TPREFN

Description

TPREFN automatically refines tie points (TP) in a CATALYST Professional OrthoEngine project file by eliminating those with large residual errors, based on various modeling methods.

Parameters

Name	Type	Length	Value range
InputText: Input OrthoEngine Project *	Text port	1 -
Output: Output OrthoEngine Project	Text port	0 -
Run RANSAC Before Refinement	Boolean	0 - 1
Rejection Method	Float	0 - 6	See parameter description
Number of TPs to Reject	Integer	0 - 1
Percentage of TPs to Reject	Float	0 -
Rejection Ratio (X to Y)	Float	0 - 1
Minimum X Standard Deviation	Float	0 - 1
Minimum Y Standard Deviation	Float	0 - 1
Minimum X Absolute Residual	Float	0 - 1
Minimum Y Absolute Residual	Float	0 - 1
Minimum X RMS Error	Float	0 - 1
Minimum Y RMS Error	Float	0 - 1
Maximum TPs to Remove per Iteration	Integer	0 - 1024
Minimum TPs to Preserve per Image	Float	0 - 1024
Thinning Option	String	1 -	Inactive \| Delete Default: Inactive
Report	String	0 - 192	See parameter description

* Required parameter

Parameter descriptions

InputText: Input OrthoEngine Project

The name of the input CATALYST Professional OrthoEngine project file that contains the TPs to refine.

Output: Output OrthoEngine Project

The name of the output OrthoEngine project file that will contain the refined TPs.

Selected by default, this check box controls whether to run the random sample consensus (RANSAC) algorithm to remove large residual points first before refinement.

RANSAC is an iterative method to estimate parameters of a mathematical model from a set of observed data that contains outliers, when outliers are to be accorded no influence on the values of the estimates. Therefore, it also can be interpreted as an outlier-detection method.

Rejection Method

The method to use to reject TPs.

In the Rejection Method list, select one of the following:

Absolute Number (1) is the absolute number of TPs to reject, starting with the ones with the highest residual. When you select this option, you must specify a value for Number of TPs to Reject and Rejection Ratio (X to Y).
Percentage Number (2) is the percentage of the points that can be rejected, starting with the one with the highest residual. When you select this option, you must specify a value for Percentage of TPs to Reject and Rejection Ratio (X to Y).
Standard Deviation (3) is the sigma (standard deviation) rejection method. When you select this option, you must specify a value for Minimum X Standard Deviation and Minimum Y Standard Deviation.
Absolute Distance (4) is the absolute distance rejection of the residuals. When you select this option, you must specify a value for Minimum X Absolute Residual and Minimum Y Absolute Residual.
RMS Error (5) is the RMS-error-rejection method. When you select this option, you must specify a value for Minimum X RMS Error and Minimum Y RMS Error.
Automatic RMS Error (6) is the automatic RMS-error-rejection method. When you select this option, TPREFN will automatically remove outliers based on its own criteria. In this case, as an option, you can specify MINPT as the second value.

The default method is RMS Error (5) with the values of Minimum X RMS Error and Minimum Y RMS Error set to 2.

Number of TPs to Reject

Available when Absolute Number (1) is selected for Rejection Method, the absolute number of TPs to reject, starting with the ones with the highest residual. For example, to reject 10 TPs, enter 10.

Note: When you specify a value for this parameter, you must also enter a value for Rejection Ratio (X to Y).

Percentage of TPs to Reject

Available when Percentage Number (2) is selected for Rejection Method, the percentage of the number of TPs to reject. For example, to reject 5 percent of the TPs, enter 5.

Note: When you specify a value for this parameter, you must also enter a value for Rejection Ratio (X to Y).

Rejection Ratio (X to Y)

Available when Absolute Number (1) or Percentage Number (2) is selected for Rejection Method, the ratio weighting between the x and y residuals. For example, to give twice the weight to the x-residual as the y-residual, enter 2. When a point has an x-residual of 0.4 and a y-residual of 0.5, the point will be given an x-residual of 0.8 and a y-residual of 0.5 for the rejection.

Note: When you specify a value for this parameter, you must also enter a value for either Number of TPs to Reject or Percentage of TPs to Reject based on your selection for Rejection Method.

Minimum X Standard Deviation

Available when Standard Deviation (3) is selected for Rejection Method, the minimum standard deviation value of the x-residual to reject. For example, to reject points with a standard deviation higher than two of the x-residual, enter 2.

Note: When you specify a value for this parameter, you must also enter a value for Minimum Y Standard Deviation.

Minimum Y Standard Deviation

Available when Standard Deviation (3) is selected for Rejection Method, the minimum standard deviation value of the y residual to reject. For example, to reject points that have a standard deviation of higher than one of the y-resolution mean, enter 1.

Note: When you specify a value for this parameter, you must also enter a value for Minimum X Standard Deviation.

Minimum X Absolute Residual

Available when Absolute Distance (4) is selected for Rejection Method, the minimum absolute x-residual to reject. The rejection starts from the point with the greatest x-residual distance. For example, to reject pixels with an x-resolution greater than three-quarters, enter 0.75.

Note: When you specify a value for this parameter, you must also enter a value for Minimum Y Absolute Residual.

Minimum Y Absolute Residual

Available when Absolute Distance (4) is selected for Rejection Method, the minimum absolute y-residual to reject. The rejection starts from the point with the greatest y-residual distance. For example, to reject pixels with a y-resolution greater than three-quarters, enter 0.75.

Note: When you specify a value for this parameter, you must also enter a value for Minimum X Absolute Residual.

Minimum X RMS Error

Available when RMS Error (5) is selected for Rejection Method, the minimum x-RMS error. For example, to reject points with an x-RMS greater than two, enter 2.

Note: When you specify a value for this parameter, you must also enter a value for Minimum Y RMS Error.

Minimum Y RMS Error

Available when RMS Error (5) is selected for Rejection Method, the minimum y-RMS error. For example, to reject points with a y-RMS greater than two, enter 2.

Note: When you specify a value for this parameter, you must also enter a value for Minimum X RMS Error.

Maximum TPs to Remove per Iteration

The maximum number of points to remove in each iteration before recomputing the model. A negative value represents the percentage of the total number of TPs that can be removed in each iteration.

The value you specify is applicable to rejection methods 1 through 5.

Minimum TPs to Preserve per Image

The minimum number of points to preserve per image. That is, by specifying a minimum, you ensure that each image retains that number of TPs after processing.

Thinning Option

Whether to delete the rejected points or render them inactive. By default, points are rendered inactive.

Report

Specifies where to direct the generated report.

Available options are:

LOG: generates a report on the terminal (default)
<modulename.RPT>: appends a report to the module's RPT file
DISK: generates a report on file "IMPRPT.LST"

Details

TPREFN eliminates TPs that have the highest residuals, based on the calculation of the math model for an image. You can run the algorithm on any OrthoEngine project file that contains TPs. Details, such as orbit information or RPCs, are read from the project file. TPREFN uses the math model derived from the supplied project to compute the residuals of existing TPs.

TPs that are deemed undesirable can be rejected by using various rejection methods. For more information, see the description of Rejection Method .

TPREFN saves an updated project file with a refined set of tie points and with updated math-model parameters.

Note: Any inactive points in the specified OrthoEngine project are copied to the output project file.

Note: If the specified OrthoEngine project includes any inactive images, they are excluded from processing.

Important: The system DEM file gmted2010 must be installed as part of the CATALYST Professional distribution. This file is used to compute approximate ground coordinates of the TPs.

Environments	PYTHON :: EASI :: MODELER
Batch Mode	Yes
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TPREFN

Tie point refinement

Description

Parameters

Parameter descriptions

Details