TechArchive

Original article date: January 1999

Industrial vision systems are increasingly being used for inspection and measurement tasks. Tommy Miller takes a look at one technology that is more than a little different.

Most industrial vision systems consist of a camera image capture board and a PC to process the data. Alternatively there are now all-in-one ’smart’ cameras which might be set-up with a PC that is afterwards removed. Depending on what you want to achieve the different systems will be better suited to different applications. Generally speaking for higher specification tasks you will be better off with separate components (the same as with hi fi audio equipment).

Ten years ago parallel processing was in its infancy and it was thought that the higher processing speed would be the answer to most power-hungry applications – including industrial vision systems. At that time two PhD students at Liverpool University were looking independently at the design of hardware and software for real-time image processing for use in welding applications. It was soon found that distributing the large image data for parallel processing was simply not fast enough so the Broadcast Bus architecture was conceived along with software to do the processing far more efficiently. The image data is “broadcast” to all of the processors on the board allowing each processor to look at specific aspects of the data. [An analogy would be a project team where everybody was given only one task to do and the results are then pooled]. An image that might otherwise be represented by 1/4MB of data can therefore be reduced to say only 1000 pixels per processor for processing all other data being ignored.

The outcome of the research being undertaken by Richard White and Simon Chambers was that an automated welding cell was demonstrated whereby an image processing system was used to control the weld head to such an extent that even violent movements of the workpiece did not affect the weld. At the heart of the system was the new hardware and software that processed the image data. Because these could not easily be exploited commercially the two graduates decided to form a new company Azure and develop the ideas into a commercial product.

Compared with existing image capture boards the new development offers significantly faster processing and exceptional image accuracy. This means that it can be used in a variety of roles ranging from 100% inspection of products on packaging lines to highly accurate measurement tasks and character recognition. In fact the first sale for the board was for an inspection system being used by an American bank for sorting paying-in slips and cheques. In this application checks (pardon the pun) were being made for signatures entries in the change-of-address box whether ‘more information’ boxes had been ticked and similar marks and deletions. At the time no other system was capable of handling the documents at the high rates required – up to 1800 documents per minute. The same broadcast bus technology is also being embedded within other products such as co-ordinate measuring machines.

The latest generation of Azure’s image capture boards the AZV30 has condensed the technology so that it will fit on a standard PCI bus board for use in a desk-top or industrialised PC taking advantage of the speed and power of modern PCs and the PCI bus. Unlike many alternative products the Azure board allows high quality video image to be displayed on-screen in real-time whereas others give jerky images or require a separate monitor to display the image from the camera. Some customers are therefore using the new board simply to eliminate the need for a second monitor whilst others are benefiting from the image quality that is far superior to that obtained by a conventional video card.

However good an image capture board is the associated software can lead to its success or failure as a commercial product. Azure has recognised this and has developed some extremely user-friendly software that makes configuration and operation point-and-click simple. A Microsoft look and feel has been achieved even to the extent that images can be cut-and-pasted from the image window to any other conventional Windows application. And because the AZV30 board is a true plug-and-play product users can get up and running as easily as with a multi-media board. Azure is so sure that anybody can get the board working that loan boards are available for prospective customers to try for themselves.

It is true that alternative boards offering the same image quality are available from other suppliers but Azure claims that nobody else provides the same combination of image quality and ease of development at a comparable price (around (UK pounds)400 for the board software and manuals). Furthermore although this is about four times the cost of a typical TV card the image quality is better and the software is easier to use making it attractive in this market as well. Microsoft’s Activex used with 4Visual Basic programming tools have also opened up many opportunities not previously considered feasible for image processing systems.

Many users and specifiers of image processing systems seem unaware of the different types of image capture board that are available. Sure there will always be a market for low-cost “vanilla” boards but those who want better image quality faster processing or more accurate measurement should be looking at the alternatives. After all the price of a modern higher specification board is remarkably low considering what can be achieved with it.

• Azure
• Tel: 01305 251771
• Contact: Dr Richard White

January 1999