Dalsa Piranha XL PX-HM-16K12B-00-R, Руководство пользователя

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The Piranha XL XDR Camera • 35
Increasing Dynamic Range (LUT)
See the section Camera Control Category in Appendix A for GenICam features associated with this
section and how to use them
Relevant Features: Output LUT Mode, HDR Gamma Correction
To enhance the camera’s ability to detect defects from the dark and bright areas of an image, a
high dynamic range look-up table (HDR LUT) is available.
When the LUT is enabled, 12 bit image data within the camera is compressed into an 8 bit output
from the camera using a conversion table that can be internally generated using a ‘gamma’ type
algorithm or a conversion table that is downloaded by the user. The gamma correction value can be
adjusted by the user at any time.
The algorithm used by the camera to convert 12bit linear data to 8bit ‘gamma type’ encoded
data is as follows:
8bit_gamma = 255.0 * ((RGB_12bit_linear/4095.0) ^ (1.0/gamma)), where gamma = 1.0 to 3.0
When the LUT is enabled, there is no change in maximum line rate or amount of data output from
the camera. The LUT can be used with any mode of the camera.
Further, when the LUT is enabled, it is recommended that the fixed Offset available in the Camera
Control category be set to zero.
To upload a LUT, use File Access Control Category > Upload / Download File > Settings and select
Look Up Table to upload a file. The file format is described in 03-084-20123 Piranha XL Binary File
Format which can be obtained from Teledyne DALSA Technical Support. This document also
includes Excel spread sheet examples.
Contrast Enhancement
See the section Camera Control Category in Appendix A for GenICam features associated with this
section and how to use them
Relevant Features: Offset, Gain
When the image does not contain useful dark image data below a particular threshold, it may be
beneficial to increase the contrast of the image. The Piranha XL camera has an offset feature that
allows a selectable level to be subtracted from the image data. The gain feature can then be used
to return the peak image data to near output saturation with the result being increased image
contrast.
First, determine the offset value you need to subtract from the image with the current gain setting
you are using. Then set this negative offset value and apply additional gain to achieve the desired
peak image data values.
Note: A positive offset value is not useful for contrast enhancement. However, it can be used while
measuring the dark noise level of the camera to ensure zero clipping is not present.