CN112911253A

CN112911253A - Projection control method, projection apparatus, and storage medium

Info

Publication number: CN112911253A
Application number: CN201911221925.8A
Authority: CN
Inventors: 曹婷; 余新; 吴超; 张贤鹏
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2019-12-03
Filing date: 2019-12-03
Publication date: 2021-06-04
Also published as: WO2021109782A1

Abstract

The embodiment of the application discloses a projection control method, projection equipment and a storage medium, wherein a target projection distance is obtained; matching the target projection distance with the initial danger detection range; determining a target danger detection range according to the matching result; judging whether a target object exists in the target danger detection range; and if so, controlling to reduce the display output brightness of the projection equipment. The target danger detection range is determined and adapted according to the matching result of the target projection distance and the initial danger detection range, misjudgment caused by dust and ambient light can be avoided, the display output brightness of the projection equipment is controlled and reduced under the condition that a target object exists in the target danger detection range, and the reliability of human eye protection of the projection equipment and the user experience are improved.

Description

Projection control method, projection apparatus, and storage medium

Technical Field

The present application relates to the field of laser projection technologies, and in particular, to a projection control method, a projection device, and a storage medium.

Background

With the development of display technology, the application of projection equipment is more and more extensive, including education projectors, home projectors, engineering projectors and the like, and the projection technology brings great changes to the lives, the study and the work of people. The light source for projection display is also developed from UHP lamp, xenon lamp, LED to laser, laser phosphor, etc. nowadays, so that the performance of projection technology in all aspects is greatly leap, for example, laser projection technology. The laser projection technology takes laser as a light source, can truly reproduce abundant and gorgeous colors of an objective world, provides more shocking expressive force, and has longer service life and high reliability of the laser light source. However, in order to improve the display brightness, the projection device emitting laser needs higher power, and the laser has a narrow spectrum and high intensity, which is easy to cause damage to human eyes.

Disclosure of Invention

In view of the above, the present application proposes a projection control method, a projection apparatus, and a storage medium to improve the above problem.

In a first aspect, an embodiment of the present application provides a projection control method, where the method includes: acquiring a target projection distance; matching the target projection distance with the initial danger detection range; determining a target danger detection range according to the matching result; judging whether a target object exists in the target danger detection range; and if so, controlling to reduce the display output brightness of the projection equipment.

In a second aspect, an embodiment of the present application provides a projection device, which includes a data acquisition module, a projection module, and a projection control module; the data acquisition module is used for acquiring a target projection distance; the projection control module is used for matching the target projection distance with the initial danger detection range and determining a target danger detection range according to a matching result; the data acquisition module is also used for judging whether a target object exists in the target danger detection range; the projection control module is also used for controlling and reducing the display output brightness of the projection module when the target object exists according to the judgment result of the data acquisition module.

In a third aspect, an embodiment of the present application provides a computer-readable storage medium, where a program code is stored in the computer-readable storage medium, where the program code executes the method according to the first aspect.

According to the projection control method, the projection equipment and the storage medium, the target projection distance is matched with the initial danger detection range by acquiring the target projection distance, the target danger detection range is determined according to the matching result, whether a target object exists in the target danger detection range is judged, and if the target object exists, the display output brightness of the projection equipment is controlled to be reduced. Therefore, the target danger detection range is determined and adapted according to the matching result of the target projection distance and the initial danger detection range, misjudgment caused by dust and ambient light can be avoided, and the display output brightness of the projection equipment is controlled and reduced to adapt to human eyes under the condition that a target object exists in the target danger detection range, so that the reliability of human eye protection of the projection equipment is improved, and the user experience is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 shows a schematic structural diagram of a projection control system proposed in an embodiment of the present application.

Fig. 2 shows a flowchart of a method of a projection control method according to an embodiment of the present application.

Fig. 3 shows a schematic diagram of installation distance setting of adjacent ranging sensors according to an embodiment of the present application.

Fig. 4 is a flowchart illustrating a method of a projection control method according to another embodiment of the present application.

Fig. 5 is a diagram showing an example of a mounting position of a TOF laser ranging sensor according to an embodiment of the present application.

Fig. 6 is a view showing another example of the mounting position of the TOF laser ranging sensor according to the embodiment of the present application.

Fig. 7 shows a schematic structural diagram between a projection device and a glass covered by the projection device according to an embodiment of the present application.

Fig. 8 is a flowchart illustrating a method of a projection control method according to another embodiment of the present application.

Fig. 9 is a block diagram illustrating a projection apparatus according to the present application for executing a projection control method according to an embodiment of the present application.

Fig. 10 illustrates a storage unit of an embodiment of the present application for storing or carrying program codes for implementing a projection control method according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

With the improvement of the performance of all aspects of the projection equipment, more projection equipment can support the use of laser as a light source, and the objective world rich and gorgeous colors can be truly reproduced. However, the inventor of the present invention has found in research that, in displaying image contents of different colors, not only the display gamut coverage of the displayed image contents needs to be more than 90% of the color space that can be recognized by human eyes, but also the display brightness needs to be improved to some extent. However, in order to improve the display brightness, the laser emitting laser needs higher power, has a narrow laser spectrum and high intensity, and is easily harmful to human eyes. And the damage to human eyes caused by lasers with different intensities in the same time or lasers with the same intensity in different times is different.

The International Electrotechnical Commission (IEC) and the Food and Drug Administration (FDA) have made safety ratings and related test regulations for projection products of laser light sources (as shown in table 1 below). Since the danger level of the laser projector is generally RG2 or RG3, in order to prevent the laser light from damaging the human eye, the projector needs to turn off or attenuate the laser light within 0.25s or less of the time that the human eye approaches the laser light, so as to protect the human eye.

TABLE 1 IEC62471 Exposure time limits for different hazard classes, different types of light

Generally, through setting up people's eye protector in projection equipment among the prior art, concrete, in time make the mode of responding when detecting someone gets into the projection area, though can prevent strong projection laser to cause the injury to people's eye to a certain extent, but detection range has the blind area and the misjudgement rate is high, and the reliability and the factor of safety that have reduced people's eye laser safeguard measure are lower, cause not good user experience, and response speed is slower for projection equipment still has the injury risk to people's eye.

Therefore, in order to improve the above problem, the present application provides a projection control method and a projection device, which can update the target hazard detection range of the ranging sensors according to the actually obtained target detection distance under the condition that a plurality of ranging sensors continuously obtain the target detection distance at a high speed in real time, so as to flexibly and rapidly control the projection display brightness of the projection device, thereby greatly improving the safety factor of the projection device and enhancing the user experience.

The projection control system related to the projection control method provided by the embodiment of the present application is described first.

Fig. 1 is a schematic structural diagram of a projection control system 10 according to an embodiment of the present disclosure. The projection control system 10 includes a data acquisition module 11, a projection module 12, and a projection control module 13. The data acquisition module 11 is electrically connected to the projection module 12, and the projection module 12 is electrically connected to the projection control module 13.

As one approach, the data acquisition module 11 may be used to acquire the target projection distance. The projection control module 13 may further obtain a target projection distance from the data obtaining module 11, match the target projection distance with a preset initial risk detection range, and determine a target risk detection range according to a matching result. The data obtaining module 11 may also obtain a target risk detection range from the projection control module 13, further determine whether a target object exists in the target risk detection range, and return the determination result to the projection control module 13. The projection control module 13 is further configured to control to reduce the display output brightness of the projection module 12 when the determination result of the data obtaining module 11 indicates that the target object exists, and perform image projection with the reduced output brightness of the projection module 12, so as to achieve human eye protection.

In this embodiment, the target projection distance may be obtained by measuring with the ranging sensing component, and the data obtaining module 11 further obtains the target projection distance obtained by measuring with the ranging sensing component. Optionally, in other embodiments, the data acquisition module 11 may include the above-mentioned ranging sensing assembly.

In this embodiment, the projection module 12 may include a projection optical device for projecting an image, such as a projection light source, a projection optical machine, and a projection lens, and the projection control module 13 may control to reduce the display output brightness of the projection module 12 by controlling to reduce the brightness of the projection light source, and modulate the optical transmittance of the projection optical machine, and optionally, the projection control module 13 may also adjust by other manners to control to reduce the display output brightness of the projection module 12, which is not limited in this application.

In this embodiment, the initial risk detection range may include a maximum value, and the projection control module 13 may include a first processing unit. The first processing unit may be configured to, after the projection control module 13 obtains a target projection distance (which may be a target projection distance measured by the ranging sensing component) from the data obtaining module 11, match the target projection distance with a preset initial risk detection range, and if the target projection distance is greater than or equal to a maximum value of the initial risk detection range, take the maximum value of the initial risk detection range as a maximum value of the target risk detection range; if the target projection distance is less than the maximum value of the initial hazard detection range, the maximum value of the target hazard detection range may be calculated based on the target projection distance.

In this embodiment, the ranging sensing assembly may include a plurality of ranging sensors. The data acquisition module 11 may determine the target projection distance from the projection distance values collected by the ranging sensing assembly based on the target rule, i.e., determine the target projection distance from the projection distance values collected by the plurality of ranging sensors based on the target rule. In this way, the first processing unit may obtain a maximum value of the target risk detection range according to a difference between the target projection distance acquired by the plurality of distance measuring sensors and the first error parameter.

In this embodiment, the projection control system 10 may further include a detection unit and a second processing unit, where the detection unit may be configured to detect whether a projection plane exists in the installation direction of the ranging sensing assembly; and determining the maximum value of the initial danger detection range of the ranging sensing assembly according to the detection result. Optionally, the second processing unit may be configured to determine, if a projection plane exists, the obtained reference target projection distance as a maximum value of the initial hazard detection range, where the reference target projection distance represents a target projection distance used by the ranging sensing assembly last time; if no projection plane exists, the specified threshold distance may be determined as the maximum value of the initial hazard detection range. Optionally, in this manner, the projection control module 13 may be configured to match the target projection distance with the maximum value of the initial hazard detection range.

In this embodiment, the projection control system 10 may further include a minimum value obtaining unit, where the minimum value obtaining unit may be configured to obtain a reference distance between a light-transmitting protection component arranged on a detection path of the ranging sensing assembly and the ranging sensing assembly before the data obtaining module 11 obtains the projection distance of the target; and taking the sum of the reference distance and the second error parameter as the minimum value of the initial danger detection range.

In this embodiment, the data obtaining module 11 may obtain the target projection distance by determining whether the strength of the detection signal received by the ranging sensing assembly is greater than or equal to a preset ambient light interference resistance index. Optionally, if the strength of the detection signal received by the ranging sensing assembly is equal to or higher than a preset ambient light interference resistance index, the projection distance of the target acquired by the ranging sensing assembly can be acquired based on the strength of the detection signal; optionally, if the strength of the detection signal received by the ranging sensing assembly is not greater than or equal to the preset ambient light interference resistance index, the strength of the detection signal may be discarded.

It should be noted that the distance measuring sensing assembly in this embodiment may include a plurality of distance measuring sensors, the plurality of distance measuring sensors may be adjacently disposed, and the installation distance between the plurality of distance measuring sensors may be set to 15 cm.

In this embodiment, the projection control module 13 may be further configured to, when the determination result of the data obtaining module 11 is that the target object exists, control to obtain a motion trend of the target object before reducing the display output brightness of the projection module 12; judging whether the movement trend meets a preset condition or not; alternatively, if a preset condition is satisfied, control may be performed to reduce the display output luminance of the projection device (projection module 12).

Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

Referring to fig. 2, an embodiment of the present application provides a projection control method applied to a projection apparatus having a projection function, where the method includes:

step S110: and acquiring the projection distance of the target.

It should be noted that, in the embodiment of the present application, the projection distance of the target may be obtained by measuring through the ranging sensing assembly, and the ranging sensing assembly may include a plurality of ranging sensors. Optionally, the distance measuring sensor may be a TOF laser distance measuring sensor (the detection time of TOF laser distance measuring is only 20ms, the response time is very short, and the purpose of protecting human eyes can be better achieved), wherein the distance measuring sensing component may include a plurality of TOF laser distance measuring sensors, for example, 2, 3 or more than 3 TOF laser distance measuring sensors. The target projection distance refers to a projection distance value of projection distance values measured by the plurality of TOF laser ranging sensors, which is used for subsequent reference to determine a target danger detection range of the ranging sensing assembly.

It can be understood that, although the projection device is configured with the optimal projection distance for the user to adjust for reference when it is shipped from a factory, or is installed according to the set distance ratio when it is installed, the projection device may need to readjust the projection distance during the actual use process due to site change, foreign object blockage, device aging, and the like, in this case, for the projection device installed with a plurality of ranging sensors, the projection distance (i.e. the distance from the projection device to the projection screen) determined by the plurality of ranging sensors will be obtained.

For example, as one approach, a plurality of TOF laser ranging sensors may be mounted near a projection light source of the projection device (e.g., mounted vertically upward on both sides of the projection light source) for measuring the distance from the projection device to the projection screen (i.e., the projection distance). It can be understood that for multiple TOF laser ranging sensors, due to differences in installation angles and possible variations in the position of the projection device, the measured projection distances may be different for different TOF laser ranging sensors at the same time, or the measured projection distances may be different for the same TOF laser ranging sensor at different times. It should be noted that the installation direction of the TOF laser ranging sensor is not unique, and optionally, the TOF laser ranging sensor may also be installed in a direction away from the projection device (i.e. a non-projection direction), for example, assuming that the projection screen is a screen installed on a television wall surface, the projection device is placed on a tea table (the horizontal distance from the tea table to the television wall is one meter five), the user sits on a sofa (the distance from the sofa to the tea table to the television wall is the same relative to the tea table, i.e. the horizontal distance from the sofa to the tea table is one meter five and the horizontal distance from the sofa to the television wall is three meters), and the direction in which the user is located is the direction away from the projection direction of the projection device. Similarly, in the case where the TOF laser ranging sensors are installed away from the projection direction of the projection apparatus, there is also a difference (error) in the projection distances measured by the plurality of TOF laser ranging sensors.

In order to reduce or reduce such measurement errors, as a way, the embodiment of the present application may acquire a minimum value (where the minimum value may be understood as a projection distance range included in each of a plurality of TOF laser ranging sensors, and the minimum value may be taken such that a plurality of projection distance values intersect in a plane where the minimum value is located, that is, coplanar) or an average value of a plurality of projection distances measured by a plurality of TOF laser ranging sensors, and use the minimum value or the average value as a target projection distance may make a plurality of acquired projection distance values (that is, target projection distances herein) more balanced, thereby achieving error reduction.

As one way, the distance measuring sensor can continuously detect the projection distance in real time, and then can judge whether the projection distance changes. Specifically, TOF laser rangefinder's reflectivity detector transmission detection signal gives the projection screen, and the projection screen reflects this signal, and TOF laser rangefinder receives the signal that the projection screen reflects back then, detects projection screen to projection equipment's distance, and then acquires the projection distance that a plurality of TOF laser rangefinder sensors measured. As an implementation manner, the projection device may read projection distance values measured by a plurality of TOF laser ranging sensors, and use a minimum value or an average value of the plurality of projection distance values as a target projection distance acquired by the ranging sensing component.

Step S120: and matching the target projection distance with an initial danger detection range.

The initial danger detection range refers to a detection distance at which the TOF laser ranging sensor detects whether or not a target object (e.g., a living organism such as a human being or a small animal) is present within the laser irradiation range. In general, when the projection apparatus is shipped from a factory, a fixed initial risk detection range is set because the position of the TOF laser ranging sensor mounted on the projection apparatus is fixed. Optionally, the initial risk detection range may be set by a third-party provider, or the initial risk detection range may be set by a user according to a projection ratio (including different risk detection distance ranges corresponding to different projection distances) given by the device when the device is shipped. By setting the initial danger detection range, the user can realize automatic eye protection when starting the projector for use after purchasing the projector, namely, the harm of the over-strong laser to the eyes of the target object is avoided. Optionally, the initial risk detection range includes a risk distance detection range, for example, the initial risk distance detection range may be 0-50cm of the projection direction of the projection apparatus, and the specific numerical value is only an example and is not limited.

In this case, if the projection device changes the position, the original initial risk detection range may not be able to accurately detect the target object within the laser irradiation range at the new projection distance, thereby causing erroneous determination. In order to effectively avoid misjudgment possibly brought in the detection process of the TOF laser ranging sensor, the embodiment of the application can match the target projection distance acquired by the TOF laser ranging sensor in real time with the preset initial danger detection range.

For example, in one implementation, the target projection distance (i.e., the minimum value or the average value of the plurality of projection distances) may be matched with a preset initial risk detection range, and whether the target distance is within the initial risk detection range is determined, so as to adjust the risk detection distance of the ranging sensing assembly in real time according to the determination result.

Step S130: and determining a target danger detection range according to the matching result.

As a mode, the distance measurement sensing component may automatically calculate a new danger detection distance range according to the matching result and send the new danger detection distance range to the projection device, so that the projection device may use the new danger detection distance range as a target danger detection range, thereby implementing determination of the target danger detection range of the distance measurement sensing component according to the matching result. Specifically, the TOF laser ranging sensor with the measured projection distance value being the minimum value can match the measured projection distance value with the initial danger detection range, and then a new danger detection distance range is calculated according to the matching result and sent to the projection equipment; or any TOF laser ranging sensor in the TOF laser ranging sensors matches the average value of the projection distances measured by the TOF laser ranging sensors with the initial danger detection range, calculates a new danger detection distance range according to the comparison result and sends the new danger detection distance range to the projection equipment. Optionally, the TOF laser ranging sensor may actively send the calculated new dangerous detection distance range to the projection device, or may send the new dangerous detection distance range to the projection device after acquiring the dangerous detection distance range acquisition instruction of the projection device, and the specific implementation manner is only used as an example and does not constitute a limitation to the present scheme.

Alternatively, the distance measurement sensing component may also send the matching result to the projection device, so that the projection device may re-determine the target hazard detection range of the distance measurement sensing component according to the matching result.

Through confirm again and range finding sensing component's dangerous detection range of target, can be so that TOF laser ranging sensor's detection response speed is faster more nimble, reduces the erroneous judgement rate, adopts new dangerous detection range of target simultaneously, can be so that TOF laser ranging sensor's dangerous detection range and projection equipment's actual projection distance more adaptation, and then promote projection system operation's stability.

Step S140: and judging whether a target object exists in the target danger detection range.

The target object in the embodiments of the present application may be a human being or a living organism such as an animal, and the following embodiments will be described with reference to a human being as the target object unless otherwise specified.

As a mode, in the process that the TOF laser ranging sensor continuously obtains the target detection distance at a high speed in real time, if a human body signal appears, the TOF laser ranging sensor can further judge whether the human body signal appears in the target dangerous detection range of the TOF laser ranging sensor, and optionally, if so, the TOF laser ranging sensor can judge that a target object exists in the target dangerous detection range. Optionally, if not, the TOF laser ranging sensor will determine that there is no target object within its target hazard detection range.

Whether a target object exists in a target danger detection range or not is detected, so that the projection equipment can timely make a response according to a judgment result, including reducing the display brightness of the projection laser (at once), turning off the projection laser (in a short time or a certain time period) and/or giving an alarm prompt (continuously/discontinuously), and the like, thereby reducing the risk that eyeballs of the target object receive laser irradiation, and improving the safety factor and the user experience of the laser projection equipment.

It should be noted that, in order to promote the reliability and the accuracy of people's eye protection, promote simultaneously whether TOF laser ranging sensor will detect the accuracy that has the target object in its dangerous detection range of target, a plurality of TOF laser ranging sensors in this application embodiment are adjacent to be set up, and the installation distance setting between a plurality of TOF laser ranging sensors is about 15 cm. As shown in fig. 3, a schematic diagram is set for the installation distance of adjacent distance measuring sensors, wherein 12.5 ° in fig. 3 represents the detection half angle (detection angle is 25 ° and is a solid angle) of the ToF laser distance measuring sensor, 33.8cm represents the projection distance detected by a single ToF laser distance measuring sensor, and the specific values of the detection half angle and the detected projection distance are only examples and do not constitute a limitation to the present solution.

Optionally, the size of the face of the human face is not greater than 15cm in width approximately, and the installation distance between the plurality of TOF laser ranging sensors is set to be about 15cm, so that the dangerous detection range of the TOF laser ranging sensors covers the face of the human face as far as possible, and the plurality of sensors can detect the approach of the human head even if gaps or detection errors exist, so that human eye protection is achieved.

Step S150: the control reduces the display output brightness of the projection device.

It will be appreciated that if the TOF laser ranging sensor determines that there is a target object within its target hazard detection range, the projection device will control the display output brightness of the projection device to be reduced (including to 0, i.e., turned off) to accommodate the human eye.

Optionally, in order to prevent adverse consequences caused by an error in reducing the display output measurement of the projection device, for example, damage to human eyes due to untimely shutdown caused by sudden failure, device aging, or delay in shutdown of laser display output brightness caused by poor line contact, the projection device may be controlled to issue an alarm to prompt a user while reducing the display output brightness of the projection device, for example, to issue a voice prompt or a prompt tone prompt, and the content of the specific prompt and the manner of the prompt are not limited in this embodiment of the application.

As a mode, if it is determined that the target object exists within the target danger detection range, the distance between the target object and the ranging sensing component may be acquired, then the current safety level of the target object is acquired according to the distance, then the corresponding safety brightness value is acquired based on the safety level, and then the display output brightness of the projection device is reduced to the corresponding safety brightness value. The current safety level representation of the target object judges the danger degree of the position of the user according to the distance between the target object and the ranging sensing assembly, optionally, the larger the distance between the target object and the ranging sensing assembly is, the safer the target object is, conversely, if the target object is close to the ranging sensing assembly enough, for example, the distance is 5 meters, 2 meters or 1 meter and the like. As an implementation manner, the corresponding relationship between the safety level and the corresponding safety brightness value may be preset and stored, so that when the projection device detects that the distance between the target object and the ranging sensing assembly reaches the distance set by the lowest safety level (i.e. the set closest distance (or distance range) between the target object and the ranging sensing assembly), the display output brightness of the projection device is reduced to the corresponding safety brightness value.

For example, in a specific application scenario, the security level may be set to A, B, C, and if the distance between the target object and the ranging sensing assembly is 1-5 meters, the corresponding security level is a, and similarly, if the distance between the target object and the ranging sensing assembly is 6-8 meters, the corresponding security level is B, and if the distance between the target object and the ranging sensing assembly is 9-10 meters, the corresponding security level is C. Optionally, if the safety brightness value corresponding to the safety level a is 5, the safety brightness value corresponding to the safety level B is 10, and the safety brightness value corresponding to the safety level C is 15. In one embodiment, assuming that the distance between the target object and the ranging sensing component is detected to be 7 meters, the current safety level of the target object may be determined to be B, and the display output brightness of the projection device may be controlled to be reduced to a safety brightness value of 10 for timely protection of human eyes.

The above examples of the safety brightness values and the specific numerical values are only described as examples, and are not limited, and the naming rules and setting modes of the safety levels are not limited.

According to the projection control method, the target projection distance is obtained, then the target projection distance is matched with the initial danger detection range, the target danger detection range is determined according to the matching result, then whether a target object exists in the target danger detection range or not is detected, and if the target object exists, the display output brightness of the projection equipment is controlled to be reduced. Therefore, the target dangerous detection range adaptive to the ranging sensing assembly is determined according to the matching result of the target projection distance and the initial dangerous detection range, misjudgment caused by dust and ambient light can be avoided, the display output brightness of the projection equipment is controlled and reduced to adapt to human eyes under the condition that a target object exists in the target dangerous detection range, the reliability of human eye protection of the projection equipment is greatly improved, and the user experience is improved.

Referring to fig. 4, another embodiment of the present application provides a projection control method applied to a projection apparatus having a projection function, where the method includes:

step S210: a target projection distance is determined from the projection distance values collected by the range sensing assembly based on a target rule.

Wherein, the ranging sensing assembly can comprise a plurality of ranging sensors, and the target rule is a determination condition for determining the target projection distance from the projection distance values acquired by the plurality of ranging sensors. For example, as described in the foregoing embodiment, the target projection distance may be the minimum value of the projection distances acquired by the plurality of ranging sensors, in which case, if the target rule is to select the minimum value from the projection distance values acquired by the plurality of ranging sensors, the minimum value will be determined as the target projection distance. Similarly, if the target rule is to obtain an average of the projection distance values acquired by the plurality of ranging sensors, the average may be determined as the target projection distance.

It should be noted that, as for the principle and the beneficial effect of selecting the minimum value or the average value of the projection distance values acquired by the plurality of ranging sensors as the target projection distance, reference may be made to the description in the foregoing embodiments, and details are not repeated herein.

It should be noted that, in some possible embodiments, if there is only one ranging sensor, the projection distance value acquired by the ranging sensor may be directly determined as the target projection distance.

It should be noted that the distance measuring sensor is installed in different directions on the projection device, and the sensing signal for a human body approaching the projection device or tending to approach the projection device is different. In order to reduce the damage of projection laser of the projector to human eyes as much as possible, the installation direction of the ranging sensing assembly can be acquired before the target projection distance is acquired in the embodiment of the application.

Specifically, a direction identifier can be built in the distance measuring sensor, before the projection equipment leaves a factory, the identifier can be set according to the installation direction of the distance measuring sensor in the projection equipment, optionally, if the distance measuring sensor is installed in the direction of projection of the projection equipment, the direction identifier can be set to be '1', and if the distance measuring sensor is installed in the direction opposite to the projection direction of the projection equipment, the direction identifier can be set to be '-1'. In this manner, the projection device may determine the installation direction of each ranging sensor within the projection device based on identifying its direction identifier.

Optionally, the projection device may also be provided with a ranging sensor management module, and in some embodiments, the projection device may instruct all the ranging sensors installed inside the projection device to transmit detection signals to the same object, assuming that the object is a certain object facing the projection direction. The ranging sensors will be able to calculate the distance value from the object based on the strength of the object return signal. In this way, the obtained distance values may be divided, that is, the obtained distance values include a larger value and a smaller value, it can be understood that the distance sensor installed inside the projection device facing the projection direction is closer to the object, the distance sensor with the smaller measured distance value may be determined as the distance sensor installed in the projection device in the forward direction, and the distance sensor with the larger measured distance value may be determined as the distance sensor installed in the projection device in the backward direction.

On the basis of obtaining the installation direction of the ranging sensing assembly, whether a projection plane which can be used for projection exists in the installation direction of the ranging sensing assembly can be further detected, so that the maximum value of the initial danger detection range of the ranging sensing assembly can be determined according to the detection result. The detection method for detecting whether there is a projection plane available for projection may adopt an existing detection technology, and is not described herein again. It should be noted that the plane usable for projection may be understood as a plane where the projection screen of the foregoing embodiment is located, and may also be understood as a plane where the projection area of the projection apparatus is located.

As an embodiment, if a projection plane exists, the obtained projection distance of the reference target may be determined as the maximum value of the initial danger detection range, where the projection distance of the reference target represents the last used projection distance of the ranging sensing assembly. For example, the reference target projection distance may be the maximum of the memorized hazard detection distances used by the ranging sensing assembly at the last projection.

As another embodiment, if there is no projection plane, the specified threshold distance may be directly determined as the maximum value of the initial hazard detection range. The predetermined threshold distance may be a distance value that is considered to be set, or may be a fixed distance value set by the system.

As one way, before the projection distance of the target is obtained, a reference distance between a transparent protection component (for example, glass) arranged on the detection path of the ranging sensing assembly and the ranging sensing assembly may also be obtained, and then the sum of the reference distance and the second error parameter is taken as the minimum value of the initial danger detection range. Wherein, referring to the description of the foregoing embodiment, the second error parameter may be understood as the thickness of the glass covering the upper side of the projection device, and optionally, the second error parameter is a constant value for preventing error, and the specific value may be set according to the thickness of the glass.

For example, in one specific application scenario, as shown in fig. 5, a plurality of TOF laser ranging sensors (3 are shown in the figure, which is equivalent to the TOF laser ranging system labeled in the figure) are installed in a direction (vertically upward in the figure, that is, installed above the projection device facing the projection direction) close to the projection light source of the projection device. This kind of mounting means makes TOF laser rangefinder sensor comparatively close to the projection light source, therefore in case TOF laser rangefinder sensor detects human target, human target will appear in projection light source coverage to a great extent. In this case, the TOF laser ranging sensor can stably detect the presence of a human target in around 20ms, regardless of the direction from which the human body approaches the projection light source. It should be noted that, since the TOF laser ranging sensor emits laser light and receives signals returned by obstacles, in order to eliminate dust interference and protect the TOF laser ranging sensor as much as possible, the TOF laser ranging sensor may be covered with glass above the TOF laser ranging sensor, and the sum of the distance (d) between the TOF laser ranging sensor and the glass covered above the TOF laser ranging sensor and the second error parameter (x) of the glass may be set as the minimum value of the range of the dangerous detection distance of the TOF laser ranging sensor, which may be expressed by Dmin, and then Dmin is d + xcm (where x is a relatively small value, which may be used to avoid the influence of the glass, and may be, for example, 2, 3, etc., and is not limited in particular).

Optionally, for the maximum value of the range of the hazard detection distance, if the projection plane can be detected, the distance between the detected projection plane and the projection apparatus may be set to the maximum value Dmax of the range of the hazard detection distance. If a plane usable for projection cannot be detected in the mounting direction, 50cm may be set as the maximum value Dmax of the range of the hazard detection distance.

In another specific application scenario, as shown in fig. 6, a plurality of TOF laser ranging sensors (5 are shown in the figure, which is equivalent to the TOF laser ranging system labeled in the figure) are installed in a direction (for example, a direction facing a user in a back projection direction) where the angle between the projection device and the illumination direction of the projection light source is larger. The installation mode is opposite to the projection direction of the projection light source, and the danger of approaching the human body can be judged in advance. In this mounting, similarly, the sum of the distance (d) between the TOF laser ranging sensor and the glass covered above it and the second error parameter (x) of the glass may be set to the minimum Dmin, d + xcm of the range of the danger detection distance of the TOF laser ranging sensor; and 50cm is set as the maximum value Dmax of the dangerous distance range.

Step S220: and matching the target projection distance with an initial danger detection range.

It will be appreciated that, in accordance with the above description, the target projection distance may be matched to the maximum value of the initial hazard detection range.

Step S230: if the target projection distance is greater than or equal to the maximum value of the initial danger detection range, taking the maximum value of the initial danger detection range as the maximum value of the target danger detection range; if the target projection distance is smaller than the maximum value of the initial danger detection range, calculating the maximum value of the target danger detection range based on the target projection distance.

It should be noted that the initial risk detection range in the embodiment of the present application refers to a risk detection distance range, and thus, it is understood that the initial risk detection range includes the maximum value.

As one mode, if the projection distance of the target acquired in step S220 is greater than or equal to the maximum value of the initial risk detection range, the maximum value of the initial risk detection range may be directly determined as the maximum value of the target risk detection range, so as to increase the accuracy of the detection distance.

For example, in a specific application scenario, assuming that the initial risk detection range is 0-50cm, that is, the maximum value of the initial risk detection range is 50cm, if the target projection distance is 60cm, in this case, since the TOF laser ranging sensor used in the present application emits and receives invisible laser with a wavelength of 940nm, the measurement of the spatial time difference of flight can quickly and accurately obtain the nearest target distance in the detection range, and the TOF laser ranging sensor has an excellent capability of resisting ambient light interference, and can be applied to a bright environment, which is very stable and reliable. For example, the second generation product VL53L0X needs 33ms of measuring time and the maximum distance measurement is 200cm in a long-distance measuring mode; even in a high-speed measurement mode in which the measurement time is only 20ms, the measurement distance can be 50cm or more. Therefore, 50cm (i.e., the maximum value of the initial risk detection range) can be directly determined as the maximum value of the target risk detection range.

Alternatively, the maximum value of the initial danger detection range exemplified above is 50cm, considering that the measurement range of most TOF laser ranging sensors can reach 50cm, whereas in the course of actual operation, the measurement range of some TOF laser ranging sensors in the high-speed measurement mode is much higher than 50cm, in which case, in order to reduce the measurement error, an elastic distance parameter may be set so that when the target projection distance is greater than or equal to the maximum value of the initial danger detection range, the sum of the maximum value of the initial danger detection range and the elastic distance parameter can be determined as the maximum value of the target danger detection range.

For example, continuing with the above example as an example, if the elastic distance parameter is set to 5cm, 55cm (i.e., the sum of the maximum value of the initial risk detection range and the elastic distance parameter) may be directly determined as the maximum value of the target risk detection range.

As another mode, if the projection distance of the target acquired in step S220 is smaller than the maximum value of the initial danger detection range, the maximum value of the target danger detection range may be determined based on the projection distance value acquired by the ranging sensing assembly. Specifically, the difference between the projection distance of the target acquired by the plurality of distance measuring sensors and the first error parameter may be obtained, and then the maximum value of the target risk detection range may be obtained according to the value. Optionally, under the condition that the projection distance of the target is smaller than the maximum value of the initial danger detection range, the position of the projection device may move, and in order to improve the accuracy and reliability of the detection performance of the TOF laser ranging sensor, the maximum value of the target danger detection range needs to be determined based on the currently actually acquired projection distance value.

It will be appreciated that in order to avoid interference from dust and ambient light, the projection device in the embodiment of the present application is covered with a layer of material 201 with interference resistance, as shown in fig. 7, for example, the material 201 may be glass or other satisfactory interference-resistant material. Similarly, the projection device is also provided with a layer of anti-interference material 203 close to the light outlet of the projection laser, and the layer of anti-interference material covers the side face of the projection device. Wherein, the

materials

201 and 203 may be the same or different; the thicknesses of the two materials can be the same or different, and can be set according to actual conditions, and are not limited specifically. Where 202 in fig. 7 identifies the distance of the projection device to the material 201.

As one mode, the maximum value of the target risk detection range may be obtained by subtracting the minimum value of the projection distance values acquired by the plurality of distance measurement sensors from the first error parameter. The first error parameter may be understood as a thickness parameter of a material covering a light emitting surface of the projection laser of the projection apparatus, for example, a thickness of the material 203 shown in fig. 7. The minimum value of the projection distance acquired by the distance measuring sensor is poor to the first error parameter, so that the reflection error caused by dust or ambient light can be reduced, the projection accuracy of the projection equipment is improved, and the user experience is improved.

For example, in a specific application scenario, taking fig. 7 as an example, assuming that the thickness of the material 203 is 0.5cm, and the minimum value of the projection distance values acquired by the plurality of distance measuring sensors is 30cm, in this case, the maximum value of the target risk detection range can be obtained to be 28 cm.

It should be noted that, according to the above description, as one mode, if the TOF laser ranging sensor is installed inside the projection apparatus so as to face the projection direction, when the maximum value of the target projection distance is smaller than the maximum value of the preset initial risk detection range, referring to the principle of calculating the maximum value of the new target risk detection range described in the foregoing embodiment and the above example, the maximum value of the new target risk detection range is (d1, d2 … dn) min-xcm, where d1, d2 … dn indicates the minimum value among the projection distance values measured by the plurality of TOF laser ranging sensors.

Note that, if a projection plane available for projection is not detected in this mounting manner, the maximum value of the target risk detection range may be set to Dmax of 50cm, that is, may be kept unchanged.

It should be noted that, in the case that the TOF laser ranging sensor is installed inside the projection device in a manner of facing away from the projection direction, the principle of re-determining the maximum value of the target risk detection range of the ranging sensing assembly is similar to that in the case of installing the TOF laser ranging sensor facing toward the projection direction, and details are not repeated here.

Step S240: and judging whether a target object exists in the target danger detection range.

Step S250: the control reduces the display output brightness of the projection device.

The projection control method determines a target projection distance from projection distance values acquired by a plurality of distance measuring sensors of a distance measuring sensing assembly based on a target rule, then matches the target projection distance with a preset initial danger detection range, determines the maximum value of the initial danger detection range as the maximum value of the target danger detection range if the target projection distance is greater than or equal to the maximum value of the initial danger detection range, determines the maximum value of the target danger detection range based on the projection distance value acquired by the distance measuring sensing assembly if the target projection distance is less than the maximum value of the initial danger detection range, then detects whether a target object exists in the target danger detection range, and controls and reduces the display output brightness of projection equipment if the target object exists. The target danger detection range adaptive to the ranging sensing assembly is determined according to the matching result of the target projection distance and the initial danger detection range, the flexibility and the accuracy of re-determining the target danger detection range are improved, the display output brightness of the projection equipment is controlled and reduced to adapt to human eyes under the condition that a target object exists in the target danger detection range, and the reliability of human eye protection of the projection equipment is greatly improved.

Referring to fig. 8, another embodiment of the present application provides a projection control method applied to a projection apparatus having a projection function, where the method includes:

step S310: and judging whether the strength of the detection signal received by the ranging sensing assembly is greater than or equal to a preset ambient light interference resistance index.

The ambient light interference resistance index refers to a preset parameter (SignalLimit) of the TOF laser ranging sensor.

Since the ToF laser ranging sensor performs ranging by emitting and receiving invisible laser light having a wavelength of 940nm, the larger the amplitude signal value of the return wave is, the larger the signal value representing the measured object is, and the closer the distance of the measured object is. The outside of the ToF laser ranging sensor (i.e. the outside of the projection device) is covered with glass, and the cover glass, dust in the air, ambient light, and the like all cause the return signal to be weakened, thereby affecting the accuracy of the measurement result. Therefore, an anti-ambient light interference index may be set for erroneous determination due to dust, ambient light, and the like. By setting a proper SignalLimit value, weak detection signals returned by non-target obstacles such as dust, ambient light and the like can be filtered, and the purposes of eliminating misjudgment and improving measurement accuracy are achieved.

It should be noted that the required SignalLimit value for different laser ranging sensors may be different, and may be tested and set according to actual measurement experience. For example, for the laser ranging module with model number VL53L0X, when the SignalLimit of the corresponding laser ranging sensor can be set to 1.0 × 65536 during initialization, the erroneous determination can be almost eliminated.

As one way, in the embodiment of the present application, the ToF laser ranging sensor or the projection device may determine whether the intensity of the detection signal received by the ranging sensing component is greater than or equal to the preset ambient light interference resistance index. Optionally, if not, that is, when the returned detection signal of the obstacle target is lower than the SignalLimit value, the detection signal may be determined as an invalid detection signal, so that the problem of misjudgment caused by errors may be reduced.

Step S320: and acquiring the projection distance of the target acquired by the distance measurement sensing assembly based on the detection signal intensity.

It can be understood that, if the determination result in the step S310 is that the intensity of the detection signal received by the ranging sensing assembly is greater than or equal to the preset ambient light interference resistance index, the target projection distance can be obtained based on the corresponding intensity of the detection signal, so as to improve the accuracy and reliability of the measurement.

Step S330: and matching the target projection distance with an initial danger detection range.

Step S340: and determining the target danger detection range of the distance measurement sensing assembly according to the matching result.

Step S350: and judging whether a target object exists in the target danger detection range.

Step S360: and acquiring the motion trend of the target object.

The movement trend of the target object in the embodiment of the present application may be understood as a variation trend of the distance between the target object and the projection device. It can be understood that, if the target object is detected to be within the target hazard detection range, if the distance between the target object and the projection device is larger and larger, that is, the distance between the target object and the projection device is longer and longer, the influence of the intensity of the laser beam of the projection device on the target object is reduced, and the target object is safer, so that the safety level becomes higher. If the target object gets closer to the projection device, the target object may be in contact with the laser beam, and in this case, fatal damage due to untimely protection may occur.

Therefore, in order to avoid such damage, in the case that the target object is detected to be present in the target danger detection range, the motion trend of the target object is further acquired. As a mode, the distance between the target object and the projection device can be obtained continuously in real time, and the distance value obtained next time is compared with the value obtained last time, so that the motion trend of the target object can be analyzed in real time.

Step S370: and judging whether the movement trend meets a preset condition.

Alternatively, the preset condition may be that 3 times or more than 3 times are detected, and the distance between the target object and the projection device is decreasing. In this case, it can be judged that the target object is at risk of coming into continuous proximity to the TOF laser ranging sensor and coming into contact with the laser light source.

As one way, whether the number of times that the distance of the target object from the projection apparatus is in a trend of being less subtracted from the distance of the last target object from the projection apparatus is greater than 3 times may be obtained to determine whether the movement trend satisfies the preset condition.

Step S380: performing the control reduces a display output brightness of the projection device.

Optionally, if the determination result in step S370 is that the motion trend meets the preset condition, the projection device controls to reduce the display output brightness of the projection device to adapt to the vision of the target object, so as to achieve protection of human eyes.

In this embodiment, if the determination result in step S370 is that the motion trend does not satisfy the preset condition, and the security level of the current position of the projection device is considered to be higher, the intensity of the detection signal is discarded to avoid misjudgment, so as to improve the operation stability of the projection device.

Step S390: discarding the probe signal strength.

Optionally, if the determination result in step S310 is that the intensity of the detection signal received by the distance measuring sensing assembly is smaller than the preset ambient light interference resistance index, it may be determined that the detection signal received by the distance measuring sensing assembly is a signal reflected by dust, a light-transmitting protective member, or other tiny obstacles, and is an invalid signal, and therefore the intensity of the detection signal is discarded.

The projection control method provided by the application comprises the steps of judging whether the intensity of a detection signal received by a distance measurement sensing assembly is larger than or equal to a preset ambient light interference resistance index, if so, obtaining a target projection distance based on the intensity of the detection signal, matching the target projection distance with an initial danger detection range, determining a target danger detection range according to a matching result, detecting whether a target object exists in the target danger detection range, obtaining the movement trend of the target object, and controlling to reduce the display output brightness of projection equipment under the condition that the movement trend meets preset conditions. The projection error caused by misjudgment of the distance measurement sensing assembly is reduced, and the safe use coefficient of the projection equipment is improved by judging the motion trend of the target object.

A projection apparatus provided by the present application will be described with reference to fig. 9.

Referring to fig. 9, based on the projection control method, another projection apparatus 100 capable of performing the projection control method is further provided in the embodiment of the present application. Projection device 100 includes one or more (only one shown) processors 102, memory 104, data acquisition module 11, projection module 12, and projection control module 13 coupled to each other to support control of reducing the brightness of the display output of projection device 100. The memory 104 stores programs that can execute the content of the foregoing embodiments, and the processor 102 can execute the programs stored in the memory 104.

Processor 102 may include one or more processing cores, among other things. Processor 102 interfaces with various components throughout projection device 100 using various interfaces and circuitry to perform various functions of projection device 100 and process data by executing or executing instructions, programs, code sets, or instruction sets stored in memory 104 and invoking data stored in memory 104. Alternatively, the processor 102 may be implemented in hardware using at least one of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor 102 may integrate one or more of a Central Processing Unit (CPU), a video Processing Unit (GPU), a modem, and the like. Wherein, the CPU mainly processes an operating system, a user interface, an application program and the like; the GPU is used for rendering and drawing display content; the modem is used to handle wireless communications. It is understood that the modem may not be integrated into the processor 102, but may be implemented by a communication chip.

The Memory 104 may include a Random Access Memory (RAM) or a Read-Only Memory (Read-Only Memory). The memory 104 may be used to store instructions, programs, code sets, or instruction sets. The memory 104 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for implementing at least one function (such as a video image projection and playback function, etc.), instructions for implementing the various method embodiments described above, and the like. The storage data area may also store data created during use of projection device 100 (e.g., audio-visual data, chat log data), and the like.

The data acquisition module 11 is used to acquire a target projection distance (distance from the projection device to the projection plane). Wherein the ranging sensing assembly comprises a plurality of ranging sensors, for example, a plurality of TOF laser ranging sensors. The data acquisition module 11 may communicate with various networks such as the internet, an intranet, a wireless network, or with other devices via a wireless network. The wireless network may comprise a cellular telephone network, a wireless local area network, or a metropolitan area network. The data obtaining module 11 is further configured to determine whether a target object exists in the target risk detection range.

The projection module 12 is used for projecting the content to be projected of the projection apparatus 100, and may be, for example, laser projection or the like.

The projection control module 13 is configured to match the target projection distance with the initial danger detection range, and determine the target danger detection range according to the matching result, and the projection control module 13 is further configured to control to reduce the display output brightness of the projection module 12 when the target object exists according to the determination result of the data acquisition module 11. The range of the dangerous detection distance of the plurality of distance measuring sensors is determined in real time, so that the output brightness of the projection equipment can be flexibly controlled and reduced to adapt to human eyes under the condition that the distance measuring sensing assembly has a target object in the dangerous detection range, and reliable human eye protection is realized.

Referring to fig. 10, a block diagram of a computer-readable storage medium according to an embodiment of the present application is shown. The computer-readable medium 600 has stored therein a program code that can be called by a processor to execute the method described in the above-described method embodiments.

The computer-readable storage medium 600 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. Alternatively, the computer-readable storage medium 600 includes a non-volatile computer-readable storage medium. The computer readable storage medium 600 has storage space for program code 610 for performing any of the method steps of the method described above. The program code can be read from or written to one or more computer program products. The program code 610 may be compressed, for example, in a suitable form.

In summary, according to the projection control method, the projection device, and the storage medium provided by the present application, the target projection distance is obtained; then matching the target projection distance with the initial danger detection range; determining a target danger detection range according to a matching result; then judging whether a target object exists in the target danger detection range; and if so, controlling to reduce the display output brightness of the projection equipment. Therefore, the target dangerous detection range adaptive to the ranging sensing assembly is determined according to the matching result of the target projection distance and the initial dangerous detection range, misjudgment caused by dust and ambient light can be avoided, the display output brightness of the projection equipment is controlled and reduced to adapt to human eyes under the condition that a target object exists in the target dangerous detection range, the reliability of human eye protection of the projection equipment is greatly improved, and the user experience is improved.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not necessarily depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A projection control method, characterized in that the method comprises:

acquiring a target projection distance;

matching the target projection distance with an initial danger detection range;

determining a target danger detection range according to the matching result;

judging whether a target object exists in the target danger detection range;

and if so, controlling to reduce the display output brightness of the projection equipment.

2. The method of claim 1, wherein the initial hazard detection range comprises a maximum value, and wherein determining a target hazard detection range from the matching results comprises:

if the target projection distance is greater than or equal to the maximum value of the initial danger detection range, taking the maximum value of the initial danger detection range as the maximum value of the target danger detection range;

if the target projection distance is smaller than the maximum value of the initial danger detection range, calculating the maximum value of the target danger detection range based on the target projection distance.

3. The method of claim 2, wherein the step of obtaining a target projection distance comprises:

determining a target projection distance from projection distance values acquired by a ranging sensing assembly based on a target rule, wherein the ranging sensing assembly comprises a plurality of ranging sensors;

the step of calculating the maximum value of the target hazard detection range based on the target projection distance comprises:

and obtaining the difference value between the target projection distance acquired by the plurality of distance measuring sensors and the first error parameter, and obtaining the maximum value of the target danger detection range according to the difference value.

4. The method of claim 1, wherein the step of obtaining the target projection distance is preceded by the step of:

detecting whether a projection plane exists in the installation direction of the ranging sensing assembly;

determining the maximum value of the initial danger detection range of the distance measurement sensing assembly according to the detection result;

the matching of the target projection distance with an initial hazard detection range includes:

and matching the target projection distance with the maximum value of the initial danger detection range.

5. The method of claim 4, wherein the step of determining the maximum value of the initial hazard detection range of the ranging sensing assembly based on the detection results comprises:

if the projection plane exists, determining the obtained reference target projection distance as the maximum value of the initial danger detection range, wherein the reference target projection distance represents the last used target projection distance of the distance measurement sensing assembly;

and if the projection plane does not exist, determining the specified threshold distance as the maximum value of the initial danger detection range.

6. The method of claim 1, wherein the step of obtaining the target projection distance is preceded by the step of:

acquiring a reference distance between a light-transmitting protective part arranged on a detection path of a ranging sensing assembly and the ranging sensing assembly;

and taking the sum of the reference distance and the second error parameter as the minimum value of the initial danger detection range.

7. The method of claim 1, wherein the step of obtaining a target projection distance comprises:

judging whether the strength of a detection signal received by the ranging sensing assembly is greater than or equal to a preset ambient light interference resistance index or not;

if yes, acquiring a target projection distance acquired by the distance measurement sensing assembly based on the detection signal intensity;

and if not, discarding the detection signal intensity.

8. The method of any of claims 3-7, wherein the ranging sensing assembly comprises a plurality of ranging sensors, the plurality of ranging sensors being adjacently disposed and an installation distance between the plurality of ranging sensors being set to 15 cm.

9. The method of claim 1, wherein the step of controlling the reduction of the display output brightness of the projection device is preceded by:

acquiring the motion trend of the target object;

judging whether the movement trend meets a preset condition or not;

and if so, executing the control to reduce the display output brightness of the projection equipment.

10. The projection equipment is characterized by comprising a data acquisition module, a projection module and a projection control module;

the data acquisition module is used for acquiring a target projection distance;

the projection control module is used for matching the target projection distance with an initial danger detection range and determining a target danger detection range according to a matching result;

the data acquisition module is also used for judging whether a target object exists in the target danger detection range;

the projection control module is also used for controlling and reducing the display output brightness of the projection module when the target object exists according to the judgment result of the data acquisition module.

11. A computer-readable storage medium, having a program code stored therein, wherein the program code when executed by a processor performs the method of any of claims 1-9.