The camera is attached to the robot's gripper. © Vista

Camera systems with ring lights and laser projectors are attached to the gripper arms of the two 6-axis robots. They generate images and 3D data of the relevant features. The 'MVTec Halcon' image processing software analyzes the images and measures the distances, depths, thicknesses and positions of the components, among other things. At the same time, the software controls the movements of the robots.

The robots move to a large number of different measuring points on the floor pan. © Vista

The so-called Flex-Inspect Platform from Vista is used. It was integrated directly into the production process as an inline solution at an automotive supplier. The aim was to achieve a fully automated measurement process within the production cycle time - something that would not have been possible manually.

"To achieve these goals, it was clear that a solution could only work on the basis of machine vision. The technology offers great flexibility, fast process integration and, unlike sensors, still works reliably even if the camera is not positioned 100 percent accurately," explains Peter Denzinger, Vice President of Engineering at Vista.

The so-called hand-eye calibration plays a central role here. It synchronizes the coordinate systems of the robot and camera system. Only then can the robot determine its exact position in relation to the component and laser.

This is made possible by the software's extensive library. According to MVTec, it contains more than 2,100 operators for different image processing tasks.

"We have been working with MVTec since 2008. In this case, we opted for MVTec's software because it's the only one that gives us the necessary range of functions and compatibility," says Peter Denzinger.

In the production process, the robots move independently of each other to defined measuring points

All measuring points are embedded in a common global coordinate system so that relative measurements can be carried out between several image acquisition positions.

During the production process, the robots move independently of each other to defined measuring points. The software determines the exact positions of relevant features in real-world coordinates. The evaluation is then carried out: "passed" or "failed". To do this, the measured values are compared with defined tolerance limits - in real time. The various image processing methods perform different tasks. "Surfaced-based matching localizes relevant objects in the image with particular precision. "Sheet-of-Light reconstructs the object surface using laser lines and enables height measurements. "Edge extraction, on the other hand, detects edges and lines with sub-pixel accuracy.

This process is repeated for each individual feature of the workpiece. Once all measurements have been completed, gauge measurements or 3D offsets can also be calculated.

"One of the great strengths of MVTec Halcon is certainly its large library. With over 2,100 operators, we can offer the right method for different activities. This increases flexibility enormously for companies, as they can carry out many different activities with Halcon," says Jan Gärtner, Product Manager Halcon at MVTec.

Potential for machine vision in industry

The solution has now been in use for a complete product cycle. According to Vista, all strategic goals have been achieved - especially the increase in component quality.

"We were in close contact with the customer even after commissioning. That's why we know that all strategic goals have been achieved. The quality improvement in particular gives the customer an advantage over the competition. In the future, we expect to see growing areas of application in the automotive industry in particular, especially for inspection solutions that work with artificial intelligence. With Vista's Flex-Inspect Platform in conjunction with MVTec Halcon, we are already very well positioned for this," explains Peter Denzinger.

MVTec also sees great potential for machine vision in industry. "Vista's solution shows how variably machine vision can be used and what advantages it offers customers. The fact that employees are relieved of monotonous work and production is fully automated, often even faster and more accurately than before, gives companies enormous competitive advantages," says Jan Gärtner.