User`s manual

Basic Operation & Standard Features

BASLER A620

f 3-19

DRAFT

3.6 Gain and Brightness

3.6.1 Gain

On A620f cameras, the gain function is ac-

complished by applying a digital multiplier to

the output from the camera’s sensor. The

size of the multiplier depends on the setting

in the Value field of the Gain control register

(see page 4-25). Increasing the setting will

increase the gain and will increase the cam-

era’s response to light as shown in Figure 3-

An increase in the gain setting can be useful

when at your brightest exposure, a gray

value of less than 255 (when the camera is

set for 8 bit output) or less than 1023 (when

the camera is set for 16 bit output with 10

bits effective) is achieved. For example, if

the camera is set for 8 bit output and gray

values no higher than 127 were achieved

with bright light, you could increase the gain setting so that the camera is operating at 6 dB (an

multiplication factor of 2) and see an increase in gray values to 254.

The range of valid settings for the Gain control register varies depending on whether the camera

is set to output 8 bits per pixel or 16 bits per pixel.

Gain Settings with Camera Set for 8 Bit Output

When the camera is set to output 8 bits per pixel, the settings in the Gain control register can range

from 0 (0x000) to 740 (0x2E4). The default gain setting when the camera is set for 8 bit output is

150 (0x096). To determine the dB of gain that you will see at a particular decimal setting, use the

following formula:

Typical settings and the resulting amplification are shown in Table 3-1.

Table 3-1: Gain Settings with 8 Bit Output

Decimal Hex dB Multiplication

Factor

Decimal Hex dB Multiplication

Factor

0 0x000 0.0 x 1.0 425 0x1A9 16.0 x 6.3

125 0x07D 8.2 x 2.6 525 0x20D 17.6 x 7.6

225 0x0E1 11.6 x 3.8 625 0x271 18.9 x 8.8

325 0x145 14.1 x 5.1 740 0x2E4 20.2 x 10.3

Figure 3-9: Gain

Gain 20 log

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