Analysis Parameters

This section contains a summary and description of the parameters that a relevant for the Analysis step, including options for automatic detection of flight configurations for aerial scenarios and stereo model selection based on relative orientation as well as image overlap estimations in object space.

Minimal matched image fraction

Minimum success ratio of initial low-level matching result for a model to be considered valid.

CLI
-minperc <value>

Default value: 0.31

During the project analysis step, stereo model candidates are evaluated by running the stereo matching algorithm on an initially low pyramid level. This parameter controls the image fraction (value of 1.0 equals 100%) that has to be successfully matched on the initial pyramid level in order for a stereo model to be considered valid. Note that when processing aerial (nadir or oblique) scenarios, valid models may still be neglected during the model selection based on the automatic flight configuration analysis.


Maximum models

Maximum number of stereo models per base image.

CLI
-maxmodels <value>

Default value: 5

Increasing the number of stereo models for each base image may lead to more accurate as well as more complete results. Note however, that this may also significantly increase the processing duration, especially during the Dense Cloud step, due to the additional stereo models which need to be processed.


Minimum/Maximum principal angle

Valid range [min/max] of the principle angle between the two images of a stereo pair.

Default value: +/- 50°

If the principle angle exceeds the specified thresholds, the stereo model will be discarded and not considered during the Dense Cloud generation.


Block analysis mode

Automatic stereo model selection for aerial scenarios.

Default value: auto

The block analysis comprises a fully automatic method for stereo model selection based on the flight configuration and specified scenario. It is applicable only in combination with aerial (nadir or oblique) scenarios. When auto mode is selected, the number of stereo models per base image in flight direction (forward and backward) as well as across flight direction (left and right) are derived from the specified scenario, especially the specified overlaps in/across flight direction.

Activating manual mode will enable the Models option in order to manually override the the stereo model configuration per base image.

By choosing off mode, the automatic model selection based on the block analysis and flight configuration can also be disabled completely. In that case the stereo model selection method will work the same way as for default scenario (usually used for UAV and close range applications) which is solely based on the three parameters


Models

Manual model selection scheme for aerial scenarios.

Default value(s): n.A.

Only configurable when manual block analysis mode has been enabled. Allows to manually specify the number of stereo models per base image in flight direction (forward and backward) as well as across flight direction (left and right). Note, however, that specific stereo models can still be discarded if certain criteria are not met, e.g. minimal matched image fraction is too low.

The calculation of color adjustment parameters

The global color balancing parameters of the input imagery can be calculated by default or using the CLI.

CLI
-color_adjustment/-no_color_adjustment

Default: the calculation of the ColorAdjustment file is active.