Slit-ray Projection Method Research Articles

スリット光投影法による複雑形状の再構築 : 微細突起形状の復元精度±0.5mmの実現

スリット光投影法による複雑形状の再構築 : 微細突起形状の復元精度±0.5mmの実現

ランダムドットを組み合わせたマルチスリットの投光による三次元形状計測

Single shot three-dimensional shape measurement system using multiple slits with random dots is introduced. In general slit-ray projection method, a laser slit is swept on the surface of an object. While the laser slit is being swept, the object and the position of the measurement apparatus should to be stationary. So, this sweeping prevents the handheld measurement. In order to cope with this problem, three-dimensional measurement system has been developed to acquire instantaneous shape without sweeping the laser slit on the object. Multiple laser slits are projected on the object and many line segments of laser slits appear in a single image. In order to calculate the three-dimensional position using triangulation geometry, each line segment has to be identified to know the direction of the laser projection. In this paper, the robust identification method is introduced. Random dots projected along the slit are utilized to identify each line segment. Some points on the line segment are randomly sampled and template images surrounding the sampled points are set. The line segment is identified by using the pattern of the random dots in the template. Experimental results show the feasibility of our method.

A Range Finder System with Electronically Maskable Photo Detecting Device Array

A range finder realizable with an easy circuit composition is proposed. The range finder is based on the slit-ray projection method. In the system, positions of slit-ray images on an image plane are detected by using pattern masks electronically provided to the image plane. Due to using the electronic pattern masks, the range finder realizes high cost performance, highspeed measurement and small size. In order to estimate measurement speed, a prototype circuit has been developed. The experimental results obtained by the circuit have indicated that the range finder will be able to take a range image of which resolution is 64 × 64 and more in 1/30[s] or less in the future. A prototype range finder which has a 32 × 32 photo diode array and a laser slit marker has been also developed, and range images have been actually taken using it. In this paper, with emphasis on indicating the availability of the proposed method, the range finder system and experimental results by the prototype circuit and the prototype range finder will be shown.

Shape measurement of columnar objects with specular surfaces by slit ray projection method

AbstractIn this paper, a method for measuring the shape of a columnar object with specular surfaces by a slit ray projection method is proposed. Although the slit ray projection method is effective for measuring the shape of an object having diffuse reflective characteristics, applying the method to an object with specular surfaces has hitherto been difficult. In this paper, a triangulation equation for a columnar object with specular surfaces is derived and used as the basis of a method for measuring the shape of an object having specular surfaces using applicable slit rays. The basic principle is that the angle of incidence of a slit ray reflected from the measured object into an image sensor is restricted specifically by the special design of the optical system. In addition to the theoretical study of the proposed principle, a system for measuring the shape of a columnar specular object and a diffuse object was created and its effectiveness was verified. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(4): 50–60, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1119

A high-speed and continuous 3D measurement system

A new system for high-speed and continuous 3D measurement is presented. It is based on the slit-ray projection method. The key component is the image plane constructed by a position-sensitive device (PSD) array that is horizontally un segmented and linear, but vertically numbered. All PSD row elements are attached to their respective analog signal processors. The analog signals are multiplexed and digitized by multiplexers and A/D converters at appropriate sampling intervals and stored in memory. By virtue of this configuration of the image plane, basis data for 3D measurement are acquired during only one scan of the slit ray at high speed in the form of memory addresses and data. Moreover, if we use large capacity and/or dual port memories, we can continuously obtain 3D range data for as many scenes as needed. The trial system has been implemented with a newly designed 128-channel PSD array and has verified our method, enabling us to obtain successive 3D range data at video rates with an error within±0.3%.

Fast Three-Dimensional Measurement Technique Using a Reference Table. Measurement of a Human Head.

This paper describes a system which enables fast 3-dimensional measurementof a human head by means of a slit ray projection method. The system developed here consists of a laser slit ray projector, two CCD TV cameras, a real-time video signal processor and a 32-bit computer. Due to the employment of this real-time video signal processor and a fast data-processing technique using a reference table, a 3-dimensional measurement of the human head can be Accomplished in 4.3 seconds, and all the image data are converted to 3-dimensional data in one second. Experimental data reveal the applicability of our system.

Fast 3-Dimensional Measuring Technique Using a Look-Up Table. Measurement of a Human Hcad.

This paper describes a system which enables fast 3-dimensional measurement of a human head by means of a slit-ray projection method. The system developed here consists of a laser slit-ray projector, two CCD TV cameras, a real-time video signal processor and a 16-bit computer. Due to the employment of this real-time video signal processor and a fast data-processing technique for using a look-up table, a 3-dimensional measurement of the human head can be accomplished in 4.3 seconds, and all the image data are converted to 3-dimensional data in 1 second. Experimental data reveal the applicability of our system.