CHIPMAT -- Image Chip Match for GCPs

Automatic GCP collection from a raw image using geocoded image chips. The results are stored inside a GCP segment.

See Also: CHIPEXT, ChipManager, GCPREFN

PARAMETERS

CHIPMAT is controlled by the following parameters: 

Name     Prompt                                  Count     Type
FILE     Input Raw Satellite Scene               1-64      Char
ORBIT    Orbit segment number                    1-1       Int
DBIC     Input channel to use in correlation     1-1       Int
CHIPFILE Name of Chip Database                   1-64      Char
CHIPSENS Sensor of chips to extract from CHIPFIL 1-16      Char
CHIPDATE Date range string for scenes            10-21     Char
CHIPDBIC Input channel of chip to use            1-1       Int
CHIPSCOR Minimum score (in %) for rejection      0-1       Int
LLMARGIN Lat/Long margin around raw scene        0-2       Float
CLOUDTHR Cloud Rejection Threshold               0-2       Float

The following parameters receive output:

LASC     Last Database Segment Created           1         Int

FILE

Specifies the PCIDSK database containing the Input Raw Satellite Scene. 

 EASI>FILE="filespec"

ORBIT

Specifies the orbit segment that contains ephemeris data for the Input Raw Satellite Scene. This is usually 2. 

 EASI>ORBIT=i
Segment must be type 160 (SEG_ORB).

DBIC

Specifies the database input channels in Raw Satellite Scene for use in correlation. 

 EASI>DBIC=i

CHIPFILE

Name of Chip Database from which to retrieve chips for correlation. 

 EASI>CHIPFILE="imageChip.cdb"

CHIPSENS

Optionally specifies the sensor from chip library to be used to matching. Default is all. 

 EASI>CHIPSENS=                 | Use all chips
 EASI>CHIPSENS="Sensor"         | Use chips with "Sensor" ID

CHIPDATE

Regular expression for chip dates that will be considered acceptable. If defaulted, all dates will be considered a match. 

 EASI>CHIPDATE="*-1996"         | Any chips from 1996
 EASI>CHIPDATE="*-Jan-*"        | Any chips from January
 EASI>CHIPDATE="01-Jan-1996"    | Chips from Jan 1, 1996

CHIPDBIC

Input channel of chip to use. 

 EASI>CHIPDBIC=i

CHIPSCOR

Minimum score (in %) for rejection. Default is 75%. 

 EASI>CHIPSCOR=i                | Minimum score of i%
 EASI>CHIPSCOR=                 | Use default value of 75%.

LLMARGIN

This parameter specifies the lat/long margin for searching. Default is 0,0. The larger the values, the larger the searching area on the raw image will be used for matching of each point. This is needed when the orbital information of the raw image is very inaccurate, for example, off by 100 to 200 pixels from the approximate positions. 

 EASI>LLMARGIN=                 | Use default value of 0,0
 EASI>LLMARGIN=i,j              | Use default value of i,j

CLOUDTHR

Optionally specifies the minimum grey level value to be treated as clouds and the percentage of cloud content in which the matching area of the raw image will be rejected. Default is grey level 255 and 100% cloud content for rejection. 

 EASI>CLOUDTHR=i,j              | Any grey level value over i is 
                                | treated as cloud; if there is
                                | more than j% cloud content, the 
                                | matching area will be rejected
 EASI>CLOUDTHR=                 | Use default value of 255 and 100

LASC

The segment number of the newly created GCP segment is saved in this output parameter for use by other EASI procedures.

MONITOR

Program progress can be monitored by printing the percentage of completed processing in odometer fashion. A system parameter, MONITOR, controls this activity: 

 EASI>MONITOR="ON"          | turn monitor ON  (default)
 EASI>MONITOR="OFF"         | turn monitor OFF (recommended if
                            | running in batch/background mode)

DETAILS

CHIPMAT is a program to perform automatic GCP collection. Input to this program is a raw satellite image (FILE) with an orbit segment (ORBIT) and an image channel (DBIC). A chip database (CHIPFILE) is required to perform the automatic matching procedure. The chip database should be created using the CHIPEXT program. The result of this program is a GCP segment stored inside the raw image. The Correlation score is stored in the elevation field of the SET 1 GCPs on the GCP segment. You can use the program GCPREFN to remove GCPs with large errors.

You can specify the chip sensor type using CHIPSENS. You can specify the date range of the chips using CHIPDATE. You can specify the chip channel to use for matching, using CHIPDBIC. CHIPSCOR can be used to reject matched GCPs with low matching scores. The range is 0 to 100. The default value is 75.

LLMARGIN allows the user to specify the searching range. This is needed only if the raw image has an inaccurate orbit segment, for example, off by 100 to 200 pixels in the approximate positions.

CLOUDTHR allows the user to specify the minimum grey level value to be treated as clouds and the percentage of cloud content in which the matching area of the raw image will be rejected. Default is grey level 255 and 100% cloud content for rejection.

EXAMPLE

The user has extracted a chip database using CHIPEXT program and the chips are stored inside "geochip.cdb" and would like to use it to collect GCPs from a raw image "raw.pix". 

 EASI>FILE="raw.pix"
 EASI>ORBIT=2
 EASI>DBIC=1
 EASI>CHIPFILE="geochip.cdb"
 EASI>CHIPSENS=                 | Use all chips 
 EASI>CHIPDATE=                 | Use all dates
 EASI>CHIPDBIC=1                | Use channel 1
 EASI>CHIPSCOR=                 | Use default score of 75
 EASI>LLMARGIN=                 | Use default of 0,0
 EASI>CLOUDTHR=                 | Use default of 50 and 5
 EASI>R CHIPMAT
About PCI Help Gateway