1To1 Correction Tables; Inverse Tables; Correction File Header - Scanlab RTC 5 PC Interface Board Installation And Operation Manual

1to1 Correction Tables

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Unlike previous RTC products, the RTC
need to have 1to1 correction tables loaded from 1to1
correction files. Instead, they can be directly
generated with load_correction_file
For Dim = 3 (with activated 3D option), the specified
correction table is replaced with a 3D 1to1 table,
otherwise with a 2D 1to1 table (see command
description).
A 1to1 correction file (Cor_1to1.ct5) is nevertheless
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supplied with the RTC 5, because some applications
require a filename and don't accept 0.

Inverse Tables

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The RTC 5's correction file format permits storage of
a table for transforming returned scanner-axis
position data into the input coordinate system. These
are called "inverse tables" (for usage, see
Monitoring", page 154. SCANLAB-generated ct5
correction files automatically contain an inverse
table, but files converted from older formats might
not always have one (see "Converting Correction
Files", page 125). If no valid inverse table exists, then
a 1to1 correction table will be used instead. Here,
precise inverse calculation of uncorrected position
data won't be possible. The correction file's header
contains entries regarding the inverse table's validity
and calculation method (see parameter 11,
page 125).
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RTC 5 PC Interface Board
Rev. 1.9 e
7 Basic Functions for Scan Head and Laser Control

Correction File Header

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5 doesn't The RTC
parameters describing the file name, the contained
data and the optical data of the corresponding
and Name = 0. optical configuration. Some of the listed parameters
were previously only obtainable from the supplied
ReadMe file with the RTC
needed to be manually incorporated into the user
application. For the RTC
in the correction files can be read out via
get_table_para
correction tables) or via
assigned correction tables) and thus directly incorpo-
rated into a user program. The file header contains
the following parameters (numbering corresponds
with that of the commands
get_head_para):
(0) Type of correction tables
"Position
– = 0.0: 2D correction table
– = 1.0: 3D correction table
(1) Calibration factor K
This parameter is generally a integer-multiple of
16. Because of the RTC
a ct5 file's calibration factor is 16 times larger
than that of a corresponding ctb correction file.
(2) Focal Length / Working Distance [mm]
– for a configuration with a scan objective, this is
the objective's effective focal length [mm]
– for a configuration without a scan objective,
this is the working distance A [mm] (distance
from the optical axis of the incident laser beam
at the first deflection mirror to the image
plane).
(3) Stretch factor for the X direction
for 3D vector commands this results in a Z-coordi-
nate-dependent modification of the image field
(4) Stretch factor for the Y direction
See parameter 3.
(5) Coefficient A of the parabolic function for Z-axis
control (offset part, ±26 Bit)
(6) Coefficient B of the parabolic function for Z-axis
control (linear part, ±11 Bit)
(7) Coefficient C of the parabolic function for Z-axis
control (square part, ±4 Bit)
(8) Number of the correction file
i.e. the filename number of the correction file
supplied by SCANLAB (e.g. 145 for D2_145.ct5 or
D3_145.ct5).
5 correction file's header contains 16
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4/RTC 3/RTC
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5, the parameters included
(from the currently loaded
get_head_para
get_table_para
[bit/mm] (see
xy
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5's 16x higher resolution,
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2 and
(from the
and
page 119)
124