A face visual range calibration size frame, calibration method and system

Abstract

The present invention discloses a face visible range calibration size frame, a calibration method and a system, and relates to the field of vehicle measurement technology. The calibration size frame includes: a head fixing component, the head fixing component has a wearing space for accommodating the head of a person to be measured; a calibration frame, the calibration frame includes: a first calibration frame and a second calibration frame that are slidably connected; the first calibration frame is connected to the head fixing component; a scale is provided on the first calibration frame; a calibration frame is formed between the first calibration frame and the second calibration frame; when the second calibration frame moves relative to the first calibration frame, the area of ​​the calibration frame is changed to measure the face size of the person to be measured. The face visible range calibration size frame can effectively improve the measurement accuracy and authenticity of the face visible range, and is free from the dependence on the cooperation of the person to be measured.

Description

Technical Field

[0001] The present invention generally relates to the field of vehicle measurement technology, and in particular to a face visible range calibration size frame, a calibration method and a system. Background Art

[0002] With the continuous improvement of living standards, the number of cars is increasing, the degree of intelligence of cars is getting higher and higher, and the demand for automatic driving and identification of persons under test is also getting higher and higher. However, there is no standard face database for identification of persons under test in my country, which leads to the fact that we can only rely on the experience of staff to judge the visible range of faces.

[0003] Patent CN104834901B-A face detection method, device and system based on binocular stereo vision, which includes: judging whether the face is within the preset common field of view of the first camera and the second camera according to the face video data collected by the first camera and the second camera; if so, generating a face image depth map according to the face video data; judging whether the face image depth map constitutes a face three-dimensional structure map by preset three-dimensional structure classification rules; if so, prompting that the face is a live face. This patent adopts a depth map and uses the special structure of the face to distinguish between photo and video attacks, and can pass the liveness detection without the cooperation of the person being detected. However, the solution of this patent is to directly use the binocular camera to collect images, and the depth map finally obtained is only the approximate outline of the face, and the visible range area of ​​the face cannot be accurately obtained. Therefore, we propose a face visible range calibration size frame, calibration method and system to solve the above problems. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a face visible range calibration size frame, calibration method and system that can effectively improve the measurement accuracy and authenticity of the face visible range.

[0005] In a first aspect, the present invention provides a face visible range calibration size frame, comprising:

[0006] A head fixing assembly, wherein the head fixing assembly has a wearing space for accommodating the head of the person being tested;

[0007] A calibration frame, the calibration frame comprising: a first calibration frame and a second calibration frame which are slidably connected; the first calibration frame is connected to the head fixing assembly; a scale is provided on the first calibration frame; a calibration frame is formed between the first calibration frame and the second calibration frame;

[0008] When the second calibration frame moves relative to the first calibration frame, the area of ​​the calibration frame is changed to measure the face size of the person being measured.

[0009] According to the technical solution provided by the present invention, the head fixing assembly includes:

[0010] A first fixing belt, wherein two ends of the first fixing belt are respectively connected to two ends of a forehead fixer; the forehead fixer is connected to the first calibration frame;

[0011] A back-of-head fixing buckle, the back-of-head fixing buckle is sleeved on the first fixing belt;

[0012] A second fixing belt, two ends of which are respectively connected to the forehead fixer and the back of the head fixing buckle;

[0013] The wearing space is formed between the first fixing belt and the second fixing belt.

[0014] According to the technical solution provided by the present invention, the first calibration frame includes a first scale and a second scale arranged perpendicularly to each other; the second calibration frame includes a third scale and a fourth scale arranged perpendicularly to each other;

[0015] The second ruler is connected to the forehead fixer; the first ruler and the third ruler are connected via a locking assembly, and the second ruler and the fourth ruler are connected via a locking assembly.

[0016] According to the technical solution provided by the present invention, the locking assembly includes:

[0017] A first locking member, the first locking member comprising: a locking body, the locking body being provided with a first channel and a second channel which are perpendicular to each other and communicate with each other; the first channel and the second channel respectively allow the corresponding first scale and the third scale or the second scale and the fourth scale to pass through; the locking body is also provided with a locking through hole which is perpendicular to the extending directions of the first channel and the second channel, the locking through hole being communicated with the first channel and the second channel;

[0018] a second locking member, wherein the second locking member is disposed at the locking through hole;

[0019] When one end of the second locking member abuts against the corresponding scale, the relative positions of the first calibration frame and the second calibration frame are restricted.

[0020] The technical solution provided by the present invention also includes:

[0021] A support plate, wherein the support plate is arranged on the first scale, the third scale and the fourth scale, and all the support plates are located on the same side of the calibration frame;

[0022] When the calibration size frame is in use, the support plate is arranged corresponding to the cheek and the jaw of the person being measured.

[0023] In a second aspect, the present invention provides a method for calibrating a visible range of a face, comprising the following steps:

[0024] When the person under test wears the above-mentioned face visible range calibration size frame on his head, the deflection angle of the person under test's head is obtained, and a first photo is captured at the current deflection angle;

[0025] Based on the face visible range calibration size frame and the deflection angle, calculate a first size of the first photo; the first size includes the length and width of the projection of the face of the person being measured on the plane where the face visible range calibration size frame is located;

[0026] Calculating a visible range of a first face according to the first size;

[0027] Repeat the above steps to obtain the first face viewing range corresponding to multiple deflection angles.

[0028] According to the technical solution provided by the present invention, the deflection angle refers to the angle at which the face of the person being measured is deflected in the vertical direction relative to the image acquisition module;

[0029] Obtaining the deflection angle of the head of the person being measured specifically includes the following steps:

[0030] The vertical point where the midpoint of the image acquisition module falls on the ground is used as the first base point, the center point of the standing position of the measured person is used as the second base point, and the line connecting the first base point and the second base point is used as the first reference line, and the extended line passing through the second base point and perpendicular to the line connecting the pubic bone and the center of the eyebrows of the measured person is used as the second reference line;

[0031] The angle between the first reference line and the second reference line is collected as the deflection angle of the head of the measured person.

[0032] According to the technical solution provided by the present invention, the deflection angle refers to the angle at which the face of the person being measured is deflected in the horizontal direction relative to the image acquisition module;

[0033] Obtaining the deflection angle of the head of the person being measured specifically includes the following steps:

[0034] The deflection angle of the head of the person being measured is obtained by a horizontal goniometer.

[0035] According to the technical solution provided by the present invention, after obtaining the first face visible range corresponding to the multiple deflection angles, the following steps are also included:

[0036] Under the premise that the face visual range calibration size frame is not worn, collecting second photos corresponding to multiple deflection angles;

[0037] Identifying the pixel side length of the second photo, and calculating the corresponding visible range of the second face according to the pixel side length;

[0038] Generate a face visible range distribution map according to the multiple deflection angles, the first face visible range, and the second face visible range;

[0039] According to the face visible range distribution map, the accuracy of the first face visible range obtained based on the face visible range calibration size frame is analyzed.

[0040] In a third aspect, the present invention provides a face visual range calibration system, the system can implement the above method, the system comprising:

[0041] A data acquisition module, configured to obtain a deflection angle of the head of the person being measured when the person being measured wears the above-mentioned face visual range calibration size frame on his head;

[0042] An image acquisition module, configured to acquire a first photo at a current deflection angle;

[0043] A processing module configured to calculate a first size of the first photo based on the face visible range calibration size frame and the deflection angle; the first size includes a length and a width of a projection of the face of the person being measured on a plane where the face visible range calibration size frame is located;

[0044] The processing module is further configured to calculate the first face visible range according to the first size; repeat the above steps to obtain the first face visible range corresponding to multiple deflection angles.

[0045] In summary, the present invention discloses a specific structure of a face visual range calibration size frame. The present invention designs a head fixing component and a calibration frame, wherein the head fixing component is provided with a wearing space for accommodating the head of a person to be measured; the calibration frame comprises: a first calibration frame and a second calibration frame which are slidably connected, and the first calibration frame is connected to the head fixing component, the first calibration frame is provided with a scale, and a calibration frame is formed between the first calibration frame and the second calibration frame; when the second calibration frame moves relative to the first calibration frame, the area of ​​the calibration frame is changed to measure the face size of the person to be measured.

[0046] The present invention uses a head fixing component to wear the face visible range calibration size frame on the head of the person being measured, and then moves the second calibration frame to change the area of ​​the calibration frame to adapt to the face of the person being measured, and reads the face size of the person being measured according to the scale. The product of the face size is the face visible range. Compared with the existing method, the measurement accuracy of the face visible range calibration size frame is not subject to deviation due to the movement of the person being measured. Similarly, the person being measured does not need to make any specific movement to cooperate with the measurement. Therefore, the face visible range calibration size frame can effectively improve the measurement accuracy and authenticity of the face visible range, and is free from dependence on the cooperation of the person being measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Other features, objectives and advantages of the present invention will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0048] Figure 1 The figure is a schematic diagram of the overall structure of a face visible range calibration size frame.

[0049] Figure 2 This is a schematic diagram of the structure of a face visual range calibration size frame worn on the head of a person being measured.

[0050] Figure 3 It is a structural diagram of calculating the visible range of the first face when the deflection angle is 45°.

[0051] Figure 4 It is a schematic diagram of the structure for calculating the visible range of the second face when the deflection angle is 45°.

[0052] Figure 5 This is the distribution map of the visible range of faces.

[0053] Figure 6 The figure is a flowchart of a method for calibrating the visible range of a face.

[0054] Figure 7 This is a structural diagram of the face visual range calibration system.

[0055] Numbers in the figure: 1. Head fixing assembly; 101. First fixing strap; 102. Second fixing strap; 103. Back of head fixing buckle; 104. Forehead fixer; 2. Calibration frame; 201. First ruler; 202. Second ruler; 203. Third ruler; 204. Fourth ruler; 205. First locking piece; 206. Second locking piece; 207. Support plate; 3. Data acquisition module; 4. Image acquisition module; 5. Processing module. DETAILED DESCRIPTION

[0056] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0057] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0058] Example 1

[0059] Please refer to Figure 1 The overall structural diagram of a face visible range calibration size frame provided by the present invention is shown, and the face visible range calibration size frame includes:

[0060] A head fixing component 1, wherein the head fixing component 1 has a wearing space for accommodating the head of the person being tested;

[0061] Wherein, the head fixing assembly 1 comprises:

[0062] A first fixing belt 101, two ends of which are respectively connected to two ends of a forehead fixer 104; the forehead fixer 104 is connected to a first calibration frame;

[0063] A back-head fixing buckle 103, which is sleeved on the first fixing belt 101;

[0064] A second fixing belt 102, two ends of which are respectively connected to a forehead fixing device 104 and a back head fixing buckle 103;

[0065] A wearing space is formed between the first fixing belt 101 and the second fixing belt 102 .

[0066] Specifically, the two ends of the first fixing belt 101 are respectively connected to the two ends of the forehead fixer 104, so that the first fixing belt 101 and the forehead fixer 104 form a ring structure, and the two ends of the second fixing belt 102 are respectively connected to the forehead fixer 104 and the back of the head fixing buckle 103, so that the wearing space of the head fixing component 1 can form a hemispherical shape so as to be worn on the head of the measured person, and the back of the head fixing buckle 103 can slide on the first fixing belt 101, such as Figure 2 As shown, when the head fixing assembly 1 is worn on the heads of different persons being measured, the second fixing strap 102 can always be located in the middle of the head, so that the first fixing strap 101 and the second fixing strap 102 can be stably placed on the head; in addition, the forehead fixer 104 is also connected to the first calibration frame to support and fix the first calibration frame.

[0067] in Figure 2 Where a and b respectively represent the length value and width value that can be read at the calibration frame 2 in the front view condition, and the visible area of ​​the face in the front view can be calculated based on the read length and width values.

[0068] Here, in order to allow the head fixing assembly 1 to adapt to different head circumferences, the first fixing belt 101 and the second fixing belt 102 can be designed to be made of elastic material.

[0069] The calibration frame 2 includes: a first calibration frame and a second calibration frame which are slidably connected; the first calibration frame is connected to the head fixing assembly 1; a scale is provided on the first calibration frame; a calibration frame is formed between the first calibration frame and the second calibration frame;

[0070] Among them, Figure 1 As shown, the first calibration frame includes a first scale 201 and a second scale 202 which are arranged perpendicularly to each other; the second calibration frame includes a third scale 203 and a fourth scale 204 which are arranged perpendicularly to each other;

[0071] The second ruler 202 is connected to the forehead fixer 104; the first ruler 201 and the third ruler 203 are connected via a locking assembly, and the second ruler 202 and the fourth ruler 204 are connected via a locking assembly.

[0072] It should be noted that the first calibration frame and the second calibration frame are both one-piece structures. The first scale 201, the second scale 202, the third scale 203 and the fourth scale 204 are scale structures of the same material, and "first", "second", "third" and "fourth" are only used to distinguish each scale, and do not impose any restrictions on the scales. In addition, the second calibration frame can move relative to the first calibration frame, change the size of the calibration frame, so as to frame the face boundary frame, and then read the face size data according to the scale on the first calibration frame.

[0073] Here, if Figure 2 As shown, the face bounding box is a bounding box formed by the extension line of the upper edge of the eyebrows, the extension line of the inner sides of the left and right ears, and the extension line of the lower edge of the chin. The accuracy of the scale is, for example, 0.5 mm, which is used to ensure the accuracy of the visible range of the face.

[0074] Furthermore, if Figure 1 As shown, the locking assembly includes:

[0075] The first locking member 205 includes: a locking body, on which a first channel and a second channel are provided, which are perpendicular to each other and communicate with each other; the first channel and the second channel allow the corresponding first scale 201 and the third scale 203 or the second scale 202 and the fourth scale 204 to pass through respectively; the locking body also has a locking through hole which is perpendicular to the extension direction of the first channel and the second channel, and the locking through hole communicates with the first channel and the second channel;

[0076] A second locking member 206, the second locking member 206 is disposed at the locking through hole;

[0077] When one end of the second locking member 206 abuts against the corresponding scale, the relative position of the first calibration frame and the second calibration frame is restricted.

[0078] When the second calibration frame moves relative to the first calibration frame, the area of ​​the calibration frame is changed to measure the face size of the person being measured.

[0079] like Figure 1 As shown, the first scale 201 and the third scale 203 respectively pass through the first channel and the second channel of the same first locking member 205 , and the second scale 202 and the fourth scale 204 respectively pass through the first channel and the second channel of the same first locking member 205 .

[0080] The connection method between the second locking piece 206 and the locking through hole is, for example, an internal thread is arranged on the inner wall of the locking through hole, the second locking piece 206 is designed as a columnar structure, and an external thread is arranged on its outer wall, the external thread and the internal thread can cooperate with each other, and the second locking piece 206 can rotate relative to the locking through hole; when the second locking piece 206 and the corresponding scale are completely out of contact, the corresponding scale can move relatively, and when the second locking piece 206 is against the surface of the corresponding scale, it can lock the current relative position of the first calibration frame and the second calibration frame.

[0081] Furthermore, if Figure 1 As shown, it also includes:

[0082] A support plate 207, wherein the support plate 207 is disposed on the first scale 201, the third scale 203 and the fourth scale 204, and all the support plates 207 are located on the same side of the calibration frame 2;

[0083] When the calibration size frame is in use, the support plate 207 is arranged corresponding to the cheek and the jaw of the person being measured.

[0084] The support plate 207 serves as a reference plate and guides the movement of the first scale 201 , the third scale 203 or the fourth scale 204 .

[0085] Specifically, the head fixing assembly 1 is worn on the head of the person being measured, and the elastic force of the first fixing belt 101 and the second fixing belt 102 is used to allow the deformation of the first fixing belt 101 and the second fixing belt 102 to make the length direction of the second ruler 202 parallel to the extension line of the upper edge of the eyebrow, and at the same time, the support plate 207 on the first ruler 201 is in contact with the inner side of the adjacent ear, and then the second calibration frame is moved. Here, the second calibration frame can move in two directions, one is the length direction of the third ruler 203, and the other is the length direction of the fourth ruler 204. Figure 2 As shown, the two directions are the vertical direction and the horizontal direction respectively. The second calibration frame moves in any one direction and then moves in the other direction. For example, the second calibration frame moves in the vertical direction first until the support plate 207 on the third scale 203 contacts the jaw of the measured person, and then the second calibration frame moves in the horizontal direction until the support plate 207 on the fourth scale 204 contacts the inner side of the ear adjacent thereto, and then the current positions of the first calibration frame and the second calibration frame are restricted by two locking components; in the calibration frame formed by the first calibration frame and the second calibration frame, the face size, i.e., the length and width of the face, is read; the product of the length and the width is the visible range of the face.

[0086] Here, the face visible range refers to the area obtained by multiplying the length and width of the face when it is facing forward. Figure 4 The face is deflected 45 degrees relative to the image acquisition module. The corresponding length and width are calculated according to the scale on the calibration frame and the deflection angle. The visible range of the face is calculated by multiplying the length and width.

[0087] The existing method of recognizing the visible range of a face mainly relies on the experience of the staff to make judgments, or requires the tested person to cooperate with the movement before the face visible range is recognized. On the one hand, there are differences in the face visible range judged based on experience, resulting in poor measurement accuracy of the face visible range. On the other hand, the person's head and face need to move together during measurement, which affects the person's experience and measurement accuracy.

[0088] The present invention designs a face visible range calibration size frame, which is worn on the head using a head fixing component 1, and then the calibration frame 2 is moved to form a calibration frame adapted to the face of the corresponding person being measured. The size is read through the scale on the first calibration frame to calculate the face visible range. Compared with the existing method, the measurement accuracy of the face visible range calibration size frame is not affected by the movement of the person being measured. Similarly, the person being measured does not need to make any specific movement to cooperate with the measurement. Therefore, the face visible range calibration size frame can effectively improve the measurement accuracy and authenticity of the face visible range, and is free from dependence on the cooperation of the person being measured.

[0089] Example 2

[0090] like Figure 6 As shown, the present invention provides a method for calibrating the visible range of a face, comprising the following steps:

[0091] S10, when the person under test wears the face visible range calibration size frame described in Example 1 on his head, obtaining the deflection angle of the person under test's head, and capturing a first photo at the current deflection angle;

[0092] It should be noted that there are two definitions of the deflection angle of the head of the person being measured, and different acquisition methods are provided for deflection angles with different definitions.

[0093] The first type, the deflection angle, refers to the angle of the measured person's face deflected in the vertical direction relative to the image acquisition module; the vertical direction here refers to Figure 2 The vertical direction in the figure; the definition of this deflection angle corresponds to the overall deflection of the person being measured.

[0094] Obtaining the deflection angle of the head of the person being measured specifically includes the following steps:

[0095] The vertical point where the midpoint of the image acquisition module 4 falls on the ground is used as the first base point, the center point of the standing position of the measured person is used as the second base point, and the line connecting the first base point and the second base point is used as the first reference line, and the extension line passing through the second base point and perpendicular to the line connecting the pubic bone and the center of the eyebrows of the measured person is used as the second reference line;

[0096] The angle between the first reference line and the second reference line is collected as the deflection angle of the head of the measured person.

[0097] The second type, the deflection angle, refers to the angle at which the face of the person being measured deflects horizontally relative to the image acquisition module; the horizontal direction here refers to Figure 2 The horizontal direction in the figure; the definition of this deflection angle corresponds to the person being measured lowering / raising his head.

[0098] Obtaining the deflection angle of the head of the person being measured specifically includes the following steps:

[0099] The deflection angle of the head of the person being measured is obtained by a horizontal goniometer.

[0100] The deflection angle is, for example, 5°, and the deflection angle can be set according to actual needs. Figure 3 This is a schematic diagram of the structure for calculating the visible range of the first face when the deflection angle is 45°. Figure 3 Where a' represents the length of the face, b' represents the width of the face, and s' represents the visible range of the first face.

[0101] In this embodiment, the deflection angle is defined in the first manner.

[0102] S20. Calculate a first size of the first photo based on the face visible range calibration size frame and the deflection angle; the first size includes the length and width of the projection of the face of the person being measured on the plane where the face visible range calibration size frame is located.

[0103] S30, calculating the visible range of the first face according to the first size;

[0104] Specifically, the visible range of the first face corresponding to the current deflection angle is calculated based on the product of the length and width of the face. Figure 3 As shown, a' can be directly read on the calibration size frame, and b' can be calculated based on the scale on the calibration size frame and the deflection angle.

[0105] S40, repeat the above steps to obtain the first face visible range corresponding to multiple deflection angles;

[0106] Furthermore, after obtaining the first face visible range corresponding to the multiple deflection angles, the method further includes the following steps:

[0107] Under the premise that the face visual range calibration size frame is not worn, second photos corresponding to multiple deflection angles are collected;

[0108] Identify the pixel side length of the face of the person under test in the second photo, and calculate the corresponding visible range of the second face according to the pixel side length;

[0109] The pixel side length of the face of the person under test in the second photo can be identified using the size tool of the image processing software (Photo Shop, PS), for example, Figure 4 This is a schematic diagram of the structure for calculating the visible range of the second face when the deflection angle is 45°. Figure 4 Where a and b represent the side lengths of two adjacent pixels respectively. The visible range of the second face is calculated based on the product of the side lengths of the two pixels.

[0110] Generate a face visible range distribution map according to the multiple deflection angles, the first face visible range, and the second face visible range;

[0111] Among them, the distribution diagram of face visible range is as follows: Figure 5 shown.

[0112] According to the face visible range distribution map, the accuracy of the first face visible range obtained based on the face visible range calibration size frame is analyzed.

[0113] Specifically, Figure 5The angle difference between adjacent deflection angles is, for example, 5°. In the line graph, Da represents the deflection angle, S represents the visible range of the face, s represents the visible range of the second face, and s' represents the visible range of the first face. Before the deflection angle of 45°, as the deflection angle increases, the area of ​​s' decreases exponentially, but after the deflection angle exceeds 45°, as the deflection angle increases, the area decreases exponentially less than before the deflection angle of 45°, and the area of ​​s is always greater than the area of ​​s', but the data change of s is completely opposite to that of s'. It can be seen from this that the difference between the visible range area of ​​the face calculated by conventional means (PS method) and the visible range area of ​​the face calculated by the present invention is quite large, which further reflects that the measurement method of the present invention is more authentic and accurate.

[0114] Example 3

[0115] like Figure 7 As shown, the present invention provides a face visual range calibration system, which can implement the method described in Example 2, and the system includes:

[0116] The data acquisition module 3 is configured to obtain the deflection angle of the head of the person being measured when the person being measured wears a face visual range calibration size frame described in Example 1 on his head;

[0117] An image acquisition module 4 is configured to acquire a first photo at a current deflection angle;

[0118] Processing module 5 is configured to calculate a first size of the first photo based on the face visible range calibration size frame and the deflection angle; the first size includes the length and width of the projection of the face of the person being measured on the plane where the face visible range calibration size frame is located;

[0119] The processing module 5 is further configured to calculate the first face visible range according to the first size; repeat the above steps to obtain the first face visible range corresponding to multiple deflection angles.

[0120] The type of the data acquisition module 3 is, for example, an angle measuring instrument; the type of the image acquisition module 4 is, for example, a camera; and the type of the processing module 5 is, for example, an electronic control unit (ECU).

[0121] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present invention (but not limited to) to form a technical solution.

Claims

1. A method for calibrating the visible range of a face, characterized in that: The following steps are involved: When a person under test wears a face visible range calibration size frame on his head, the deflection angle of the person under test's head is obtained, and a first photo is captured at the current deflection angle; the face visible range calibration size frame comprises: a head fixing component (1), the head fixing component (1) having a wearing space for accommodating the head of the person under test; a calibration frame (2), the calibration frame (2) comprising: a first calibration frame and a second calibration frame slidably connected; the first calibration frame is connected to the head fixing component (1); a scale is provided on the first calibration frame; a calibration frame is formed between the first calibration frame and the second calibration frame; when the second calibration frame moves relative to the first calibration frame, the area of ​​the calibration frame is changed to measure the face size of the person under test; Based on the face visible range calibration size frame and the deflection angle, calculate a first size of the first photo; the first size includes the length and width of the projection of the face of the person being measured on the plane where the face visible range calibration size frame is located; Calculating a visible range of a first face according to the first size; Repeat the above steps to obtain the first face viewing range corresponding to multiple deflection angles.

2. A method for calibrating the visible range of a face according to claim 1, characterized in that: The deflection angle refers to the angle at which the face of the person being measured deflects in the vertical direction relative to the image acquisition module; Obtaining the deflection angle of the head of the person being measured specifically includes the following steps: The vertical point where the midpoint of the image acquisition module falls on the ground is used as the first base point, the center point of the standing position of the measured person is used as the second base point, and the line connecting the first base point and the second base point is used as the first reference line, and the extended line passing through the second base point and perpendicular to the line connecting the pubic bone and the center of the eyebrows of the measured person is used as the second reference line; The angle between the first reference line and the second reference line is collected as the deflection angle of the head of the measured person.

3. The method for calibrating the visible range of a face according to claim 1, characterized in that: After obtaining the first face visible range corresponding to the multiple deflection angles, the following steps are also included: Under the premise that the face visual range calibration size frame is not worn, collecting second photos corresponding to multiple deflection angles; Identify the pixel side length of the face of the person being measured in the second photo, and calculate the corresponding visible range of the second face according to the pixel side length; Generate a face visible range distribution map according to the multiple deflection angles, the first face visible range, and the second face visible range; According to the face visible range distribution map, the accuracy of the first face visible range obtained based on the face visible range calibration size frame is analyzed.

4. The method for calibrating the visible range of a face according to claim 1, characterized in that: The head fixing assembly (1) comprises: A first fixing belt (101), wherein two ends of the first fixing belt (101) are respectively connected to two ends of a forehead fixer (104); the forehead fixer (104) is connected to the first calibration frame; A back-of-head fixing buckle (103), wherein the back-of-head fixing buckle (103) is sleeved on the first fixing belt (101); A second fixing belt (102), wherein two ends of the second fixing belt (102) are respectively connected to the forehead fixer (104) and the back of the head fixing buckle (103); The wearing space is formed between the first fixing belt (101) and the second fixing belt (102).

5. The method for calibrating the visible range of a face according to claim 4, characterized in that: The first calibration frame comprises a first scale (201) and a second scale (202) which are arranged perpendicular to each other; the second calibration frame comprises a third scale (203) and a fourth scale (204) which are arranged perpendicular to each other; The second ruler (202) is connected to the forehead fixer (104); the first ruler (201) and the third ruler (203) are connected via a locking assembly, and the second ruler (202) and the fourth ruler (204) are connected via a locking assembly.

6. A method for calibrating the visible range of a face according to claim 5, characterized in that: The locking assembly comprises: A first locking member (205), the first locking member (205) comprising: a locking body, the locking body being provided with a first channel and a second channel which are perpendicular to each other and communicate with each other; the first channel and the second channel respectively allow the corresponding first scale (201) and the third scale (203) or the second scale (202) and the fourth scale (204) to pass through; the locking body is also provided with a locking through hole which is perpendicular to the extension direction of the first channel and the second channel, the locking through hole being communicated with the first channel and the second channel; A second locking member (206), the second locking member (206) being arranged at the locking through hole; When one end of the second locking member (206) abuts against the corresponding scale, the relative position of the first calibration frame and the second calibration frame is restricted.

7. The method for calibrating the visible range of a face according to claim 5, characterized in that: Also includes: a support plate (207), the support plate (207) being arranged on the first scale (201), the third scale (203) and the fourth scale (204), and all the support plates (207) being located on the same side of the calibration frame (2); When the calibration size frame is in use, the support plate (207) is arranged corresponding to the cheek and jaw of the person being measured.

8. A face visual range calibration system, characterized in that: The system can implement the method described in any one of claims 1 to 7, and the system comprises: A data acquisition module, configured to obtain a deflection angle of the head of the person being measured when the person being measured wears the face visual range calibration size frame on his head; An image acquisition module, configured to acquire a first photo at a current deflection angle; A processing module configured to calculate a first size of the first photo based on the face visible range calibration size frame and the deflection angle; the first size includes a length and a width of a projection of the face of the person being measured on a plane where the face visible range calibration size frame is located; The processing module is further configured to calculate the first face visible range according to the first size; repeat the above steps to obtain the first face visible range corresponding to multiple deflection angles.

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