Image processing
Goldeye Technical Manual
V2.2.0
57
Short introduction: Two-point correction
(A, B, E, J, K, N)
The two-point correction is the most elaborate correction module of the
Goldeye xy-...
camera models. For this reason initially a general survey of the
two-point correction functioning shall be given.
By means of the two-point correction (also called
gain offset correction
) usu-
ally, the distinctive underground structure of the
InGaAs
sensor can be equal-
ized. The target is to transmit the individual characteristic curve of each pixel to
a set characteristic curve, being valid for all pixels. In order to achieve this
result, initially the effective characteristic curve of each single pixel is deter-
mined by taking up data samples. A linear characteristic curve is supposed so
that two data samples are sufficient for a definite determination. By means of
recording two reference images at the
light levels
T
A
and T
B
the data samples
can be determined for all pixels. Furthermore the digital set values J and K each
belonging to the temperatures T
A
and T
B
are determined.
Owing to the four parameters mentioned above, the two-point correction is now
able to modify the gain and the offset of each pixel characteristic curve in a way
that it is congruent with the set characteristic curve. Therefore, in an optimum
linear
case, an image structure, caused by the sensor, does no longer occur. The
below mentioned diagram tries to exemplary explain the facts on the basis of
one single pixel characteristic curve:
Note
For more information see Chapter
This will probably be sufficient for most users, due to the fact
that the determining and adjustment of nearly all parameters
is already executed ex factory and normally, no user interven-
tion is necessary at all.
For more extensive details of the current parameters see Chap-
ter
Advanced parameters and commands
Figure 21: Two-point correction
