Image analysis – Histogram processing – For setting a threshold
Patent
1991-08-28
1994-01-18
Moore, David K.
Image analysis
Histogram processing
For setting a threshold
382 26, 382 28, 382 67, 364559, 36457107, 36447437, 340686, 356375, 358101, 2502061, G06K 900, G06K 946, G01B 1114, H04N 700
Patent
active
052805425
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an XYZ coordinates measuring system and, more particularly, to improvements in an apparatus for accurately and quickly measuring XYZ coordinates on a moving or vibrating object whose physical position varies along a slit line. Also, the invention relates to improvements in an apparatus for accurately and quickly measuring XYZ coordinates on an object which exhibits very different reflectivities because it is painted in different colors.
BACKGROUND ART
In production processes for manufacturing mechanical parts or products, it is often required that XYZ coordinates on a moving or vibrating object be detected at a high speed, for measuring the dimensions of the object or for inspecting it. Especially, where the object to be investigated has a three-dimensional contour, there is strong demand for quick detection of the XYZ coordinates of numerous points on the surface of the object under investigation to efficiently and precisely measure the three-dimensional profile of the object, for grasping the geometrical features of the object. One known measuring means consists in projecting pulses of slit light onto the surface of an object and arithmetically processing only the vicinities of the two-valued slit light image to quickly detect the profile of the moving object (Japanese Patent Laid-Open No. 78109/1989).
In this known measuring means, the central position of the slit line is transformed into a thin line after the central position is converted into two values. Therefore, the ability to resolve the central position of the slit line is 0.5 picture element and thus the accuracy with which the profile is detected is poor. Also, a special camera controller and a special arithmetic control portion are necessary to read parts of TV camera signals. Hence, the system is expensive. In this way, some problems must be solved for putting the system into practical use.
The present inventor and others have devised an apparatus which detects XYZ coordinates on a real-time basis by the optical triangulation, using a slit light source and a TV camera. Each time the TV camera takes a horizontal scan, the center of gravity of the slit line is detected, and then the XYZ coordinates are detected on a real-time basis by referring to a table of data.
However, this apparatus is unable to detect XYZ coordinates appropriately. In particular, slit light is projected continuously, and the reflected light is imaged by the TV camera for 1/30 second. If the object under investigation moves during this time interval of 1/30 second, then the image is blurred.
Where disturbing light having a wide range of wavelengths such as sunlight exists in a factory or the like, a sufficiently high signal-to-noise ratio (referred to as s
hereinafter) will not be obtained using only a band-pass filter which passes only the wavelength of the slit light source.
SUMMARY OF THE INVENTION
The present invention is intended to solve the foregoing problems with the prior art techniques. It is an object of the invention to provide an XYZ coordinates measuring system which correctly detects XYZ coordinates on an object moving at a high speed, can change the intensity of the projected slit light over a wide range to obtain good reflected light from objects exhibiting unprecedentedly greatly different reflectivities, automatically and appropriately adjusts the intensity of the projected slit light for objects exhibiting different reflectivities, makes a correct measurement of XYZ coordinates even though multiple reflection occurs, and is capable of correctly measuring XYZ coordinates even under disturbing light such as sunlight.
An XYZ coordinates measuring system forming a first aspect of the present invention comprises: a slit light source for projecting slit light toward the surface of an object to be measured at a given angle; a TV camera for imaging the slit line formed on the surface of the object by the slit light; a pulse signal generating circuit which supplies a pulse light projection signal for driv
REFERENCES:
patent: 4396945 (1983-08-01), DiMatteo et al.
patent: 4435835 (1984-03-01), Sakow et al.
patent: 4498778 (1985-02-01), White
patent: 4607387 (1986-08-01), Miyagawa
patent: 4668983 (1987-05-01), Werson
patent: 4731853 (1988-03-01), Hata et al.
patent: 4794262 (1988-12-01), Sato et al.
patent: 4961155 (1990-10-01), Ozeki et al.
patent: 5076697 (1991-12-01), Takagi et al.
patent: 5129010 (1992-07-01), Higuchi et al.
Japanese Laid-Open Patent Publication No. 209105/1985, "Displacement Measuring Instrument", Itaru Ichikawa, Oct. 21, 1985. Abstract only.
Higuchi Kazunori
Ozeki Osamu
Yamamoto Shin
Commarata Michael
Kabushiki Kaisha Toyota Chuo Kenkyusho
Moore David K.
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