CN-121838025-B - Method and device for measuring and calculating moment of rocket take-off moment based on event camera

CN121838025BCN 121838025 BCN121838025 BCN 121838025BCN-121838025-B

Abstract

The invention discloses a method and a device for measuring and calculating the moment of rocket take-off based on an event camera, which belong to the technical field of aerospace measurement and control, wherein the method for measuring and calculating the moment of rocket take-off comprises the steps of acquiring a rocket launching event set acquired by the event camera, and decomposing the rocket launching event set into two subsets according to the polarity of the event; setting dynamic time windows to respectively segment, stack and project two event sequences to generate event frames with space dense characteristics so as to eliminate sensor noise and environmental interference, extracting central line characteristics by line segment detection, determining initial motion moment of rocket based on central line coincidence judgment in continuous time windows, starting a self-adaptive time backtracking mechanism, adjusting backtracking step length in a nonlinear mode according to the quantity change of characteristic line segments, and precisely determining moment of rocket take-off moment at critical points of characteristic line segment disappearance. The invention realizes microsecond precision detection at the moment of rocket take-off and has the advantages of high detection precision and strong anti-interference capability.

Inventors

LIU HAOYUE
FENG LUXIN
YAN LUXIN
CHANG YI
Yang Jiuwen
LI CHUNYU
WANG CHEN
ZHANG YASHENG

Assignees

华中科技大学
中国人民解放军63729部队

Dates

Publication Date: 20260508
Application Date: 20260313

Claims (8)

1. The method for measuring and calculating the moment of the rocket take-off moment based on the event camera is characterized by comprising the following steps: S1, setting the step length as With a width of Collecting the starting time of event acquired by event camera in the process of rocket launching To the point of Positive and negative event sets within a period of time 、 Projecting to obtain positive and negative event frames 、 ; S2, for positive and negative event frames And Respectively performing line segment detection to obtain line segment groups And (3) with Is directed to Middle (f) Strip line segment Middle (f) Segment pair of strip segments From which pairs of feature line segments satisfying the correlation condition are found To form Feature line segment pair set at moment, if The feature line segment pair set of the moment comprises a plurality of And at least two of them Is to be coincident with the center line Sliding the first time window along a time axis to obtain 、、 Respectively corresponding characteristic line segment pair sets, judging 、、 Whether it is a candidate moment of motion: if yes, determining The moment is the moment of rocket movement If not, sliding the first time window along the time axis until finding 、、 Are all candidate motion moments and will As moment of rocket movement ; S3, setting the step length as With a width of From the moment of rocket movement Start sliding against the time axis to Time of day, pair Multiple groups of central lines corresponding to time are overlapped Stacking positive and negative events in a plurality of areas occupied by the medium event points to form a plurality of positive and negative event frames, dividing the positive and negative event frames into two groups according to polarities, and if the effective events in the two groups are lower than a threshold value, then judging the moment As the moment of the rocket taking off; step size of the first time window Width of window The relation between them satisfies ; The step size of the second time window is a dynamic step size, Based on the detected slope of Dynamically adjusting the ratio of the maximum number of events to the initial value on the straight line of (a), if the ratio becomes smaller The reduction of the number of the components, wherein, For the moment of rocket movement The slopes of the sets of line segments with corresponding centerlines coincident, Is arranged to be big at first and then small at second, Setting the step length as the initial step length Minimum adjustment to 。
2. The event camera based rocket takeoff moment measuring and calculating method according to claim 1, further comprising, before S1: event during rocket launching process acquired by event camera Constructing event sets ; For the event set The denoising process comprises shielding To the point of The internal event trigger frequency is higher than a first threshold The pixel point of the pixel is shielded from the positive and negative polarity alternation frequency higher than a second threshold value All pixels in the fixed area of (a).
3. The event camera-based rocket takeoff moment measuring and calculating method as recited in claim 1, wherein a plurality of characteristic line segment pairs are judged Whether or not to coincide, including calculating each characteristic line segment pair Middle line segment And line segment The method comprises the steps of obtaining center point coordinates of each center point, connecting the two center points to obtain a center line to construct a center line set, clustering center lines in the center line set, and judging that a plurality of corresponding characteristic line segments are center line coincidence if at least two center lines are contained in the same cluster.
4. The event camera-based rocket takeoff moment measuring and calculating method according to claim 1, wherein the correlation condition is: and (3) with Parallel and equal in length; and (3) with The line of the central point of (2) is perpendicular to the line segment And (3) with ; And (3) with Is less than a set threshold.
5. A method for measuring moment of rocket takeoff based on event camera as recited in claim 1, wherein the moment is determined if the effective events in the two groups are below a threshold value The moment of taking off the rocket is that if the event frame of any polarity is satisfied, all the event frames are taken as The number of event points on the straight line with the slope is smaller than the set value, and the moment is taken As the moment of the rocket taking off 。
6. A device for measuring and calculating moment of rocket takeoff based on event camera, characterized in that it is used for executing the method for measuring and calculating moment of rocket takeoff based on event camera according to any one of claims 1-5, comprising: the acquisition processing module is used for setting the step length as And has a width of Collecting the starting time of event acquired by event camera in the process of rocket launching To the point of Positive and negative event sets within a period of time 、 Projecting to obtain positive and negative event frames 、 ; A forward processing module for processing positive and negative event frames And Respectively performing line segment detection to obtain line segment groups And (3) with Is directed to Middle (f) Strip line segment Middle (f) Segment pair of strip segments From which pairs of feature line segments satisfying the correlation condition are found To form Feature line segment pair set at moment, if The feature line segment pair set of the moment comprises a plurality of And at least two of them Is to be coincident with the center line Sliding the first time window along a time axis to obtain 、、 Respectively corresponding characteristic line segment pair sets, judging 、、 Whether it is a candidate moment of motion: if yes, determining The moment is the moment of rocket movement If not, sliding the first time window along the time axis until finding 、、 Are all candidate motion moments and will As moment of rocket movement ; A backtracking processing module for setting the step length as With a width of From the moment of rocket movement Start sliding against the time axis to Time of day, pair Multiple groups of central lines corresponding to time are overlapped Stacking positive and negative events in a plurality of areas occupied by the medium event points to form a plurality of positive and negative event frames, dividing the positive and negative event frames into two groups according to polarities, and if the effective events in the two groups are lower than a threshold value, then judging the moment As the moment of the rocket taking off.
7. An electronic device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the event camera based rocket takeoff moment calculation method of any of claims 1 to 5.
8. A computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the event camera based method for measuring moment of takeoff of a rocket according to any of claims 1 to 5.

Description

Method and device for measuring and calculating moment of rocket take-off moment based on event camera Technical Field The invention belongs to the technical field of aerospace measurement and control, and particularly relates to a method and a device for measuring and calculating moment of a rocket taking-off moment based on an event camera. Background The accurate measurement of the rocket take-off moment is one of key technologies in the field of aerospace measurement and control, and has important significance for launching process control, engine state and fault diagnosis. Currently, frame-based imaging techniques, such as high-speed cameras and photoelectric measurement devices, are mainly used to determine the moment of rocket ground clearance by analyzing a sequence of successive images. However, such techniques are limited by the principle of integral sampling, and have inherent limitations in that the frame rate needs to be greatly improved to achieve high time resolution, resulting in a sharp increase in data volume and heavy processing load, and in that spatial resolution or image quality often needs to be sacrificed when high frame rate is ensured, affecting detection accuracy. The event camera is used as a novel neuromorphic sensor, has the advantages of microsecond time resolution, high dynamic range, low data redundancy and the like, and is very suitable for high-speed monitoring of a rocket take-off process in theory. However, event data has space-time sparsity, and rocket launch sites have complex background noise and light interference, and accurately identifying takeoff critical moments directly from event streams faces a great challenge. The existing event processing method often excessively depends on traditional image information or lacks an optimal design aiming at a specific scene of rocket take-off, and is difficult to meet the requirement of high-precision detection. Therefore, there is an urgent need to develop a solution that can fully exploit the advantages of event cameras, specifically for rocket takeoff transients. Disclosure of Invention Aiming at the defects or improvement demands of the prior art, the invention provides a method and a device for measuring and calculating the moment of the rocket taking off based on an event camera, and aims to solve the technical problem that the existing event processing method is difficult to meet the high-precision detection demands of measuring and calculating the moment of the rocket taking off. In order to achieve the above object, according to one aspect of the present invention, there is provided a method for measuring and calculating moment of takeoff of a rocket based on an event camera, comprising: S1, setting the step length as With a width ofCollecting the starting time of event acquired by event camera in the process of rocket launchingTo the point ofPositive and negative event sets within a period of time、Projecting to obtain positive and negative event frames、; S2, for positive and negative event framesAndRespectively performing line segment detection to obtain line segment groupsAnd (3) withIs directed toThe first of (3)Strip line segmentThe first of (3)Segment pair of strip segmentsFrom which pairs of feature line segments satisfying the correlation condition are foundTo formFeature line segment pair set at moment, ifThe feature line segment pair set of the moment comprises a plurality of feature line segment pairsAnd at least two of themIs to be coincident with the center lineThe moment is taken as a candidate movement moment, and the first time window is slid along a time axis to obtain、、Corresponding characteristic line segment pair set, judgment、、Whether it is a candidate moment of motion: if yes, determiningThe moment is the moment of rocket movementIf not, continuing to slide the first time window along the time axis until the condition that the first time window meets the requirement is found、、Are all candidate motion moments and willTime of day as rocket movement time; S3, setting the step length asWith a width ofFrom the moment of rocket movementStart against the time axisSlide to timeFor a pair ofMultiple groups with coincident central linesStacking positive and negative events in a plurality of areas occupied by the medium event points to form a plurality of positive and negative event frames, dividing the positive and negative event frames into two groups according to polarities, and if the effective events in the two groups are lower than a threshold value, then taking the momentAs the moment of the rocket taking off. Further, before S1, the method also comprises the steps of collecting the event camera to acquire the event in the rocket launching processConstructing event setsFor the event setComprises: shielded atTo the point ofThe event triggering frequency is higher than a first thresholdThe pixel point of the pixel is shielded from the positive and negative polarity alternation frequency higher than a s