Osamu Ozeki

Real-Time Range Measurement Device for Three-Dimensional Object Recognition

This correspondence describes a real-time range measurement device for detecting the range, shape, and position of a three-dimensional object by a light stripe projection method. The device consists of a light stripe projection unit, a light stripe scanning control unit, a TV camera, a signal processing unit, and a microcomputer. While a laser light stripe is projected and scanned on an object at a high speed, range measurements and their calculations are done with special hardware. Range data are obtained by triangulation. This device can detect the range and shape of the object placed in a 60 cm square area at a distance of 100 cm in 490 ms by 48 × 50 points. The measurement accuracy of the device is ±2.0 cm. A sorting system for machine parts using this device has also been developed. By use of a unique range gating method, the system can discriminate three types of machine parts on a conveyor belt in 4.0 s.

Electrical environmental characteristics for automotive electric systems

The electrical environment is one of the most important factors in the design of high reliability electronic systems mounted on automobiles. Studies were made of the generation mechanisms and characteristics of both transients and high-frequency conducted noise generated in automotive electrical components. The high-frequency conducted noise data were obtained in terms of amplitude-frequency through real-time statistical treatment of the acquired data. The most important transient for automotive electronic systems has been found to be the alternator load dump transient caused by battery disconnection, and the most influential high-frequency conducted noise is caused by contact breaking. The high-frequency conducted noise characteristics can be expressed in the amplitude-frequency relation in the frequency range of 100 kHz-80 MHz.

RF Conducted noise measurements of automotive electrical and electronic devices using artificial network

Two RF conducted noise measurement systems have been developed for laboratory measurements of automotive electrical and electronic devices. One is a noise emission measurement system for measuring noise level from the electrical devices while the other is a susceptibility measurement system for measuring the susceptibility level of the electronic devices to the noise. The formers function is to measure a histogram of noise level, and the latter functions both to measure the malfunction level and to judge a malfunction mode of the electronic devices. These measurement systems are applicable to the frequency of 150 kHz-60 MHz. These are for laboratory measurements performed with the measurement systems connected to an artificial network of the automotive electrical network. This artificial network represents electrical networks used on Japanese compact passenger vehicles.

Properties of High-Frequency Conducted Noise from Automotive Electrical Accessories

This paper describes generation mechanisms and electrical characteristics of high-frequency conducted noise from electrical contacts and accessory drive/control motors, which may cause logic errors in automotive electronic devices. High-frequency conducted noise due to contacts in both horn sounding and lighting circuits results from spark discharge initiated by breakdown across the contacts; and a showering arc which sustains spark discharge for hundreds of microseconds was observed at contacts in lighting circuits. High-frequency conducted noise due to accessory drive/control motors was caused by reactance voltage fluctuations and commutator sparks. To analyze electrical characteristics of high-frequency conducted noise, a measuring system for amplitude distributions in both the time domain and the frequency domain was developed, and an attempt was made to fit a distribution pattern to observed data in each domain. In the time domain, the noise voltages due to contact breaking were distributed between 360 and 530 V. The distribution pattern in the time domain fitted closely to the normal distribution curve, while the pattern in the frequency domain fitted to the lognormal distribution curve.

A new video-thresholding method for recognition of low-quality stamped alphanumerals

With the widespread use of factory automation, there has been an increasing demand for the recognition of stamped characters. The stamped characters are sometimes of high-quality, and sometimes of low-quality, due to the variation of hollow depth and shape. This paper discusses the thresholding method for the recognition of such low-quality stamped characters. The proposed method determines the optimum threshold characteristic for each stamped character, by which the thresholding for each character is performed. The recognition experiment was performed using 120 samples of stamped characters O, D and 8 of low quality. Ninety-four samples were recognized correctly by the traditional fixed-thresholding method, while all 120 samples were recognized correctly by the proposed optimum thresholding method. The recognition rate was examined for 2000 samples composed of sixteen alphanumerals. The correct recognition rate was 99.8 percent, indicating that the proposed method is effective. The stamped character recognition system has been developed for the cylindrical machine part, which can recognize 3 digits of sixteen alphanumerals in 0.95 s.

Recognition System For Machine Parts With A 3-D Vision Sensor

A 3-D vision sensor and a recognition system for machine parts with the vision sensor have been developed. The 3-D vision sensor with hardwares is capable of detect-ing range data of 150 x 241 points in 2.5 sec. This recognition system can discrimi-nate any of nine similarly shaped machine parts moving on a belt conveyor in 3.5 sec. with a correct recognition rate of 99.6 %.

Recognition of position and orientation of jumbled parts using cross slit light 3-D vision sensor

A vision system and a recognition algorithm to detect position and orientation of jumbled simple-shape parts have been developed. The vision system is composed of a TV camera to detect the two-dimensional position of the parts in a shallow pallet and a recently developed cross slit light three-dimensional vision sensor to detect three-dimensional position and orientation of the parts. In a gripping experiment involving 100 parts, in five shallow pallets, using the vision system and the algorithm, the gripping of jumbled parts with maximum inclination of 30 degrees was successful.<<ETX>>

Real‐time range measurement device using slit‐ray projection

This paper describes the construction and the performance of a real-time measurement device for detecting the range, shape and position of a three-dimensional object, using the slit-ray projection method. An experimental machine part sorting system by the device is also described. The real-time range measurement is performed as follows. The laser slit-ray is projected on the object, scanning its surface with a high speed. In the meantime, the range to each point on the object surface is determined by triangulation. The operations are executed by a dedicated hardware. The experimental device is composed of a slit-ray projecting unit, a slit-ray scanning control unit, a TV camera for the imaging of the ray reflected from the object and the signal processing unit, which calculates the range and the shape of the object. The performance of the device is such that the range to the object and its shape, located in the range of 60 cm × 60 cm at the distance of 100 cm are determined for 48 points (x-direction) × 50 points (z-direction) in 490 ms. The accuracy of the range measurement is ±3.0 percent in the above condition. An experimental sorting system of machine parts has been developed using this method. By applying a new range gating method to this device, the sorting of three-dimensional machine parts was realized in realtime by a simple algorithm, indicating the effectiveness of the proposed method and the device.