Star point centroid extraction method based on attitude correlation

An extraction method and star point technology, which are applied in the field of star point centroid extraction based on attitude correlation, can solve the problems of the adjacent rectangle of star points becoming larger, affecting the accuracy of star point extraction, reducing the amount of calculation, etc. Good measurement accuracy and real-time performance, the effect of a wide range of applications

Pending Publication Date: 2022-04-29
中国人民解放军火箭军工程大学
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Problems solved by technology

The grayscale cross-projection method proposed by LUO et al. in the article "Improved centroid extraction algorithm for autonomous star sensor" published in "IET Image Processing" Volume 9, Issue 10 in 2015 significantly reduces the amount of calculation, but when there are When overlapping, the adjacent rectangle of the star point will become larger, and more independent noise points will participate in the centroid calculation, which will seriously affect the accuracy of star point extraction

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  • Star point centroid extraction method based on attitude correlation
  • Star point centroid extraction method based on attitude correlation
  • Star point centroid extraction method based on attitude correlation

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Embodiment 1

[0041] Step 1: Star map denoising

[0042] In the case of high dynamics, it is necessary to extract the centroid after restoring the fuzzy star points, but in any case, filtering and denoising is a necessary step. This paper adopts an improved multi-window sampling adaptive threshold selection method. Determining the threshold can effectively denoise without consuming too much time. details as follows:

[0043] Step 1.1: Select a sampling window with an appropriate size. The determination principle is as follows: In order to quickly obtain the segmentation threshold and reduce the processing time of star image denoising, the sum of pixels in all sampling windows is generally 4%-8 of the total pixels of the star image during sampling. %, the number of sampling windows is generally 30-50 and the positions of each sampling window are distributed as evenly as possible, the ratio between the sum of the pixels of the sampling window and the number of sampling windows is the size of...

Embodiment 2

[0065] Step 3: Fine extraction of star point area

[0066] see image 3 , Figure 4 , Figure 5 , Figure 6 :

[0067] Depend on figure 2 The projection results of star points 1, 2, and 3 show that the grayscale cross-projection method based on distance discrimination cannot remove all isolated noise points, so the results cannot be directly used for centroid calculation, and further refined star points need to be extracted pixels. The invention proposes a line segment encoding mark rule based on a position matrix. It takes the target pixel line segment as the basic processing unit, and the label determination is only carried out when a pixel line segment is detected. During line-by-line detection, if a certain coded line segment n in the i+1th line is only matched with the label in the i-th line as " If the coded line segment of k" is connected, then the coded line segment n is also marked as "k"; if the coded line segment n is connected to a plurality of line segment...

Embodiment 3

[0071] In order to explain more intuitively, the more complex image 3 As the original figure to illustrate the line segment encoding marking method based on the position matrix of the present invention, the value of the blank pixel in the figure is 0, and the specific execution steps are as follows:

[0072] Step 3.1: The rules for judging whether the two line segments in the uplink and downlink are connected are as follows:

[0073] x a ≤x c ≤x b or x c ≤x a ≤x d (6)

[0074] xa, xb are the left and right endpoint values ​​of the i-th line segment, xc, xdb are the left and right endpoint values ​​of the i+l line segment; judge the left and right endpoint values ​​xa, xb of the i-th line segment and the left and right endpoint values ​​xc of the i+l line segment , whether xd satisfies the rule (6), if satisfied, then the two line segments are connected, otherwise, they are not connected.

[0075] According to the rules, N of the position matrix coor[N*M] is 7, M is 7...

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Abstract

The invention relates to an attitude-associated star point centroid extraction method in the astronomical positioning and orientation technology, which comprises the four steps of star map denoising, star point local area limitation, star point area fine extraction, motion blurred star point restoration and centroid calculation, compared with the prior art, an improved multi-window adaptive threshold determination strategy is adopted to improve the robustness of the algorithm, and the accuracy of the attitude-associated star point centroid extraction is improved. On the basis of ensuring the reasonability of threshold selection, the calculation amount is reduced to the greatest extent, and the real-time performance is improved; carrying out crude extraction of a star point dispersion range by means of cross projection and distance discrimination; marking of a star point communication area is completed through a coordinate marking and coding method, the noise influence is effectively avoided, the accurate range of a star point dispersion area is obtained, and a powerful guarantee is provided for subsequent fuzzy star point restoration; the RL algorithm is used for processing the star point trailing area, the star point extraction problem under the high dynamic condition is solved, and the wide application range is achieved on the basis that good measurement precision and real-time performance are guaranteed.

Description

technical field [0001] The invention belongs to the technical field of astronomical positioning and orientation, and relates to a star point centroid extraction method based on attitude correlation. Background technique [0002] Accurate navigation information is the basis for the spacecraft to successfully complete various specified tasks. Navigation information mainly includes position information and attitude information. Among them, the attitude information is mainly measured by attitude sensors in real time. Common attitude sensors include star sensors, gyroscopes, horizon instruments, magnetometers, and so on. The star sensor is one of the attitude sensors with the highest precision at present. It takes the star as a reference, can improve the attitude data to the arc-second level, and has good stability. Therefore, it is widely used in the aerospace field. Star point extraction is the basic work before star map recognition, and it is also one of the most time-consumi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T5/00G06T7/66
CPCG06T5/002G06T7/66
Inventor 周召发张志利段辉赵军阳常振军冯磊
Owner 中国人民解放军火箭军工程大学
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