Measurements using three-dimensional product imaging (original) (raw)

A A R C H I V E S The use of optical scanning for analysis of casting shape

In the paper the use of optical scanning for inspection of casting shape and its accuracy was described. Optical system applied to digitization of objects determines all dimensions and shape of inspected object. This technology is used in quality control and reverse engineering. System is based on triangulation: sensor head performs projection of different patterns of fringes onto measured object and scanner tracks their distribution with two cameras. Basing on optical transform equations, a processing unit automatically and with remarkable accuracy calculates 3D coordinates for every pixel of camera. Depending on camera resolution the result of such a scan is a cloud of points with up to 5 million points for every image. In the paper examples of applications for castings with different designation was presented.

Methods of 3D imaging used in quality inspection systems in manufacturing

2017

This paper presents a review of methods used for the acquisition of 3D images. A classification of such methods into contact and contactless and into active and passive methods is given. Special attention is given to show imaging methods that can be used for tasks involving product-manufacturing systems. Metody budowy obrazu 3D wykorzystywane w systemach kontroli jakości w procesach

Surface defects detection using a 3D vision system

Proceedings of the 13th International Carpathian Control Conference (ICCC), 2012

The article discusses usage of an innovative threedimensional vision system in a quality control process for surface defect detection. A method of 3D image building and selecting cross section profile on 3D images is presented. The article discusses problems connected with the resolution of the 3D vision system, resolution of the laser beam analysis, and resolution connected with the application of the successive height profiles on sample cast planes. On the basis of the model, measurements allowing assessment of dimension parameters and surface defects of a given cast are presented. On the basis of tests and analyses of such a three-dimensional cast model, a range of checks which are possible to conduct using 3D vision systems is indicated.

Designing a Visual Inspection System for Quality Characteristics Dimensions

Mechanical Engineering Research, 2011

Industrial inspection is one of the crucial tasks to ensure quality conformance of products. The inspection tasks can be done by using several methods like non-scaled go/not go gauging, measuring instruments, or advanced non-touching tools. In this research visual inspection using a developed optical system is conducted. One of the aims of this research is to design an on line visual inspection system that is capable to test geometrical quality characteristics of 2-D machined products. The design process includes developing an economical optical system to acquire inspected product's images. Image processing tools are utilized to deal with the product image; and extract features of its geometrical characteristics. A neural network-based methodology is developed and applied to decide whether the product conforms to pre-specified tolerances. The results of the developed methodology are compared to some statistics based visual approaches from the literature. The results show the goodness of the system as an automated visual inspection system and prove its superior performance with respect to other methods.

Visual system for fast and automated inspection of 3 D parts Flavio Prieto

1999

The recent requirement for increased speed in the design and manufacturing of new products led to a rapid evolution of the technics for fast production (rapid prototyping, machining at high speed, etc.). But a significant component did not follow this evolution, that is the dimensional and functional checking process. To automate this significant phase of production, it is necessary to develop some new analysis method. We presented an inspection method designed around three modules: a first one registrates the CAD model of a part and its 3D data obtained with an active optical range sensor, the second module segments the homogeneous cloud of 3D points in areas representing each surface of the object, and the third one is a visual check of the dimensions of the part. RÉSUMÉ.La nécessité récente d’augmenter la vitesse de conception et de réalisation de nouveaux produits a permis de développer de nouvelles techniques de production rapide (prototypage rapide, usinage à très grande vites...

Non-destructive quality evaluation of the die-casting by laser control system

2009

Automotive quality demands are getting higher every year. Aluminium die-castings are especially important components in the automotive industry because of their light weight, rigidity, good corrosion resistance and heat dissipation. Since the pressure die-casting process is a very complex procedure, there must also be a number of quality controls to avoid dimensional, internal and surface defects. The dimensional and internal objective quality controls are already implemented on in-line real time production. As for the surface quality control of die-castings only subjective visual control of the worker is used. This subjective visual control of surface is substituted with objective surface quality control by the laser control system. The laser control system acquires the three-dimensional (3D) data by the principle of laser triangulation and analyses the surface defects by LACO (Laser Casting Control) analysis. 3D data representing the measured surface of the die-casting is statistically analyzed and evaluated. It is capable of detecting the most common die-casting surface defects, such as laminations, cold shuts, non-fills, stains and imprints. We found that the LACO system satisfies the requirements for detecting surface defects on diecastings. Combined with the dimensional and internal quality controls, it is a good way of obtaining a total automatic quality inspection with records of die-castings in real time production.

3D inspection system for manufactured machine parts

Machine Vision Applications in Industrial Inspection VII, 1999

This paper presents a new system for inspecting 3D manufactured machine parts with high accuracy. The system focuses on two main aspects: a definition of specific tools for inspection and 3D measurement and high flexibility for feature selection. As a result, a novel system for inspecting objects with 3D characteristics has been developed. The input information is a complete knowledge of the inspection workbench setting (elements, characteristics and resolution ranges) and a CAD model of the part to be inspected. Using an interactive interface, the user may define the features to inspect and the precision required for each one. Some of the operations the system performs are dimensional control with subpixel accuracy, surface inspection and object edge finish. Based on the CAD model and the features to inspect the system automatically designs an inspection planning responsible for managing the different resources involved in the inspection process. Provided that the aim of the system is to obtain the greatest possible accuracy, a great effort has been done in the area of mechanical devices and camera calibration. Also, in order to quantify the goodness of the results obtained, an uncertainty propagation strategy has been carried out throughout the measurement process.

Surface defect identification and measurement for metal castings by vision system

Manufacturing Letters, 2018

An inspection system based on vision technology was developed to identify defects on the surface of a metal part produced by a casting process. In the proposed methodology, binary images of the bright and dark regions of the surface are first obtained. Connected components of these images are processed to find the shadows originated from defects. The algorithm to process the binary images was implemented on a Jetson TK1 board, and programmed in CUDA. The setup performs the computation in 900 ms for images of 5 megapixels, and the connected components algorithm is three times faster compared to commercial software running on a CPU. The parameters to find the shadows are independent of the field of view and resolution, i.e., the quantities that relate the two binary images can be expressed in pixels.

Optical inspection of cutting parts by 3D scanning

Physica D: Nonlinear Phenomena, 2019

The verification of 3D scanning application for the purpose of dimensional inspection.  The dimensional and geometric deviations of cylindrical shoots of aluminium alloy parts.  Coordinate measuring machine (CMM) and PC DMIS software.  A brief overview of the inspection procedure.

An approach to computer-aided quality control based on 3D coordinate metrology

Journal of Materials Processing Technology, 2000

The quality of manufactured products usually needs to be veri®ed. This paper presents an advanced CAQ approach to compare manufactured objects with reference data from underlying CAD models. First, an overview about the current state-of-the-art in optical 3D measurement techniques is given. After that the research method adopted in this paper is discussed. Furthermore, a software prototype of the presented approach in which a stripe projection system with combined gray-code and phase shifting is described. With this equipment, 3D shapes of objects or manufactured products can be measured. In order to compare the 3D data (represented in sensor coordinate system) a registration to the CAD coordinate system is needed. At ®rst, the selection of a starting point for the orientation parameters is described. For the registration process different numerical algorithms are used to minimize a distance function. To achieve a better performance, an optimization process based on 3D voxel arrays is introduced. After the registration process, several parameters for the kind of geometric displacement can be calculated and visualized. For objects that cannot be measured from one direction, a pair-wise registration as well as a global registration have been developed. Furthermore, some rapid prototyping examples to which our CAQ approach has been applied are presented. Those examples show that our method works well in practice. Finally, some application ®elds for the CAQ approach presented here are outlined. #