Watermark embedding method and display apparatus

Abstract

The present application provides a watermark embedding method and a display device. The watermark embedding method comprises the following steps. An input image is received by a processing circuit. A watermark signal is generated by the processing circuit according to time series data and a preset scheme to generate watermark information of the watermark signal. In each of a plurality of consecutive periods, the phases of the time series data are opposite and the average values of the gray scales of the preset scheme are equal during a dark state period and a bright state period. The watermark signal is embedded into the input image signal by the processing circuit to generate an output image signal with the watermark information. An image is displayed by a display panel according to the output image signal.

Description

Technical Field

[0001] This application relates to a watermark embedding method, and more particularly to a watermark embedding method and display device that are difficult for human vision to detect. Background Technology

[0002] In modern life, with the dramatic increase in people's reliance on monitors, users often need to use them to present presentations, data, screens, and images. However, in such situations, if the images or screens displayed on the monitor do not indicate their source and are photographed and freely disseminated, it is usually very difficult to trace their origin. Therefore, how to improve the situation where display data leaks out after being photographed and whose source cannot be traced is an important issue in this field. Summary of the Invention

[0003] This disclosure provides a watermark embedding method comprising the following steps: An input image is received by a processing circuit. A watermark message is generated by the processing circuit based on time-series data and a preset scheme. In each of multiple consecutive periods, during the dark and bright states, the phases of the time-series data are opposite, and the average grayscale values ​​of the preset scheme are equal. The watermark signal is embedded into the input image signal by the processing circuit to generate an output image signal with the watermark message. An image is displayed on a display panel based on the output image signal.

[0004] This disclosure provides an electronic device. The display device includes processing circuitry and a storage device. The processing circuitry is electrically coupled to the display device. The processing circuitry is configured to perform the following steps: receiving an input image; generating a watermark message based on time-series data and a preset scheme, wherein the phase of the time-series data is opposite during the dark and bright periods of each of a plurality of consecutive periods, and the average grayscale values ​​of the preset scheme are equal; embedding the watermark message into the input image signal to generate an output image signal having the watermark message.

[0005] In summary, the display device provided in this disclosure is used to display an image with watermark information, and when the camera captures the display device, it extracts the information of the watermark pattern, thereby ensuring the data source and further reducing the risk of data leakage. Attached Figure Description

[0006] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the accompanying drawings are described below:

[0007] Figure 1 These are schematic diagrams illustrating display devices and electronic devices according to some embodiments of this disclosure.

[0008] Figure 2This is a flowchart illustrating a watermark embedding method according to some embodiments of this disclosure.

[0009] Figure 3 This is a schematic diagram illustrating time-series data, preset schemes, and grayscale information of watermark signals according to some embodiments of this disclosure.

[0010] Figure 4 This is a schematic diagram illustrating the input image signal, the output image, and the image perceived by human vision, based on some embodiments of this disclosure.

[0011] Figure 5 This is a schematic diagram illustrating the grayscale information of the watermark signal, the camera shutter speed, and the output image according to some embodiments of this disclosure.

[0012] Figure 6 This is a schematic diagram illustrating the grayscale information of the watermark signal, the camera shutter speed, and the output image according to some embodiments of this disclosure.

[0013] Figure 7 These are schematic diagrams illustrating camera devices, display devices, and screens according to some embodiments of this disclosure.

[0014] Figure 8A as well as Figure 8B This is a schematic diagram of a screen captured by a camera device according to some embodiments of this disclosure.

[0015] Figure 9 This is a schematic diagram illustrating time-series data, preset schemes, and watermark signals according to some embodiments of this disclosure.

[0016] Figure 10 This is a schematic diagram illustrating time-series data, preset schemes, and watermark signals according to some embodiments of this disclosure.

[0017] Figure 11 This is a schematic diagram illustrating time-series data, preset schemes, and watermark signals according to some embodiments of this disclosure.

[0018] [Symbol Explanation]

[0019] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the appended symbols are explained as follows:

[0020] 100: Display device

[0021] 110: Processing circuit

[0022] 120: Display panel

[0023] 130: Storage device

[0024] 200: Watermark Embedding Method

[0025] 410, 411, 412: Screen

[0026] 710: Camera device

[0027] 720: Screen

[0028] 730: Display device

[0029] 811, 812: Footage taken

[0030] HUMV: screen

[0031] DEC: Electronic Devices

[0032] GPU: Graphics Processor

[0033] VIN: Input image signal

[0034] VOUT: Output image signal

[0035] TSD: Time Series Data

[0036] PGP: Preset Scheme

[0037] TSD, TSDa~TSDd: Time series data

[0038] PGP, PGPa~PGPd: ​​Preset scheme

[0039] IGRAa~IGRAd: Grayscale Messages

[0040] IMG1L~IMG3L, IMG1H~IMG3H: Screen

[0041] C1~C3: Period

[0042] S210~S240: Steps Detailed Implementation

[0043] The following detailed description provides examples in conjunction with the accompanying drawings. However, the provided examples are not intended to limit the scope of this disclosure, and the description of the structural operation is not intended to limit the order of execution. Any structure resulting from the recombination of elements and producing an apparatus with equivalent functionality is within the scope of this disclosure. Furthermore, the illustrations are for illustrative purposes only and are not drawn to their original dimensions. For ease of understanding, the same or similar elements will be designated with the same symbols in the following description.

[0044] Unless otherwise specified, the terms used throughout the specification and claims generally have their ordinary meaning in the context of the art, the disclosure, and the specific content.

[0045] Furthermore, the terms "comprising," "including," "having," "containing," etc., used in this document are all open-ended terms, meaning "including but not limited to." Additionally, the term "and / or" as used in this document includes any one or more of the related listed items and all combinations thereof.

[0046] In this document, when a component is referred to as “coupled” or “coupled,” it may mean “electrically coupled” or “electrically coupled.” “Coupled” or “coupled” can also be used to indicate that two or more components operate or interact with each other. Furthermore, although terms such as “first,” “second,” etc., are used in this document to describe different components, these terms are only used to distinguish components or operations described using the same technical terms.

[0047] Please see Figure 1 , Figure 1 This is a schematic diagram illustrating a display device 100 and an electronic device DEC according to some embodiments of this disclosure. In some embodiments, the display device 100 may be implemented as a display. In other embodiments, the display device 100 may be implemented as a screen of a computer, tablet, or mobile phone, and its associated elements, components, circuits, or modules. Therefore, this application is not limited thereto.

[0048] like Figure 1 As shown, the display device 100 includes a processing circuit 110, a storage device 130, and a display panel 120. In some embodiments, the processing circuit 110 may be a central processing unit, a microprocessor, a graphics processor, a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or other hardware devices suitable for retrieving or executing instructions stored in memory.

[0049] Storage device 130 may be implemented as an electrical, magnetic, optical memory device or other memory for storing instructions or data. In some embodiments, storage device 130 may be implemented as volatile or non-volatile memory. In some embodiments, storage device 130 may be implemented as random access memory (RAM), dynamic random access memory (DRAM), magnetoresistive random access memory (MRAM), phase-change random access memory (PCRAM) or other memory.

[0050] In some embodiments, the electronic device DEC includes a graphics processing unit (GPU). The GPU provides a first image signal VIDEO1 to the processing circuit 110. The processing circuit 110 receives the first image signal VIDEO1 from the GPU and acquires time-series data TSD and a preset scheme PGP from the storage device 130. The time-series data TSD is used to determine the display timing of the watermark in a relatively bright or relatively dark state. The preset scheme PGP includes the position to be overlaid for the watermark pattern and grayscale data.

[0051] The processing circuit 110 generates a watermark signal based on the time-series data TSD and the preset scheme PGP. Furthermore, the processing circuit 110 embeds the watermark signal into the input image signal VIN, thereby generating an output image signal VOUT for display on the display panel 120.

[0052] Please refer to the following: Figures 1 to 4 . Figure 2 This is a flowchart illustrating a watermark embedding method 200 according to some embodiments of this disclosure. Figure 3 This is a schematic diagram illustrating time series data TSDa, preset scheme PGPa, and grayscale information IGRAA of the watermark signal according to some embodiments of this disclosure. Figure 4 This is a schematic diagram illustrating screen 410 of the input image signal, screens 411 and 412 of the output image, and screen HUMV of human visual perception, according to some embodiments of this disclosure. In some embodiments, the grayscale information of the watermark signal can be understood from the watermark information of the watermark signal.

[0053] like Figure 2As shown, the watermark embedding method 200 includes steps S210 to S240. In step S210, the processing circuit 110 receives an input image VIN. In some embodiments, the processing circuit 110 receives the input image VIN from a graphics processing unit (GPU).

[0054] In step S220, the processing circuit 110 generates the grayscale message IGRAAa of the watermark signal based on the time series data TSDa and the preset scheme PGPa. For example... Figure 3 As shown, in the periods t0-t1, t2-t3, and t4-t5 of periods C1-C3, the phase of the time series data TSDa is negative (value -1). Therefore, the periods t0-t1, t2-t3, and t4-t5 of each period C1-C3 can be understood from the dark phase of the watermark. On the other hand, in the periods t1-t2 and t3-t4 of periods C1-C2, the phase of the time series data TSDa is positive (value +1). Therefore, the periods t1-t2 and t3-t4 of each period C1-C2 can be understood from the bright phase of the watermark. In other words, the phase of the time series data TSDa is opposite during the dark phase (e.g., time t0-t1) and the bright phase (e.g., time t1-t2) of each period (e.g., period C1).

[0055] In some embodiments, to make the watermark pattern difficult or impossible for human vision to detect, the preset scheme sets the value of PGPa to be equal during the dark state (e.g., t0-t1) and the bright state (e.g., time t1-t2) in each period (e.g., any one of periods C1-C3). The watermark flashes at a high frequency in both high and low grayscale levels, creating a visual persistence phenomenon that makes it difficult for human vision to detect.

[0056] In some embodiments, it is assumed that the preset scheme PGPa is set to a value of "x", where "x" can be any value. In some embodiments, the processing circuit 110 multiplies the time series data TSDa and the preset scheme PGPa to generate the grayscale message IGRAAa of the watermark signal. Therefore, the value range of the grayscale message IGRAAa of the watermark signal will fall between "-x" and "+x".

[0057] Specifically, during the dark state period (e.g., time t0-t1, t2-t3, or t4-t5) of each period (e.g., any one of periods C1 to C3), the grayscale value of the grayscale message IGRAAa of the watermark signal is "-x". Therefore, the image displayed on the display panel 120 will include the image of the relatively low grayscale watermark (e.g., the triangle pattern in the low grayscale of the image IMG1L, IMG2L, or IMG3L).

[0058] During the bright state period (e.g., time t1-t2, t3-t4) in each period (e.g., any one of periods C1-C2), the grayscale value of the grayscale message IGRAAa of the watermark signal is "+x". Therefore, the image displayed on the display panel 120 will include the image of the relatively high grayscale watermark (e.g., the triangle pattern in the high grayscale of the image IMG1H, IMG2H or IMG3H).

[0059] In some embodiments, the frequency of the time series data TSDa (the reciprocal of the duration of each period (e.g., periods C1 to C3)) corresponds to / approximates the refresh rate of the display panel at 120 Hz (e.g., 30, 60, 120 Hz or other frequencies). In other embodiments, the frequency of the time series data TSDa corresponds to / approximates a multiple of the refresh rate of the display panel at 120 Hz.

[0060] Thus, the displayed image on the display panel 120 contains a watermark pattern that flickers at a high frequency (e.g., 60, 120, 240 Hz or other frequencies), making it difficult for the human eye to detect.

[0061] like Figure 4 As shown, after the input image is processed by the processing circuit 110 to embed the grayscale information IGRAA of the watermark signal, the output image frame 411 contains the watermark pattern at a low grayscale, and the output image frame 412 contains the watermark pattern at a high grayscale. In some embodiments, the output image frames 411 and 412 correspond to the dark state (e.g., t0 to t1) and the bright state period (e.g., t1 to t2) of a period (e.g., any one of periods C1 to C3) of the time series data TSDa. Furthermore, by setting the frequency of the time series data TSDa to a certain value (e.g., 30 or 60 Hz) or higher, the image HUMV perceived by human vision will not contain the watermark pattern.

[0062] Please refer to Figures 1 through 8. Figure 5 This is a schematic diagram illustrating the grayscale information IGRAAa of the watermark signal, the camera shutter speed, and the output image frames IMG1L to IMG3L and IMG1H to IMG3H, according to some embodiments of this disclosure. Figure 6 This is a schematic diagram illustrating the grayscale information IGRAAa of the watermark signal, the camera shutter speed, and the output image frames IMG1L to IMG3L and IMG1H to IMG3H, according to some embodiments of this disclosure. Figure 7 This is a schematic diagram illustrating a camera device 710, a display device 730, and a screen 720 according to some embodiments of this disclosure. Figure 7 The display device 730 in the middle corresponds to Figure 1The display device 100 in the middle. Figure 8A as well as Figure 8B This is a schematic diagram of a photograph taken by a camera device 710 of a display device 730 screen 720 according to some embodiments of this disclosure.

[0063] In some embodiments, such as Figure 5 As shown, when using the camera device 710 to capture images of the screen 720 of the display device 730, if the reciprocal of the exposure time of the camera device 710 (e.g., 1 / 60 second) corresponds to or is equal to the frequency of the time series data TSDa, then during the exposure time of the camera device 710, the integral average of the watermark pattern will be equal to the grayscale of the original image, resulting in the captured image not carrying the information of the watermark image.

[0064] In some embodiments, such as Figure 6 As shown, the frequency of the time-series data TSDa is set to a prime number (e.g., 23Hz, 37Hz, 41Hz, 43Hz, 53Hz, 73Hz, 79Hz, 83Hz, 127Hz, 131Hz, 137Hz, 139Hz, 149Hz, 251Hz, 257Hz, 263Hz, 269Hz, or other prime numbers) or a specific value that does not correspond to the exposure time of the camera device 710. In this case, the frequency of the time-series data TSDa is different from and / or approximately equal to the refresh rate of the display panel 120. Thus, when the camera device 710 captures an image of the screen 720 of the display device 730, the integral average of the watermark pattern will differ from the grayscale of the original image during the exposure time of the camera device 710, resulting in the captured image carrying the information of the watermark image. Figure 8A as well as Figure 8B As shown, the captured image 811 produced by the camera device 710 capturing the screen 720 of the display device 730 includes a low grayscale watermark pattern (e.g., Figure 8A The image 812 contains a low-grayscale watermark pattern (e.g., "AUO"), and the image is captured in a low-grayscale area. Figure 8A (AuO) at higher gray levels. In other words, when the reciprocal of the exposure period of the camera device 710 cannot completely correspond to the frequency of the time series data TSDa, the image captured by the camera device 710 will carry the information of the watermark pattern.

[0065] It is worth noting that the frequency of the time series data TSDa can also be implemented by the sum of other factors that do not correspond to the reciprocal of the exposure time of the camera device. Therefore, this application is not limited thereto.

[0066] Figure 9This is a schematic diagram illustrating time-series data TSDb, a preset scheme PGPb, and grayscale information IGRAB of a watermark signal, based on some embodiments of this disclosure. The time-series data TSDb includes periods C1 to C3, each period C1 to C3 comprising a dark state period (e.g., times 0 to 1 / 3t, t to 4 / 3t, and 2t to 7 / 3t, where "t" is any positive number) and a bright state period (e.g., times 1 / 3t to t, 4 / 3t to 2t). Here, "t" is any positive number, and the time length "t" represents the time length of each period C1 to C3.

[0067] exist Figure 9 In the embodiments, the duration of the dark state period within each period C1 to C3 can be different from the duration of the bright state period. Furthermore, the preset scheme IGRAB is set accordingly so that the product of the value of the preset scheme IGRAB during the dark state period and the duration of the dark state period is equal to the product of the value of the preset scheme IGRAB during the bright state period and the duration of the bright state period.

[0068] For example, during the dark period (e.g., time 0 to 1 / 3t), the preset scheme IGRAB has a first grayscale value (e.g., 2x, where "x" can be any positive integer), and during the bright period (e.g., time 1 / 3t to t), the preset scheme IGRAB has a second grayscale value (e.g., x), and the product of the first grayscale value and the duration of the dark period (e.g., time 0 to 1 / 3t) is equal to the product of the second grayscale value and the duration of the bright period (e.g., time 1 / 3t to t), thereby preventing human vision from perceiving the watermark pattern.

[0069] Thus, the grayscale information IGRAB of the watermark signal has grayscale values ​​of "low, high, high" in the first 1 / 3, 1 / 3 to 2 / 3, and 2 / 3 to 3 / 3 periods of each period C1 to C3, thereby increasing the probability of the camera capturing the watermark.

[0070] Figure 10 This is a schematic diagram illustrating time-series data TSDc, a preset scheme PGPc, and the grayscale information IGRAC of the watermark signal according to some embodiments of this disclosure. The time-series data TSDc includes periods C1 to C3, each period C1 to C3 comprising a dark state period (e.g., times 0 to 2 / 3t, t to 5 / 3t, and 2t to 8 / 3t, where "t" is any positive number) and a bright state period (e.g., times 0t to 2 / 3t, 5 / 3t to 2t). Here, "t" is any positive number, and the time length "t" represents the time length of each period C1 to C3.

[0071] exist Figure 10In the embodiments, the duration of the dark state period within each period C1 to C3 can be different from the duration of the bright state period. Furthermore, the preset scheme IGRAC is set accordingly so that the product of the value of the preset scheme IGRAC during the dark state period and the duration of the dark state period is equal to the product of the value of the preset scheme IGRAC during the bright state period and the duration of the bright state period.

[0072] and Figure 9 Compared to the previous embodiments, Figure 10 The differences between the time series data TSDc, the preset scheme PGPc, and the grayscale information IGRAC of the watermark signal are the duration of the time series data TSDc during the dark and bright states and the corresponding settings of the preset scheme IGRAC.

[0073] Specifically, during the dark state period (e.g., time 0 to 2 / 3t), the preset scheme IGRAC has a first grayscale value (e.g., x, where "x" can be any positive integer), and during the bright state period (e.g., time 2 / 3t to t), the preset scheme IGRAC has a second grayscale value (e.g., 2x). The product of the first grayscale value and the duration of the dark state period (e.g., time 0 to 2 / 3t) is equal to the product of the second grayscale value and the duration of the bright state period (e.g., time 2 / 3t to t), thereby preventing human vision from perceiving the watermark pattern.

[0074] Thus, the grayscale information IGRAC of the watermark signal has grayscale values ​​of "low, low, high" in the first 1 / 3, 1 / 3 to 2 / 3, and 2 / 3 to 3 / 3 periods of each period C1 to C3, thereby increasing the probability of the camera capturing the watermark.

[0075] Figure 11 This is a schematic diagram illustrating time-series data TSDd, a preset scheme PGPd, and grayscale information IGRAD of a watermark signal, according to some embodiments of this disclosure. The time-series data TSDd includes periods C1 to C3, each period C1 to C3 comprising a dark state period (e.g., times 0 to 1 / 2t, t to 3 / 2t, and 2t to 5 / 2t, where "t" is any positive number) and a bright state period (e.g., times 1 / 2t to t, 3 / 2t to 2t). Here, "t" is any positive number, and the time length "t" represents the time length of each period C1 to C3.

[0076] exist Figure 11In the embodiments, the duration of the dark state period within each period C1 to C3 can be different from the duration of the bright state period. Furthermore, the preset scheme IGRAD is set accordingly so that the product of the value of the preset scheme IGRAD during the dark state period and the duration of the dark state period is equal to the product of the value of the preset scheme IGRAD during the bright state period and the duration of the bright state period.

[0077] and Figure 9 Compared to the previous embodiments, Figure 11 The differences between the time series data TSDd, the preset scheme PGPd, and the grayscale information IGRAD of the watermark signal are the duration of the time series data TSDd during the dark and bright states and the corresponding settings of the preset scheme IGRAD.

[0078] Specifically, during the dark period (e.g., time 0 to 1 / 2t), the preset scheme IGRAD has a first grayscale value (e.g., x, where "x" can be any positive integer), and during the bright period (e.g., time 1 / 2t to t), the preset scheme IGRAD has a second grayscale value (e.g., x). The product of the first grayscale value and the duration of the dark period (e.g., time 0 to 1 / 2t) is equal to the product of the second grayscale value and the duration of the bright period (e.g., time 1 / 2t to t), thereby preventing human vision from perceiving the watermark pattern.

[0079] Thus, the grayscale information IGRAD of the watermark signal has grayscale values ​​of "low, medium, and high" in the first 1 / 3, 1 / 3 to 2 / 3, and 2 / 3 to 3 / 3 periods of each period C1 to C3, thereby increasing the probability of the camera capturing the watermark.

[0080] In summary, the display device 100 provided in this disclosure displays an image based on an output image signal embedded with a watermark signal. Since the watermark pattern flickers at a high frequency between high and low grayscale levels, it is difficult for the human eye to perceive. Furthermore, by utilizing the settings in the preset schemes PGPa to PGPd, the overlap between the watermark and the exposure time of the camera device during one display cycle of high and low grayscale switching can be avoided, thereby increasing the probability that the watermark pattern is present in the image captured by the camera device of the display device's screen.

[0081] Although this disclosure has been described above with reference to embodiments, it is not intended to limit this disclosure. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the scope defined in the appended claims.

Claims

1. A watermark embedding method, comprising: The processing circuit receives the input image signal; The processing circuit generates grayscale information of the watermark signal based on time series data and a preset scheme. In each of the dark and bright periods of multiple consecutive cycles, the phase of the time series data is opposite and the average value of the grayscale of the preset scheme is equal. In the dark period, the preset scheme has a first grayscale value. In the bright period, the preset scheme has a second grayscale value. The product of the first grayscale value and the duration of the dark period is equal to the product of the second grayscale value and the duration of the bright period. The processing circuit embeds the watermark signal into the input image signal to generate an output image signal containing the grayscale information; and The display panel displays the image based on the output image signal.

2. The watermark embedding method as claimed in claim 1, wherein the first grayscale value is different from the second grayscale value, and wherein the duration of the dark state period is different from the duration of the bright state period.

3. The watermark embedding method as described in claim 1, wherein the first grayscale value is equal to the second grayscale value, and wherein the duration of the dark state period is equal to the duration of the bright state period.

4. The watermark embedding method as described in claim 1, wherein the reciprocal of the time length of each of the consecutive periods is a prime number.

5. The watermark embedding method as described in claim 1, wherein the reciprocal of the time length of each of the consecutive periods is a composite number.

6. The watermark embedding method as described in claim 1, wherein the floating watermark message of the output image signal switches between a bright state and a dark state according to the frequency of the time series data, wherein the frequency is a frequency imperceptible to human vision.

7. The watermark embedding method as claimed in claim 1, wherein the reciprocal of the time length of each of the consecutive periods corresponds to the refresh rate of the display panel.

8. The watermark embedding method as claimed in claim 1, wherein the reciprocal of the time length of each of the consecutive periods corresponds to a multiple of the refresh rate of the display panel.

9. A display device comprising Processing circuitry; as well as A storage device, electrically coupled to the processing circuit, is used to store instructions or data for execution by the processing circuit, wherein the processing circuit is used to: Receive input image signals; The grayscale information of the watermark signal is generated based on time series data and a preset scheme. In each of the dark and bright periods of multiple consecutive periods, the phase of the time series data is opposite and the average value of the grayscale of the preset scheme is equal. In the dark period, the preset scheme has a first grayscale value. In the bright period, the preset scheme has a second grayscale value. The product of the first grayscale value and the duration of the dark period is equal to the product of the second grayscale value and the duration of the bright period. as well as The watermark signal is embedded into the input image signal to generate an output image signal with the grayscale information.

Images