Photon Focus MV1-R1280-50-G2 Camera Series, Руководство пользователя

Страница: 50 / 95

5 Functionality
5.4 Gain and Offset
There are two different gain settings on the camera:
Gain (Digital Fine Gain) Digital fine gain accepts fractional values from 0.01 up to 15.99. It is
implemented as a multiplication operation.
Digital Gain Digital Gain is a coarse gain with the settings x1, x2, ..., x2048. It is implemented
as a binary shift of the image data where the two LSB from the image sensor and ’0’ are
shifted to the LSB’s of the gray values. E.g. for gain x2, the output value is shifted by 1
and bit 0 is set to sensor LSB bit 1.
The resulting gain is the product of the two gain values, which means that the image data is
multiplied in the camera by this factor.
Digital Fine Gain and Digital Gain may result in missing codes in the output im-
age data.
A user-defined value can be subtracted from the gray value in the digital offset block. If digital
gain is applied and if the brightness of the image is too big then the interesting part of the
output image might be saturated. By subtracting an offset from the input of the gain block it
is possible to avoid the saturation.
5.5 Hotpixel Correction
Image noise is amplified when operating at high gain values. In this case some pixels appear as
very bright pixels. There is a hotpixel correction that corrects this issue.
The hotpixel correction compares the grey value of the pixel with the grey values of the the
two neighbours on each side and determines if the pixel should be corrected.
The hotpixel correction is enabled with the property
Correction_EnHotpixel
.
Only pixels brighter than a predefined grey value ( Correction_HotpixelMinVal ) are corrected.
The value
Correction_HotpixelMinVal
can be modified by the user.
5.6 Crosshairs
5.6.1 Functionality
The crosshairs inserts a vertical and horizontal line into the image. The width of these lines is
one pixel. The grey level is defined by a 12 bit value (0 means black, 4095 means white). This
allows to set any grey level to get the maximum contrast depending on the acquired image.
The x/y position and the grey level can be set via the camera software. Figure Fig. 5.19 shows
two examples of the activated crosshairs with different grey values. One with white lines and
the other with black lines.
The 12-bit format of the grey level was chosen to be compatible with other
Photonfocus cameras.
The x- and y-positon is absolute to the sensor pixel matrix. It is independent on the ROI
configuration.
.
50