CN112013810A

CN112013810A - Distance measurement method, device and equipment

Info

Publication number: CN112013810A
Application number: CN202010844943.8A
Authority: CN
Inventors: 翟云峰
Original assignee: Hangzhou Hikmicro Sensing Technology Co Ltd
Current assignee: Hangzhou Hikmicro Sensing Technology Co Ltd
Priority date: 2020-08-20
Filing date: 2020-08-20
Publication date: 2020-12-01

Abstract

The application provides a distance measuring method, a distance measuring device and distance measuring equipment, wherein the method comprises the following steps: acquiring an image acquired by the camera, and stopping rotating the holder if the image comprises a target object and the target object is located at a specified position in the image; after the tripod head stops rotating, acquiring an acceleration value generated by an acceleration sensor; determining a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the acceleration value; determining a second angle between the visual axis of the camera and the horizontal direction according to the first angle and the stored installation deviation angle; wherein the installation deviation angle is an angle difference between the angle of the acceleration sensor installation plane and the horizontal direction and the angle of the camera visual axis and the horizontal direction; and determining the horizontal distance between the target object and the image acquisition equipment according to the second angle and the installation height of the image acquisition equipment. According to the technical scheme, the accuracy of target object detection can be improved.

Description

Distance measurement method, device and equipment

Technical Field

The present application relates to the field of image processing technologies, and in particular, to a distance measurement method, apparatus, and device.

Background

For an image acquisition device with a visible light camera and a thermal imaging camera deployed at the same time, a visible light image and a thermal imaging image can be acquired at the same time. For example, the visible light camera is used for collecting a visible light image, the visible light image is an image in a range of visible light (the visible light is a part which can be perceived by human eyes in an electromagnetic spectrum, for example, the wavelength is between 400 nm and 760 nm), and the visible light image is an image which can be seen by human eyes and contains abundant spectral information. The thermal imaging camera is used to acquire a thermal imaging image, which is not an image in the visible range, but an image related to the temperature of the surface of the object. For example, an object in nature may radiate infrared rays, and by detecting a specific waveband signal of the infrared rays, the signal is converted into an image which can be distinguished by human eyes, and the image is a thermal imaging image which can reflect a temperature value of the surface of the object.

The image acquisition equipment can detect whether a fire point (namely an ignition point) exists in a scene based on the visible light image and the thermal imaging image, and if so, alarm information is output to a user so that the user can timely know that the fire point exists in the scene, and greater economic loss is avoided. When a fire point exists in a scene, a user can arrive at the scene in time and find the position of the fire point. However, in some complex scenes, such as mountain forests, if the distance between the fire point and the image capturing device is relatively long, the user cannot find the fire point.

Disclosure of Invention

The application provides a distance measuring method, which is applied to image acquisition equipment, wherein the image acquisition equipment at least comprises a holder, a camera and an acceleration sensor; wherein the camera is fixed to the pan/tilt head and the acceleration sensor is fixed to the pan/tilt head, the method comprising:

acquiring an image acquired by the camera, and stopping rotating the holder if the image comprises a target object and the target object is located at a specified position in the image;

after the tripod head stops rotating, acquiring an acceleration value generated by the acceleration sensor;

determining a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the acceleration value;

determining a second angle between the visual axis of the camera and the horizontal direction according to the first angle and the stored installation deviation angle; wherein the installation deviation angle is an angle difference between the angle of the acceleration sensor installation plane and the horizontal direction and the angle of the camera visual axis and the horizontal direction;

and determining the horizontal distance between the target object and the image acquisition equipment according to the second angle and the installation height of the image acquisition equipment.

In one possible embodiment, the acceleration sensor comprises a three-axis acceleration sensor, the acceleration value produced by the three-axis acceleration sensor comprising: acceleration value in X-axis direction, acceleration value in Y-axis direction and acceleration value in Z-axis direction; the determining a first angle between an acceleration sensor mounting plane and a horizontal direction according to the acceleration value includes:

and determining the first angle according to the acceleration value in the Y-axis direction and the acceleration value in the Z-axis direction.

In one possible embodiment, the determining a second angle of the camera viewing axis from the horizontal direction according to the first angle and the stored installation deviation angle includes:

determining an angle difference between the first angle and the installation deviation angle as the second angle.

In a possible embodiment, the determining a horizontal distance between the target object and the image capturing device according to the second angle and the installation height of the image capturing device includes:

determining a tangent value of the second angle; determining a quotient between the installation height and the tangent value as a horizontal distance between the target object and the image acquisition device.

In a possible implementation, after the acquiring the image captured by the camera, the method further includes: if the image comprises the target object and the target object is not located at the designated position in the image, continuing to rotate the holder until the image acquired by the camera comprises the target object and the target object is located at the designated position in the image; alternatively, the first and second electrodes may be,

and if the image does not comprise the target object, continuing to rotate the holder until the image acquired by the camera comprises the target object, and the target object is positioned at the specified position in the image.

In a possible embodiment, said determining a first angle of an acceleration sensor mounting plane from a horizontal direction based on said acceleration values comprises:

performing median filtering on N groups of acceleration values generated by the acceleration sensor to obtain filtered acceleration values, wherein N is a positive integer greater than 1, and determining a target acceleration value based on the filtered acceleration values;

and determining a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the target acceleration value.

In a possible embodiment, before the image capturing device leaves factory, the image capturing device is placed on a horizontal table, and a collimator is placed on the horizontal table, light rays of the collimator are in a horizontal direction, and the obtaining manner of the installation deviation angle includes:

rotating the holder to align the visual axis of the camera with the collimator, wherein the center of the image picture of the camera is superposed with the target of the collimator;

and acquiring an acceleration value generated by the acceleration sensor, determining a third angle between an installation plane of the acceleration sensor and the horizontal direction according to the acceleration value, and determining the third angle as the installation deviation angle.

In one possible embodiment, the image capturing device further comprises a non-volatile storage medium, and after determining the third angle as the installation deviation angle, the method further comprises:

saving the installation deviation angle to the non-volatile storage medium;

before determining a second angle of the camera's visual axis from the horizontal direction based on the first angle and the stored mounting deviation angle, the method further comprises:

reading the mounting deviation angle from the non-volatile storage medium.

The application provides a distance measuring device, which is applied to image acquisition equipment, wherein the image acquisition equipment at least comprises a holder, a camera and an acceleration sensor; wherein, the camera is fixed the cloud platform, just acceleration sensor fixes the cloud platform, the device includes:

the acquisition module is used for acquiring an image acquired by the camera, and if the image comprises a target object and the target object is located at a specified position in the image, the rotation of the holder is stopped;

the first determining module is used for acquiring an acceleration value generated by the acceleration sensor after the pan-tilt stops rotating, and determining a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the acceleration value;

the second determining module is used for determining a second angle between the visual axis of the camera and the horizontal direction according to the first angle and the stored installation deviation angle; wherein the installation deviation angle is an angle difference between the angle of the acceleration sensor installation plane and the horizontal direction and the angle of the camera visual axis and the horizontal direction;

and the third determining module is used for determining the horizontal distance between the target object and the image acquisition equipment according to the second angle and the installation height of the image acquisition equipment.

The application provides an image acquisition device, includes: the system comprises a tripod head, a camera, an acceleration sensor, a processor and a machine-readable storage medium, wherein the camera is fixed on the tripod head, the acceleration sensor is fixed on the tripod head, and the machine-readable storage medium stores machine-executable instructions capable of being executed by the processor;

the processor is configured to execute machine executable instructions to perform the steps of:

According to the technical scheme, in the embodiment of the application, a first angle between an installation plane of the acceleration sensor and the horizontal direction can be determined based on the acceleration value, a second angle between a visual axis of the camera and the horizontal direction can be determined according to the first angle and the installation deviation angle, and the horizontal distance between the target object and the image acquisition equipment can be determined according to the second angle and the installation height of the image acquisition equipment. When the target object is the fire point, the horizontal distance between the fire point and the image acquisition equipment can be accurately detected by the method, the position of the fire point is analyzed according to the horizontal distance, the accuracy of fire point detection can be improved, the position of the fire point is conveniently and quickly positioned, and the deviation problem of fire point distance measurement is avoided.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments of the present application or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art according to the drawings of the embodiments of the present application.

FIG. 1A is a schematic view of an installation deviation angle of an acceleration sensor and a pan/tilt head;

FIG. 1B is a schematic illustration of the acquisition process of the installation deviation angle;

FIG. 2 is a schematic flow chart of a ranging method according to an embodiment of the present application;

FIG. 3 is a schematic illustration of a determination of a first angle of an acceleration sensor from a horizontal direction;

FIG. 4 is a schematic view of a second angle of the pan/tilt head from horizontal;

FIG. 5 is a schematic flow chart of a ranging method according to another embodiment of the present application;

FIG. 6 is a schematic structural diagram of a distance measuring device according to an embodiment of the present application;

fig. 7 is a hardware configuration diagram of an image capturing apparatus according to an embodiment of the present application.

Detailed Description

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein is meant to encompass any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe various information, the information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. Depending on the context, moreover, the word "if" as used may be interpreted as "at … …" or "when … …" or "in response to a determination".

The embodiment of the application provides a distance measuring method, which is applied to an image acquisition device, wherein the image acquisition device can include but is not limited to a pan-tilt, a camera and an acceleration sensor (also can be called as an accelerometer).

For example, the camera may be fixed to the pan/tilt head, i.e. the positional relationship between the camera and the pan/tilt head does not change. The cloud platform can the rotation about, and the cloud platform also can the tilting, and when the cloud platform rotated, the camera also can rotate along with the cloud platform, for example, when the cloud platform rotated to the left, then the camera also rotated along with the leftwards, when the cloud platform upwards rotated, then the camera also rotated along with upwards. In summary, by controlling the rotation direction of the pan/tilt head, the camera is rotated towards the direction, and then the camera captures images at different positions.

Illustratively, the acceleration sensor is fixed on the tripod head, that is, the position relationship between the acceleration sensor and the tripod head is not changed, and the camera is also fixed on the tripod head, that is, the position relationship between the camera and the tripod head is not changed. Therefore, the positional relationship between the acceleration sensor and the camera does not change, that is, the angle between the acceleration sensor mounting plane and the horizontal direction and the angle between the camera visual axis and the horizontal direction do not change, that is, the angle difference between the acceleration sensor mounting plane and the horizontal direction is fixed, and the angle difference is defined as the mounting deviation angle θ₀。

Referring to FIG. 1A, the angle difference between the horizontal direction and the horizontal direction of the mounting plane of the acceleration sensor and the horizontal direction and the angle between the visual axis of the camera and the horizontal direction, i.e. the mounting deviation angle θ₀。

For example, before the image capture device is shipped from factory, the installation deviation angle θ between the installation plane of the acceleration sensor and the visual axis of the camera needs to be obtained₀And will install the deviation angle theta₀The type of the nonvolatile storage medium is not limited, and the nonvolatile storage medium may be a FLASH memory, or other types of nonvolatile storage media.

To obtain a mounting deviation angle theta₀The image acquisition equipment can be placed on the horizontal table, the collimator is placed on the horizontal table, the light of the collimator is in the horizontal direction, the camera visual axis is aligned to the collimator through rotating the holder, and the center of the image picture of the camera is overlapped with the target of the collimator. On the basis, an acceleration value generated by the acceleration sensor is obtained, a third angle between the installation plane of the acceleration sensor and the horizontal direction is determined according to the acceleration value, and the third angle is determined as an installation deviation angle theta₀。

The following is combined with FIG. 1BApplication scenario to installation deviation angle θ₀The acquisition process of (a) will be explained.

Step a1, placing the collimator on a horizontal table, wherein the light of the collimator is in the horizontal direction.

For example, referring to fig. 1B, the light rays emitted from the collimator are adjusted to be horizontal to the ground (i.e. the light rays of the collimator are in the horizontal direction), and then the collimator is placed on a horizontal table through a bracket (the bracket is not shown in fig. 1B), on the basis of which the light rays of the collimator are in the horizontal direction.

The collimator is an optical instrument for generating parallel light beams, can be used for the linearity inspection of moving workpieces, is an important tool for adjusting the optical instrument, and is also an important component in an optical measuring instrument. In this embodiment, the light direction (i.e., horizontal direction) of the collimator is used as a reference for correcting the pitch angle of the pan/tilt head.

Step a2, placing the image acquisition equipment on a horizontal table, and enabling the visual axis of the camera to be aligned with the collimator by rotating the holder, wherein the center of the image picture of the camera is overlapped with the target of the collimator.

Illustratively, referring to FIG. 1B, the image capture device is placed on a horizontal stage with the image capture device facing the collimator, i.e., with the camera axis of the camera disposed at the image capture device aligned with the collimator.

And the pitch angle of the camera is synchronously adjusted by adjusting the pitch angle of the holder, so that the center of an image picture of the camera is superposed with the target of the collimator tube. Since the light of the collimator is in the horizontal direction, when the center of the image frame of the camera coincides with the target of the collimator, the direction in which the optical axis of the visible light of the camera (i.e., the camera visual axis) is aligned is in the horizontal direction, i.e., the angle between the camera visual axis and the horizontal direction is 0 degree.

Before the pitch angle of the tripod head is adjusted, the visible light multiplying power of the camera can be adjusted to the maximum visible light multiplying power, and the pitch angle of the tripod head is adjusted after the visible light multiplying power is adjusted to the maximum visible light multiplying power.

Aiming at the process of adjusting the pitch angle of the tripod head, the tripod head can be rotated up and down to adjust the pitch angle of the tripod head, and then the pitch angle of the camera is synchronously adjusted. For example, the amplitude of the up-and-down rotating holder is controlled by adjusting the value T of the holder, and then the pitch angle of the holder is adjusted, which is not repeated.

Step a3, the image acquisition equipment acquires an acceleration value generated by the acceleration sensor, determines a third angle between the installation plane of the acceleration sensor and the horizontal direction according to the acceleration value, and determines the third angle as an installation deviation angle theta₀。

For example, after the camera viewing axis is aligned with the collimator and the center of the image frame of the camera coincides with the target of the collimator, the image capture device may stop rotating the pan/tilt head. After the rotation of the holder is stopped, the image acquisition equipment acquires an acceleration value generated by the acceleration sensor, and determines a third angle between the installation plane of the acceleration sensor and the horizontal direction according to the acceleration value, wherein the third angle is also called a horizontal inclination angle.

For example, after the camera visual axis of the camera is aligned with the collimator and the center of the image frame of the camera coincides with the target of the collimator, the user sends the installation deviation angle θ to the image acquisition device through the terminal device (such as a personal computer, a mobile terminal, a laptop, a smart phone, etc.)₀The acquisition command of (1). And after receiving the acquisition command, the image acquisition equipment stops rotating the holder, acquires an acceleration value generated by the acceleration sensor, and determines a third angle between the acceleration sensor and the horizontal direction installation plane according to the acceleration value.

After the image acquisition equipment determines a third angle between the installation plane of the acceleration sensor and the horizontal direction, an execution result is returned to the terminal equipment, and the execution result indicates that the installation deviation angle theta is successfully acquired₀。

Illustratively, referring to the above embodiment, the angle between the acceleration sensor mounting plane and the horizontal direction is the third angle, and the angle between the camera viewing axis and the horizontal direction is 0 degree, so the angle between the acceleration sensor mounting plane and the horizontal direction (i.e., the third angle) and the angle between the camera viewing axis and the horizontal direction (i.e., 0 degree)) The angle difference therebetween is a third angle (i.e., the difference between the third angle and 0 degrees), and therefore, the third angle can be used as the installation deviation angle θ between the acceleration sensor installation plane and the camera visual axis₀。

For example, the acceleration sensor may include, but is not limited to, a three-axis acceleration sensor, and the acceleration values generated by the three-axis acceleration sensor may include: acceleration value in the X-axis direction, acceleration value in the Y-axis direction, and acceleration value in the Z-axis direction. In summary, the acquiring of the acceleration value generated by the acceleration sensor by the image capturing device, and determining the third angle between the installation plane of the acceleration sensor and the horizontal direction according to the acceleration value may include, but is not limited to: the image acquisition equipment acquires an acceleration value in the X-axis direction, an acceleration value in the Y-axis direction and an acceleration value in the Z-axis direction generated by the acceleration sensor, and determines a third angle between the installation plane of the acceleration sensor and the horizontal direction according to the acceleration value in the Y-axis direction and the acceleration value in the Z-axis direction.

For example, when the object is completely stationary, the object is subjected to only gravity acceleration, and according to this principle, the third angle of the installation plane of the acceleration sensor with respect to the horizontal direction can be determined according to the acceleration value generated by the acceleration sensor, and the third angle is used as the installation deviation angle θ₀. For example, the installation deviation angle θ is determined by the following formula₀：θ₀＝arctan(a_y0/a_z0) In the above formula, a_y0Acceleration value in the Y-axis direction, a, which can be generated by an acceleration sensor_z0May be the Z-axis direction acceleration value generated by the acceleration sensor.

For example, the image capturing device may obtain M sets of acceleration values generated by the acceleration sensor, perform median filtering on the M sets of acceleration values to obtain filtered acceleration values, where M may be a positive integer greater than 1, and determine the target acceleration value based on the filtered acceleration values, for example, a maximum acceleration value of the filtered acceleration values is used as the target acceleration value, or a minimum acceleration value of the filtered acceleration values is used as the target acceleration value, or an average value of all the filtered acceleration values is used as the target acceleration value. And determining a third angle between the installation plane of the acceleration sensor and the horizontal direction according to the target acceleration value.

For example, the image capturing device acquires the acceleration values of M groups generated by the acceleration sensor, and for each acceleration value group, the acceleration values of the X-axis direction, the acceleration values of the Y-axis direction and the acceleration values of the Z-axis direction may be included. Then, median filtering is performed on the acceleration values of the M Y-axis directions, and the average value of the filtered acceleration values of all the Y-axis directions is used as a target acceleration value of the Y-axis direction, and the target acceleration value of the Y-axis direction is used as a in the above formula_y0. And performing median filtering on the acceleration values of the M Z-axis directions, and taking the average value of the acceleration values of all the filtered Z-axis directions as a target acceleration value of the Z-axis direction, and taking the target acceleration value of the Z-axis direction as a in the formula_z0。

Obviously, after obtaining the target acceleration value in the Y-axis direction and the target acceleration value in the Z-axis direction, the third angle between the acceleration sensor mounting plane and the horizontal direction can be determined based on the above formula.

Since an error of one acceleration value may be large, when determining the third angle of the acceleration sensor mounting plane from the horizontal direction based on the acceleration value, the error of the third angle may be large. In order to reduce the error of the third angle, in this embodiment, median filtering may be performed on the M acceleration values, and the target acceleration value may be determined based on the filtered acceleration values. Obviously, even if the error of the acceleration value is large in the M acceleration values, the error of the acceleration value can be reduced after the M acceleration values are subjected to median filtering, and when the third angle between the installation plane of the acceleration sensor and the horizontal direction is determined based on the target acceleration value, the error of the third angle is small, so that the accuracy of the third angle is improved, and the third angle is more accurate.

Step a4, the image acquisition equipment installs the deviation angle theta₀To a non-volatile storage medium (e.g., FLASH memory), and, as described above,before the image acquisition equipment leaves factory, the installation deviation angle theta can be adjusted₀Saving to a non-volatile storage medium.

Exemplary, due to installation offset angle θ₀Will not change, therefore, will install deviation angle theta₀After being saved in a nonvolatile storage medium, the installation deviation angle theta is not required to be determined again after the image acquisition equipment leaves the factory₀The mounting deviation angle theta in the non-volatile storage medium can be directly corrected₀The angle difference between the angle of the acceleration sensor mounting plane and the horizontal direction and the angle of the camera visual axis and the horizontal direction is used.

Based on the mounting deviation angle theta₀The image capturing device may implement a distance measurement method, which is described below with reference to specific embodiments. Referring to fig. 2, a schematic flow chart of the distance measuring method is shown, and the method may be applied to an image capturing device, where the image capturing device at least includes a pan-tilt, a camera and an acceleration sensor, the camera is fixed to the pan-tilt, and the acceleration sensor is fixed to the pan-tilt, and the method may include:

step 201, acquiring an image acquired by a camera, and if the image includes a target object and the target object is located at a specified position in the image, stopping rotating the pan/tilt head. Alternatively, if the image includes a target object and the target object is not located at a designated position in the image, the pan/tilt head may continue to rotate until the image captured by the camera includes the target object and the target object is located at the designated position in the image. Alternatively, if the image does not include the target object, the pan/tilt head may continue to be rotated until the image captured by the camera includes the target object, and the target object is located at a specified position in the image.

For example, since the camera is fixed to the pan/tilt head, that is, the positional relationship between the camera and the pan/tilt head does not change, and when the pan/tilt head rotates, the camera also rotates along with the pan/tilt head, the image capturing device enables the camera to capture images in different directions by rotating the pan/tilt head, and the image capturing process is not limited.

For each frame of image collected by a camera, whether the image comprises a target object is judged firstly. And if the target object is not included, continuing to rotate the holder, enabling the camera to rotate along with the holder, and continuing to acquire images.

If the image includes a target object, it is continuously determined whether the target object is located at a designated position in the image. And if the target object is not located at the specified position in the image, continuing to rotate the tripod head, enabling the camera to rotate along with the tripod head, and continuing to acquire the image until the target object is located at the specified position in the image.

If the target object is located at a specified position in the image, the rotation of the pan/tilt head may be stopped, and subsequent steps may be performed, based on which the distance between the target object and the image acquisition device is determined.

For example, the target object may be a fire point (i.e., a fire point), and may also be other types of objects, which are not limited to this, and the fire point is taken as an example for illustration. The designated position may be any position in the image, such as a center position, an upper left corner position, an upper right corner position, a lower left corner position, a lower right corner position, and the like, which is not limited to this. a may be greater than or equal to 1 and b may be greater than or equal to 1.

In summary, if the image collected by the camera includes a fire point, and the fire point is located at the center of the image, the rotation of the pan/tilt head is stopped. Alternatively, if the image captured by the camera includes a fire, but the fire is not located at the center of the image, the rotational motion of the pan and tilt head may be continued until the image captured by the camera includes a fire, and the fire is located at the center of the image. Or if the image collected by the camera does not include the fire point, continuing to rotate the holder until the image collected by the camera includes the fire point, and the fire point is located at the center of the image.

Step 202, after the rotational motion of the pan/tilt head is stopped, obtaining an acceleration value generated by the acceleration sensor, and determining a first angle between the installation plane of the acceleration sensor and the horizontal direction according to the acceleration value.

For example, if the image captured by the camera includes a target object, and the target object is located at a specified position in the image, the rotation of the pan/tilt head is stopped, an acceleration value generated by the acceleration sensor is acquired, and a first angle between the installation plane of the acceleration sensor and the horizontal direction, that is, a horizontal tilt angle, is determined according to the acceleration value.

In one possible implementation, the acceleration sensor may include, but is not limited to, a three-axis acceleration sensor, and the acceleration values generated by the three-axis acceleration sensor may include: acceleration value in the X-axis direction, acceleration value in the Y-axis direction, and acceleration value in the Z-axis direction. Based on this, in step 202, an acceleration value generated by the acceleration sensor is obtained, and a first angle of the installation plane of the acceleration sensor with the horizontal direction is determined according to the acceleration value, which may include but is not limited to: the method comprises the steps of obtaining an acceleration value in the X-axis direction, an acceleration value in the Y-axis direction and an acceleration value in the Z-axis direction generated by an acceleration sensor, and determining a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the acceleration value in the Y-axis direction and the acceleration value in the Z-axis direction.

For example, when the object is completely static, the object is only subjected to gravity acceleration, and according to the principle, the first angle between the installation plane of the acceleration sensor and the horizontal direction can be determined according to the acceleration value generated by the acceleration sensor. For example, the first angle θ is determined by the following equation: θ ═ arctan (a)_y/a_z) In the above formula, a_yAcceleration value in the Y-axis direction, a, which can be generated by an acceleration sensor_zMay be the Z-axis direction acceleration value generated by the acceleration sensor. Of course, the above formula is merely an example, and is not limited thereto.

In summary, in this embodiment, if the image captured by the camera includes the target object, the target object may be controlled to be located at a specified position in the image. Then, the rotation of the pan/tilt head is stopped, and the pan/tilt head is kept in a stationary state. On the basis, referring to fig. 3, the acceleration value a in the Y-axis direction can be determined_yAnd acceleration value a in the Z-axis direction_zAnd determining a first angle theta between the installation plane of the acceleration sensor and the horizontal direction.

In a possible embodiment, N sets of acceleration values generated by the acceleration sensor may be obtained, and a median filtering may be performed on the N sets of acceleration values to obtain filtered acceleration values, where N may be a positive integer greater than 1, and the target acceleration value may be determined based on the filtered acceleration values, for example, a maximum acceleration value of the filtered acceleration values is used as the target acceleration value, or a minimum acceleration value of the filtered acceleration values is used as the target acceleration value, or an average value of all the filtered acceleration values is used as the target acceleration value. Then, a first angle of the acceleration sensor mounting plane with the horizontal direction is determined according to the target acceleration value.

For example, after the pan/tilt is stopped, obtain N sets of acceleration values that acceleration sensor produced, to every set of acceleration value, can include the acceleration value of X axle direction, the acceleration value of Y axle direction and the acceleration value of Z axle direction, to sum up, can obtain the acceleration value of N Y axle directions, the acceleration value of N Z axle directions. Then, median filtering is performed on the acceleration values of the N Y-axis directions, and the average value of the filtered acceleration values of all the Y-axis directions is used as a target acceleration value of the Y-axis direction, and the target acceleration value of the Y-axis direction is used as a in the above formula_y. And carrying out median filtering on the acceleration values of N Z-axis directions, and taking the average value of the acceleration values of all the filtered Z-axis directions as a target acceleration value of the Z-axis direction, and taking the target acceleration value of the Z-axis direction as a in the formula_z。

Obviously, after obtaining the target acceleration value in the Y-axis direction and the target acceleration value in the Z-axis direction, the first angle θ of the acceleration sensor mounting plane with respect to the horizontal direction can be determined based on the above formula.

And step 203, determining a second angle between the visual axis of the camera and the horizontal direction according to the first angle and the stored installation deviation angle, wherein the installation deviation angle is an angle difference between the installation plane of the acceleration sensor and the horizontal direction and the angle between the visual axis of the camera and the horizontal direction.

Referring to the above embodiments, image acquisitionThe non-volatile storage medium of the device is stored with an installation deviation angle theta₀Therefore, prior to step 203, the mounting deviation angle θ may be read from the non-volatile storage medium₀Based on the mounting deviation angle theta₀And a first angle theta of the acceleration sensor mounting plane with the horizontal direction, a second angle of the camera visual axis with the horizontal direction can be determined.

In one possible embodiment, the first angle θ can be related to the installation deviation angle θ₀The angular difference between the two angles is determined as a second angle between the camera's visual axis and the horizontal, which may be the pitch angle of the pan/tilt head. For example, the second angle may be determined by the following formula

Illustratively, referring to fig. 4, the first angle θ represents a first angle between the installation plane of the acceleration sensor and the horizontal direction, and the installation deviation angle θ₀The angular difference between the angle of the mounting plane of the acceleration sensor with respect to the horizontal direction and the angle of the visual axis of the camera with respect to the horizontal direction is shown, and as can be seen from fig. 4, the first angle θ and the mounting deviation angle θ₀The angle difference between the two is the second angle between the visual axis of the camera and the horizontal direction

And step 204, determining the horizontal distance between the target object and the image acquisition equipment according to the second angle and the installation height of the image acquisition equipment (namely the installation height of the camera).

In one possible embodiment, a tangent value of the second angle may be determined, and a quotient between the installation height and the tangent value may be determined as a horizontal distance between the target object and the image acquisition device.

For example, the installation height h of the image recording device can be determined, for whichThe determination method is not limited, for example, the installation height h of the image capturing device can be measured by using a vertical line, and the installation height h of the image capturing device is also the installation height h of the camera. At a known mounting height h of the camera, a second angle of the camera's visual axis to the horizontal

On the basis of (2), triangulation may be employed to determine the horizontal distance d between the target object and the image acquisition device. For example, the horizontal distance d between the target object and the image acquisition device may be determined by the following formula:

of course, the above-described manner of triangulation is merely an example, and is not limiting.

In the above embodiments, for a_yAnd a_zAre positive or negative, i.e. theta and theta₀Also has positive and negative polarity, and therefore, for the second angle

Said, the second angle

May be positive, second angle

Negative values are also possible. For example, the angle downward from the horizontal may be defined as the positive direction, i.e., the second angle

Greater than 0, defining the angle in the horizontal direction upward as the negative direction, i.e. the second angle

Less than 0.

In a possible implementation manner, the target object may be a fire (i.e., a fire), and in order to detect whether the image includes the fire, in this embodiment, the image capturing device may include a camera which is a binocular camera and can capture a visible light image and a thermal imaging image simultaneously, or the image capturing device may include a camera which is a visible light camera and a thermal imaging camera, and the visible light camera captures a visible light image and the thermal imaging camera captures a thermal imaging image. Of course, the above are only two examples, and there is no limitation as long as the image capture device can capture a visible light image and a thermal imaging image by a camera.

The image acquisition device analyzes whether a fire exists in the scene based on the thermal imaging image, for example, if the temperature of a certain object is greater than a threshold value, the object is indicated as the fire. When a fire exists, the image acquisition device acquires a visible light image acquired by the camera (i.e., the visible light image is used as the image in step 201, and the camera visual axis is the visual axis of the visible light camera), if the visible light image includes the fire and the fire is located at a specified position in the visible light image, the rotation of the pan-tilt is stopped, and steps 202-204 are performed to determine the distance between the fire and the image acquisition device. And if the visible light image comprises the fire point and the fire point is not located at the specified position in the visible light image, continuing rotating the holder until the visible light image collected by the camera comprises the fire point and the fire point is located at the specified position in the visible light image. And if the visible light image does not comprise the fire point, continuing rotating the holder until the visible light image collected by the camera comprises the fire point, wherein the fire point is positioned at a specified position in the visible light image.

In another possible embodiment, the image acquisition device analyzes whether a fire is present in the scene based on the thermographic image. When a fire exists, the image acquisition device acquires a thermal imaging image acquired by the camera (i.e., the thermal imaging image is taken as the image in step 201, and the camera visual axis is the visual axis of the thermal imaging camera), and if the thermal imaging image includes the fire and the fire is located at a specified position in the thermal imaging image, the rotation of the cradle head is stopped, and steps 202-204 are performed to determine the distance between the fire and the image acquisition device. And if the thermal imaging image comprises the fire point and the fire point is not located at the specified position in the thermal imaging image, continuing to rotate the cradle head until the thermal imaging image collected by the camera comprises the fire point and the fire point is located at the specified position in the thermal imaging image. And if the thermal imaging image does not comprise the fire point, continuing to rotate the holder until the thermal imaging image collected by the camera comprises the fire point, wherein the fire point is positioned at a specified position in the thermal imaging image.

According to the technical scheme, in the embodiment of the application, a first angle between an installation plane of the acceleration sensor and the horizontal direction can be determined based on the acceleration value, a second angle between a visual axis of the camera and the horizontal direction can be determined according to the first angle and the installation deviation angle, and the horizontal distance between the target object and the image acquisition equipment can be determined according to the second angle and the installation height of the image acquisition equipment. When the target object is the fire point, the horizontal distance between the fire point and the image acquisition equipment can be accurately detected by the method, the position of the fire point is analyzed according to the horizontal distance, the accuracy of fire point detection can be improved, the position of the fire point is conveniently and quickly positioned, and the deviation problem of fire point distance measurement is avoided. When the fire point exists in the scene, the alarm information can be output to the user, so that the user can know the fire point in the scene in time, and the larger economic loss is avoided. When a fire point exists in a scene, a user can arrive at the scene in time, and the position of the fire point is found based on the horizontal distance between the fire point and the image acquisition equipment.

Referring to fig. 5, a flow chart of another ranging method is shown, where the method may include:

step 501, acquiring an image acquired by a camera, and judging whether the image includes a fire point, wherein the fire point is located at a specified position in the image. If yes, go to step 502; if not, the cradle head continues to rotate, the image collected by the camera is obtained, the step 501 is returned to, and the step of judging whether the image comprises fire points or not is continuously executed.

Step 502, judging whether the holder is in a static state.

If not, step 503 is executed, and if yes, step 505 is executed.

And step 503, issuing a stop command to the pan/tilt head, wherein the stop command is used for stopping rotating the pan/tilt head.

And step 504, judging whether the cradle head stops, namely whether the cradle head stops rotating.

If yes, step 505 is executed, and if not, after waiting for a preset time length (which can be configured according to experience), step 504 is executed again, that is, whether the cradle head stops completing is judged again. In the process of waiting for the preset duration, the rotation of the pan/tilt head may be stopped based on the stop command, i.e., waiting for the rotation of the pan/tilt head to be stopped.

And 505, acquiring N groups of acceleration values generated by the acceleration sensor.

Step 506, performing median filtering on the N sets of acceleration values to obtain filtered acceleration values, where N may be a positive integer greater than 1, and determining the target acceleration value based on the filtered acceleration values.

And step 507, determining a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the target acceleration value.

And step 508, reading the installation deviation angle from the nonvolatile storage medium, determining a second angle between the visual axis of the camera and the horizontal direction according to the first angle and the installation deviation angle, and determining the horizontal distance between the target object and the image acquisition equipment according to the second angle and the installation height of the image acquisition equipment.

Based on the same application concept as the method, the embodiment of the application provides a distance measuring device which is applied to image acquisition equipment, wherein the image acquisition equipment at least comprises a holder, a camera and an acceleration sensor; wherein, the camera is fixed at the cloud platform, and the acceleration sensor is fixed at the cloud platform, refer to fig. 6 and show, for the structure sketch map of range unit, the device can include:

an obtaining module 61, configured to obtain an image acquired by the camera, and if the image includes a target object and the target object is located at a specified position in the image, stop rotating the pan/tilt head;

the first determining module 62 is configured to obtain an acceleration value generated by the acceleration sensor after the pan-tilt stops rotating, and determine a first angle between an installation plane of the acceleration sensor and the horizontal direction according to the acceleration value;

a second determining module 63, configured to determine a second angle between the visual axis of the camera and the horizontal direction according to the first angle and the stored installation deviation angle; the installation deviation angle is an angle difference between the angle between the installation plane of the acceleration sensor and the horizontal direction and the angle between the visual axis of the camera and the horizontal direction;

a third determining module 64, configured to determine a horizontal distance between the target object and the image capturing device according to the second angle and the installation height of the image capturing device.

In one possible embodiment, the acceleration sensor comprises a three-axis acceleration sensor, the acceleration value produced by the three-axis acceleration sensor comprising: acceleration value in X-axis direction, acceleration value in Y-axis direction and acceleration value in Z-axis direction; the first determining module 62 is specifically configured to, when determining the first angle between the installation plane of the acceleration sensor and the horizontal direction according to the acceleration value:

In a possible implementation, the second determining module 63 is specifically configured to determine, according to the first angle and the stored installation deviation angle, a second angle between the camera visual axis and the horizontal direction:

In a possible implementation, the third determining module 64 is specifically configured to determine the horizontal distance between the target object and the image capturing device according to the second angle and the installation height of the image capturing device: determining a tangent value of the second angle; determining a quotient between the installation height and the tangent value as a horizontal distance between the target object and the image acquisition device.

In a possible implementation, the obtaining module 61 is further configured to: if the image comprises the target object and the target object is not located at the designated position in the image, continuing to rotate the holder until the image acquired by the camera comprises the target object and the target object is located at the designated position in the image; or if the image does not comprise the target object, continuing to rotate the holder until the image acquired by the camera comprises the target object and the target object is located at the specified position in the image.

In a possible embodiment, the first determining module 62 is specifically configured to determine, according to the acceleration value, a first angle between the acceleration sensor mounting plane and the horizontal direction:

In a possible implementation manner, before the image capturing device leaves factory, the image capturing device is placed on a horizontal table, and a collimator is placed on the horizontal table, light rays of the collimator are in a horizontal direction, and the second determining module 63 is further configured to obtain the installation deviation angle;

for example, when the second determining module 63 obtains the installation deviation angle, it is specifically configured to:

Based on the same application concept as the method, the embodiment of the present application provides an image capturing apparatus, which includes a pan-tilt head, a camera, an acceleration sensor, a processor and a machine-readable storage medium, where the camera is fixed to the pan-tilt head, and the acceleration sensor is fixed to the pan-tilt head, as shown in fig. 7, taking a processor 71 and a machine-readable storage medium 72 as an example, the machine-readable storage medium 72 stores machine-executable instructions that can be executed by the processor 71; the processor 81 is configured to execute machine executable instructions to perform the following steps:

Based on the same application concept as the method, embodiments of the present application further provide a machine-readable storage medium, where a plurality of computer instructions are stored on the machine-readable storage medium, and when the computer instructions are executed by a processor, the ranging method disclosed in the above example of the present application can be implemented.

The machine-readable storage medium may be any electronic, magnetic, optical, or other physical storage device that can contain or store information such as executable instructions, data, and the like. For example, the machine-readable storage medium may be: a RAM (random Access Memory), a volatile Memory, a non-volatile Memory, a flash Memory, a storage drive (e.g., a hard drive), a solid state drive, any type of storage disk (e.g., an optical disk, a dvd, etc.), or similar storage medium, or a combination thereof.

The systems, devices, modules or units illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions. A typical implementation device is a computer, which may take the form of a personal computer, laptop computer, cellular telephone, camera phone, smart phone, personal digital assistant, media player, navigation device, email messaging device, game console, tablet computer, wearable device, or a combination of any of these devices.

For convenience of description, the above devices are described as being divided into various units by function, and are described separately. Of course, the functionality of the units may be implemented in one or more software and/or hardware when implementing the present application.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Furthermore, these computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A distance measurement method is characterized by being applied to image acquisition equipment, wherein the image acquisition equipment at least comprises a holder, a camera and an acceleration sensor; wherein the camera is fixed to the pan/tilt head and the acceleration sensor is fixed to the pan/tilt head, the method comprising:

2. The method of claim 1, wherein the acceleration sensor comprises a three-axis acceleration sensor that produces acceleration values comprising: acceleration value in X-axis direction, acceleration value in Y-axis direction and acceleration value in Z-axis direction; the determining a first angle between an acceleration sensor mounting plane and a horizontal direction according to the acceleration value includes:

3. The method of claim 1, wherein determining a second angle of the camera's visual axis from horizontal based on the first angle and the stored installation deviation angle comprises:

4. The method of claim 1,

the determining a horizontal distance between the target object and the image acquisition device according to the second angle and the installation height of the image acquisition device comprises:

5. The method of claim 1,

after the acquiring the image collected by the camera, the method further comprises:

if the image comprises the target object and the target object is not located at the designated position in the image, continuing to rotate the holder until the image acquired by the camera comprises the target object and the target object is located at the designated position in the image; alternatively, the first and second electrodes may be,

6. The method of claim 1, wherein determining a first angle of an acceleration sensor mounting plane from a horizontal direction based on the acceleration value comprises:

7. The method according to claim 1, wherein before the image capturing device is shipped, the image capturing device is placed on a horizontal table, and a collimator is placed on the horizontal table, wherein the light of the collimator is in a horizontal direction, and the installation deviation angle is obtained by:

8. The method of claim 7,

the image capture device further includes a non-volatile storage medium, the method further comprising, after determining the third angle as the installation deviation angle:

saving the installation deviation angle to the non-volatile storage medium;

reading the mounting deviation angle from the non-volatile storage medium.

9. A distance measuring device is characterized by being applied to image acquisition equipment, wherein the image acquisition equipment at least comprises a tripod head, a camera and an acceleration sensor; wherein, the camera is fixed the cloud platform, just acceleration sensor fixes the cloud platform, the device includes:

10. An image acquisition apparatus, characterized by comprising: the system comprises a tripod head, a camera, an acceleration sensor, a processor and a machine-readable storage medium, wherein the camera is fixed on the tripod head, the acceleration sensor is fixed on the tripod head, and the machine-readable storage medium stores machine-executable instructions capable of being executed by the processor;