Isis 3 Application Documentation
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The application cnetref finds the best reference for a Control Point based on criteria like Emission Angle or Incidence Angle or Resolution or Interest
The application cnetref finds the best reference for a Control Point based on user specified Criteria.
Application takes in as input the Control Net CNET and its corresponding images list FROMLIST. FROMLIST contains the filenames of all the images that are part of the input Control Net.
The resulting output Control Net is placed in the user specified file ONET. The Id and Description for the output Control Net can be specified in NETWORKID and DESCRIPTION parameters respectively. If the values are not entered then the information is taken from the input Control Net.
Best Reference for the Control Point can be chosen based on the
following four CRITERIAs. For all the criterias, picking the best Reference
is skipped if the Control Point is not Free or if either the Control
Point or the Reference is EditLocked.
The Interest operator reads in a chip of size Delta Samples and Lines from
each Control Measure(Cube) in a point. If the Overlap list is
included then the overlap polygon is taken into consideration when the chip
reads the cube. For each pixel in the chip, it extracts a sub chip of box
size (Samples, Lines) around the pixel. It first checks the pixel for
validity as specified in the DEFFILE. If the pixel passes the above tests,
then the Interest is calculated for the box around the pixel using the
chosen algorithm. This way it calculates the interest for all the pixels in
the chosen area (chip) around the Control Measure and the best Interest
(highest value) is chosen among them. The best Interest is calculated for
all the Control Measures in a Control Point.
1.If Control Measures with no camera is encountered, then the application is halted and no ouput Control Net is generated.
2. The values Samples, Lines, DeltaLine, DeltaSamp, MinimumInterest for the Operator are entirely dependent on the images in the Control Net. Recommended preprocessing would be to run "gradient" filter or "svfilter" and run "hist" to get the image stats and set the values for the Operator accordingly.
For all the criterias except Interest, the application first validates each measure for the properties specified in the "ValidMeasure" PvlGroup in DEFFILE. The Validity test is optional for all the Criterias.
Validation is little different if using the Interest Critera. The Interest Operator while finding Interest for a Valid Control Measure, first Validates each Sample, Line location in the DeltaSample, DeltaLine area of the Control Measure and then calculates the Interest for that location. This way the expensive Interest calculation is bypassed for an invalid Sample, Line location. Validity test is also performed after moving the Control Measure to the new location of the BestReference chosen after the Interest operation for all the Control Measures in the Control Point. If the moved Control Measure fails the Validity test, then it is set to be Ignored.
Following is the format for the Pvl DEFFILE file with the
defaults for Control Measure validation:
If the Control Measure does not pass the validity test, then it will be be Ignored. If the number of Valid Control Measures in a Control Point is less than 2, then the Control Point is Ignored.
If the "Required" parameters are not entered or misspelled, then the application will throw an error. If "Optional" parameters are not entered then the Control Measure will not be validated against that option.
The entire Control Net processing can be logged in an output LOG file. Log information such as Control Point and Control Measure details and change statistics are placed in LOG file if specified in PVL. Following is the format of the Log File:
This file contains all the the cube filenames which are associated with the input Control Net.
This file must contain Control Net with valid Control Points and Control Measures
This file will contain the new adjusted Control Net
This file stores log information such as Control Point and Control Measure details and change statistics in PVL.
The ID or name of the output Control Net. This string should be unique. If not specified, the ID is taken from the input Control Net.
A string describing purpose of this Output Control Net. If not specified, the ID is taken from the input Control Net.
This parameter lets the user choose one of the four ways to choose the best Reference in a Control Point.
PVL file containing the options for which a Control Measure has to be validated and/or operator plugin if Interest criteria is chosen. Refer to documentation for DEFFILE format.
Limit the movement of all Control Measures to be within their overlaps. The application makes sure that when enabled, even if the point moves it will be within the defined overlap area. Uncheck LIMIT if there is no overlap list for example Control Net from seedgrid application or if it is ok if the point moves beyond the overlap area.
Use this parameter to select the filename which contains the overlap list. You can obtain this file by running the application "findimageoverlaps."
This parameter lets the user choose the different Resolution choices available
This parameter is associated with the parameter NEAREST and holds the Resolution value. The Control Measure closest to this value is chosen as the Control Point Reference.
This parameter is associated with parameters RANGE and MAXRES and represents the Minimum Resolution for a Control Measure to be considered to be a Control Point Reference.
This parameter is associated with parameters RANGE and MINRES and represents the Maximum Resolution for a Control Measure to be considered to be a Control Point Reference.