Yaw, Pitch, Roll and Omega, Phi, Kappa angles define the orientation of the drone or the camera during the image acquisition.

The main difference between the two sets of angles is:

- Yaw, Pitch, Roll angles define the rotation of a body, for example,
**aircraft or a drone**with respect to its navigation coordinate system. Mostly used by drone manufacturers. - Omega, Phi, Kappa angles define the rotation between the
**image coordinate system**and a projected coordinate system. Mostly used in photogrammetry software.

**IN THIS ARTICLE**

Yaw, Pitch, Roll definition

Omega, Phi, Kappa definition

How to convert Yaw, Pitch, Roll to Omega, Phi, Kappa

Using Omega, Phi, Kappa and Yaw, Pitch, Roll angles in Pix4D

## Yaw, Pitch, Roll definition

Yaw, Pitch, Roll angles define the relation between the navigation coordinate system and the body coordinate system. The coordinate systems and rotations are defined as:

### Example

Assuming that the camera is mounted such that the camera looks down and the top of the image points to the front of the aircraft, the yaw, pitch, roll angles are defined as follows:

**Yaw**

- If yaw = 0° and the camera is looking to the ground (i.e. nadir), it means that the top of the image points to the north.
- If yaw = 90° and the camera is looking nadir, it means that the top of the image points to the east.
- If yaw = 270° and the camera is looking nadir, it means that the top of the image points to the west.

**Pitch**

- If pitch = 0°, it means that the camera is looking down (i.e. nadir).
- If pitch = 90°, it means that the camera is looking forward.

**Roll**

- If using a gimbal, this value is usually 0°.

**Some more examples:**

- yaw = 0°, pitch = 0°, roll = 0° means: the camera is nadir (looking down perpendicular to the ground), the top of the image points to the north.
- yaw = 0°, pitch = 90°, roll = 0° means: the camera is looking forward from the aircraft, towards north.
- yaw = 90°, pitch = 0°, roll = 0° means: the camera is nadir (looking down perpendicular to the ground), the top of the image points to the east.

## Omega, Phi, Kappa definition

The omega, phi, kappa angles are defined as the angles used in order to rotate a (X, Y, Z) geodetic coordinate system and align it with the image coordinate system. The rotations are applied in the following order:

- Omega (ω), the rotation around the Χ axis.
- Phi (φ), the rotation around the Y axis.
- Kappa (κ), the rotation around the Z axis.

Rotation around the X-axis (Omega) | Rotation around the Y-axis (Phi) | Rotation around the Z-axis (Kappa) |

Exterior orientation rotations/angles. |

More information about the coordinate system definition see the How are the Internal and External Camera Parameters defined? article.

## How to convert Yaw, Pitch, Roll to Omega, Phi, Kappa

Successfully converting from Yaw, Pitch, and Roll to Omega, Phi, and Kappa depends on several factors, including the camera's position on Earth.

There are many ways to convert Yaw, Pitch, and Roll to Omega, Phi, and Kappa. Pix4D's method is described in the attached documents:

- Yaw, Pitch, Roll, and Omega, Phi, Kappa angles and conversion - Pix4D companion notes (150 KB)
- How are the Internal and External Camera Parameters defined?
- M. Bäumker and F.J. Heimes, New Calibration and Computing Method for Direct Georeferencing of Image and Scanner Data Using the Position and Angular Data of an Hybrid Inertial Navigation System, Proceedings of OEEPE Workshop on Integrated Sensor Orientation, 2002 (400 KB)

## Using Omega, Phi, Kappa and Yaw, Pitch, Roll angles in Pix4D

### Importing angle values into Pix4D

Pix4D has worked with a number of UAV partners to automatically calculate Omega, Phi, and Kappa using Yaw, Pitch, and Roll stored in a flight log that belongs to any of our listed UAV manufacturers: Input files.

### Processing options

Accurate angle values can be incorporated to accelerate processing time and produce more accurate results using the **Accurate Geolocation and Orientation** Calibration Method: Menu Process > Processing Options... > 1. Initial Processing > Calibration.

For more information see FAQ on the accurate geolocation pipeline.

It is possible to test the accuracy of the initial Omega, Phi, and Kappa values according to the variance (RMS) which appears in the Quality Report or compare the initial orientation with the optimized orientation calculated by Pix4Dmapper.

To test the accuracy of the initial Omega, Phi, and Kappa values apply **Standard** or **Alternative** Calibration Method: Menu Process > Processing Options... > 1. Initial Processing > Calibration.

Pix4Dmapper calculates the optimized orientation during Step 1. *Initial Processing*.

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