S
ENSOR
C
OMMANDS AND
R
ESPONSES
Copyright LMI Technologies Inc. 2003
25
If using ChkSum
: None
NOTE:
The filters are applied in the following order:
1st - Drop Out Filter.
2nd - Moving Average Filter
3rd - High / Low Sampling
Drop Out Filter
When the laser sensor returns a dropout (no value) a 32768 (8000h) sample will be put in the
buffer. The dropout filter replaces all 32768 sample scan areas with the value preceding the
dropout where the
number
of contiguous 32768 samples is less than the [Dropout Factor]. If
the [Dropout Factor] is set to 1 then no dropouts are filtered. For example:
With the [Dropout Factor] = 3,
Buffer
before = ..101, 102, 32768, 32768, 104, 0, 0, 0, 103...
after = ..101,102, 102, 102, 104, 0, 0, 0,103...
The [Dropout Factor] is set in the S
ET
S
CAN
F
ILTER
F
ACTOR
command.
Moving Average (Smooth) Filter
This filter takes an average of an odd number of samples on either side of the original sample
and creates a new value by adding percentage of the average to a percentage of the original.
The filter will smooth the scan with no phase shift. Two filter factors control these filters:
(a)
Order Factor - The number of samples to average. It must be an odd number
between 3..19. A value of 5 will cause two readings before and two readings
after to be averaged.
(b)
Smooth Factor - The percentage of the average to add to the opposite percentage
of the original sample is a percentage 0 to 100 %, e.g.:
Newsample = (average*smooth%) + (original sample*(100%-smooth%)
If smooth is 0 then no smoothing takes place.
4.2.5
Command
15
Filter Scan Buffer
P
URPOSE
Causes the contents of the scan buffer to be processed and modified
using the parameters defined by the SET SCAN FILTER FACTORS
command. This command should only be sent after the STOP SCAN
command and not while the buffer is still being filled.
Command Format
[command]
[command]
1 byte 15
Response Format
:
if using CRC
: [Command]
Command (Byte) 15 Succes
0
Fail
