Dimensional, position and orientation inspection with machine vision
Machine vision can do more than detect whether a part is present. It can also determine where it lies and whether dimensions, distances or angles are within defined tolerances.
Measurement and positioning tasks can therefore be integrated directly into automated production processes.
Discuss your applicationTypical measured quantities
- length and width
- inner and outer diameter
- distances
- gap dimensions
- edge positions
- angles
- roundness
- center point
- X/Y position
- rotation
- part alignment
The required accuracy determines the system
For a measurement application, specifying a “5 megapixel camera” is not enough. What matters is the ratio between the field of view and the required measurement accuracy.
The larger the field of view at the same sensor resolution, the fewer pixels are available for a given detail.
The measurement result is also influenced by:
- lens distortion
- perspective
- working distance
- part height
- lighting
- calibration
- mechanical positioning
This is exactly why a measurement application should always be specified starting from the required measuring range and tolerance.
When do telecentric lenses make sense?
For precise 2D measurement tasks, a telecentric lens can be decisive.
Ordinary lenses produce perspective effects: a part appears larger or smaller as the distance changes. Telecentric optics reduce this effect and are therefore particularly suited to:
- dimensional inspection
- contour inspection
- diameters
- edge distances
- precise position determination
Determining position and rotation
Besides measured values, machine vision can also determine the position of a workpiece. This is relevant for:
- assembly processes
- aligning parts
- part feeding
- robot guidance
- position correction before machining
- checking label positions
This information helps us specify the system
Example values - field of view and tolerance already allow a good estimate of the resolution needed.
- Field of view
- 80 × 60 mm
- Tightest tolerance
- ± 0.05 mm
- Working distance
- approx. 250 mm
- Part height varies by
- ± 2 mm
- Cycle time
- 300 ms
Suitable product groups
You have a tolerance, a field of view and a part?
That is already enough to estimate which camera and lens combination is required.
Discuss your measurement taskFrequently asked questions
What information do you need for a dimensional inspection?
The most important details are the field of view, the tightest relevant tolerance, the working distance and whether the position or height of the part varies.
Is a higher camera resolution always better?
No. The resolution has to match the task. Optics, lighting, mechanics and calibration are at least as important.
Can measuring and defect inspection run at the same time?
Yes. Depending on the system, one image can be used by several inspection tools.
Related applications
- Robot guidance & pick-and-placeLocate parts, determine position and rotation, and guide robots while gripping, aligning and placing.
- Industrial quality controlCombine several inspection features - from completeness and dimensional accuracy to surface, code and plain text.
- Presence & completeness inspectionCheck whether parts, screws, seals, labels or machining features are present and completely assembled.