Laboratory for Technical Vision|
Head of the Lab. Prof. Yuri Chugui
Main activity fields
Investigations in the following fields:Images and diffraction patterns of 3D objects appliedto dimensional inspection;
Laser optical metrology based on various measurement methods (shadow, interference, structural, illumination).
In 1991, a Specialized Scientific Research Laboratory for Technical Vision became a part of the Technological Design Institute of Scientific Instrument Engineering. This laboratory was established in 1987 by a joint order of Ministry of Atomic Energy of Soviet Union and Siberian Branch of USSR Academy of Sciences.
One of the trends of laboratory activity is the development of a constructive theory of formation and filtration of Fourier spectra and images of three-dimensional objects applied to dimensional inspection.
Within the framework of this direction, a constructive method for calculation of diffraction phenomena by three-dimensional objects with clear shadow projections, in particular, by bodies of constant thickness with the use of a model of equivalent diaphragms, has been proposed and developed. As compared with the existing methods, this one is simple, physically obvious and at the same time sufficiently strict for engineering applications. On this basis, highly precise algorithms for the determination of the dimensions of extended bodies with constant thickness have been developed. Also, the peculiarities of formation and high-frequency filtration of images of typical three-dimensional objects in passing light were investigated. This provides a possibility for the creation of technical vision systems of a new generation.
The second main trend of the laboratory activity is the development of high-speed optical electronic methods for precision inspection of the geometrical parameters of one-, two-, and three-dimensional objects followed by the development of technical vision systems of wide use.
Some unique technical vision systems have been produced within the framework of the second direction. For instance, a laser optical method with the use of structured multi-point illumination of an object in the form of a matrix of light beams (on the basis of the Damann grid) was developed for three-dimensional objects inspection. This method was used for the production of a laser measurement device for non-contact integral inspection of the geometric parameters of grid spacers for nuclear reactors VVER-1000. This was ordered by the Joint-Stock Company TVEL. The developed specialized software makes possible high-precision measurement of all necessary basic parameters of a complex three-dimensional object, such as a grid spacer.
At the present time, the laser measurement device is under testing by the Joint - Stock Company Novosibirsk Chemical Concentrates Plant, which is incorporated into Joint – Stock Company “TVEL”. Its efficiency is up to 5 articles per hour. This is ten times higher than the efficiency of the available contact coordinate measurement machines.
A high-efficiency optical electronic system “Blik-M” based on shadow and triangulation measurement method has been developed at the laboratory. This system is designed for noncontact integral inspection of internal and external dimensions of bushing articles (fuel elements). The system makes it possible to measure not only inside and outside diameters, but also the straightness deviation of the generatrix as well as the height of products. A program specifies the number and location of diametral and transverse cross-sections at which the parameters of an article are measured. This system makes possible to measure more than 100 dimensions of articles with the productivity of 100 articles per hour. Since 1996, the system is in industrial operation at the Joint-Stock Company Novosibirsk Chemical Concentrates Plant.
For instance, to order of the Joint – Stock Company Novosibirsk Chemical Concentrates Plant, meters were used to create devices called “Control-1” and “Control-2”. They are designed for automatic measurement of the geometric parameters of atomic TVEL reactors of the VVER-440 and VVER-1000 types. (The length of a fuel element varies from 2.5 to 4 m).The devices are part of the functioning TVEL-producing technological lines. They make it possible to make inspection the outer parameters of claddings and end plugs of fuel elements, their length, deviation from rectilinearity, location, and length of defect sections. The use of such devices improves the quality of Joint-Stock Company Novosibirsk Chemical Concentrates Plant production.
An industrial technical vision system for automatic inspection of surface defects of fuel pellets of TVEL nuclear reactors ordered by the TVEL company for a machine-building plant in the city of Electrostal is under development.
Defects (spalling, cracks, pores, and others) are detected by obtaining of highly contrasted images of fuel pellets with the use of special illumination and subsequent digital data processing. The expected probability of missing defects is 10-4. The use of this system will increase the safety and reliability of inspected operations.
An interference method of measurement is used for precision inspection of the diameters of cylindrical products. This method is based on the recording and processing of the image resulting from the interaction of two light beams: a transmitted one and the one reflected from the cylindrical surface of the article under control. A measuring system called “Rolik” was created on the basis of this method. The complex is designed for the inspection of the diameters and lengths of bearing rollers of railway locomotives. It measures the diameters in a range from 18 to 54 mm with an error not greater than ±0,5 mm, as well as the lengths and deviations of the generatrix from rectilinearity. The use of this system in railroading will increase the quality of bearings under repair and, hence, the safety of railway transport.
Also, the laboratory has developed a system for the inspection of the misalignment and beatings of cord clutch flanges of electric trains for this industry (the error is no more than 50 mm). The system allows automatic accumulation and analysis of the measurement information. Since 2000, several such systems are in pilot production at the West-Siberian railway.