8.Features
© China Daheng Group, Inc. Beijing Image Vision Technology Branch 43
The expected gray value is set by the user and it is related to the data bit depth. For 8bit pixel data, the
expected gray value range is 0-255, and for 12bit pixel data, the expected gray value range is 0-4095.
The camera adjusts the exposure time in the range [minimum exposure time, maximum exposure time]
which is set by the user.
The auto exposure feature can be used with the auto gain at the same time, when target grey is changed
from dark to bright, the auto exposure adjust is prior to auto gain adjust. Vice versa, when target grey is
changed from bright to dark, the auto gain adjust is prior to auto exposure adjust.
8.3.5.
Test Pattern
The VEN-U3 series camera supports gray gradient test image. When the camera captures in RAW10
mode, the gray value of test image is: the pixel gray value in RAW8 mode multiplies by 4, as the output of
pixel gray value in RAW10 mode.
The following three test images are illustrated in the RAW8 mode.
In the gray gradient test image, all the pixels' gray values are the same in the frame. In the adjacent frame,
the gray value of the next frame increases by 1 compared to the previous frame, until to 255, and then the
next frame gray value returns to 0, and so on. A printscreen of a single frame is shown in Figure 8-24.
Figure 8-24 Gray gradient test image
8.3.6.
User Set Control
By setting various parameters of the camera, the camera can perform the best performance in different
environments. There are two ways to set parameters: one is to modify the parameters manually, and the
other is to load parameter set. In order to save the specific parameters of the users, avoiding to set the
parameters every time when you open the camera, the VEN-U3 series camera provides a function to save
the parameter set, which can easily save the parameters that the user use, including the control
parameters that the camera needed. There three types of configuration parameters: the currently effective
configuration parameters, the vendor default configuration parameters (Default), and the user
configuration parameters (UserSet).
Three operations can be performed on the configuration parameters, including save parameters
(UserSetSave), load parameters (UserSetLoad), and set the startup parameter set (UserSetDefault). The
UserSetSave is to save the effective configuration parameters to the user configuration parameter set
which is set by the user. The UserSetLoad is to load the vendor default configuration parameters (Default)
