C Module: pixelLineConverter

Executive Summary

Converter that takes a image processing message and camera information and outputs a relative position to the object.

The module PDF Description contains further information on this module’s function, how to run it, as well as testing.

Measurement Freshness

The module consumes each written circles message once. After the first write, its message-header write time must increase strictly, including after an invalid measurement. Unwritten, retained, or older inputs leave the output and its write time unchanged, allowing slower consumers to read the last result. A new invalid input produces a zero output with valid = 0. Consumers must check the output write time to detect new results. Updating camera or attitude data alone does not trigger another conversion. Reset clears the timestamp history, allowing a write at time zero. Producers must timestamp new measurements when writing them; republishing an old image with a newer write time is treated as a new measurement.

Message Connection Descriptions

The following diagram and table list all the module input and output messages. The module message connection is set by the user from Python. The message type contains a link to the message structure definition, while the description provides information on what this message is used for.

Module I/O Messages
Msg Variable Name	Msg Type	Description
opNavOutMsg	OpNavMsgPayload	optical navigation output message
cameraConfigInMsg	CameraConfigMsgPayload	camera config input message
attInMsg	NavAttMsgPayload	attitude input message
circlesInMsg	OpNavCirclesMsgPayload	circles input message

Functions

void SelfInit_pixelLineConverter(PixelLineConvertData *configData, int64_t moduleID)

This method transforms pixel, line, and diameter data into heading data for orbit determination or heading determination.

Parameters:

configData – The configuration data associated with the ephemeris model
moduleID – The module identification integer

void Update_pixelLineConverter(PixelLineConvertData *configData, uint64_t callTime, int64_t moduleID)

This method reads in the camera and circle messages and extracts navigation data from them. It outputs the heading (norm and direction) to the celestial body identified in the inertial frame. It provides the heading to the most robust circle identified by the image processing algorithm.

Parameters:

configData – The configuration data associated with the ephemeris model
callTime – The clock time at which the function was called (nanoseconds)
moduleID – The module identification integer

void Reset_pixelLineConverter(PixelLineConvertData *configData, uint64_t callTime, int64_t moduleID)

This resets the module to original states.

Parameters:

configData – The configuration data associated with the ephemeris model
callTime – The clock time at which the function was called (nanoseconds)
moduleID – The module identification integer

struct PixelLineConvertData

#include <pixelLineConverter.h>

The configuration structure for the pixelLine Converter module.

Public Members

OpNavMsg_C opNavOutMsg: [-] output navigation message for relative position

CameraConfigMsg_C cameraConfigInMsg: camera config input message

NavAttMsg_C attInMsg: attitude input message

OpNavCirclesMsg_C circlesInMsg: circles input message

int32_t planetTarget: The planet targeted (None = 0, Earth = 1, Mars = 2, Jupiter = 3 are allowed).

uint64_t lastWriteTime: [ns] Last consumed circles message write time

int hasReadMessage: Whether a circles message has been consumed since reset.

BSKLogger *bskLogger: BSK Logging.