TWI817551B - Image encryption system and image encryption method - Google Patents

Abstract

An image encryption system includes a memory and a processor. The memory is configured to store a plurality of commands. The processor is configured to perform the following steps according to the plurality of commands from the memory: adding a text string to an area on an image, and the text string includes a high grayscale text string and a low grayscale text string; during the time period, obtaining an average value of the encrypted high gray level of the high gray level text string and the encrypted low grayscale of the low grayscale text string; and when the average value is equal to a display grayscale of the image, outputting the image and the text string.

Description

Screen encryption system and screen encryption method

This case relates to an encryption system and an encryption method, and in particular to a picture encryption system and a picture encryption method.

Currently, in order to protect the privacy of the screen, watermarks or text strings are often added to the screen. However, watermarks or text strings will hinder the viewing or reading of viewers or readers.

This summary is intended to provide a simplified summary of the disclosure to provide the reader with a basic understanding of the disclosure. This summary is not an extensive overview of the disclosure, and it is not intended to identify key/critical elements of the embodiments or to delineate the scope of the disclosure.

One of the technical aspects of this case relates to a screen encryption system. The screen encryption system includes memory and processor. Memory is used to store multiple instructions. The processor is used to perform the following steps according to the plural instructions of the memory: add a text string to the area in the screen, and the text string includes a high gray-scale text string and a low gray-scale text string; obtain the high gray-scale text in the time interval string The average value of the encrypted low grayscale of the encrypted high grayscale and low grayscale text strings; and when the average is equal to the display grayscale of the screen, output the screen and text string.

Another technical aspect of this case relates to a picture encryption method. The screen encryption method includes the following steps: add a text string to the area in the screen, and the text string includes a high grayscale text string and a low grayscale text string; in a time interval, obtain the encrypted high grayscale and low grayscale text strings of the high grayscale text string The average value of the encrypted low grayscale text string; and when the average value is equal to the display grayscale of the screen, the screen and text string are output.

Therefore, according to the technical content of this case, the screen encryption system and the screen encryption method shown in the embodiment of this case can adjust the high and low grayscale display frequencies in the text string to achieve a text string that cannot be seen by the human eye, but can be captured by the camera At this time, the text string can be photographed.

After referring to the following embodiments, those with ordinary knowledge in the technical field to which this case belongs can easily understand the basic spirit and other purposes of the invention, as well as the technical means and implementation styles adopted in this case.

100:Screen encryption system

110:Host

111:Memory

113: Processor

900:Display

200:Screen

210:Area

211: text string

GH: Encrypted high grayscale

IG: display grayscale

GL: Encrypted low grayscale

T: time interval

200A:Screen

210A:First area

211A: First text string

220A:Second area

221A: Second text string

GH1: The first encrypted high grayscale

GL1: The first encrypted low grayscale

GH2: The second encryption high grayscale

GL2: The second encryption low gray level

T1: the first time interval

T2: The second time interval

TC1: First shutter closing time

TC2: Second shutter closing time

TC3: Third shutter closing time

TC4: The fourth shutter closing time

700, 800: Screen encryption method

710~730: steps

810~850: steps

In order to make the above and other objects, features, advantages and embodiments of the present invention more obvious and easy to understand, the accompanying drawings are described as follows: Figure 1 is a block diagram illustrating a picture encryption system according to an embodiment of the present invention.

Figure 2 is a usage scenario diagram of a picture encryption system according to an embodiment of the present case.

Figure 3 illustrates various aspects of a picture encryption system according to an embodiment of the present case. Grayscale level diagram.

Figure 4 is a usage scenario diagram of a picture encryption system according to an embodiment of the present case.

Figure 5 is a schematic diagram showing multiple grayscale levels of an image encryption system according to an embodiment of the present invention.

Figure 6 is a schematic diagram showing multiple grayscale levels of an image encryption system according to an embodiment of the present invention.

Figure 7 is a flow chart illustrating a picture encryption method according to an embodiment of the present case.

Figure 8 is a flow chart illustrating a picture encryption method according to an embodiment of the present case.

In accordance with common practice, the various features and components in the drawings are not drawn to scale, but are drawn in such a way as to best present the specific features and components relevant to this case. In addition, the same or similar reference symbols are used to refer to similar elements/components in different drawings.

In order to make the description of this disclosure more detailed and complete, the following provides an illustrative description of the implementation aspects and specific embodiments of this case; but this is not the only form of implementing or using the specific embodiments of this case. The embodiments cover features of multiple specific embodiments as well as method steps and their sequences for constructing and operating these specific embodiments. However, other specific embodiments may also be used to achieve the same or equivalent functions and step sequences.

Unless otherwise defined in this specification, scientific and technical words used herein The meaning of "Hui" is the same as that commonly understood and commonly used by those with ordinary knowledge in the technical field to which this case belongs. In addition, unless there is conflict with the context, the singular noun used in this specification covers the plural form of the noun; and the plural noun used also covers the singular form of the noun.

Figure 1 is a block diagram illustrating a picture encryption system according to an embodiment of the present invention. As shown in the figure, the image encryption system 100 includes a memory 111 and a processor 113. In connection relationship, the memory 111 is coupled to the processor 113 . In some embodiments, the screen encryption system 100 may include a host 110 and a display 900 . The host 110 includes a memory 111 and a processor 113 . The display 900 can be used to display a screen (for example, the screen 200 shown in Figure 2 below), but the present case is not limited to this.

In order to achieve the effect that the text string on the screen cannot be seen by the human eye, but can be captured by the camera when shooting, this case provides detailed instructions for the relevant operations of the screen encryption system 100 as shown in Figure 1 as follows.

In one embodiment, the memory 111 is used to store a plurality of instructions. The processor 113 is used to perform the following steps according to the plural instructions of the memory 111: add a text string to the area in the screen, and the text string includes a high grayscale text string and a low grayscale text string; in the time interval, obtain the high grayscale text string. The average value of the encrypted high grayscale and low grayscale text strings of the encrypted low grayscale grayscale text string; and when the average value is equal to the displayed grayscale of the screen, the screen and text string are output.

In order to make the above operation of the screen encryption system 100 easy to understand, please refer to Figure 2 and Figure 3 together. Figure 2 is a usage scenario diagram of a screen encryption system according to an embodiment of the present case. Figure 3 is a schematic diagram showing multiple grayscale levels of an image encryption system according to an embodiment of the present invention.

Please refer to Figures 1 to 3 together. In operation, in one embodiment, the processor 113 is used to add only the text string 211 to the area 210 in the screen 200 according to the plural instructions of the memory 111, and The text string 211 includes a high grayscale text string and a low grayscale text string. For example, the area 210 can be any area in the screen 200. The content of the text string 211 can be XXX Confidential or any other text symbol content. The text string 211 can include a high grayscale text string and a low grayscale text string with the same text content. Text strings, and high gray-scale text strings and low gray-scale text strings can be displayed at the same frequency (for example: 120Hz), but this case is not limited to this.

)，故時間區間T為1/60，且加密高灰階GH的顯示時間及加密低灰階GL的顯示時間各佔時間區間T的一半，即為1/120，但本案不以此為限。 Then, in a time interval (such as the time interval T in Figure 3), the processor 113 obtains the average value of the encrypted high gray level GH of the high gray level text string and the encrypted low gray level GL of the low gray level text string. For example, in the time interval T, the encrypted high gray level GH of the high gray level text string can be 137, and the encrypted low gray level GL of the low gray level text string can be 117, so the average value can be (137+117) ÷2=127. In addition, the text string 211 can be displayed at a frequency of 60Hz, and the time interval T can be the reciprocal of the frequency f displayed by the text string 211 (i.e.

), so the time interval T is 1/60, and the display time of the encrypted high grayscale GH and the display time of the encrypted low grayscale GL each occupy half of the time interval T, which is 1/120, but this case is not limited to this .

Subsequently, when the average value is equal to the display grayscale IG of the picture 200, the processor 113 outputs the picture 200 and the text string 211. For example, the display grayscale IG of the screen 200 can be 127. Therefore, when the average value of the encrypted high grayscale GH of the high grayscale text string and the encrypted low grayscale GL of the low grayscale text string is 127, the processor 113 can Output screen 200 and text string 211, But this case is not limited to this.

In one embodiment, the text string 211 is displayed on the screen 200 at a frequency. For example, the text string can be displayed on the screen 200 at 60 Hz, and the text string can also be displayed on the screen 200 at 120 Hz, but this case is not limited to this.

In addition, the image seen by the human eye is the result of a longer integration time (that is, for the human eye, the time it takes for the human eye to capture an image will be much longer than the time interval T), while the image seen by the camera is the result of a shorter integration ( That is to say, for the camera, the time when the camera shoots or captures the image will be less than or equal to the time interval T), so for the human eye, using the above example, the encrypted high grayscale GH of the high grayscale text string can be 137, and the low grayscale GH can be 137. For the encryption of gray-scale text strings, the low-gray-scale GL can be 117, so the average value can be 127, and the display gray-scale IG of the screen 200 can be 127. To the human eye, due to the encryption of high-gray-scale text strings The average value of the encrypted low grayscale GL of the high grayscale GH and the low grayscale text string is the same as the displayed grayscale IG, so the human eye cannot recognize or capture the text string 211.

，當文字串用60Hz顯示於畫面200中時(此時高灰階文字串的顯示時間為1/120，且低灰階文字串的顯示時間同樣為1/120)，相機可以擷取到高灰階文字串或低灰階文字串，當然如果相機的快門收光時間小於

時，同樣可以擷取到高灰階文字串或低灰階文字串。 In comparison, for a camera, if the shutter closing time of the camera is

, when the text string is displayed in the screen 200 at 60Hz (at this time, the display time of the high-grayscale text string is 1/120, and the display time of the low-grayscale text string is also 1/120), the camera can capture high-definition Grayscale text string or low grayscale text string. Of course, if the camera’s shutter exposure time is less than

At the same time, you can also capture high-grayscale text strings or low-grayscale text strings.

However, if the shutter closing time of the camera is 1/60, the sum of the display time of the high-grayscale text string and the display time of the low-grayscale text string can be the time interval T, and the time interval T can be 1/60, so in time interval At T, the display grayscale IG of the screen 200 can be 127, the encrypted high grayscale GH of the high grayscale text string can be 137, and the encrypted low grayscale GL of the low grayscale text string can be 117. For the camera, Since the average value of the encrypted high grayscale GH of the high grayscale text string and the encrypted low grayscale GL of the low grayscale text string is the same as the displayed grayscale IG, the camera cannot recognize or capture the text string 211.

Referring to Figure 1, the processor 113 is further configured to perform the following steps according to the plurality of instructions from the memory 111: add a first text string to the first area of the screen, and the first text string includes a first high grayscale text string and The first low gray level text string; add the second text string to the second area of the screen, and the second text string includes the second high gray level text string and the second low gray level text string; in the first time interval , obtain the first average value of the first encrypted high grayscale of the first high grayscale text string and the first encrypted low grayscale of the first low grayscale text string; in the second time interval, obtain the second highest grayscale The second average value of the second encrypted high grayscale of the text string and the second encrypted low grayscale of the second low grayscale text string; and when the first average value and the second average value are equal to the display grayscale of the screen, output The screen, the first text string and the second text string.

In order to make the above operations of the screen encryption system 100 easy to understand, please refer to Figures 4 and 5 together. Figure 4 is a usage scenario diagram of a screen encryption system according to an embodiment of the present case. Figure 5 is a schematic diagram showing multiple grayscale levels of an image encryption system according to an embodiment of the present invention.

Please refer to Figures 1, 4 and 5 together. In one embodiment, the processor 113 is further configured to perform the following steps according to the plurality of instructions from the memory 111: add First place Text string 211A, and the first text string 211A includes a first high grayscale text string and a first low grayscale text string; a second text string 221A is added to the second area 220A in the screen 200A, and the second text string 221A includes The second highest grayscale text string and the second lowest grayscale text string. For example, the first area 210A can be any area in the screen 200, the second area 220A can be any other area other than the first area 210A in the screen 200, and the content of the first text string 211A can be XXX Confidential or For any other text symbol content, the first text string 211A may include the first high grayscale text string and the first low grayscale text string with the same text content. Similarly, the content of the first text string 211A may be XXX Confidential or any other text symbol. Content, the second text string 221A may include the second highest grayscale text string and the second low grayscale text string with the same text content, but this case is not limited to this. In one embodiment, the content of the first text string 211A may be XXX Confidential or any other text symbol content. The first text string 211A may include a first high grayscale text string and a first low grayscale text string of the same text content. Different , the content of the second text string 221A can be OOOO Confidential or any other text symbol content different from the first text string 211A. The second text string 221A can include the second highest grayscale text string and the second lowest grayscale text string with the same text content. Level text string.

)，故第一時間區間T1為1/60，且第一加密高灰階GH1的顯示時間及第一加密低灰階GL1的顯示時間各佔第一時間區間T1的一半，即為1/120，但本案不以此為限。 In one embodiment, in the first time interval T1, the processor 113 obtains the first encrypted high grayscale GH1 of the first high grayscale text string and the first encrypted low grayscale GL1 of the first low grayscale text string. First average. For example, in the first time interval T1, the first encrypted high gray level GH1 of the first high gray level text string may be 137, and the first encrypted low gray level GL1 of the first low gray level text string may be 117, Therefore, the first average value can be (137+117)÷2=127. In addition, the first text string 211A can be displayed at a frequency of 60Hz, and the first time interval T1 can be the reciprocal of the frequency f1 displayed by the first text string 211A (i.e.

), so the first time interval T1 is 1/60, and the display time of the first encrypted high grayscale GH1 and the display time of the first encrypted low grayscale GL1 each occupy half of the first time interval T1, which is 1/120 , but this case is not limited to this.

)，故第二時間區間T2為1/40，且第二加密高灰階GH2的顯示時間佔第二時間區間T2的三分之一，即為1/120，第二加密低灰階GL2的顯示時間佔第二時間區間T2的三分之二，即為1/60，但本案不以此為限。 In one embodiment, in the second time interval T2, the processor 113 obtains the second encrypted high grayscale GH2 of the second high grayscale text string and the second encrypted low grayscale GL2 of the second low grayscale text string. Second average. For example, in the second time interval T2, the second encrypted high grayscale GH2 of the second high grayscale text string may be 147, and the second encrypted low grayscale GL2 of the second low grayscale text string may be 117, Therefore, the second average value can be (147+117×2)÷3=127. In addition, the second text string 221A can be displayed at a frequency of 40Hz, and the second time interval T2 can be the reciprocal of the frequency f2 displayed by the second text string 221A ( Right now

), so the second time interval T2 is 1/40, and the display time of the second encrypted high gray level GH2 accounts for one third of the second time interval T2, which is 1/120. The second encrypted low gray level GL2 The display time occupies two-thirds of the second time interval T2, which is 1/60, but this case is not limited to this.

In one embodiment, when the first average value and the second average value are equal to the display grayscale of the image, the processor 113 outputs the image 200A, the first text string 211A and the second text string 221A. For example, screen 200A The display grayscale IG may be 127, when the first average value of the first encrypted high grayscale GH1 of the first high grayscale text string and the first encrypted low grayscale GL1 of the first low grayscale text string is 127, and the When the second average value of the second encrypted high grayscale GH2 of the two high grayscale text strings and the second encrypted low grayscale GL2 of the second low grayscale text string is also 127, the processor 113 can output the picture 200A and the first text. string 211A and the second text string 221A, but this case is not limited to this.

In one embodiment, the first text string 211A is displayed in the screen 200A at the first frequency f1. For example, the first frequency f1 can be 60Hz, and the first text string 211A can be displayed on the screen 200A at 60Hz, but this case is not limited to this.

In one embodiment, the second text string 221A is displayed in the screen 200A at the second frequency f2. For example, the second frequency f2 can be 40Hz, and the second text string 221A can be displayed on the screen 200A at 40Hz, but this case is not limited to this.

In addition, the image seen by the human eye is the result of a longer time integration (that is, for the human eye, the time it takes for the human eye to capture the image will be much longer than the first time interval T1 or the second time interval T2), and the image seen by the camera is It is the result of shorter integration (that is, for the camera, the time for the camera to shoot or capture images will be less than or equal to the first time interval T1 or the second time interval T2).

To the human eye, using the above example, the first encrypted high gray level GH1 of the first high gray level text string may be 137, and the first encrypted low gray level GL1 of the first low gray level text string may be 117. An average value may be 127, and the second encrypted high gray level GH2 of the second high gray level text string may be 147, and the second When the second encrypted low grayscale GL2 of the two low grayscale text strings can be 117, the second average value can be 127, and the display grayscale IG of the screen 200A can be 127, to the human eye, due to the first The first average value of the first encrypted high grayscale GH1 of the high grayscale text string and the first encrypted low grayscale GL1 of the first low grayscale text string is the same as the display grayscale IG, so the human eye cannot recognize or capture the first text. String 211A, similarly, since the second average value of the second encrypted high grayscale GH2 of the second high grayscale text string and the second encrypted low grayscale GL2 of the second low grayscale text string is the same as the display grayscale IG, Therefore, human eyes cannot recognize or capture the second text string 221A.

Figure 6 is a schematic diagram showing multiple grayscale levels of an image encryption system according to an embodiment of the present invention. Please refer to Figure 6. The shutter closing time of the camera can be the first shutter closing time TC1, the second shutter closing time TC2, the third shutter closing time TC3 or the fourth shutter closing time TC4. For example, the first shutter light closing time TC1 may be 1/120, the second shutter light closing time TC2 may be 1/60, the third shutter light closing time TC3 may be 1/40, and the fourth shutter light closing time TC4 It can be 1/30, but this case is not limited to this.

In some embodiments, the first encrypted high gray level GH1 of the first high gray level text string may be 137, the first encrypted low gray level GL1 of the first low gray level text string may be 117, and the second high gray level text string may be 117. When the second encrypted high grayscale GH2 of the string can be 147, the second encrypted low grayscale GL2 of the second low grayscale text string can be 117, and the display grayscale IG of the screen 200A can be 127, the first text string 211A can be displayed on the screen 200A at 60Hz, and the second text string 221A can be displayed on the screen at 40Hz. In the surface 200A, for the camera, when the first shutter closing time TC1 of the camera is 1/120, the camera can capture the first text string 211A. Similarly, the camera can also capture the second text string 221A.

The main reason is that when the first shutter closing time TC1 is 1/120, the camera can capture the first encrypted high grayscale GH1 of the first high grayscale text string and the first low grayscale text string. One encrypted low gray level GL1, the second encrypted high gray level GH2 of the second high gray level text string, or the second encrypted low gray level GL2 of the second low gray level text string, but this case is not limited to this.

When the camera's second shutter closing time TC2 is 1/60, the camera cannot capture the first text string 211A, but the camera can also capture the second text string 221A. The main reason is that when the second shutter closing time TC2 is 1/60, the camera captures the first encryption high gray level GH1 of the first high gray level text string and the first encryption of the first low gray level text string The first average value of the low grayscale GL1 will be the same as the display grayscale IG, so the camera cannot recognize or capture the first text string 211A. However, the camera can capture the second encrypted high grayscale GH2 of the second high grayscale text string. Or the second encrypted low gray level GL2 of the second low gray level text string.

When the third shutter closing time TC3 of the camera is 1/40, the camera can capture the first text string 211A, but the camera cannot capture the second text string 221A. The main reason is that when the third shutter closing time TC3 is 1/40, the camera can capture the first encrypted high grayscale GH1 of the first high grayscale text string or the first low grayscale text string. One encrypted low grayscale GL1, however, the second encrypted high grayscale GH2 of the second highest grayscale text string captured by the camera and the second encrypted low grayscale of the second low grayscale text string The second average value of the level GL2 will be the same as the display gray level IG, so the camera cannot recognize or capture the second text string 221A.

When the fourth shutter closing time TC4 of the camera is 1/30, the camera cannot capture the first text string 211A, but the camera can also capture the second text string 221A. The main reason is that when the camera's fourth shutter closing time TC4 is 1/30, the camera captures the first encryption of the first high gray level text string, high gray level GH1, and the first encryption of the first low gray level text string. The first average value of the low grayscale GL1 is the same as the display grayscale IG, so the camera cannot recognize or capture the first text string 211A. However, the camera can capture the second encrypted high grayscale GH2 of the second high grayscale text string or The second encrypted low gray level GL2 of the second low gray level text string.

Figure 7 is a flow chart illustrating a picture encryption method according to an embodiment of the present case. As shown in the figure, the screen encryption method 700 in Figure 7 includes the following steps: Step 710: Add a text string to the area in the screen, and the text string includes a high grayscale text string and a low grayscale text string; Step 720: In In the time interval, obtain the average value of the encrypted high grayscale of the high grayscale text string and the encrypted low grayscale of the low grayscale text string; Step 730: When the average value is equal to the display grayscale of the screen, output the screen and text string.

In order to make the screen encryption method 700 in Figure 7 easy to understand, please refer to Figures 1, 2, 3 and 7 together. In one embodiment, please refer to step 710, through the processor 113. Only the text string 211 is added to the area 210 in the screen 200, and the text string 211 includes a high grayscale text string. and low grayscale text strings. For example, the area 210 can be any area in the screen 200. The content of the text string 211 can be XXX Confidential or any other text symbol content. The text string 211 can include a high grayscale text string and a low grayscale text string with the same text content. Text strings, and high gray-scale text strings and low gray-scale text strings can be displayed at the same frequency (for example: 120Hz), but this case is not limited to this.

)，故時間區間T為1/60，且加密高灰階GH的顯示時間及加密低灰階GL的顯示時間各佔時間區間T的一半，即為1/120，但本案不以此為限。 In one embodiment, please refer to step 720. In a time interval (such as the time interval T in Figure 3), the processor 113 obtains the encrypted high gray level GH of the high gray level text string and the encrypted low gray level text string. Encrypt the average value of low grayscale GL. For example, in the time interval T, the encrypted high gray level GH of the high gray level text string can be 137, and the encrypted low gray level GL of the low gray level text string can be 117, so the average value can be (137+117) ÷2=127. In addition, the text string 211 can be displayed at a frequency of 60Hz, and the time interval T can be the reciprocal of the frequency f displayed by the text string 211 (i.e.

), so the time interval T is 1/60, and the display time of the encrypted high grayscale GH and the display time of the encrypted low grayscale GL each occupy half of the time interval T, which is 1/120, but this case is not limited to this .

In one embodiment, please refer to step 730. When the average value is equal to the display grayscale IG of the image 200, the processor 113 outputs the image 200 and the text string 211. For example, the display grayscale IG of the screen 200 can be 127. Therefore, when the average value of the encrypted high grayscale GH of the high grayscale text string and the encrypted low grayscale GL of the low grayscale text string is 127, the processor 113 can Output screen 200 and text string 211, but this case is not limited to this.

In one embodiment, please refer to step 710, the text string 211 is A frequency is displayed in screen 200. For example, the text string can be displayed on the screen 200 at 60 Hz, and the text string can also be displayed on the screen 200 at 120 Hz, but this case is not limited to this.

Figure 8 is a flow chart illustrating a picture encryption method according to an embodiment of the present case. As shown in the figure, the screen encryption method 800 in Figure 8 includes the following steps: Step 810: Add a first text string to the first area in the screen, and the first text string includes a first high grayscale text string and a first low grayscale text string. Grayscale text string; Step 820: Add a second text string to the second area in the screen, and the second text string includes a second high grayscale text string and a second low grayscale text string; Step 830: At the first time In the interval, obtain the first average value of the first encrypted high gray level of the first high gray level text string and the first encrypted low gray level of the first low gray level text string; Step 840: In the second time interval, obtain The second average value of the second encrypted high gray level of the second high gray level text string and the second encrypted low gray level of the second low gray level text string; Step 850: When the first average value and the second average value are equal to the screen When displaying grayscale, output the screen, the first text string and the second text string.

To make the screen encryption method 700 in Figure 8 easy to understand, please refer to Figures 1, 4, 5, 6 and 8 together. In one embodiment, please refer to step 810, by The processor 113 adds the first text string 211A to the first area 210A in the screen 200A, and the first text The 21A string includes the first high grayscale text string and the first low grayscale text string.

In one embodiment, please refer to step 820, the processor 113 adds a second text string 221A to the second area 220A in the screen 200A, and the second text string 221A includes a second high grayscale text string and a second Low grayscale text string. For example, the first area 210A can be any area in the screen 200, the second area 220A can be any other area other than the first area 210A in the screen 200, and the content of the first text string 211A can be XXX Confidential or For any other text symbol content, the first text string 211A can include the first high grayscale text string and the first low grayscale text string with the same text content. Similarly, the content of the second text string 221A can be XXX Confidential or any other text. Symbol content, the second text string 221A may include the second highest grayscale text string and the second low grayscale text string with the same text content, but this case is not limited to this. In one embodiment, the content of the first text string 211A may be XXX Confidential or any other text symbol content. The first text string 211A may include a first high grayscale text string and a first low grayscale text string of the same text content. Different , the content of the second text string 221A can be OOOO Confidential or any other text symbol content different from the first text string 211A. The second text string 221A can include the second highest grayscale text string and the second lowest grayscale text string with the same text content. Level text string.

)，故第一時間區間T1為1/60，且第一加密高灰階GH1的顯示時間及第一加密低灰階GL1的顯示時間各佔第一時間區間T1的一半，即為1/120，但本案不以此為限。 In one embodiment, please refer to step 830. In the first time interval T1, the processor 113 obtains the first encrypted high gray level GH1 of the first high gray level text string and the first encrypted high gray level GH1 of the first low gray level text string. The first average of an encrypted low grayscale GL1. For example, in the first time interval T1, the first encrypted high gray level GH1 of the first high gray level text string may be 137, and the first encrypted low gray level GL1 of the first low gray level text string may be 117, Therefore, the first average value can be (137+117)÷2=127. In addition, the first text string 211A can be displayed at a frequency of 60Hz, and the first time interval T1 can be the reciprocal of the frequency f1 displayed by the first text string 211A (i.e.

), so the first time interval T1 is 1/60, and the display time of the first encrypted high grayscale GH1 and the display time of the first encrypted low grayscale GL1 each occupy half of the first time interval T1, which is 1/120 , but this case is not limited to this.

)，故第二時間區間T2為1/40，且第二加密高灰階GH2的顯示時間佔第二時間區間T2的三分之一，即為1/120，第二加密低灰階GL2的顯示時間佔第二時間區間T2的三分之二，即為1/60，但本案不以此為限。 In one embodiment, please refer to step 840. In the second time interval T2, the processor 113 obtains the second encrypted high gray level GH2 of the second high gray level text string and the second encrypted high gray level GH2 of the second low gray level text string. The second average of two encrypted low grayscale GL2. For example, in the second time interval T2, the second encrypted high grayscale GH2 of the second high grayscale text string may be 147, and the second encrypted low grayscale GL2 of the second low grayscale text string may be 117, Therefore, the second average value can be (147+117×2)÷3=127. In addition, the second text string 221A can be displayed at a frequency of 40Hz, and the second time interval T2 can be the reciprocal of the frequency f2 displayed by the second text string 221A ( Right now

), so the second time interval T2 is 1/40, and the display time of the second encrypted high gray level GH2 accounts for one third of the second time interval T2, which is 1/120. The second encrypted low gray level GL2 The display time occupies two-thirds of the second time interval T2, which is 1/60, but this case is not limited to this.

In one embodiment, please refer to step 850. When the first average value and the second average value are equal to the display grayscale of the image, the processor 113 outputs the image 200A, the first text string 211A and the second text string 221A. For example, the display grayscale IG of the screen 200A may be 127, when the first encrypted high grayscale GH1 of the first high grayscale text string and the first encrypted low grayscale GL1 of the first low grayscale text string are When the average value is 127, and the second average value of the second encrypted high grayscale GH2 of the second high grayscale text string and the second encrypted low grayscale GL2 of the second low grayscale text string is also 127, the processor 113 The screen 200A, the first text string 211A and the second text string 221A can be output, but this case is not limited to this.

In one embodiment, please refer to step 810, the processor 113 displays the first text string 211A in the screen 200A at the first frequency f1. For example, the first frequency f1 can be 60Hz, and the first text string 211A can be displayed on the screen 200A at 60Hz, but this case is not limited to this.

In one embodiment, please refer to step 810, the processor 113 displays the second text string 221A in the screen 200A at the second frequency f2. For example, the second frequency f2 can be 40Hz, and the second text string 221A can be displayed on the screen 200A at 40Hz, but this case is not limited to this.

In addition, the image seen by the human eye is the result of a longer time integration (that is, for the human eye, the time it takes for the human eye to capture the image will be much longer than the first time interval T1 or the second time interval T2), and the image seen by the camera is It is the result of shorter integration (that is, for the camera, the time for the camera to shoot or capture images will be less than or equal to the first time interval T1 or the second time interval T2).

To the human eye, using the above example, the first encrypted high gray level GH1 of the first high gray level text string may be 137, and the first encrypted low gray level GL1 of the first low gray level text string may be 117. An average value may be 127, and the second encrypted high gray level GH2 of the second high gray level text string may be 147, and the second When the second encrypted low grayscale GL2 of the two low grayscale text strings can be 117, the second average value can be 127, and the display grayscale IG of the screen 200A can be 127, to the human eye, due to the first The first average value of the first encrypted high grayscale GH1 of the high grayscale text string and the first encrypted low grayscale GL1 of the first low grayscale text string is the same as the display grayscale IG, so the human eye cannot recognize or capture the first text. String 211A, similarly, since the second average value of the second encrypted high grayscale GH2 of the second high grayscale text string and the second encrypted low grayscale GL2 of the second low grayscale text string is the same as the display grayscale IG, Therefore, human eyes cannot recognize or capture the second text string 221A.

It can be seen from the above embodiments that the application of this case has the following advantages. The screen encryption system and screen encryption method shown in the embodiment of this case can adjust the high and low grayscale display frequencies in the text string to achieve a text string that cannot be seen by the human eye, but can be captured when the camera is shooting. Effect.

Although the above implementation mode discloses specific examples of the present case, it is not intended to limit the present case. Persons with ordinary knowledge in the technical field to which the present case belongs can, without departing from the principles and spirit of the present case, proceed with it. Various changes and modifications, therefore the scope of protection in this case shall be subject to the scope of the accompanying patent application.

100:Screen encryption system

110:Host

111:Memory

113: Processor

900:Display

Claims (10)

A picture encryption system includes: a memory for storing a plurality of instructions; and a processor for performing the following steps according to the instructions of the memory: adding a text string to an area in a picture, The text string includes a high grayscale text string and a low grayscale text string; in a time interval, an encrypted high grayscale of the high grayscale text string and an encrypted low grayscale of the low grayscale text string are obtained an average value of the levels; when the average value is equal to a display gray level of the screen, the screen and the text string are output; in a first time interval, the high gray level is displayed in a first area of the screen text string; in a second time interval, display the low grayscale text string in the first area of the screen; in the first time interval, display the high grayscale text string in a second area of the screen text string; and in the second time interval and a third time interval, display the low grayscale text string in the second area of the screen; wherein the second time interval continues after the first time interval, The third time interval follows the second time interval, a time length of the second time interval plus a time length of the third time interval is greater than a time length of the first time interval, and the area includes the the first region and the second region. The screen encryption system as claimed in claim 1, wherein the text string is displayed in the screen with a frequency. The screen encryption system as claimed in claim 1, wherein the processor is further configured to perform the following steps according to the instructions of the memory: add a first text string to the first area in the screen, wherein the third A text string includes a first high gray level text string and a first low gray level text string; a second text string is added to the second area in the screen, wherein the second text string includes a second high gray level text string. level text string and a second low gray level text string; in the first time interval, obtain a first encrypted high gray level of the first high gray level text string and a first encrypted high gray level of the first low gray level text string. A first average value of an encrypted low gray level; in the second time interval, obtain a second encrypted high gray level of the second high gray level text string and a second low gray level of the second low gray level text string. Encrypt a second average value of low grayscale; and when the first average value and the second average value are equal to the display grayscale of the screen, output the screen, the first text string and the second text string. The screen encryption system as claimed in claim 3, wherein the first text string is displayed in the screen at a first frequency. The screen encryption system as claimed in claim 4, wherein the second text string is displayed in the screen at a second frequency. A picture encryption method, including: adding a text string to an area in a picture, wherein the text string includes a high grayscale text string and a low grayscale text string; obtaining the high grayscale text in a time interval An average value of an encrypted high gray level of the string and an encrypted low gray level of the low gray level text string; when the average value is equal to a display gray level of the screen, output the screen and the text string; in a first In a time interval, the high gray level text string is displayed in a first area of the screen; in a second time interval, the low gray level text string is displayed in the first area of the screen; in the third time interval, the high gray level text string is displayed in the first area of the screen. In a time interval, the high grayscale text string is displayed in a second area of the screen; and in the second time interval and a third time interval, the low grayscale text string is displayed in the second area of the screen. hierarchical literal string; wherein the second time interval continues after the first time interval, the third time interval continues after the second time interval, a time length of the second time interval plus a length of the third time interval A time length is greater than a time length of the first time interval, and the area includes the first area and the second area. The screen encryption method as described in claim 6, wherein the high grayscale text string and the low grayscale text string are displayed in the screen with a frequency. The screen encryption method described in claim 6, wherein the step of adding the text string to the area in the screen, wherein the text string includes the high grayscale text string and the low grayscale text string includes: adding the text string to the screen. Add a first text string to the first area in the screen, where the first text string includes a first high grayscale text string and a first low grayscale text string; and add a first text string to the second area in the screen. A second text string, wherein the second text string includes a second high grayscale text string and a second low grayscale text string. The screen encryption method as described in claim 8, wherein the first high grayscale text string and the first low grayscale text string are displayed in the screen with a first frequency, wherein the second high grayscale text string and The second low grayscale text string is displayed in the screen at a second frequency. The screen encryption method as described in claim 8, wherein in the time interval, the step of obtaining the average value of the encrypted high gray level of the high gray level text string and the encrypted low gray level of the low gray level text string is Including: in the first time interval, obtaining a first average value of a first encrypted high gray level of the first high gray level text string and a first encrypted low gray level of the first low gray level text string. ;as well as In the second time interval, obtain a second average value of a second encrypted high gray level of the second high gray level text string and a second encrypted low gray level of the second low gray level text string; wherein When the average value is equal to the display grayscale of the picture, the step of outputting the picture and the text string includes: when the first average value and the second average value are equal to the display grayscale of the picture, outputting the picture , the first text string and the second text string.

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