3D Time-of-flight distance measurement with custom - Universität ...
3D Time-of-flight distance measurement with custom - Universität ...
3D Time-of-flight distance measurement with custom - Universität ...
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50 CHAPTER 3<br />
the smearing effect, resulting in lines in the image having an origin in very bright<br />
points [TEU].<br />
(a)<br />
(c)<br />
Start<br />
CCD<br />
optical generation<br />
<strong>of</strong> signal charge<br />
charge<br />
transport<br />
Destination<br />
charge to voltage<br />
conversion in the<br />
output stage<br />
charge to voltage<br />
conversion<br />
Output<br />
Start<br />
charge to voltage<br />
conversion in the pixel<br />
CMOS-APS<br />
Column select<br />
Destination<br />
Row select<br />
Output<br />
Figure 3.1 CCD and CMOS-APS principle: Hydrostatic equivalent and principle<br />
architecture.<br />
Due to the steady miniaturization in microelectronics, photodiode arrays, in the form<br />
<strong>of</strong> CMOS APS sensors (Active Pixel Sensor), have experienced a sort <strong>of</strong><br />
renaissance in recent years. They are gradually beginning to replace CCDs in<br />
certain market areas, such as low-cost applications or applications where certain<br />
features/functionality are required (high speed, low power, logarithmic response, no<br />
blooming or smearing, temporal convolution, …). CMOS APS sensors, in contrast<br />
to the classical photodiode arrays, give each pixel its own buffer amplifier, which<br />
converts the charge signal into a voltage (or current) <strong>with</strong>in the pixel. With this<br />
principle it is avoided that the small photocurrent <strong>of</strong> each pixel has to drive the<br />
relatively large capacity <strong>of</strong> metal wires. The optical signal information is then read<br />
(b)<br />
(d)
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