Composed Relative Extrinsics

Created by: All Components and Objects

Overview

These metrics refer to the error between relative extrinsics measurements (that are composed between components and objects) and the current estimated extrinsic. What does this mean?

• Components $A$ and $B$ have a relative extrinsic formed by object $O$ represented by $\Gamma^A_O \cdot \Gamma^O_B$.
• The current estimated extrinsic between $A$ and $B$ is just the transform between the two components, $\Gamma^A_B$.

Ideally, these two should be the same:

$$\Gamma^A_B \approx \Gamma^A_O \cdot \Gamma^O_B$$

...but nothing's perfect in optimization. The error between these two is what we capture in the Composed Relative Extrinsics.

Since MetriCal optimizes for both components and objects, both components and objects have relative constraints. When the kind is a component relative extrinsic, each common_uuid will refer to object spaces. Correspondingly, when the kind is an object relative extrinsic, common_uuid will refer to components.

Description

Composed relative extrinsics metrics contain the following fields:

Field	Type	Description
kind	String	The kind of relative extrinsic (either "Component" or "Object").
from	UUID	The UUID of the "from" coordinate frame.
to	UUID	The UUID of the "to" coordinate frame.
extrinsics_differences	An array of extrinsics objects	The differences from a unit extrinsic when subtracting the composed world extrinsics from the estimated component or object extrinsic.
common_uuids	An array of UUIDs	The "common" UUIDs that link a component relative extrinsic or object relative extrinsic.