Accurate and Robust Synchronous Extraction Algorithm for Star Centroid and Nearby Celestial Body Edge

Yong Zhang,Jie Jiang,Guangjun Zhang,Yan Lu

doi:10.1109/access.2019.2939148

Abstract

Celestial body features are important navigation information in deep space exploration. This study provides a synchronous high-precision extraction algorithm for star centroid and nearby celestial body edges for a miniaturized independent optical navigation sensor, which combines the functions of a star tracker and a navigation camera. The image is filtered by a ring filter template to eliminate the interference information of background and improve the contrast between the target and the background. The second-order directional derivative and specific area characteristic method aim to roughly extract and distinguish the features (star centroid and the nearby celestial body edge). In local area template where feature points are located, the 1D energy deviation effect is proposed to extract the features of the two different light intensity distribution models. The accuracy and robustness of our algorithm are verified by simulation and ground-based experiments. The algorithm has certain reference significance for other types of dim target and edge detections, such as infrared detection, medical image, target measurement, and machine vision.

Highlights

Deep-space autonomous navigation can achieve tasks, such as orbit determination and control, attitude orientation, and target tracking, in the event of loss of ground communication; it greatly enhances the survivability of the spacecraft [1]
Autonomous navigation technology used in several representative missions and plans of deep space exploration shows that the current mainstream autonomous navigation technology of deep space exploration is based on the image information of navigation star or target celestial body obtained by optical autonomous navigation (OPNAV) sensor [2], [3]
SYNCHRONOUS EXTRACTION OF STAR AND NEARBY CELESTIAL BODY FEATURES we propose a synchronous high-precision extraction algorithm for star centroid and nearby celestial body edge

Summary

INTRODUCTION

Deep-space autonomous navigation can achieve tasks, such as orbit determination and control, attitude orientation, and target tracking, in the event of loss of ground communication; it greatly enhances the survivability of the spacecraft [1]. The 1D energy deviation effect is based on the Gaussian function model of the light intensity distribution of the pixel where the feature point is located, combined with the relationship between the gray scale and the area on both sides of the feature point. C. SUB-PIXEL FEATURE EXTRACTION BASED ON 1D ENERGY DEVIATION EFFECT The pixel-level star centroid and the nearby celestial body circular arc edge are extracted and positioned at the sub-pixel level. The 1D light intensity distribution of the nearby celestial body in the gradient direction satisfies blurred edge model [33]–[35]. Similar to the method of solving x1, we select the horizontal direction 3 × 7 pixels as the local area template to find the star centroid y1 on the y-axis.

STAR FEATURE EXTRACTION PERFORMANCE

NEARBY CELESTIAL BODY FEATURE

CONCLUSION