Machine Vision: Design Challenges and Best Practices
Machine vision can solve a wide range of applications with automation solutions that can improve manufacturing efficiency, lower costs, and increase customer satisfaction with close to zero defects and recalls. To maximize the benefits of machine vision, integrators must focus on the design of the integrated system.
Whether machine vision is used for basic automated inspection or for highly precise vision-guided automation, a well-conceived and developed design is key to achieving a high return on investment (ROI). The core design for a machine vision system revolves around the integration of a vision subsystem with a motion subsystem. Emphasis on this core piece of the design provides an early and accurate bill of materials, mitigates risk from incompatible motion and vision components, reduces integration time and costs, and lowers the total cost of ownership while delivering the benefits of machine vision.
Let’s look at some of the challenges that one needs to be mindful of when building machine vision solutions.
Challenge: Interoperability and technical support
Component selection, setup, and configuration of a motion and a vision system are challenging tasks. Integrators typically choose motion and vision components from multiple vendors. These components are not readily interoperable, and technical support from the vendor(s) is usually insufficient. These factors significantly increase the integration time, resulting in higher integration costs.
When designing a machine vision system, first consider an off-the-shelf, integrated machine vision solution. These integrated solutions, offered by limited vendors, provide turnkey solutions at the expense of cost. These solutions result in a shorter integration time and faster deployment. So, if a standard integrated solution meets the requirements at a reasonable cost, it is the best option to pursue.
The second option is to consider a vendor who offers the motion and the vision components or, at minimum, the core programmable motion and vision components. With this option, there is guaranteed compatibility between the components, a single programming environment, and one source for technical support. These factors contribute to a significantly shorter integration time. A third option is vendors that have a partnership. With such partnering initiatives, vendors usually offer solutions to interface between at least a subset of their products, and workarounds for compatibility issues are often well documented.
With any option, evaluate the amount of support you will receive from the vendor. If required, budget and pay for support packages such as premium phone or individual support from a systems engineer. Support becomes increasingly important with custom and high-performance applications. Good support from a vendor can significantly reduce your integration time, and hence reduce your integration costs.
Challenge: Software programming
While higher software performance is enabling the adoption of vision-guided motion solutions, software integration challenges are still the main barrier for integrators and manufacturers. Typically, there are two different programming environments for the motion and vision components. Learning the distinct environments often requires a huge time investment. Even after getting acquainted with the environments, transferring and translating commands and information between them is cumbersome. Integration of HMI and I/O adds an additional burden and increases integration time. Hardware integration across various communication buses (such as GigE, Cameralink, and EtherCAT) further complicates the issue.
Real-time and FPGA programming, as well as customization, are often required in high-speed vision-guided motion systems, visual servo systems, and highly specialized applications such as those found in the biomedical and life sciences industries. Typically, any customization added by the vendor is available at a premium price. User customization, if available, is often in the form of firmware-level programming, requiring very high domain knowledge and familiarity with vendor hardware.
One environment is simpler
Select one programming environment that is easy to learn and that can seamlessly integrate motion, vision, HMI, and I/O across various hardware platforms and buses. This programming environment must also allow customized real-time and FPGA programming to solve current and next-generation machine vision applications. The environment must feature tools for quick prototyping and early validation of the mechanical and vision components of your machine. Figure 2 shows an example where an embedded vision system with a GigE camera is connected to a servo motor drive over EtherCAT. Vision and motion programming modules provide the tools required to implement the high-level functions to process the images captured from the camera and control the axis through the servo drive. Additional high-level APIs provide simple integration of the HMI and I/O.
Quality, control, efficiency, less cost
A well-designed machine vision system enables manufacturers to improve product quality, enhance process control, and increase manufacturing efficiency while lowering the total cost of ownership. A good machine vision design starts with selecting a motion-vision integration type, which is based on the automation tasks that must be performed by the machine. To successfully develop the design, integrators must carefully consider motion and vision vendors with a focus on interoperability and quality of support services. Integrators must select a single programming environment that enables seamless hardware integration. When solving highly customized and advanced applications, integrators should choose a software platform that makes customization easy and real-time and FPGA programming possible.
In our next post, we will look at the various motion vision integrators that can be applied to your specific industry applications.