A size information evaluation method for space target adaptive image dataset

Abstract

The present invention relates to the field of image evaluation technology, and in particular to a method for evaluating the size information of a space target adaptive image dataset. The method comprises: S1: establishing a target coordinate system; S2: establishing a circumferential angle set that records the target's circumferential angle size information; S3: calculating the pixel resolution, solar illumination angle, and observation angle in the image based on the target coordinate system; wherein the solar observation angle includes the solar illumination azimuth angle and the solar illumination pitch angle, and the observation angle includes the observation azimuth angle and the observation pitch angle; S4: calculating the information degree of the image; S5: calculating the angle coverage set of the image based on the solar illumination angle and the observation angle; S6: comparing the information degree with the value information of the elements in the angle coverage set; if the information degree is greater than the value information, the information degree is used as the new value information, otherwise the original value information is kept unchanged; S7: repeating S3-S7 to process each image; and S8: evaluating the size of the dataset based on the value information.

Description

Technical Field

[0001] The present invention relates to the technical field of image evaluation, and in particular to a method for evaluating the size information of a space target adaptive image data set. Background Art

[0002] Long-term astronomical observations have accumulated a vast amount of image data of Earth-orbiting targets, including satellites, debris, and space stations. These images can be divided into individual image file packages based on the target and accompanied by corresponding measurement-related information to form datasets recording target information. These datasets are crucial inputs for studying the operational status, shape, and posture of these targets. They can be widely used in applications such as intelligence analysis and artificial intelligence learning. However, during the data transfer from the measurement unit to the processing unit, the dataset's quality must be evaluated, primarily focusing on the image quality and the completeness of the information contained in the dataset, to ensure that it meets data processing requirements.

[0003] The size information of space targets under visual conditions is a crucial parameter for inferring their shape and attitude. Furthermore, the richness of dimensional information contained in an image is positively correlated with its quality. Therefore, evaluating the dimensional information contained in a space target image dataset can largely describe the dataset's quality. However, optical images of space targets are significantly affected by lighting conditions, observation conditions, and atmospheric disturbances. Simply counting the number of images or the percentage of the target's field of view within the image cannot accurately describe the information content of the dataset.

[0004] Therefore, in view of the above shortcomings, there is an urgent need for an evaluation method for the size information of image datasets. Summary of the Invention

[0005] An embodiment of the present invention provides a method for evaluating the size information of a space target adaptive image dataset, which can provide a method for evaluating the size information of an image dataset.

[0006] An embodiment of the present invention provides a method for evaluating the size information of a space target adaptive image dataset, comprising:

[0007] S1: Establishing a target coordinate system; wherein the origin of the target coordinate system is the center of the target, and the target coordinate system includes a spatial rectangular coordinate system and a polar coordinate system with the same origin;

[0008] S2: establishing a circumferential angle set that records the target circumferential angle dimension information; wherein the circumferential angle set includes points uniformly distributed on the surface of a unit sphere, and the information of the points includes position information and value information, and the initial value of the value information is 0;

[0009] S3: Calculate the pixel resolution, solar radiation angle and observation angle in the image based on the target coordinate system; wherein the solar observation angle includes the solar radiation azimuth angle α 入射 and the solar pitch angle β 入射 , the observation angle includes the observation azimuth angle α 观测 and the observed pitch angle β 观测 ;

[0010] S4: Calculate the information degree of the image;

[0011] S5: Calculating an angle coverage set of an image according to the sun illumination angle and the observation angle;

[0012] S6: comparing the information degree with the value information of the elements in the angle coverage set; if the information degree is greater than the value information, taking the information degree as the new value information; otherwise, keeping the original value information unchanged;

[0013] S7: Repeat S3-S7 to process each image;

[0014] S8: Evaluate the dataset size according to the value information.

[0015] In one possible design, the z-axis of the spatial rectangular coordinate system is the line connecting the target position and the center of the earth, the direction of outer space is the positive direction of the z-axis, the tangent of the target orbit is the x-axis direction of the spatial rectangular coordinate system, the velocity direction of the target is the positive direction, and based on the x-axis and the z-axis, the direction of the y-axis is determined by the right-hand screw rule. The pitch angle ρ of the polar coordinate system is the angle between the ray direction and the xy plane, and the azimuth angle α of the polar coordinate is the angle between the projection of the ray direction on the xy plane and the positive direction of the x-axis.

[0016] In one possible design, calculating the information degree of the image includes:

[0017] Extract the minimum outer rectangle of the connected domain of the target in the image, and obtain the side lengths of the rectangle as A and B; where the unit of A and B is the number of pixels;

[0018] Extracting a resolution value k of the target in the image; wherein the value of k is the ratio of the full width at half maximum h of the point spread function of the optical image measurement system to the detector size l of the optical image measurement system, and the unit of k is the number of pixels;

[0019] Use the formula Q = (A * B) / k 2 , calculate the information degree Q of the image.

[0020] In one possible design, calculating an angle coverage set of an image according to the sun illumination angle and the observation angle includes:

[0021] Calculating an incident coverage set based on the circumferential angle set and the solar radiation angle; wherein the incident coverage set is a spatial matrix point illuminated by the sun;

[0022] Calculating an observation coverage set based on the circumferential angle set and the observation angle; wherein the observation coverage set is the observed spatial matrix points;

[0023] The intersection of the incident coverage set and the observation coverage set is an angle coverage set.

[0024] In one possible design, the circumferential angle set M includes multiple elements m n =(x n ,y n , z n , v n ), x n ,y n , z n is the position information, v n is the value information, x n =cos(ρ)cos(α),y n =cos(ρ)sin(α),z n =sin(ρ), where n is a positive integer and is the sequence number of element m.

[0025] In one possible design, evaluating the size of the data set according to the value information includes:

[0026] Set the error requirement k;

[0027] The value information v of the elements in the circumferential angle set n Greater than 1 / k 2 Count the elements and find a value greater than 1 / k 2 The data percentage is T k , T k As an indicator to evaluate the completeness of the size information of the space target optical image measurement dataset, T k The value ranges from 0 to 100%. k The larger the dataset size, the more complete the information.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The advantage of the present invention is that it provides an indicator for quantitatively evaluating the completeness of the dimensional information of the space target optical image measurement data set, and gives a calculation method, which can automatically evaluate the completeness of the dimensional information of the data set and provide guidance for data preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 This is a flow chart of a method for evaluating the size information of a space target adaptive image dataset provided by an embodiment of the present invention;

[0032] Figure 2 Schematic diagram of element distribution of a target circumferential angle set M provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" described in the embodiments of the present invention are described from the perspectives shown in the accompanying drawings and should not be understood as limiting the embodiments of the present invention. In addition, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" of another element, it can not only be directly connected "upper" or "lower" of the other element, but also indirectly connected "upper" or "lower" of the other element through an intermediate element.

[0036] like Figure 1 As shown, an embodiment of the present invention provides a method for evaluating the size information of a space target adaptive image dataset, comprising:

[0037] S1: Establish a target coordinate system; wherein the origin of the target coordinate system is the center of the target, and the target coordinate system includes a spatial rectangular coordinate system and a polar coordinate system with the same origin;

[0038] S2: establishing a circumferential angle set for recording target circumferential angle dimension information; wherein the circumferential angle set includes points uniformly distributed on the surface of the unit sphere, and the point information includes position information and value information, and the initial value of the value information is 0;

[0039] S3: Calculate the pixel resolution, solar radiation angle and observation angle in the image based on the target coordinate system; the solar observation angle includes the solar radiation azimuth angle α 入射 and the solar pitch angle β 入射 , the observation angle includes the observation azimuth angle α 观测 and the observed pitch angle β 观测 ;

[0040] S4: Calculate the information degree of the image;

[0041] S5: Calculate the angle coverage set of the image based on the sun's illumination angle and the observation angle;

[0042] S6: Compare the information degree with the value information of the elements in the angle coverage set. If the information degree is greater than the value information, the information degree is used as the new value information; otherwise, the original value information remains unchanged.

[0043] S7: Repeat S3-S7 to process each image;

[0044] S8: Evaluate the dataset size based on the value information.

[0045] The advantage of the present invention is that it provides an indicator for quantitatively evaluating the completeness of the dimensional information of the space target optical image measurement data set, and gives a calculation method, which can automatically evaluate the completeness of the dimensional information of the data set and provide guidance for data preparation.

[0046] In some embodiments of the present invention, the z-axis of the spatial rectangular coordinate system is the line connecting the target position and the center of the earth, the direction of outer space is the positive direction of the z-axis, the tangent of the target orbit is the x-axis direction of the spatial rectangular coordinate system, the velocity direction of the target is the positive direction, and based on the x-axis and the z-axis, the direction of the y-axis is determined by the right-hand screw rule. The pitch angle ρ of the polar coordinate system is the angle between the ray direction and the xy plane, and the azimuth angle α of the polar coordinate is the angle between the projection of the ray direction on the xy plane and the positive direction of the x-axis.

[0047] In some embodiments of the present invention, calculating the information degree of an image includes:

[0048] Extract the minimum outer rectangle of the connected domain of the target in the image, and obtain the side lengths of the rectangle as A and B; where the units of A and B are pixels;

[0049] Extract the resolution value k of the target in the image; where k is the ratio of the full width at half maximum h of the point spread function of the optical image measurement system to the detector size 1 of the optical image measurement system, and the unit of k is the number of pixels;

[0050] Use the formula Q = (A * B) / k 2 , calculate the information degree Q of the image.

[0051] In some embodiments of the present invention, calculating an angle coverage set of an image based on a sun illumination angle and an observation angle includes:

[0052] The incident coverage set is calculated based on the circumferential angle set and the solar radiation angle; wherein the incident coverage set is the spatial matrix point illuminated by the sun;

[0053] The observation coverage set is calculated based on the circumferential angle set and the observation angle; wherein the observation coverage set is the observed spatial matrix points;

[0054] The intersection of the incident cover set and the observation cover set is the angle cover set.

[0055] Calculate the angular coverage of the image. According to the incident angle (α 入射 , β 入射 ) corresponds to (x 入射 ,y 入射 , z 入射 ) direction vector, find the rotation matrix R that rotates it to the (0, 0, 1) direction 入射 , using the rotation matrix R 入射 Convert the first three parameters of the elements in the circumferential angle set M (x n ,y n , z n ), the conversion formula is

[0056]

[0057] If z nr If it is less than 0, the sequence number n is included in the incident cover set K n入 ;

[0058] Similarly, according to the image observation angle (α 观测 , β 观测 ) corresponds to (x 观测 ,y 观测 , z 观测 ) direction vector, find the rotation matrix R that rotates it to the (0, 0, 1) direction 观测 , using the rotation matrix R观测 Processing converts the first three parameters of the elements in the circumferential angle set M (x n ,y n , z n ), the conversion formula is

[0059]

[0060] If z nr If it is less than 0, the sequence number n is included in the observation covering set K n观 ;

[0061] Find the image incident cover set K n入 and observation cover set K n观 The intersection of K n交 .

[0062] In some embodiments of the present invention, the circumferential angle set M includes multiple elements m n =(x n ,y n , z n , v n ), x n ,y n , z n is the location information, v n is the value information, x n =cos(ρ)cos(α),y n =cos(ρ)sin(α),z n =sin(ρ), where n is a positive integer and is the sequence number of element m.

[0063] In the present invention, it is necessary to establish a circumferential angle set M. The set contains different elements m n =(x n ,y n , z n , v n ), n is the serial number subscript, (x n ,y n , z n ) is the point coordinate, corresponding to the point coordinate of a unit sphere surface in the target coordinate system. The points in the set M are evenly distributed on the unit sphere surface, such as Figure 2 As shown. Set M in (x n ,y n , z n ) is to traverse and obtain values according to the azimuth angle α and pitch angle ρ of the target polar coordinates. A preferred solution is to obtain a series of αρ value combinations at intervals of 2°, and then calculate the value of the target polar coordinates according to the formula x. n =cos(ρ)cos(α),y n =cos(ρ)sin(α),zn =sin(ρ) establishes a mapping relationship between the point coordinates and the azimuth angle α and pitch angle ρ.

[0064] In some embodiments of the present invention, evaluating the size of a data set according to the value information includes:

[0065] Set the error requirement k;

[0066] The value information v of the elements in the circumferential angle set n Greater than 1 / k 2 Count the elements and find a value greater than 1 / k 2 The data percentage is T k , T k As an indicator to evaluate the completeness of the size information of the space target optical image measurement dataset, T k The value ranges from 0 to 100%. k The larger the dataset size, the more complete the information.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for evaluating the size information of a space target adaptive image dataset, characterized in that: include: S1: Establishing a target coordinate system; wherein the origin of the target coordinate system is the center of the target, and the target coordinate system includes a spatial rectangular coordinate system and a polar coordinate system with the same origin; S2: establishing a circumferential angle set that records the target circumferential angle dimension information; wherein the circumferential angle set includes points uniformly distributed on the surface of a unit sphere, and the information of the points includes position information and value information, and the initial value of the value information is 0; S3: Calculating the pixel resolution, solar illumination angle, and observation angle in the image based on the target coordinate system; wherein the solar observation angle includes the solar illumination azimuth angle and the solar illumination pitch angle, and the observation angle includes the observation azimuth angle and the observation pitch angle; S4: Calculate the information degree of the image; S5: Calculating an angle coverage set of an image according to the sun illumination angle and the observation angle; S6: comparing the information degree with the value information of the elements in the angle coverage set; if the information degree is greater than the value information, taking the information degree as the new value information; otherwise, keeping the original value information unchanged; S7: Repeat S3-S7 to process each image; S8: Evaluate the dataset size based on the value information.

2. The method according to claim 1, characterized in that The z-axis of the spatial rectangular coordinate system is the line connecting the target position and the center of the earth, the direction of outer space is the positive direction of the z-axis, the tangent of the target orbit is the x-axis direction of the spatial rectangular coordinate system, the velocity direction of the target is the positive direction, and based on the x-axis and the z-axis, the direction of the y-axis is determined by the right-hand screw rule. The pitch angle ρ of the polar coordinate system is the angle between the ray direction and the xy plane, and the azimuth angle α of the polar coordinate is the angle between the projection of the ray direction on the xy plane and the positive direction of the x-axis.

3. The method according to claim 1, characterized in that The calculating the information degree of the image includes: Extract the minimum outer rectangle of the connected domain of the target in the image, and obtain the side lengths of the rectangle as A and B; where the unit of A and B is the number of pixels; Extracting a resolution value k of the target in the image; wherein the value of k is the ratio of the full width at half maximum h of the point spread function of the optical image measurement system to the detector size l of the optical image measurement system, and the unit of k is the number of pixels; Use the formula Q = (A * B) / k 2 , calculate the information degree Q of the image.

4. The method according to claim 1, wherein The calculating an angle coverage set of an image according to the sun illumination angle and the observation angle includes: Calculating an incident coverage set based on the circumferential angle set and the solar radiation angle; wherein the incident coverage set is a spatial matrix point illuminated by the sun; Calculating an observation coverage set based on the circumferential angle set and the observation angle; wherein the observation coverage set is the observed spatial matrix points; The intersection of the incident coverage set and the observation coverage set is an angle coverage set.

5. The method according to claim 2, characterized in that The circumferential angle set M includes multiple elements m n =(x n ,y n , z n , v n ), x n ,y n , z n is the position information, v n is the value information, x n =cos(ρ)cos(α),y n =cos(ρ)sin(α),z n =sin(ρ), where n is a positive integer and is the sequence number of element m.

6. The method according to claim 5, characterized in that The evaluating the size of the data set according to the value information includes: Set the error requirement k; The value information v of the elements in the circumferential angle set n Greater than 1 / k 2 Count the elements and find a value greater than 1 / k 2 The data percentage is T k , T k As an indicator to evaluate the completeness of the size information of the space target optical image measurement dataset, T k The value ranges from 0 to 100%. k The larger the dataset size, the more complete the information.

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