developed in LABVIEW. It focuses on extracting meaningful data in an experiment and recording them to elucidate the behavior of paramecia. The algorithm can also continue to track paramecia even if they are transposed or collide with each other. The experiment demonstrates that this multitarget tracking design can really track more than five paramecia and simultaneously yield meaningful data from the moving paramecia at a maximum speed of 1.7 mm/s.