Easy to Use Vision Systems: Reality or Myth?
| By: Winn Hardin, Contributing Editor
Intuitive GUI's are only part of the solution toward the complex problem of automated inspection systems.
Less-crowded GUI's with easy-to-read instructions and information is one way to make vision systems more user-friendly. Photo Courtesy of Insight Integration.
Ease of use is a mantra in the machine vision market. Like perfection, it seems a goal that is always sought, but rarely achieved. Surprisingly, end users and manufacturers are not that far apart on the subject. Both groups agree that vision systems need to be more transparent - and are more than willing to suggest some ways to achieve systems that maintain their flexibility and power while making training, operation and selection easier on the customer.
Ask a vision integrator or supplier what 'easy to use' systems mean to them and you're likely to get the same answer. 'Two things immediately come to mind,' said David Dechow, president of Insight Integration/ISRA Vision Systems North America (Lansing, MI). One is that machine vision has become easy to use just like computers. We have certainly followed the Window's environment. You could really make a parallel to the development of the PC with advances in machine vision's ease-of-use. Virtually all or most vision systems are windows based and that inherently gives it a degree of ease-of-use that everyone is looking for.'
Echoing Dechow's second point, Chief Technology Office (CTO) of Cognex, Bill Silver (Natick, MA), said that after the human interface the most important aspects of the system are the vision tools themselves. 'A system isn't worth anything if it can't do what the human wants it to& Vision jobs generally involve complete vision finding and inspection tasks and the key is: Are the tools powerful enough that it can take one or two tools and see what the human sees. If the only tools you've got require you to drop down 20 or 30 tools and develop all this complex logic and analysis to see if the part is good or bad, that isn't easy to use even if the user interface is pleasant and helpful. Our emphasis at Cognex has always been a good GUI, but you've got to first and foremost have vision tools with the sophistication to enable the system to find complex patterns and inspect them.'
Steve Spicer, vision systems engineering specialist at 3M, refines the question to one of easy training and programming, not operation. 'My example of an easy system is one that is totally self-training for a middle-of-the road type inspection. We have some lines that we handle thousands of products on and it would be nice if we set up the system to inspect a couple of the products, that the system could adapt to small changes automatically. For instance, we set up inspection on a square part, but maybe the next product is a square with a small feature on one corner. Also, self-training options are usually add-ons to the original system. It would be nice if that was part of the base package. We're not looking for an intelligent system, necessarily, but if it's a similar application, it would be nice if the system could use the previous set as a model to self-train,' he said.
'Everyone says their system is self-training, but they're not. Some operator input is acceptable, but most of the time you have to call over a process engineer or a maintenance person in addition to the operator and you're using a lot of time in changeover,' Spicer added.
Changeover and movement in today's workplace added constraints on vision systems tasked with complex inspection. 'We need to continue to work so that these system become more intuitive,' said Tom Madsen, president of Key Technologies (Walla Walla, WA), to a recent gathering at the AIA Business Conference in Orlando. 'I'm sure we have the same problems [many vision companies have], our systems are operated by people with a relatively low skill level.'
'What a user really wants is for his machine vision system to work like a PLC. He wants a technology that has become so second nature to him that he can go in and understand it completely, and with an [inexpensive] piece of hardware, he can control his process,' explained Insight's Dechow.
Making the complex, simple
While both suppliers and users agree that vision has way to go to become 'easy to use,' all would agree that vision has made significant strides towards this goal. The first steps toward point-and-click programming have brought vision systems out of the code-only world, however, Spicer and other users claim that as more applications tend toward process control, tracking and analysis, his engineers are still writing code about half the time.
Several new approaches may change that. Applied Vision's (Akron, OH) president, Amir Novini, related some of his companies recent efforts toward ease-of-use during the creation of their Genius glass inspection systems during the AIA Business Conference in Orlando. Operators set the parameters for an application by placing a product in front of the camera and then raising or lowering accept/reject threshold lines on a graphical representation of the image, rather than asking the operator to set some abstract numerical values.
Cognex has taken another approach to developing an intuitive programming system that comes in a familiar format. 'We've announced a new product & that is designed to be a lower cost, very easy to use vision system. We start with powerful pattern finding and inspection tools& but when you fire it up it looks like a spreadsheet - just like Lotus or Excel,' Silver said. 'The spreadsheet is superimposed on the image, and in the cells of the spreadsheet, in addition to normal calculations, you can also put vision tools. You write an application in the same way you would write a spreadsheet. It gives you the flexibility people like - because spreadsheets are extraordinarily flexible - with the advantage that everyone from a secretary to an engineer already knows how to use them.'
'One direction is to separate the functions by application, not by actual function. The way to bring the user into the technology is to create an environment where they are putting a window around a bolt hole, for instance, and select the bolt-hole finder tool& One of the best steps towards that end are specific-solution tools, and application-specific solutions in general and that's a hard thing to achieve,' Dechow said.
Silver agrees. 'Let's say you've got a robot and the robot has to pick up engine parts on a conveyor belt. The way we would do it is to have tools that allow you to teach a pattern of what the engine looks like, draw a box around it, and with single image training say, 'find it anywhere in the 360 degree field of view.' To me, that does more than all the fancy GUI's you're ever going to make,' he said.
MV: Make it easier on your company
Part of the problem lies in creating realistic expectations. According to most manufacturers, vision companies in the '80s and early '90s made it hard on themselves by promising that their systems could do just about anything. 'Manufacturer's are creating their own problem, sliding back to the '80s when machine vision was over-promising. Today, manufacturers are promising that systems can do almost anything and customers are asking why it can't do their application for $5000. The answer is that vision has progressed, but not enough to make your application that much easier or cheaper,' Dechow said. 'Again, in the rush to the sell the box or its ease-of-use, I think that very often in the marketplace - and we're guilty of it sometimes as well - the needs of the customer on the plant floor get ignored for the technology. And in all fairness, it's the customer's fault as much as anybody's. They get enamored with the technology and get lost in the fundamental need for inspection. They inevitably fail to specify their needs and qualifications for the system. As an industry, we don't spend as much time guiding them in that direction. We want to guide them to our products, saying it will solve all your problems. What we're seeing on a day-to-day basis are the vision systems that are being turned off because they don't deliver as promised& and that leaves a bad taste with the plant engineer.'
Customers may have part of the answer. 'Something we would like to see in the industry is a universal way to pick systems or not pick systems. Let's say if I have a standard image, it would be nice to qualify that system to see what systems operate the fastest and most accurately. The industry needs a way to be comparable. Standards. Even at the language level where one system refers to a window and another as a region of interest. Even these small changes can confuse an operator,' said 3M's Spicer.
Rather than using simplified programming tools such as visual basic, some manufacturers are integrating programming elements that mimic well-known software programs, such as Microsoft's Excel spreadsheet. Photo courtesy of Cognex.