Real object candid photographing prevention method and device based on human eye and camera time domain response difference

Abstract

The invention discloses a real object candid photographing prevention method and device based on human eye and camera time domain response difference, belongs to the technical field of optical display, and aims to solve the problem that candid photographing prevention cannot be performed on a real object in the prior art. The upper computer is respectively connected with the light source projection device and the holder, outputs driving instructions of the light source projection device and the holder, and is used for controlling the light source projection device and the holder to work; the light source projection device is mounted on the holder and is used for emitting a modulation illumination light source containing a watermark image to the surface of the candid shooting prevention object according to a received instruction of the upper computer; and the holder is used for controlling the direction of the light beam emitted by the light source projection device according to the received instruction of the upper computer. Based on the principle of time domain response difference between human eyes and a camera, the method and device for modulating light source irradiation are adopted, and the application range of the candid photographing prevention method is widened. And the method is simple and easy to operate.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical display, and relates to a method and device for preventing hidden camera shots of real objects based on the time domain response difference between human eyes and cameras. Background Art

[0002] In today's data-rich, highly interactive society, smartphones, digital cameras and other shooting devices have become an indispensable part of people's daily lives. However, this also provides opportunities for criminals to take advantage of the convenience of these devices to shoot and disseminate content involving personal privacy or legally protected intellectual property without authorization. In addition, in some content confidentiality occasions, projection displays, PPT displays, etc., there is a risk of leakage due to the lack of limited blocking measures. In addition, with the development of technology, the quality of shooting is getting higher and higher, which exacerbates this problem. Therefore, the need for methods and devices to effectively prevent cameras and other shooting devices from secretly shooting real objects is becoming more and more urgent.

[0003] See the journal "Journal of Display Technology", the paper published by Zhai Guangtao et al. is titled "Defeating Camcorder Piracy by Temporal Psychovisual Modulation", which provides a technology to prevent cameras from shooting movie videos. It aims to interfere with the quality of movie videos shot by cameras through temporal psychovisual modulation technology. The specific method is to decompose the movie video content into multiple frames and quickly alternately display these specially designed frames, thereby introducing interference artifacts in the final recorded video, thereby preventing or reducing voyeurism. However, the application scope of this method is limited to the protection of movie videos and other content from voyeurism, and it cannot effectively prevent voyeurism of physical objects in the physical world (such as screens, calligraphy and paintings, etc.). Summary of the invention

[0004] The present invention aims to solve the problem that the prior art cannot prevent real objects from being secretly photographed, and proposes a method and device for preventing real objects from being secretly photographed based on the difference in time domain responses between human eyes and cameras.

[0005] The technical solution of the present invention to solve the technical problem is:

[0006] The present invention provides a physical anti-secret-shooting device based on the time domain response difference between human eyes and cameras, which includes a host computer, a light source projection device and a pan-tilt platform; the host computer is respectively connected to the light source projection device and the pan-tilt platform, outputs driving instructions of the light source projection device and the pan-tilt platform, and is used to control the operation of the light source projection device and the pan-tilt platform; the light source projection device is installed on the pan-tilt platform, and is used to emit a modulated illumination light source containing a watermark image to the surface of the anti-secret-shooting object according to the instructions received from the host computer; the pan-tilt platform is used to control the direction of the light beam emitted by the light source projection device according to the instructions received from the host computer.

[0007] The light source projection device comprises: a host computer interface, a control module, an illumination light source, a digital micro-mirror and a projection objective lens; the host computer interface is respectively connected to the control module and the illumination light source, and the host computer interface can receive instructions issued by the host computer and send them to the control module and the illumination light source; the control module is connected to the digital micro-mirror, and the control module controls the digital micro-mirror to reflect light according to the received watermark image file and instructions; the illumination light source emits light and is incident on the digital micro-mirror; the digital micro-mirror reflects the watermark image light to the projection objective lens, so as to emit a modulated illumination light source containing a watermark image to the surface of an object to be protected from voyeurism.

[0008] A method for preventing hidden camera shooting of physical objects based on the time domain response difference between human eyes and cameras, comprising the following steps:

[0009] Step 1: The host computer outputs the drive instruction.

[0010] The host computer outputs instructions to the light source projection device, and frequency-modulates the light source containing the "watermark" image information in the time domain, so that the bright frames and dark frames are alternately emitted at a critical flicker fusion frequency not less than the human eye; the projected watermark image is adjusted in the spatial domain, which includes two display frames: one is a bright frame with a bright pattern and a dark background, and the other is a dark frame with a dark pattern and a bright background; the light intensity of the pattern and background of the bright and dark frames in the watermark image is adjusted; the host computer outputs a driving instruction to the pan / tilt head, so that the pan / tilt head controls the direction of the light beam emitted by the light source projection device.

[0011] Step 2: The light source projection device emits a modulated illumination light source.

[0012] The light source projection device, according to the instructions received from the host computer, alternately emits bright frame and dark frame modulated light sources to the surface of the anti-sneak peek object at a frequency not less than the critical flicker fusion frequency to cover the surface of the anti-sneak peek object. The flickering frequency of the bright frame and the dark frame can be changed randomly to deal with the situation where criminals change the exposure time of the camera to avoid interference from the modulated illumination light source.

[0013] Step three, the pan / tilt control modulates the light beam direction of the illumination light source.

[0014] The pan-tilt platform moves according to the instructions received from the host computer, so that the modulated illumination light source containing the watermark image emitted by the light source projection device installed on the pan-tilt platform moves accordingly, so as to control the modulated illumination light source to point to the surface of the object to be protected from sneak shots.

[0015] The beneficial effects of the present invention are:

[0016] 1) Based on the principle of the difference in time domain response between the human eye and the camera, the present invention adopts the method of modulated light source illumination to broaden the scope of application of the anti-secret photography method and expand the scope of digital content to any physical object in the room. At the same time, the watermark image information embedded in the photos and videos can not only act as an "artifact" to greatly reduce the quality of the photos and videos taken, but also act as a "watermark" to protect the copyright of the target object and track the location information of the photographer.

[0017] 2) Compared with the traditional digital content preprocessing method, the present invention does not need to preprocess the digital source file, thus avoiding the risk of digital content being stolen in the early preparation stage.

[0018] 3) Traditional digital content preprocessing methods need to be reprocessed for different digital contents, which is cumbersome and labor-intensive. The method and device of the present invention have the advantages of being simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of the anti-secret camera device provided by the present invention.

[0020] Figure 2 This is a simplified structural diagram of the light source projection device provided by the present invention.

[0021] Explanation of the reference numerals: 1 host computer; 2 light source projection device; 3 pan / tilt head; 4 anti-sneak-shooting object; 2-1 host computer interface; 2-2 control module; 2-3 illumination light source; 2-4 digital micro-mirror; 2-5 projection objective lens.

[0022] Figure 3 Schematic diagram of a dark frame with a dark pattern and a light background.

[0023] Figure 4 It is a schematic diagram of a bright frame with a bright pattern and a dark background.

[0024] Figure 5 Schematic diagram of the projected time frame sequence.

[0025] Figure 6 Schematic diagram of the light source intensity changing with time.

[0026] Figure 7 Schematic diagram of the results taken with a smartphone. Figure 7 (a) shows a dark frame with a dark pattern and a bright background in the modulated illumination source. Figure 7 (b) shows a bright frame with a bright pattern and a dark background embedded in the modulated illumination source. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0028] like Figure 1As shown, the physical anti-secret-shooting device of the present invention based on the time domain response difference between the human eye and the camera includes a host computer 1, a light source projection device 2 and a pan-tilt 3. The host computer 1 is connected to the light source projection device 2 and the pan-tilt 3 respectively, and outputs driving instructions of the light source projection device 2 and the pan-tilt 3 to control the operation of the light source projection device 2 and the pan-tilt 3. The light source projection device 2 is installed on the pan-tilt 3, and is used to emit a modulated illumination light source containing a watermark image to the surface of the anti-secret-shooting object 4 according to the instructions received from the host computer 1; the pan-tilt 3 is used to control the direction of the light beam emitted by the light source projection device 2 according to the instructions received from the host computer 1.

[0029] The host computer 1 can be programmed and store operation instructions, process the control signal input by the operator to make it an operation instruction that can be recognized by the light source projection device 2 and the pan-tilt head 3, and output the operation instruction to the light source projection device 2 and the pan-tilt head 3 to realize the control of the light source projection device 2 and the pan-tilt head 3.

[0030] like Figure 2 As shown, the light source projection device 2 includes: a host computer interface 2-1, a control module 2-2, an illumination light source 2-3, a digital micro-mirror 2-4 and a projection objective lens 2-5. The host computer interface 2-1 is connected to the control module 2-2 and the illumination light source 2-3 respectively, and the host computer interface 2-1 can receive instructions issued by the host computer 1 and send them to the control module 2-2 and the illumination light source 2-3; the control module 2-2 is connected to the digital micro-mirror 2-4, and the control module 2-2 controls the digital micro-mirror 2-4 to reflect light according to the received watermark image file and instructions; the illumination light source 2-3 emits light incident on the digital micro-mirror 2-4; the digital micro-mirror 2-4 reflects the watermark image light to the projection objective lens 2-5, so as to emit the modulated illumination light source containing the watermark image to the surface of the anti-secretly photographed object 4.

[0031] The watermark image includes two display frames: one is a dark frame with a dark pattern and a bright background, such as Figure 3 The other is a bright frame with a bright pattern and a dark background, such as Figure 4 As shown. Figure 5 As shown, the light source projection device 2 displays light frames and dark frames alternately every several microseconds, and the frequency of the alternating display is not less than the critical flicker fusion frequency of the human eye, wherein the flickering frequency of the light frames and the dark frames can be changed randomly to deal with criminals changing the exposure time of the camera to avoid interference from the modulated illumination light source.

[0032] like Figure 6As shown, the light intensity of the pattern L1 and the background L2 areas in the modulated illumination light source emitted by the light source projection device 2 at the same time is a and b; the light intensity of the two areas changes in a and b with a period of T=t1+t2; within the T period, the time when the light intensity of the pattern L1 is b and the light intensity of the background L2 is a is t1, and the time when the light intensity of the pattern L1 is a and the light intensity of the background L2 is b is t2, and t1=t2.

[0033] An optional small-area anti-secret photography embodiment of the present invention: the control module 2-2 is a DLP control board, and the DLP control board is a DLPC350 controller; the lighting light source 2-3 is an R, G, B LED; the digital micro-mirror 2-4 is a DLP4500 digital micro-mirror.

[0034] The platform 3 may be an electric platform, and the light source projection device 2 is mounted on the electric platform. According to the received instruction of the host computer 1, the platform 3 drives the motor to move, and finally makes the modulated illumination light source emitted by the light source projection device 2 point to the surface of the object 4 to be protected from sneak shots.

[0035] A method for preventing hidden camera shooting of physical objects based on the time domain response difference between human eyes and cameras, comprising the following steps:

[0036] Step 1: The host computer 1 outputs a drive instruction.

[0037] The host computer 1 outputs instructions to the light source projection device 2, and frequency modulates the light source containing the "watermark" image information in the time domain, so that the bright frame and the dark frame are alternately lit at a critical flicker fusion frequency not less than the human eye; the projected watermark image is adjusted in the spatial domain, which includes two display frames: one is a bright frame with a bright pattern and a dark background, and the other is a dark frame with a dark pattern and a bright background; the light intensity of the pattern and background of the bright and dark frames in the watermark image is adjusted. The host computer 1 outputs a driving instruction to the pan / tilt 3, so that the pan / tilt 3 controls the direction of the light beam emitted by the light source projection device 2.

[0038] Step 2: the light source projection device 2 emits a modulated illumination light source.

[0039] The light source projection device 2, according to the instructions received from the host computer 1, emits light frames and dark frames modulated light sources alternately at a certain frequency to the anti-sneak peek object surface 4 to cover the anti-sneak peek object surface 4, wherein the flashing frequency of the light frames and the dark frames can be changed randomly to deal with criminals changing the exposure time of the camera to avoid interference from the modulated illumination light source.

[0040] Step three, the pan / tilt platform 3 controls the direction of the light beam of the modulated illumination light source.

[0041] The pan-tilt platform 3 moves according to the received command from the host computer 1, so that the modulated light source containing the watermark image emitted by the light source projection device 2 installed on the pan-tilt platform 3 moves accordingly, so as to control the modulated illumination light source to point to the surface of the anti-secretly-photographing object 4.

[0042] In this embodiment, the watermark image contained in the modulated illumination light source emitted by the light source projection device 2 is a QR Code, and the object 4 to prevent candid photography is a physical text information. Without substantially changing the technical content, it should also be regarded as the scope of the implementation of the present invention. The protection scope of the present invention is not limited to the above embodiments, and all technical solutions under the idea of ​​the present invention belong to the protection scope of the present invention.

[0043] This embodiment uses a smart phone to test the effectiveness of the embodiment in preventing hidden camera shots. Two watermark images can be embedded in the actual photos. One is: Figure 7 (a) shows a dark frame with a dark pattern and a bright background in the modulated illumination source, and the other is as shown in Figure 7 (b) shows a bright frame with a bright pattern and a dark background in the modulated illumination source; the human eye sees a spatially uniform and stable illumination source, and cannot detect the hidden watermark image information, which does not affect the viewing experience of the human eye when viewing these objects normally. The watermark image embedded in the photos taken by the smartphone can not only act as an "artifact" to greatly reduce the quality of the photos and videos taken, but also act as a "watermark" to protect the copyright of the target object and track the location information of the photographer to achieve the function of preventing physical objects from being secretly photographed.

Claims

1. A physical anti-secret camera device based on the time domain response difference between human eyes and cameras, characterized in that: The invention comprises a host computer (1), a light source projection device (2) and a pan-tilt platform (3); the host computer (1) is connected to the light source projection device (2) and the pan-tilt platform (3) respectively, and outputs driving instructions of the light source projection device (2) and the pan-tilt platform (3) to control the operation of the light source projection device (2) and the pan-tilt platform (3); the light source projection device (2) is installed on the pan-tilt platform (3) to emit a modulated illumination light source containing a watermark image to the surface of an anti-secretly-photographing object (4) according to the instructions received from the host computer (1); The pan / tilt platform (3) is used to control the direction of the light beam emitted by the light source projection device (2) according to the instructions received from the host computer (1).

2. The physical anti-secret camera device based on the time domain response difference between human eyes and cameras according to claim 1, characterized in that: The light source projection device (2) comprises: a host computer interface (2-1), a control module (2-2), an illumination light source (2-3), a digital micro-mirror (2-4) and a projection objective lens (2-5); the host computer interface (2-1) is respectively connected to the control module (2-2) and the illumination light source (2-3); the host computer interface (2-1) can receive instructions issued by the host computer (1) and send them to the control module (2-2) and the illumination light source (2-3); the control module (2-2) is connected to the digital micro-mirror (2-4); the control module (2-2) controls the digital micro-mirror (2-4) to reflect light according to the received watermark image file and instructions; the illumination light source (2-3) emits light that is incident on the digital micro-mirror (2-4); the digital micro-mirror (2-4) reflects the watermark image light to the projection objective lens (2-5), so as to emit a modulated illumination light source containing the watermark image to the surface of the anti-secretly photographed object (4).

3. The physical anti-secret camera device based on the time domain response difference between human eyes and cameras according to claim 1, characterized in that: The watermark image includes two display frames: one is a dark frame with a dark pattern and a bright background, and the other is a light frame with a bright pattern and a dark background. The light source projection device 2 displays the light frame and the dark frame alternately every several microseconds, and the frequency of the alternating display is not less than the critical flicker fusion frequency of the human eye. The flickering frequency of the light frame and the dark frame can be randomly changed to deal with the interference of the modulated illumination light source in case of criminals changing the exposure time of the camera.

4. The anti-secret-shooting method based on the physical anti-secret-shooting device based on the time domain response difference between human eyes and cameras as claimed in claim 1 is characterized in that: It includes the following steps: Step 1: the host computer (1) outputs a drive instruction; The host computer (1) outputs instructions to the light source projection device (2), performs frequency modulation on the light source containing the watermark image information in the time domain, so that the bright frame and the dark frame are alternately emitted at a critical flicker fusion frequency not less than the human eye; adjusts the projected watermark image in the space domain, which includes two display frames: a bright frame with a bright pattern and a dark background, and a dark frame with a dark pattern and a bright background; adjusts the light intensity of the pattern and background of the bright and dark frames in the watermark image; the host computer (1) outputs a driving instruction to the pan / tilt (3), so that the pan / tilt (3) controls the direction of the light beam emitted by the light source projection device (2); Step 2: the light source projection device (2) emits a modulated illumination light source; The light source projection device (2) emits light frames and dark frames modulated light sources alternately at a certain frequency to the surface of the object (4) to be protected from voyeurism according to the instructions received from the host computer (1), so as to cover the surface of the object (4) to be protected from voyeurism, wherein the flashing frequency of the light frames and the dark frames can be changed randomly to prevent the interference of the modulated illumination light source by changing the exposure time of the camera in case of criminals; Step 3, the pan / tilt platform (3) controls the direction of the light beam of the modulated illumination light source; The pan-tilt platform (3) moves according to the received command from the upper computer (1), so that the modulated light source containing the watermark image emitted by the light source projection device (2) installed on the pan-tilt platform (3) moves accordingly, so as to control the modulated illumination light source to point to the surface of the anti-secretly-photographing object (4).

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