THORLABS DCC1645C Description And Sdk Manual

© 2016 Thorlabs Scientific Imaging
2 Camera Basics
47
2.5.2 Bit Depth and Digital Contrast Adjustment
Digitizing
Image sensor pixels first generate an analog voltage signal proportional to the amount of light that
strikes them. The image is digitized for further processing, i.e. the stepless signal is converted to a
digital numerical value. The following figure shows this using a gray gradient as an example
Various bit depths using a gray-scale gradient as an example
If the stepless gradient is imaged in a digital range in 2 bits, for example, the result is 2
2
= 4 levels;
for 4 bits, it is 2
4
= 16 levels, and so on. The intermediate brightness values of the original gradient
are irreversibly lost after digitization.
With around 200 levels or more, the jumps in brightness can no longer be discerned with the eye,
which is why current monitors and digital cameras use 8 bits (256 levels) per color channel (fully
adequate for visualization).
Bit depth in image processing
If digital image data undergoes further image processing, a bit depth greater than 8 may be
necessary. The computer is able to differentiate between these very fine differences in brightness
(no longer discernable by the eye) and process them. This is why industrial cameras often use 12
bits.
Bit depth
Brightness levels
8
2
8
= 256
10
2
10
= 1024
12
2
12
= 4096
14
2
14
= 16.384
Note
Greater bit depths require extremely low-noise image sensors, however. As soon as the
differences in brightness created by noise are greater than the digitization levels, no further data is
gained.
Bit depth by sensors
Platform
USB 2.0
USB 3.0
CMOS sensors
8 bit
10 bit
CCD sensors
8 bit
-
Note
Color formats with a bit depth of more than 8 bits per channel are only supported by USB 3
DCC3240x camera models. Using color formats with higher bit depth increases the bandwidth
used by a camera.

THORLABS DCC1645C Specifications

General

Brand	THORLABS
Model	DCC1645C
Category	Security Camera
Language	English