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Tablets

Aim:

The aim of the program is to detect missing or damaged tablets on a conveyor belt.

Input:

A series of images from the conveyor of a production line.

Output:

Detected missing or damaged tablets:

Hints:

To detect damaged tablets, it is recommended to consider using the DetectMultipleCircles filter together with the CheckPresence_Intensity filter to verify object presence by analyzing pixel intensities. To ensure that the inspection is performed once for each batch of tablets, you can specify a Region Of Interest, where the inspection should be performed, as an input of the CheckPresence_EdgeAmount filter.

Labeling connections is explained in this article.

Solution (FIS):

  1. In Workspace Explorer, open the workspace Examples, and in the Filmstrip window, select the Tablets dataset. Drag the Image channel to the ACQUIRE section.

  2. Add the CheckPresence_EdgeAmount filter.

    • Label the outIsPresent as IsKeyFrame.
    • Connect the ReadFilmstrip output to the inImage input of the current one.
    • In Properties window, in the bottom left corner, set the inEdgeScale to 2.
    • Set the inMinAmount to 0.27 to determine the minimum amount of the pixels that should be detected.
    • Click on the CheckPresence_EdgeAmount filter and select the inRoi parameter in the Properties window to mark the region as shown on image below:

  3. Add a formula that converts an input image into Nil when no tablets are found:

    KeyFrame = if IsKeyFrame then Image else Nil

  4. Add the DetectMultipleCircles filter.

    • Set the inRadius to 7 (approximate radius of tablets), the inMaxOverlap to 0 (to avoid overlapping), the inMinScore to 15 (in order not to miss any tablet) and the inEdgeThreshold to 6 (the minimum accepted edge magnitude).

  5. Add the CircleBoundingRectangle and connect its inCircle with the DetectMultipleCircles's outCircles

  6. Add the CheckPresence_Intensity filter.

  7. Now create HMI by clicking on HMI Designer in the upper toolbar.

    • Add the View2dBox control and connect the ReadFilmstrip output to its inImage input. It is going to display the images from the production line.
    • Connect the IsPresent with the View2dBox.InStatus1.
    • Connect the TabletCircles with the View2dBox.InData1.

Macrofilter Main

Used Filters

Icon Name Description
CheckPresence_EdgeAmount Quick and easy presence verification, e.g. for missing caps, screws, labels.
CheckPresence_Intensity Quick and easy presence verification, e.g. for missing caps, screws, labels.
CircleBoundingRectangle Computes the smallest rectangle containing a circle.
DelayByPeriod Suspends the program workflow for inTime milliseconds relative to the end of the filter's last invoke time.
DetectMultipleCircles Detection of circular or close-to-circular objects like holes, pins, pills, particles.

Further Readings