USER
MANUAL
22
www.vareximaging.com
2315NDT v2 CMOS X-ray Detector User Manual
15.2
Image Quality Guidelines
Use the following guidelines for achieving optimum image quality:
•
When creating flood and dark calibration images, and when doing frame-averaging
operations, set the
Quantity
to as large a value as possible, within practical time constraints.
When the Quantity is large, the images will take longer to acquire, but the noise is reduced. As
a general rule, the noise reduces by a factor of
√
2 (
≈
1.4) when Quantity is doubled.
•
When changing the frame time significantly or the gain setting, create a new dark calibration
image with the same exposure time as the image that is to be acquired. Frequently renewing
the dark images is recommended to improve the image quality.
•
Update the flood calibration image if changing the technique frame time, gain setting, energy
range kV, SID, or beam incident angle. For industrial applications, several sets of flood
images can be stored and called up according to the X-ray generator settings.
•
Aim for an open-field signal level of around 12,000–14,000 for flood calibration images, this
will give good dynamic range without saturation for a general application. In case of a
specific application, the acquired intensity should be in the dynamic range of the desired
region of interest.
•
The Varex Imaging CMOS flat panel X-ray detector is designed for maximum sensitivity to
X-rays, enabling optimal image quality for a low dose exposure. In some situations, a higher
dose is used to improve the image quality, but this may cause the pixels to saturate.
•
You can program the following settings of pixel gain by using the
Configuration
menu:
•
High Full Well
should be used where high saturation dose is important. This applies to
most NDT imaging or static X-ray imaging applications.
•
Low Full Well
increases the pixel gain by a factor of approximately 6.7 in comparison to
High Full Well. This option should be used where high sensitivity (low dose per frame) is
required; it is suitable for fluoroscopy.
16.0
External DC Power Supply Requirements
The system manufacturer must provide a means of isolating the power supply, which enables
the disconnection of both Live and Neutral poles simultaneously.
As low DC voltages are used to supply the detector, the voltage drop in the DC cable is a
significant factor.
WARNING
The power supply must in all cases provide double insulation,
Class II or Class I with protective earth.
See
for detector power requirements.
