Omron V430-F-series User Manual page 88

Focus Position
Definition: The reader's focus position can be configured by entering the target
distance value, so focus position can usually be configured without calibration.
However, if it is necessary to calibrate the focus distance there are two
methods: the standard Search Method and a Quick Focus method,
both of which are defined below.
Serial Cmd: <K529,gain,exposure,focus position,symbol type,WOI framing,WOI margin,
line scan height,processing>
Default: Quick Focus
Options: 0 = Disabled
1 = Enabled (Decode Required)
2 = Quick Focus
Disabled
The focus position is fixed and is not part of the calibration process.
Enabled (Search Method)
Focus position is calibrated to provide the best image quality and performance. This
method is a simple search algorithm that cycles through focus settings and configurates
camera settings to try and locate the desired focus as quickly as possible. This is accomplished
when a symbol is decoded. Once a focus distance that produces a successful decode has
been located, the algorithm fine tunes the search to locate the inside and outside focal
distances. The final focus distance is between the inside and outside values. This method
may be time-consuming if the focus is not found on the first pass.
Quick Focus
Quick Focus is quickly locates the focus setting for an object at the center of the field of
view. This is accomplished with minimal image processing, by analyzing a histogram of
the image frame. Before performing focus calibration, a value for exposure and gain is
determined. The process then steps through the focus range of the system capturing the
required number of image frames for each focal position. Then a histogram is performed
on each image frame, and the histogram results for each focal position are averaged.
When the process is finished, the data is analyzed and the optimal focus position is determined.
Note: This method may not work for all applications. This method is not ideal for very
small symbols.
Auto Focus Multi Code Reader V430-series User's Manual (Z392)
Calibration
4-5