A method for analyzing the outside visual field of a helicopter cockpit

Abstract

The present application belongs to the technical field of helicopter man-machine efficacy design, and particularly relates to a helicopter cabin outside view analysis method. First, the three-dimensional feature point set of the view shielding object is all converted into a two-dimensional view discrete point set, the edge point set of the view shielding area is extracted, the contour line is generated by fitting, the corresponding view shielding area is formed, and thus the outside view area of the driver not affected by the obstruction is obtained. The problems of low accuracy, long time consumption and limited scope of application of the current cabin outside view analysis method are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter human-machine efficiency design, and in particular relates to a method for analyzing visual field outside a helicopter cockpit. Background Art

[0002] The helicopter cockpit's external field of view is a crucial way for the pilot to observe the external environment. Visibility is typically assessed using an equivalent area field of view diagram. This involves plotting the portion of the field of view obstructed by structural components, detection devices, and other components / equipment within an unobstructed field of view at ±180° in azimuth and ±90° in elevation, relative to the pilot's designed eye position. This provides the pilot with an unobstructed field of view. Currently, the obstructed field of view in a field of view diagram is primarily determined by extracting a discrete set of three-dimensional boundary points from the obstructing objects, calculating the azimuth and elevation angles of each point relative to the designed eye position, and then fitting the resulting two-dimensional obstructed field of view edge point set. The disadvantage of this method is that the extracted three-dimensional boundary points are difficult to define as the edge points of the field of view occlusion area, especially the points with curved surface features, so that the formed field of view occlusion area deviates from the actual one. At the same time, the extraction of three-dimensional boundary points has high requirements. If too few points are extracted, the fitting accuracy of the two-dimensional field of view occlusion area contour line is low, and the shape of the formed field of view occlusion area is easily distorted; if too many points are extracted, it takes a long time and is easy to generate pseudo-edge points of the field of view, which directly affects the field of view contour line fitting and reduces the quality of the field of view occlusion area generation. Summary of the Invention

[0003] The present invention provides a method for analyzing the visual field outside a helicopter cockpit, which solves the problems of low precision, long time consumption and limited application scope of the current method for analyzing the visual field outside a helicopter cockpit.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions to achieve it.

[0005] A method for analyzing visual field outside a helicopter cockpit comprises the following steps:

[0006] Step 1: Select the pilot's design eye position and give its three-dimensional point coordinates in the helicopter's global coordinate system, recorded as P0(x0,y0,z0);

[0007] Step 2: Select the field of view obstruction arranged in the whole aircraft coordinate system and obtain the corresponding three-dimensional point set coordinates P of the field of view obstruction i (x i ,y i ,z i )(i=1,2,…n);

[0008] Step 3: Based on the driver's eye position P0, for each point P in the three-dimensional point set coordinates i , obtain the corresponding two-dimensional field of view discrete points, and form a two-dimensional field of view discrete point set p i (u i,ν i )(i=1,2,…n), denoted as M;

[0009] Step 4: For any point p(u,ν) in the point set M, search for all points in M ​​whose Euclidean distance to the point p(u,ν) is less than the preset distance, which is recorded as the point set E;

[0010] Step 5: Select any point p′(u′,ν′) in the point set E and calculate the coordinates p″(u″,ν″) and p″′(u″′,ν″′) of the center of the rolling circle with radius R passing through p and p′;

[0011] Step 6: Calculate the distances from all points in the point set E except point p′ to p″ and p″′;

[0012] If the distances from other points to point p″ or p″′ are all greater than the R value, then point p(u,ν) is determined to be an edge point;

[0013] Step 7: If the distances from other points to point p″ or p″′ are not all greater than the R value, then traverse all points in the point set E and rotate them to point p′;

[0014] Repeat steps 5 and 6. If point p(u,ν) is determined to be an edge point, stop judging the point and proceed to step 4 to judge the next point in M. If no point like p′ exists among all the neighboring points in E, it indicates that point p(u,ν) is not an edge point, and proceed to step 4 to judge the next point in M.

[0015] Step 8: Traverse all points in the point set M, obtain the edge point set of the field of view occlusion area, perform contour fitting, form the corresponding field of view occlusion area, and thus obtain the driver's unobstructed external field of view area.

[0016] Further,

[0017] In step 3, for each point P in the three-dimensional point set coordinates i , obtain the corresponding two-dimensional field of view discrete points, and form a two-dimensional field of view discrete point set p i (u i ,ν i )(i=1,2,…n), specifically:

[0018] Solve point P by formula (1) i The corresponding field of view azimuth μ i and pitch angle ν i , obtain the two-dimensional field of view discrete point set p i (u i ,ν i )(i=1,2,…n), denoted as M;

[0019]

[0020] Further,

[0021] In step 4, the preset distance is 2R, where R is the given search rolling circle radius.

[0022] Further,

[0023] In step 5, the coordinates of the center of the rolling circle p″(u″,ν″) and p″′(u″′,ν″′) passing through p and p′ and with a radius R are calculated as follows:

[0024]

[0025] Where: intermediate variable H

[0026]

[0027] Further,

[0028] The helicopter cockpit is a parallel double-seat cockpit, a tandem double-seat cockpit or a single-row single-seat cockpit.

[0029] Further,

[0030] The surface feature of the field of view obstruction is a plane, a regular curved surface, an irregular curved surface, or any combination of a plane, a regular curved surface, and an irregular curved surface.

[0031] Further,

[0032] The search rolling circle radius adopts an empirical fixed value, or adopts an adaptive radius with a fixed number of neighboring points.

[0033] Further,

[0034] The contour line fitting method of the visual field occlusion area is least square fitting, weighted regression fitting or spline fitting.

[0035] This paper proposes a method for analyzing the out-of-cockpit view of a helicopter. The method first converts the three-dimensional feature points of all vision obstructing objects into a two-dimensional discrete point set. The edge points of the obstructed area are then extracted and fitted to generate contour lines, forming the corresponding obstructed area. This method, therefore, provides the pilot with an unobstructed view of the outside world. This method is applicable to vision obstructing objects with various surface features and can quickly and accurately reproduce the obstructed area, significantly improving the quality of out-of-cockpit view assessment. This method has been successfully applied to a certain type of helicopter and could be applied to other helicopters in the future, demonstrating its engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the cockpit layout provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a two-dimensional field of view point set and edge point extraction under occlusion of a detection device provided by an embodiment of the present invention;

[0038] Figure 3 A schematic diagram of a driver's external field of view analysis and comparison provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0040] An embodiment of the present invention provides a method for analyzing the visual field outside a helicopter cockpit. The method first converts all three-dimensional feature point sets of visual field obstructions into two-dimensional discrete point sets, then extracts the edge point sets of the visual field obstruction area, and generates contour lines by fitting to form the corresponding visual field obstruction area, thereby obtaining the unobstructed external visual field area for the pilot.

[0041] Specifically, a method for analyzing the visual field outside a helicopter cockpit includes the following steps:

[0042] Step 1: Select the driver's eye position, such as Figure 1 As shown, the three-dimensional coordinates of the point in the helicopter's global coordinate system are given, denoted as P0(x0,y0,z0);

[0043] Step 2: Select the visual field obstruction arranged in the whole aircraft coordinate system, such as Figure 1 As shown, get the corresponding three-dimensional point set coordinates P i (x i ,y i ,z i )(i=1,2,…n);

[0044] Step 3: Design the eye position P0 based on the driver, and for each point P i , calculate the corresponding field of view azimuth μ by formula (1) i and pitch angle ν i , obtain the two-dimensional field of view discrete point set p i (u i ,ν i )(i=1,2,…n), denoted as M; Figure 2 As shown, there are 2200 two-dimensional field of view points under the occlusion of the detection device, and a total of 176 field of view occlusion points are extracted using the method of the present invention.

[0045]

[0046] Step 4: For any point p(u,ν) in the point set M, search for all points in M ​​whose Euclidean distance from point p is less than 2R, recorded as point set E, where R is the given search rolling circle radius;

[0047] Step 5: Select any point p′(u′,ν′) in the point set E and calculate the coordinates of the center of the rolling circle p″(u″,ν″) and p″′(u″′,ν″′) passing through p and p′ with a radius of R:

[0048]

[0049] Where: intermediate variable H

[0050]

[0051] Step 6: Calculate the distances from all points in the point set E except point p' to p", p''. If the distances from all other points to p'' or p'' are greater than R, then point p(u, ν) is considered an edge point.

[0052] Step 7: If the distances from other points to point p″ or p″′ are not all greater than the R value, then traverse all points in the point set E and rotate to point p′. If there is a point in E that satisfies steps 5 and 6, then point p is determined to be an edge point, stop judging at this point, and proceed to step 4 to continue judging the next point in M. If there is no point like p′ in all neighboring points in E, then it indicates that point p is not an edge point, and proceed to step 4 to judge the next point in M.

[0053] Step 8: Traverse all points in the point set M to obtain the edge point set of the field of view occlusion area, perform contour fitting, form the corresponding field of view occlusion area, and thus obtain the driver's unobstructed external field of view area. Figure 2 As shown in the figure, the traditional field of view occlusion contour line is extracted based on the entity boundary line. Figure 3 The midpoint horizontal line boundary is shown, and the visual field occlusion edge points and areas extracted by the method of the present invention are as follows Figure 3 Shown as mid-point line.

[0054] The helicopter cockpit external visual field analysis method of the present invention is applicable to visual field obstructions with various surface features and can quickly and accurately reproduce the visual field obstruction area.

[0055] The helicopter cockpit may be a parallel two-seat cockpit, a tandem two-seat cockpit, a single-row single-seat cockpit or other manned cockpit;

[0056] The shape of the field of view obstruction is not limited, and the surface features can be flat, regular curved, irregular curved, and various combinations thereof;

[0057] The search rolling circle radius may adopt an empirical fixed value or an adaptive radius with a fixed number of neighboring points.

[0058] The contour line fitting method of the visual field obstruction area can be least square fitting, weighted regression fitting, spline fitting or other arbitrary curve fitting.

[0059] This paper proposes a method for analyzing the out-of-cockpit view of a helicopter. The method first converts the three-dimensional feature points of all vision obstructing objects into a two-dimensional discrete point set. The edge points of the obstructed area are then extracted and fitted to generate contour lines, forming the corresponding obstructed area. This method, therefore, provides the pilot with an unobstructed view of the outside world. This method is applicable to vision obstructing objects with various surface features and can quickly and accurately reproduce the obstructed area, significantly improving the quality of out-of-cockpit view assessment. This method has been successfully applied to a certain type of helicopter and could be applied to other helicopters in the future, demonstrating its engineering application value.

Claims

1. A method for analyzing the visual field outside a helicopter cockpit, characterized in that: The following steps are involved: Step 1: Select the pilot's design eye position and give its three-dimensional point coordinates in the helicopter's global coordinate system, recorded as P0(x0,y0,z0); Step 2: Select the field of view obstruction arranged in the whole aircraft coordinate system and obtain the corresponding three-dimensional point set coordinates P of the field of view obstruction i (x i ,y i ,z i )(i=1,2,…n); Step 3: Based on the driver's eye position P0, for each point P in the three-dimensional point set coordinates i , obtain the corresponding two-dimensional field of view discrete points, and form a two-dimensional field of view discrete point set p i (u i ,ν i )(i=1,2,…n), denoted as M; Step 4: For any point p(u,ν) in the point set M, search for all points in M ​​whose Euclidean distance to the point p(u,ν) is less than the preset distance, which is recorded as the point set E; Step 5: Select any point p′(u′,ν′) in the point set E and calculate the coordinates p″(u″,ν″) and p″′(u″′,ν″′) of the center of the rolling circle with radius R passing through p and p′; Step 6: Calculate the distances from all points in the point set E except point p′ to p″ and p″′; If the distances from other points to point p″ or p″′ are all greater than the R value, then point p(u,ν) is determined to be an edge point; Step 7: If the distances from other points to point p″ or p″′ are not all greater than the R value, then traverse all points in the point set E and rotate them to point p′; Repeat steps 5 and 6. If point p(u,ν) is determined to be an edge point, stop judging the point and proceed to step 4 to judge the next point in M. If no point like p′ exists among all the neighboring points in E, it indicates that point p(u,ν) is not an edge point, and proceed to step 4 to judge the next point in M. Step 8: Traverse all points in the point set M, obtain the edge point set of the field of view occlusion area, perform contour fitting, form the corresponding field of view occlusion area, and thus obtain the driver's unobstructed external field of view area.

2. A helicopter cockpit external field of view analysis method according to claim 1, characterized in that: In step 3, for each point P in the three-dimensional point set coordinates i , obtain the corresponding two-dimensional field of view discrete points, and form a two-dimensional field of view discrete point set p i (u i ,ν i )(i=1,2,…n), specifically: Solve point P by formula (1) i The corresponding field of view azimuth μ i and pitch angle ν i , obtain the two-dimensional field of view discrete point set p i (u i ,ν i )(i=1,2,…n), denoted as M; 3. The method for analyzing the visual field outside a helicopter cockpit according to claim 1, characterized in that: In step 4, the preset distance is 2R , where R is the given search rolling circle radius.

4. The method for analyzing the visual field outside a helicopter cockpit according to claim 1, characterized in that: In step 5, the coordinates of the center of the rolling circle p″(u″,ν″) and p″′(u″′,ν″′) passing through p and p′ and with a radius R are calculated as follows: Where: intermediate variable H 5. The method for analyzing the visual field outside a helicopter cockpit according to claim 1, characterized in that: The helicopter cockpit is a parallel double-seat cockpit, a tandem double-seat cockpit or a single-row single-seat cockpit.

6. The method for analyzing the visual field outside a helicopter cockpit according to claim 1, characterized in that: The surface feature of the field of view obstruction is a plane, a regular curved surface, an irregular curved surface, or any combination of a plane, a regular curved surface, and an irregular curved surface.

7. The method for analyzing the visual field outside a helicopter cockpit according to claim 3, characterized in that: The search rolling circle radius adopts an empirical fixed value, or adopts an adaptive radius with a fixed number of neighboring points.

8. The method for analyzing the visual field outside a helicopter cockpit according to claim 1, characterized in that: The contour line fitting method of the visual field occlusion area is least square fitting, weighted regression fitting or spline fitting.

Images