Zero-gravity seat passenger sitting posture measuring method and system based on TOF camera

Abstract

The invention discloses a zero-gravity seat passenger sitting posture measurement method and system based on a TOF camera, which can output 3D information of a target point location, is basically not influenced by ambient light, and greatly improves the convenience and accuracy of an experiment. The measuring system comprises an automobile seat, a seat fixing platform and a TOF camera. The automobile seat comprises a seat back, a seat cushion, a leg support and a headrest. Five concentric square identification marks are attached to the automobile seat and located in the center of a headrest, the upper end of a seat back, the rotating center of the seat back and a seat cushion, the rotating center of the seat cushion and a leg support and the tail end of the leg support respectively, and a first H-point mark and a second H-point mark which are used for marking the H-point position of the automobile seat are attached to the seat cushion and the seat back respectively. By adjusting the relative position relation of all parts of the seat device, the device meets various vehicle characteristics, seat comfort measurement is more comprehensively and systematically carried out, and the accuracy of seat collection results is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of passenger sitting posture measurement, and in particular to a method and system for measuring the sitting posture of a zero-gravity seat passenger based on a TOF camera. Background Art

[0002] With the continuous development of automobile intelligence and networking technology, cars have gradually evolved into people's third living space. Driving comfort, especially in long-distance driving, traffic congestion and other scenarios, has become more important. The comfort design of seats has become an important factor in improving user satisfaction. Especially in the field of car seats, comfort is not only related to user experience, but also involves safety issues. For example, seat discomfort may lead to poor driver posture, which in turn affects driving safety. Comfortable seats can help drivers maintain a correct sitting posture, reduce fatigue, and improve the ability to drive safely.

[0003] In the passenger sitting posture measurement method, the existing angle and distance measurement methods are mainly divided into two modes: optical measurement and non-optical measurement. Non-optical measurement elements are mainly represented by Hall sensors. However, they cannot distinguish between living and non-living objects in target recognition, and a Hall sensor must be arranged at each recognition position, which poses a challenge to the convenience of the experiment. Optical measurement elements are mainly represented by binocular cameras, but they have a strong dependence on the light source of the experiment and cannot be applied in dark conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for measuring the sitting posture of a zero-gravity seat occupant based on a TOF camera, which can output 3D information of the target point and is basically not affected by ambient light, thereby greatly improving the convenience and accuracy of the experiment.

[0005] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0006] First aspect

[0007] The present application provides a zero-gravity seat occupant sitting posture measurement system based on a TOF camera, including a car seat, a seat fixing platform and a TOF camera;

[0008] The car seat comprises a seat back, a seat cushion, a leg rest and a headrest; five concentric square identification marks are affixed to the car seat, which are respectively located at the center of the headrest, the upper end of the seat back, the rotation center of the seat back and the seat cushion, the rotation center of the seat cushion and the leg rest, and the end of the leg rest; the seat cushion and the seat back are respectively affixed with an H-point mark 1 and an H-point mark 2 for marking the H-point position of the car seat;

[0009] The seat fixing platform includes: a seat connecting tool and a control console; the seat connecting tool includes: a pressure plate, a seat guide connecting block, and a pressure plate bolt; wherein, the pressure plate is provided with a pressure plate bolt moving groove for the pressure plate bolt to cooperate with the support plate bolt hole to connect the seat guide connecting block to the support plate; the seat guide connecting block is provided with a seat bolt moving groove for assembling and connecting the seat guide bolt installed at the lower end of the car seat with the seat guide connecting block, and is suitable for a variety of car seats through two seat guide connecting blocks; after the seat guide connecting block is fixed to the car seat, it is fixed to the support plate through four pressure plates; the control platform includes a support plate, a bottom plate, and a hydraulic support column And a hydraulic support column control box, a base plate support column, a 12V voltage-stabilized power supply, a support plate rotation center, an infrared remote control power connection box, a support plate bolt hole, a hydraulic support column connection end, and a base plate two; a base plate support column is respectively arranged at the four corners of the lower end of the base plate one, a mounting groove is arranged in the middle of the base plate one, a 12V voltage-stabilized power supply, an infrared remote control power connection box and a hydraulic support column control box are arranged on the base plate two of the mounting groove, a hydraulic support column is arranged at the upper end of the hydraulic support column control box, the hydraulic support column is connected to the hydraulic support column connection end installed on the support plate, one end of the support plate is hingedly connected to the base plate one, and the support plate is used to rotate around the rotation center of the support plate through the hydraulic support column;

[0010] The TOF camera is installed on a TOF camera fixing device.

[0011] Wherein, two groups of support plate bolt holes are arranged on the support plate.

[0012] Wherein, the infrared remote control connection box is provided with a wiring hole.

[0013] Among them, the TOF camera fixing device includes a horizontal movable guide rail, a vertical movable guide rail and a fixed base, the fixed base is provided with a vertical movable guide rail, the vertical movable guide rail is provided with a horizontal movable guide rail, and the horizontal movable guide rail is provided with a TOF camera.

[0014] Second aspect

[0015] The present application provides a method for measuring the sitting posture of a zero-gravity seat occupant based on a TOF camera, the method being performed using the above-mentioned system, and comprising the following steps:

[0016] Step 1: Screening of surveyors;

[0017] Step 2: Install the car seat. Place the car seat on the seat fixing platform through the seat rail connection block and fix the seat through the pressure plate. Adjust the hydraulic support column to make the seat angle meet the actual vehicle installation angle required. Connect the control lines of the seat front and rear, backrest pitch, seat cushion height, leg rest extension and leg rest pitch to the infrared remote control power box.

[0018] Step 3: Adjust the standard position of the car seat. The seat position includes three positions, namely sitting position, zero-gravity position, and self-selected comfortable position. Among them, the sitting position and zero-gravity position are standard definitions, and the self-selected comfortable position is the most comfortable position adjusted by the measurer himself. The seat angle is adjusted through the three-dimensional H-point device and the angle data is recorded and the H-point position is marked. The leg support and seat backrest angles are collected through the six-axis angle sensor in the standard position.

[0019] Step S4: posture data collection: using a TOF camera to measure and record the key position angles of the human body in three postures.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. By adjusting the relative position relationship of each part of the seat device, the device can meet the characteristics of various vehicles, and the seat comfort measurement can be carried out more comprehensively and systematically to improve the accuracy of the seat collection results.

[0022] 2. Through TOF camera recognition and intelligent algorithm calculation of key angles, the comfort posture parameters of the human body in the zero-gravity chair can be quickly and accurately obtained. It is simple to operate, highly economical and applicable, and meets the current human seat comfort measurement methods, improving convenience and reducing dependence on ambient light intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the overall structure assembly of a zero-gravity seat occupant sitting posture measurement system based on a TOF camera provided in an embodiment of the present application;

[0024] Figure 2 A schematic side view of a zero-gravity seat occupant sitting posture measurement system based on a TOF camera provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the seat rail connection structure provided in an embodiment of the present application;

[0026] Figure 4 A schematic diagram of the seat fixing platform structure provided in an embodiment of the present application;

[0027] Figure 5 This is a schematic diagram of human body posture collection marker points in the embodiment of this application;

[0028] Figure 6 This is a diagram of the YOLOv5 algorithm architecture in the embodiment of this application;

[0029] In the figure, 1-car seat, 2-seat fixing platform, 3-horizontal moving guide rail, 4-TOF camera, 5-vertical moving guide rail, 6-fixed base, 7-seat cushion, 8-leg support, 9-pressure plate, 10-seat guide rail connecting block, 11-support plate, 12-hydraulic support column, 13-bottom plate, 14-hydraulic support column control box, 15-bottom plate support column, 16-seat back, 17-H point mark one, 18-H point mark two, 19-12V voltage stabilized power supply, 20-support plate rotation center, 21-infrared remote control connection box, 22-wiring hole, 23-support plate bolt hole, 24-hydraulic support column connection end, 25-bottom plate two, 26-pressure plate bolt, 27-pressure plate bolt moving groove, 28-seat bolt moving groove. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected, set, or detachably connected, set, or integrally connected, set, and can refer to direct connection or indirect connection. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0033] See also Figure 1-Figure 5 The figure shows an embodiment structure provided by the present invention.

[0034] This embodiment provides a zero-gravity seat occupant sitting posture measurement system based on a TOF camera, including a car seat 1, a seat fixing platform 2 and a TOF camera 4;

[0035] The car seat comprises a seat back 16, a seat cushion 7, a leg rest 8, and a headrest; five concentric square identification marks are affixed to the car seat, which are respectively located at the center of the headrest, the upper end of the seat back, the rotation center of the seat back and the seat cushion, the rotation center of the seat cushion and the leg rest, and the end of the leg rest; the seat cushion 7 and the seat back 16 are respectively affixed with an H point mark 17 and an H point mark 2 18 for marking the H point position of the car seat;

[0036] The seat fixing platform 2 includes: a seat connection tool and a control console; the seat connection tool includes: a pressure plate 9, a seat guide connection block 10, and a pressure plate bolt 26; wherein, the pressure plate 9 is provided with a pressure plate bolt moving groove 27 for the pressure plate bolt 26 to cooperate and connect with the support plate bolt hole 23, thereby connecting the seat guide connection block 10 with the support plate 11; the seat guide connection block 10 is provided with a seat bolt moving groove 28 for assembling and connecting the seat guide bolt installed at the lower end of the car seat with the seat guide connection block 10, and is suitable for a variety of car seats through two seat guide connection blocks 10; after the seat guide connection block 10 is fixed to the car seat, it is fixed to the support plate 11 through four pressure plates 9; the control platform includes a support plate 11, a bottom plate 13, a hydraulic support column 12 and a hydraulic support column Control box 14, bottom plate support column 15, 12V voltage-stabilized power supply 19, support plate rotation center 20, infrared remote control power box 21, support plate bolt hole 23, hydraulic support column connection end 24, bottom plate two 25; a bottom plate support column 15 is respectively arranged at the four corners of the lower end of the bottom plate one 13, a mounting groove is arranged in the middle of the bottom plate one 13, a 12V voltage-stabilized power supply 19, an infrared remote control power box 21 and a hydraulic support column control box 14 are arranged on the bottom plate two 25 of the mounting groove, a hydraulic support column 12 is arranged at the upper end of the hydraulic support column control box 14, the hydraulic support column 12 is connected to the hydraulic support column connection end 24 installed on the support plate 11, one end of the support plate 11 is hingedly connected to the bottom plate one 13, and the hydraulic support column 12 is used for the support plate 11 to rotate around the support plate rotation center 20;

[0037] The TOF camera 4 is installed on a TOF camera fixing device.

[0038] In order to facilitate the adjustment of the seat's forward and backward, pitch, height and other functions, the seat control line is connected through the infrared remote control connection box, and the seat movement is controlled by infrared remote control. Since the installation angles of seats of different models are different when installed on the car, in order to facilitate the adjustment of the seat installation angle, a hydraulic support column is used for regulation. The hydraulic support column control box and the infrared remote control connection box control the angle of the support plate through infrared remote control.

[0039] Wherein, two groups of support plate bolt holes 23 are arranged on the support plate 11 .

[0040] Wherein, the infrared remote control connection box 21 is provided with a wiring hole 22 .

[0041] Among them, the TOF camera fixing device includes a horizontal movable guide rail 3, a vertical movable guide rail 5 and a fixed base 6, the fixed base 6 is provided with a vertical movable guide rail 5, the vertical movable guide rail 5 is provided with a horizontal movable guide rail 3, and the horizontal movable guide rail 3 is provided with a TOF camera 4.

[0042] In addition, a method for measuring the sitting posture of a zero-gravity seat occupant based on a TOF camera is characterized in that the method is performed using the above-mentioned system and includes the following steps:

[0043] Step 1: Screening of measurement personnel; 100 people in the 5th, 50th, and 95th percentiles were screened by height and weight, including 20 people in the 5th percentile, 60 people in the 50th percentile, and 20 people in the 95th percentile.

[0044] Step 2: Install the car seat. Place the car seat on the seat fixing platform through the seat rail connection block and fix the seat through the pressure plate. Adjust the hydraulic support column to make the seat angle meet the actual vehicle installation angle required. Connect the control lines of the seat front and rear, backrest pitch, seat cushion height, leg rest extension and leg rest pitch to the infrared remote control power box.

[0045] Step 3: Adjust the standard position of the car seat. The seat position includes three positions, namely sitting position, zero-gravity position, and self-selected comfortable position. Among them, the sitting position and zero-gravity position are standard definitions, and the self-selected comfortable position is the most comfortable position adjusted by the measurer himself. The seat angle is adjusted through the three-dimensional H-point device and the angle data is recorded and the H-point position is marked. The leg support and seat backrest angles are collected through the six-axis angle sensor in the standard position.

[0046] Step S4: posture data collection: using a TOF camera to measure and record the key position angles of the human body in three postures.

[0047] It should be noted that

[0048] (1) TOF camera selection

[0049] The TOF camera will emit a group of infrared light that is invisible to the human eye. When it encounters an object, it will be reflected back to the camera. By calculating the time difference or phase difference from emission to reflection back to the camera, the depth information of the object can be obtained. Therefore, the TOF camera can not only provide 2D data containing only grayscale information, but also provide depth information of pixels. The TOF information used in this experiment is as follows:

[0050]

[0051] (2) Marking point design

[0052] The marking points are concentric circles with a radius of 2 cm and concentric squares with a radius of 2 cm, which are used as seat marking points and human body marking points respectively. The outer part of the marking point is made of light-absorbing material, and the inner part is made of reflective material, which together form the shape of the marking point. Figure 2 and Figure 5 shown.

[0053] (3) Identification of key feature points

[0054] The key points are artificially defined in this experiment, and the purpose is to simulate the seat and human body shape through the key points, including the key points of the seat and the key points of the human body.

[0055] Seat key point selection:

[0056] Usually, a seat consists of four parts: leg rest, seat cushion, seat back and headrest. In order to simulate the seat shape and measure the angles between the various parts, we set five key points of the seat and then simulate these parts with lines between the key points. The five key points are shown in the figure.

[0057] Human body key point selection:

[0058] Select five key joints on the body to simulate the shape of the entire human body. These five key points are the tragus point, the acromion point, the anterior superior iliac spine point, the fibula point and the lateral malleolus point. It can describe the posture angles of the human body as a whole and each part in detail, including the angle of the neck, torso, thigh and calf. Figure 5 shown.

[0059] (4) Recognition algorithm design

[0060] On the 2D grayscale data provided by the TOF camera, the neural network yolov5s algorithm is used to identify the marker points, and then the center of the marker point is located through Hough transform to obtain the pixel coordinates of the key points. Further, the 3D position information of the key points in the camera coordinate system is obtained through the TOF characteristics. The distance information between two key points and the angle information between three key points are further obtained.

[0061] YOLOv5 is an open source single-stage target detection algorithm. The innovation of this invention is to adapt it to this experiment and use the Adam optimization algorithm to increase the algorithm's ability to recognize markers. The algorithm architecture is as follows Figure 6 As shown in the figure, the center point is located by Hough transform. First, the image is edge detected, and then the center of the marked point is obtained by mathematical calculation of the edge line.

[0062] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A zero-gravity seat occupant sitting posture measurement system based on TOF camera, characterized in that: It comprises a car seat (1), a seat fixing platform (2) and a TOF camera (4); The automobile seat comprises a seat back (16), a seat cushion (7), a leg rest (8), and a headrest; five concentric square identification marks are affixed to the automobile seat, which are respectively located at the center of the headrest, the upper end of the seat back, the rotation center of the seat back and the seat cushion, the rotation center of the seat cushion and the leg rest, and the end of the leg rest; the seat cushion (7) and the seat back (16) are respectively affixed with an H point mark 1 (17) and an H point mark 2 (18) for marking the H point position of the automobile seat; The seat fixing platform (2) comprises: a seat connection tool and a control console; the seat connection tool comprises: a pressure plate (9), a seat rail connection block (10), and a pressure plate bolt (26); wherein the pressure plate (9) is provided with a pressure plate bolt moving groove (27) for the pressure plate bolt (26) to be matched and connected with the support plate bolt hole (23), thereby connecting the seat rail connection block (10) with the support plate (11); the seat rail connection block (10) is provided with a seat bolt moving groove (28) for assembling and connecting the seat rail bolt installed at the lower end of the car seat with the seat rail connection block (10), and the two seat rail connection blocks (10) are suitable for a variety of car seats; after the seat rail connection block (10) is fixed to the car seat, it is fixed to the support plate (11) through four pressure plates (9); the control platform comprises a support plate (11), a bottom plate (13), a hydraulic support column (12) and a hydraulic support column control box (1 4), bottom plate support column (15), 12V voltage stabilized power supply (19), support plate rotation center (20), infrared remote control power connection box (21), support plate bolt hole (23), hydraulic support column connection end (24), bottom plate two (25); a bottom plate support column (15) is respectively arranged at the four corners of the lower end of the bottom plate one (13), a mounting groove is arranged in the middle of the bottom plate one (13), and a 12V voltage stabilized power supply (19) is arranged on the bottom plate two (25) of the mounting groove , an infrared remote control electrical box (21) and a hydraulic support column control box (14), wherein a hydraulic support column (12) is disposed at the upper end of the hydraulic support column control box (14), wherein the hydraulic support column (12) is connected to a hydraulic support column connection end (24) mounted on a support plate (11), wherein one end of the support plate (11) is hingedly connected to the bottom plate (13), and the support plate (11) is rotated around a rotation center (20) of the support plate through the hydraulic support column (12); The TOF camera (4) is installed on a TOF camera fixing device.

2. A zero-gravity seat occupant sitting posture measurement system based on a TOF camera according to claim 1, characterized in that: The support plate (11) is provided with two groups of support plate bolt holes (23).

3. The zero-gravity seat occupant sitting posture measurement system based on TOF camera according to claim 1 is characterized in that: The infrared remote control power connection box (21) is provided with a wiring hole (22).

4. The zero-gravity seat occupant sitting posture measurement system based on a TOF camera according to claim 1, characterized in that: The TOF camera fixing device comprises a horizontal movable guide rail (3), a vertical movable guide rail (5) and a fixed base (6); the fixed base (6) is provided with a vertical movable guide rail (5); the vertical movable guide rail (5) is provided with a horizontal movable guide rail (3); and the horizontal movable guide rail (3) is provided with a TOF camera (4).

5. A method for measuring the sitting posture of a zero-gravity seat occupant based on a TOF camera, characterized in that: The method is performed using a system as described in any one of claims 1 to 4, comprising the following: Step 1: Screening of surveyors; Step 2: Install the car seat. Place the car seat on the seat fixing platform through the seat rail connection block and fix the seat through the pressure plate. Adjust the hydraulic support column to make the seat angle meet the actual vehicle installation angle required. Connect the control lines of the seat front and rear, backrest pitch, seat cushion height, leg rest extension and leg rest pitch to the infrared remote control power box. Step 3: Adjust the standard position of the car seat. The seat position includes three positions, namely sitting position, zero-gravity position, and self-selected comfortable position. Among them, the sitting position and zero-gravity position are standard definitions, and the self-selected comfortable position is the most comfortable position adjusted by the measurer himself. The seat angle is adjusted through the three-dimensional H-point device and the angle data is recorded and the H-point position is marked. The leg support and seat backrest angles are collected through the six-axis angle sensor in the standard position. Step S4: posture data collection: using a TOF camera to measure and record the key position angles of the human body in three postures.

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