QMT Features: January 2010
Vision interface is the key
A properly designed user interface is critical for the successful implementation of a machine vision system for complex inspection tasks. By Earl Yardley, director – Industrial Vision Systems

Due to the ever increasing complexity of machine vision solutions the user interface of the system has become a critical factor in deploying such solutions. Rapid changes in the technology over the last three years and the increased requirements for complex communication protocols and information storage has lead to the user interface becoming a critical part of the selection process when customers are faced with selecting a suitable vision system solution.

Machine vision systems for complex inspection tasks in automated production processes usually exhibit a high degree of technical complexity in terms of the functions used and how they are deployed. Machine vision solutions are ineffective though, if the user is unable to operate the system properly after it is deployed. Poorly designed user interfaces quickly lead to the operator being overwhelmed and might endanger the smooth production operation. This results in higher costs because of erroneous inspections, downtime and call out services that can easily reach a multiple of the inspection system's original purchase price.

User Interface Options
The user interface of a machine vision system must be simple to understand and as detailed as necessary when it comes to displaying what the inspection system is doing and what means of interaction are available. What is important, though, is that a high degree of internal complexity is compensated by an exemplary and intuitive guidance for the operator.

The user interface has to address two different user groups. One of these types is the highly qualified engineer who, besides selecting the cameras and optical components, develops an evaluation strategy necessary for a robust solution of the inspection task and configures the software accordingly during the commissioning of the vision system on the shop floor.

After the successful deployment of an inspection line, an operator takes on the responsibility for the system. This person monitors the automated inspection process and, if necessary, changes inspection parameters interactively. Usually, the operator is responsible for a number of different assembly and inspection stations on a line. The operator's knowledge concerning the system and the software behind it is therefore not on the same level as that of the engineer who commissioned the system.

The operator is not necessarily interested in the complex functionality behind the system but is interested in historical data, images of defective products, statistical data, charts and so forth.

The operators' requirements on process data visualization and the means for interaction can vary greatly. For various reasons, some companies regard a minimal interface as sufficient: start the automated inspection process, stop it, and display the most important global results. Other users value the option to change many process and system parameters interactively in a comfortable way during operation and prefer an elaborate display of a number of intermediate results.
The various requirements for machine vision deployment and visualization on the production shop floor are placed into two categories, visualization of process data and interaction.

Visualization of process data
To care for a system productively, operators require the following features for their vision system:

  • Clear arrangement: Visualization of the results, measurement values, and other process data and system states must be clearly structured and well-arranged.
  • Diverse display options should be available for showing camera images and visualizing iconic intermediate results of the evaluation process itself. This includes both freely definable zoom settings as well as configurable parameters for additional information made up of overlaid geometrical drawings and text. Font size and colour should be freely configurable.
  • Disturbances in the system or errors during the inspection run should be located and described unambiguously.
  • By visualizing the history of individual measurement values, it should be possible to recognize in time (by visual inspection) whether a production process might be slowly leaving the tolerance range.

Even in fully automated inspection systems a certain degree of human interaction is needed or desired. For this the following requirements can be stated:

  • Upon deployment, the details and contents of the user interface can be freely configured for each inspection process.
  • Menu structure and labelling of commands may be adapted to an existing company standard. It is clear what action is caused by each menu item.
  • During operation, the level of detail of (process) visualization can be easily switched interactively if necessary, e.g. to display the detail view of the camera position in question for a work piece classified as faulty.
  • Optionally, the system can be operated using keyboard, touch screen or multi touch screens.

Modern solution: control panel and process view
Irrespective of the purely functional requirements, it is clear to see that users nowadays expect and attach great importance to an appealing and modern design of the user interface. In order to serve such diverse and, in parts, mutually exclusive requirements on a standard inspection system the latest generation of machine software has to be designed with these requirements in mind.

The latest generation of machine vision software recently released has been designed to accommodate these parameters. Industrial Vision Systems Ltd and sister company NeuroCheck GmbH have analysed and appraised more than 2,000 customer feedback comments in order to develop the NeuroCheck machine vision application software and understand the user requirements in detail. With the new software release, NeuroCheck 6.0, the possibilities for designing the user interface have once more been greatly augmented.

The software interface is divided into two separate output windows within automatic operation in order to address the needs of all users: a "Control Panel" and a "Process View" (which is displayed optionally).

The keyboard-oriented Control Panel is the central operating element and is displayed permanently.

Commands are entered using the function keys or a menu. The control panel provides a compact and rapid visualization of the inspection process.
Customers wishing for a detailed visualization can display a second, optional window called Process View.

The arrangement and display of the two cooperating windows can be configured at will. For example, the Control Panel can disappear "behind" the Process View window after a certain amount of time to use the maximum available screen area to visualize the inspection process.

Solution: graphical development tools
For the applications engineer to be able to set all the parameters and settings without any programming knowledge, NeuroCheck offers a specially developed graphical interactive design tool (the "Designer") for the Control Panel and Process View integrated into the software.

The Designers enables the user to design a window interface interactively from a number of predesigned output windows (Controls) using “Drag & Drop”. Graphically attractive controls are available for the visualization of:

  • evaluation results for the current inspection piece
  • intermediate results in the form of images or lists of values
  • status, diagnosis and result messages of the system
  • I/O states
  • statistical information and measurement data series
  • target values of the peripheral equipment
  • complex process control and event logging

Buttons for commands and the selection of menus can be added interactively as well. What command is assigned to one of the 12 function keys on a typical PC keyboard, is up to the user. A high degree of operating security at the line is achieved by links to password-protected user profiles.

In the future OEMs, system integrators, machine builders and end users using the NeuroCheck platform can fully realize their corporate design. Hundreds of freely configurable colour, font and style settings for the controls allow for the implementation of individual designs of the user interface. It is also possible to adapt to the operating philosophy and user interface of a PLC manufacturer already familiar in the company, thus reducing the amount of training for the operating personnel.

All user interface designs and menus are saved as XML files and can be transferred between computers.

Also available are a large number of pre-defined designs for various screen resolutions and applications that come with the software and can be selected with a mouse click. Based on this concept even novice users can design and implement completely new and exceptional user interfaces such as the digital phone sample shown opposite

Machine vision solutions in the future will be more visually appealing and provide extensive user interaction, and will be achievable we no prior knowledge of traditional software programming. Due to the new approach described above and the software tools available, user interfaces optimized for any kind of machine vision application can be easily designed. According to the customer's needs, a customized and safe-to-use system can be quickly delivered. In the end, efficient production is the aim of every customer, a proven operating concept is a vital contribution.

email: eyardley@industrialvision.co.uk

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