Application: Presence Verification

Inspection Challenge:

A manufacturer needed to check for inclusions (knots) in pieces of wood. Requirements included size, x-y co-ordinates and quantity. The wood would be passing along a high-speed production line.

Verify and Measure:

• Check to see if there are any defects within the pieces of wood.
• Measure and count the defects.

Machine Vision Solution:

The following DT Vision Foundry Tools were added to the Point and Click Script to solve this inspection challenge:

• Avi Player Tool – This tool shows a variety of images for display purposes. It is ideal for rapid prototyping because it is fast – in a run-time operation, it would be replaced with the more sophisticated Picture Tool, which takes the image of the product in order for the measurements to be processed.
• Blob Analysis Tool - The tool will be used to threshold the ROI to check for any defaults contained in the wood. This tool will use its 78 different statistics to pick up on any defect in the product. This information can be passed through our Serial I/O Tool.
• Text Tool – This tool visually displays the results of the test.
• Status Tool – This tool also displays the PASS/FAIL results and will also show the pass/fail rate, variables and will save any images either passed or failed to a folder for later failure analysis to be completed.

The screen shot below shows that the image has been captured from a camera and has been displayed upon the screen in a view port. The screen first shows that the Blob Analysis Tool has found that the pieces of wood have a variety of defects. If necessary, the results can be displayed on the screen. The green halo effects are the found problems within the wood. The Change Tool can then if needed change the ROI’s (Regions of Interest) to a more prominent colour so that the operator can notice a defect.

The screen below shows the user that there is a very good GUI (Graphical User Interface) available within the package. The software has picked up the defects and has changed the colour of the defects so that they are more visible to the operator. This Status Tool shows the user all the vital information that is needed for the quality inspection of the product to be as efficient as possible.

The statistics shown are as follows:

Pass or Fail sign (green or red respectively). Pass/Fail percentages. Variables that the user is looking for. The ability to save all the statistics and pass/failed images for later failure analysis inspection. Warnings, e.g. in case there are five failures consecutively.

This routine will continue to check the different pieces of wood until the user/programmer is satisfied that the job is done. From then on, there are a number of scenarios that can be implemented. The Digital I/O Tool can signal the user’s PLC to operate a robot to discard the failed articles and to let the passed articles carry on down the production line. The Digital I/O Tool can even stop the production line if there are any faults found with the products that are being checked.

Result:

The Data Translation machine vision solution automated the inspection process, resulting in improved quality and efficiency for the manufacturer.