Takahiko Inari

Optical inspection system for the inner surface of a pipe using detection of circular images projected by a laser source

Abstract An optical inspection system for the inner wall of a pipe has been developed. This system uses the projection of a circular pattern formed by a conically reflecting mirror on the inner wall, and detection of circular images from the illuminated circumferential surface. Irregularities of the images due to corrosion or accumulation of deposits on the inner surface are inspected by this system. Inspection of the shape of the inner wall has been impossible by current methods. The experimental system reported in this paper has the following practical specifications: resolution of detection on ±0.1 mm, and inspection speed of 30 mm/s at an interval of 1 mm along the pipe. The system is now being used for practical inspection.

Ultrasonic imaging system for robots using an electronic scanning method

A suction stabilizer for reciprocating pumps and method of stabilizing the inflow of liquid to the suction side of the pump. The stabilizer comprises a substantially cylindrical tank, a perforate-walled cage at one end of the tank, and a flexible resilient gas-filled bladder within the cage. Liquid passes through the tank as it moves from a source to the suction side of the pump. Between suction strokes the liquid compresses gas in the bladder. During suction strokes the pressure of the gas adds to the head of liquid entering the pump. The invention involves critical ratios of the tank volume to both the pump displacement and the bladder volume.

Relationships-based recognition of structural industrial parts stacked in a bin

This paper describes an algorithm which recognizes the position and the orientation of a structural industrial part, such as a crankshaft, utilizing the relationships between its elementary blobs. Crankshafts are arranged tightly and piled up in multiple layers and their image from above includes regions (i.e. pictures) of crankshafts not only of the current top layer but also of the lower ones; it thus becomes complicated. First, the algorithm carries out the connectivity analysis for an input binary image, and then extracts elementary blobs by applying a line fitting procedure on every sequence of boundary pixels of connected regions. Next, each blob is judged to determine to which component of a part it corresponds, using the size model. Then the relationships (distances and orientations) between blobs are examined, using their relational models, and a group of blobs of one part is recognized. Its position and orientation are calculated simultaneously. This model matching algorithm is implicitly included in the procedures.

Generation of Lamb Wave Using Linear Array Probe and Its Application for Flaw Detection

The method with which a Lamb wave of the required mode is generated and detected by electronically adjusting the incident angle using a linear array probe, and its application to flaw detection is presented. To test the ability of this method, experiments were carried out using specimens with an artificial flaw. The method was shown to be successful. The two dimensional CRT display method of the detected flaws, in which the polar coordinates consist of the propagation time and the incident angle of the wave, and the brightness corresponds to the amplitude of echo is also presented.

Two-Dimensional Ultrasonic Scanning Method Using a Circular-Array Transducer

We developed a new two-dimensional (2-D) ultrasonic scanning method using a circular-array transducer in which numbers of small piezoelectric elements are arranged in a circle. By computer simulation, it was proved that the circular-array had higher signal-to-noise ratio and made more uniform scanning in space than a matrix-array. The results of experiments for generation of an ultrasonic beam and 2-D imaging using a trial transducer confirmed directivity of the transducer and possibility of three-dimensional (3-D) imaging by the circular-array transducer.

On-Line Monitoring Of Surface Roughness By Using Laser

This paper deals with a basic research on an on-line monitoring of surface roughness by using laser. The relation between an intensity distribution of the reflected laser light and the surface profile is studied. A function of the processed r.m.s. roughness is used, which is taken from the spatial filtering of the surface profile measured by stylus method. An experiment was carried out by using a rolled metallic sheet and pieces finished by an electrical discharge machine. The results show that the intensity distribution is approximately proportional to the r.m.s. roughness of a certain filterd surface profile. The experimental results are proved to be reasonable by theoretical analysis.

Detection of Near-Surface Flaws Using Linear FM Ultrasonic Wave

A Method using linear FM ultrasonic wave to detect near-surface flaws and to measure distances from a surface to the flaw (flaw depth) in billets is presented. To test the ability of the detection and the measurement of this method, experiments were carried out using specimens with artificial flaws. The method was shown to be successful for artificial flaws with shapes such as slits and drilled holes formed at a 0.5 mm depth under the surface.

A simplified visual inspection system using a personal computer

For a practical visual inspection system, data processing in real time, flexibility for variety of products, and cost performance have been required. This article describes a simplified visual inspection system that has well-balanced performance that meets these requirements. Inspection data processing by software makes the inspection system flexible. Development of a simplified pattern matching method based on limiting the inspection within the area pointed by an user and direct memory access of binary image data performs a high speed inspection function. By using a personal computer as a processor of this system, a cost effective inspection system is realized.