MICRO-EPSILON surfaceCONTROL SC2500, Руководство по эксплуатации, Страница: 28 / 42

Page 28
Operation
surfaceCONTROL 3D SC2500 / SC2510
Fig. 26 Example of an optimally selected exposure time
The distribution of gray values in the histogram should be approximately uniform with the projected pattern. The number
of overexposed and underexposed pixels should be reduced to a minimum.
The screens shown were created with the 3DInspect software from Micro-Epsilon.
6.5 Interferences
6.5.1 Reflection Factor of the Surface of the Target
The sensor evaluates the diffuse portion of the reflected light. Any statement about a minimum reflection factor is only
possible with reservations. A preliminary examination is necessary for using the sensor on reflective or highly reflective
objects.
6.5.2 Color Differences
Color differences between test objects result in apparent changes of the surface texture of the test object and thus also
influence the calculation of the 3D data from the acquired images. Therefore color differences can result in increased
measurement inaccuracies and reduced detection performance.
As the exposure parameters can only be changed as a whole, careful matching of the exposure to the target surface is
recommended.
6.5.3 Temperature Influences
When the sensor is commissioned a warm-up time of at least 30 minutes is required to achieve uniform temperature dis-
tribution in the sensor. Large temperature fluctuations and changes of the ambient climate act directly on the sensor and
its fixing elements and can thus change the detection performance.
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It is recommended to operate the sensor under as constant as possible ambient conditions. A new calibration is
required if the ambient conditions change permanently.
6.5.4 Ambient Light
For external light suppression, the sensor is equipped with corresponding filters in front of the camera lenses. They allow
only a narrow (band-limited) wavelength range around the wavelength of the light projected onto the test object. In gen-
eral, additional shielding of external light directly emitted on the target or reflected in the sensor is advisable.
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Pay particular attention to unwanted reflections of the projected structured light outside the target area (back-
ground, object holder or similar) which can be reflected back again into the view area of the sensor.
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Matt black surface coatings are recommended for all objects outside the measurement area (object holders, trans-
port equipment, grippers or similar).
6.5.5 Mechanical Vibrations
As high resolutions in the µm range will be achieved with the inspection system, particular attention must be paid to as
vibration-free a set-up of sensor and test object as possible.