Precaution Using Cmos Image Sensor - Hamamatsu Photonics C11440-36U Instruction Manual

C11440-36U Instruction Manual Ver.1.1
10. PRECAUTION USING CMOS IMAGE
SENSOR
This camera uses CMOS image sensor. Careful attention must be paid to the following
points when using CMOS image sensor:
(1) White spot
Subjecting CMOS image sensor to extended exposures may cause failure in part of the
silicon wafer, resulting in white spots. This phenomenon is not currently preventable. If
CMOS image sensor is at a fixed temperature, recurrence of the white spot increases
proportionally with the exposure time, so this can be rectified with dark subtraction*.
Cosmic ray may generate white spot.
*
After an image made using a certain exposure time is loaded, the CMOS image sensor is exposed to darkness for the
same amount of time, and another image is obtained. After this, the difference between the images is determined, and
the data for the dark portion of the original image is nullified.
(2) Folding distortion
A rough-edged flicker may be visible when imaging striped patterns, lines, and similar
subject matter.
(3) Over light
(4) Brighter phenomenon
Over extended exposure may cause the brighter phenomenon on the right and bottom
of image especially in Level trigger mode and Synchronous readout trigger mode.
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Be careful not to input too strong light such as high-energy
•
laser into CMOS image sensor because CMOS image sensor
may be damaged by over light.