3d in two dimensions with unique camera

IVP, Integrated Vision Products in Linköping, has developed a multi-functional camera that can measure 3D, RGB spectra and laser scatter all in the same unit. The secret behind the camera is a integrated circuit developed in-house that can be tailored to the customers’wishes.  The circuit is based on 15 years of experience, which has also resulted in a matrix-based CMOS sensor and 512 RISC processors to calculate image data on the chip. The camera also has a high-speed communication capability of 330 Mbit per second, sent to a Windows NT computer with a framegrabber card. Machine vision has come a long way in Sweden, and IVP is a world leader in its field. 

This is largely due to the Royal Institute of Technology here in Linköping, explains Anders Murhed at IVP. Our business is a continuation of the research done at the Institute in the beginning of the 80’s, which we continued at IVP.

Refined visual information

An advantage of the IVP camera is that the visual information is processed on the chip before being transferred to a PC via a high-speed communication link.  The chip can also be configured for different purposes, explains Anders Murhed.
The result is that our multi-functional camera can process very large amounts of data. Compared to a traditional CCD chip, operating at 25-50 images per second, ours can process up to 8,000 images per second.  We can moreover provide three different image types using the same chip.

3D through laser triangulation

The company has received the most customer response for its 3D data processing technique, which uses laser triangulation. The technique is based upon the projection of a laser line from a Parameter laser projector. The objects that are to be inspected pass under the laser line,while an area camera simultaneously records variations in the projected line from another angle, which provides the data for calculating the geometry.
Half of the world market for vision is in the electronics industry and it is here that our camera has found the most uses, continues Anders Murhed. A typical use for the camera is in the automated soldering of circuit board components. The first check is that the soldering paste has been correctly applied. After assembly and soldering, the position and height of the components are checked to ensure that all legs are correctly positioned and that the components are sitting horizontally after soldering, which would not be the case if a leg were incorrectly inserted.
The earlier these defects are found in production, the less expensive they are. If the soldering paste has been incorrectly applied and production still continues to the final inspection, the cost of discarding the defective circuit board will be substantially more than if it is discovered directly after the first step.

CVB compatibility

-IVP’s multi-functional camera is compatible with all machine vision tools in the Common Vision Blox (CVB), which is a reason why many OEM manufacturers choose to use this equipment, Anders Murhed continues.
Using off-the-shelf modules, such as OCR/OCV or bar code, to verify that the right component has been mounted in the right circuit board location considerably shortens development time. It is also possible to develop your own software programs in C++, Visual Basic or Delphi to directly address the visual information.  The conversion of 3D information to a 2D image makes it possible for all 2D-based modules to process 3D information. Image information obtained from laser triangulation is displayed as a gray scale or in different color levels. By setting tolerance limits to variations in the height of a component, for example, it is possible to determine if the component has been incorrectly mounted.  The CVB “blob” tool has found many applications in the food manufacturing industry. Portioning meat has become a common use for the tool, where the weight of irregular pieces of fillet, for example, is continuously calculated and pieces are cut when the correct weight is reached.

Combined measurements

Because we have several functions in a single camera, it is possible to carry out measurements that combine 3D imagery and color measurement. This is common in the food industry, explains Anders Murhed. While the weight is being calculated it is possible to simultaneously check that color is within acceptable limits,which is common in the processing of vegetables. Cucumbers cannot be too irregular in shape and carrots must have an approved color.
The chip in IVP’s camera has an area with three filters for red, green and blue. If there is no specific need to assess color, the same area can be used for gray-scale information, which gives better sensitivity. 
 

Scattering measurement in the wood industry

The third function obtained from the same chip is scatttering measurement, in which the subject material is illuminated with a number of laser points. Light from the laser points is scattered throughout the material and recorded. This technique first came into use in the wood industry, but today has also found uses in other fields.  One example is identifying rocks when sorting potatoes, but here this is called the halo effect.

Refined information

The first prototype chip, from 1985, had 128 x 1 built-in image points, compared to the 512 x 512 points used today. Since then the built-in processors have also been added, enabling the visual information to be processed on the chip before it is transferred. Even if the chip is the heart of IVP’s products, laser projectors and the possibility of creating your own applications with CVB has meant quite a bit for the company’s success. In this regard IVP’s collaboration with Parameter has been very important.
 
 

Contact:
Oy Optoparameter Ab
Timo Pelli
Tekniikantie 4 D
FIN-02150 ESPOO
Finland
Tel- +358 9 435 550 0
Email: sales.fi@parameter.se
www.parameter.se