Image quality check of door projection lamps
The door projection lamp is powered in its fixture and projects its pattern onto a screen inside a dark enclosure. A camera captures the image on the screen; sharpness, brightness and the match of the pattern to the reference are measured. A module outside the limits is removed from the line.
Sharpness, brightness and match values are logged against the module serial number. A module outside the limits is pushed into the reject bin at the next station; the result is sent to the table PLC.
- 01 Index
- 02 Power on
- 03 Acquire
- 04 Measure
- 05 Decide
The table indexes one step and a module arrives at the test station.
- Sharpness
- —
- Brightness
- —
- Pattern match
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
The image the module produces forms not on the part itself but on the surface it projects onto. A small offset between the lens and the pattern film blurs or shifts the image; ambient light and the screen distance also change the measured brightness.
Solution approach
The module projects onto a matt screen at a fixed distance inside a light-tight enclosure; the camera views the screen head-on. Sharpness is computed from the edge transitions, brightness and uniformity from calibrated grey values; the pattern is matched to a reference template to check its position, rotation and identity.
Process steps
- 01
Index
The table indexes one step and a module arrives at the test station.
- 02
Power on
The probes make contact and the module projects onto the screen.
- 03
Acquire
The camera captures the pattern on the screen.
- 04
Measure
Sharpness, brightness and pattern match are computed.
- 05
Decide
The values are compared with the limits.
Related applications
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