Pulnix TS-9720EN Series Manuel d'instructions télécharger pdf (Page 46)

Page 38

Camera Features

TS-9720EN Series Progressive Scan Shutter Cameras

6.3 ADR (Automatic Dynamic Range) Control

ADR (Automatic Dynamic Range) control is a key algorithm of EN cameras. The ADR algorithm

controls the EN camera parameters on a continuous basis to maintain the contrast-to-noise of the license

plates on passing vehicles to a suitable level required for automatic license plate reading algorithms.

The EN ADR algorithm is unique in that it requires no moving parts and can perform this contrast-

maintenance function without having to take multiple images of a vehicle in order to achieve the

required plate contrast. The key to this ability is a separate smart light sensor. Each EN camera can

communicate with up to two smart light sensors. Using these smart light sensors, the EN cameras

automatically optimize Exposure time (or shutter speed), Video Amplifier Gain (“Gain” in short), and

A/D converter parameters (Vtop and Vbottom).

Using EN setup software, user can turn on or off ADR control by accessing “Camera ADR Control”

config register (Address = 50).

6.3.1 Electronic Shutter

Normally, exposure time is controlled automatically by ADR (Automatic Dynamic Range) control

algorithm inside the EN, based on the output from light sensor. However during nighttime installations

it is often convenient to manually adjust the shutter time to a larger value so that the focusing targets and

vehicle used for setup are easily seen with the available road lighting. Manually adjusting shutter speed

can also be useful for certain types of debugging (See Section 7.2, “Problem 2: EN Setup Software

Found the Camera, But the Video Image is Too Dark or Just Black,” on page 47).

The following exposure times are supported:

TABLE 5. Exposure Times

Shutter Dial Exposure Time (H)

810

911

A12

B15

C31

D63

E 126

F 262

0 525

1 2 ... 41 42 43 44 45 46 47 48 49 50 51 ... 62 63

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Pulnix TS-9720EN Series Manuel d'instructions Page 46