Engineering design software tools are well established in mechanical, optical or electrical engineering and many new products are first designed and optimized with such software packages. Vision system design and integration should be no exception.

Application engineering is a major cost factor and the ability to simulate, evaluate and optimize enables engineers to build better, more complex and more refined systems in a shorter amount of time. Just like other CAD software packages, vision system CAD software should provide an interactive environment where a user can describe and model relevant system and component properties. Functions specific for vision systems can then assist with performance analysis, compliance verification, optimization and simulation.

Vision System Modeling
A new software product called VisionSystemDesigner 1.0 has these features. Modeling a vision system with this software starts by importing 3D geometric CAD models of the application context, the target machine and the product to be inspected. The user can then place a camera model in the virtual machine. A camera model describes the camera geometry, interfaces and internal camera characteristics related to the image formation. When a lens model is connected to the camera the combined system then provides simulated images as seen by the sensor. The next step includes motion or lighting. By dragging configured parts from a database catalog into the 3D-workspace or by modeling lenses, cameras, and lighting individually, developers are able to compose and simulate virtual vision systems corresponding to the anticipated installation on a target machine. A vision system modeled in this way is documented in an electronic format. Based on this description the VisionSystemDesigner software can calculate various system performance characteristics. For example, in a detection or mea-surement application the software calculates or visualizes image noise, lighting levels, image resolution, field and depth of view, the impact of perspective and lens distortions, variations due to displacements, existing motion blur or possible specular reflections. Such perfor-mance characteristics are helpful for integrators who need an easier and more systematic way to evaluate different configurations with respect to their feasibility and compliance with requirements.

Component Specification
The VisionSystemDesiger software is also useful for specifying requirements and selecting appropriate components. Planning a machine vision system starts with understanding and defining of application requirements. Requirements can be specified in the VisionSystemDesiger software by annotating the 3D-CAD models. For example, to describe a dimensional measurement application a user would mark the measurement locations on the CAD model and specify the desired measurement accuracy in mm with a sigma bound. For a detection application, a user would mark a location on the CAD model, specify the feature diameter in mm and the size of an image patch in pixel (e.g. 16 x 16) that will contain the feature. Specific annotation tools for several standard problems are implemented in the software. With such annotations, the VisionSystemDesiger software can then calculate component requirements such as a lens f-number, focal length, integration time, number of pixels on the detector, data rates, required object irradiance levels, type of lighting etc. A user can then compare different proposed lens, camera, lighting configurations and select the most appropriate system for a specific application.

Semi-realistic Experience
The new VisionSystemDesiger software provides several benefits. A user can with the software evaluate the feasibility of a vision system application with respect to avail­able hardware, simulate images as seen by the sensor and generate a report, which describes the vision system, the requirements and the performance characteristics. The semi-realistic user experience in the interactive environment also has a great potential if used in marketing, training or service. Three-dimensional visualizations of potential systems and components create a visual system understanding and can promote purchase decisions.
Application areas that would most benefit from the VisionSystemDesiger software are applications with multiple cameras, applications that require system performance analysis, and projects with constrained testing conditions. However, machine vision applications in general will benefit from documentation and optimized component selection and less time spend in the laboratory. In Summary: the VisionSystemDesigner software makes building vision systems easier.

Reduced Field Tests
There are some limitations. Not all types of variations are simulated and image simulations involve approximations and cannot completely replace a field test. However, it is known which effects and type of perturbations can be simulated accurately and which ones are conceptual simulations. With this knowledge field tests can focus more on the remaining scenarios that are difficult to simulate. Vision system applications are also very diverse and the application level requirements in the software represent only a common but smaller set. For this reason, a user can also enter vision system level requirements directly to model other application types.