JP3856358B2 - Image transmission system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image transmission system, and more particularly to an image transmission system for transmitting encrypted information by adding encryption information to an image.
[0002]
[Prior art]
In recent years, MPEG4 (Moving Picture Experts Group 4), which enables video and audio coding at an ultra-low bit rate up to about several tens of kbps, has been studied. The shape coding method represented by MPEG4 is a screen coding method. This is a technique of decomposing an object inside into an arbitrary shape and encoding it separately. For example, as shown in FIG. 4, the encoding side 1 separates the person 2, the character 3, and the background image 4 that are the subjects of the camera as a plurality of objects constituting the screen, and the respective information is encoded by the encoders 5 and 6. And 7 are encoded separately, and at the same time, shape information representing the position and shape of each object is encoded, and the encoded data is multiplexed by the multiplexer 8 and transmitted.
[0003]
The multiplexed encoded data transmitted in this way is transmitted to the decoding side 9. On the decoding side 9, the separator 10 separates the input multiplex encoded data into encoded data and shape information for each object, and the encoded data for each object is decoded by the decoders 11, 12 and 13, respectively. . Each decrypted object is synthesized by the synthesizer 14 so as to form a screen based on the shape information, and is displayed as a screen 15.
[0004]
FIG. 5 is a block diagram of an example of a conventional encoding unit that encodes one object extracted in an arbitrary shape, and FIG. 6 is a block diagram of an example of a conventional decoding unit corresponding to the encoding unit shown in FIG. Indicates. First, in the encoding unit in FIG. 5, an arbitrarily shaped image taken out for each object, for example, an object composed of a circle and a parallelogram shown in FIG. 7A is surrounded by a block indicated by a dotted line. The object image in the region is input to the object image encoder 23 via the input terminal 21 and encoded. On the other hand, a shape plane representing the shape and position of the object is input to the shape plane encoder 24 via the input terminal 22 and encoded.
[0005]
The encoded data extracted from the object image encoder 23 and the shape plane encoder 24 are multiplexed by the multiplexer 25 and then sent to the transmission line via the terminal 26. For example, when an example of the shape plane is shown in FIG. 7, the shape plane is the outline of the object and its inside in the thick frame screen as shown in FIG. This represents a state in which only the pixels corresponding to are displayed.
[0006]
As the simplest example, there is a bitmap representation in which a pixel to be displayed is 1 and a pixel not to be displayed is specified by a binary value of 0. In addition, when the adjacent portion of the object and the background is smoothly connected or when a plurality of objects are overlapped, a method of using a multi-value gray scale as a weight can be used.
[0007]
The encoded data output from the encoding unit of FIG. 5 is input to the separator 32 via the input terminal 31 of the decoder of FIG. 6 , where it is separated into encoded data of the object and the shape plane, The encoded data is input to the object image decoder 33 and decoded into an object image, and the encoded data of the shape plane is input into the shape plane decoder 34 and decoded into the shape plane.
[0008]
The object image extracted from the object image decoder 33 and the shape plane extracted from the shape plane decoder 34 are supplied to the display synthesizer 35. Based on the information on the shape plane, FIG. As shown in the drawing, the image is output to the terminal 36 as an image in which only the outline and the internal portion of the object are displayed.
[0009]
[Problems to be solved by the invention]
However, in the conventional image transmission method comprising the encoding unit shown in FIG. 5 and the decoding unit shown in FIG. 6, when the encryption information is concealed and transmitted in the image data, the encryption information is directly added to the input image data. When embedded, there is a problem that image deterioration occurs and information loss occurs in encoding.
[0010]
The present invention has been made in view of the above points, and an object of the present invention is to provide an image transmission method capable of adding and transmitting encryption information to an image without causing deterioration of the image.
[0011]
Another object of the present invention is to provide an image transmission method that can add and transmit encryption information to an image without causing loss of image information.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a shape plane encoder that encodes information of a shape plane that represents the shape of an object image extracted in an arbitrary shape, a cipher generator that generates encryption information, and an object image A region designator for generating a region designating signal for designating a block including a contour portion of an object image having an empty region based on the information on the shape plane, The object image and the region designation signal from the region designator are input as input, and the encryption information from the encryption generator is interpolated in the empty region part in the block designated by the region designation signal in the object image Then, an object image encoder that encodes the object image in units of blocks, and an encryption that is extracted from the object image encoder. A multiplexer that multiplexes the encoded data of the object image in which the information is interpolated and the encoded data of the shape plane extracted from the shape plane encoder, and sends the multiplexed data to the transmission line, and the transmission A separator that receives multiplexed data through a path and separates the encoded data of the object image into which the encryption information is interpolated and the encoded data of the shape plane, and the encoded data of the shape plane separated by the separator Based on the shape plane decoder to be decoded and the shape plane information extracted from the shape plane decoder, the block including the outline portion of the object image having the empty area portion is detected, and the encryption information is interpolated. A region detector that generates a feedback signal that determines whether the block is a block, encoded data of the object image in which the encryption information separated by the separator is interpolated, and a feedback signal An object image decoder that receives as input and extracts encoded information encoded based on a feedback signal from encoded data of the object image in which the encrypted information is interpolated, and decodes the encoded data of the object image; Based on the information on the shape plane extracted from the shape plane decoder and the encryption / decryption device for decoding the encoded encryption information extracted by the object image decoder, the object image decoder And a display synthesizer for setting the display area of the extracted object image.
[0013]
In the present invention, a block including an empty area portion is detected in an object image extracted in an arbitrary shape in the encoding unit, and the encoding is performed by interpolating encryption information in the empty area portion. When the encrypted data is decrypted, the encryption information can be extracted and only the inside of the contour of the object image can be displayed.
[0014]
The area designator detects a block including the contour area of the object image based on the shape plane information, and the area (number of pixels) occupied by the object image in the block exceeds the threshold value from the detected block. Depending on whether the block is a block that conceals encryption information or not, outputs a signal that specifies whether or not the block is a block that conceals encryption information detected based on the region specification signal. The area detector detects a block including the contour portion of the object image based on the shape plane information extracted from the shape plane decoder, and based on the detected block A feedback signal is generated, and the object image decoder decodes the encoded data of the object image and detects based on the feedback signal. Depending on whether or not the decoded image of the block exceeds the area occupied by the block (number of pixels) of the threshold information of the free space in the block may be judged whether encryption information.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of an image transmission system encoding unit according to the present invention, and FIG. 2 is a block diagram of an image transmission system decoding unit of an embodiment of the present invention. Encoding unit shown in FIG. 1 represents the object image encoder 43 for encoding in units of blocks an object image inputted through the input terminal 41, the shape of an object inputted through the input terminal 42 shape shape planar encoder 44 for encoding the information plane, an encryption generator 45 for generating the encryption information, a region specifier 46 to specify the region for inserting the encrypted information into the object image, the object image coder 43 and both outputs encoded data of the shape encoder 44 are multiplexed is more configuration and multiplexer 47 to be output to the terminal 48. Encoding unit shown in FIG. 1, as compared to conventional coding unit shown in FIG. 5, that the cryptographic generator 45 and the area designated 46 is further provided are different.
[0016]
Also, the decoding unit shown in FIG. 2 includes a separator 52 that separates the multiplexed data input via the input terminal 51 into the encoded data of the object image and the encoded data of the shape plane, An object image decoder 53 for decoding the encoded data, a shape plane decoder 54 for decoding the encoded data on the shape plane, and an area detector 55 for detecting an encryption information area concealed in the object image. And an encryption / decryption device 56 for decrypting the encryption information, and a display synthesizer 57 for setting the display area and outputting the decrypted object image to the terminal 58 based on the decrypted shape plane. ing. The decryption unit shown in FIG. 2 is different from the conventional decryption unit shown in FIG. 6 in that a region detector 55 and an encryption / decryption device 56 are further provided.
[0017]
Next, the operation of this embodiment will be described. First, in the encoding unit in FIG. 1, an object image extracted in an arbitrary shape is supplied to an object image encoder 43 and a region designator 46 via an input terminal 41. On the other hand, information on the shape plane representing the shape and position of the object image is supplied to the shape plane encoder 44 and the region designator 46 via the input terminal 42 in synchronization with the object image. The shape plane encoder 44 performs an encoding process on the input shape plane information, and outputs encoded data. The area designator 46 analyzes the object image divided into blocks and information on the shape plane, and designates a block including the contour portion of the object.
[0018]
Here, when the object image is actually displayed on the decoding side, as shown in FIG. 7, the outline and the inside of the object are displayed using the information of the shape plane, and the object is enclosed in the block surrounding the object. Empty areas that are not images are not displayed. Further, since the user on the decryption side does not recognize such an empty area part, it can be said that the use value of this empty area part is high in order to interpolate and transmit encryption information or the like.
[0019]
Therefore, the area designator 46 designates a block including the contour portion of the object, generates a block designation signal for designating a block in the empty area portion, and supplies it to the object image encoder 43. For example, when the object image is an object image in which the circle I and the parallelogram II partially overlap as shown in FIG. 3, among the blocks in the rectangular area surrounded by the dotted line in FIG. The block shown is a block including a contour portion of only the circle I or the parallelogram II, and is also a block including a free space portion, and the block shown in white does not have a contour portion or is a contour portion of one figure Are the blocks inside the other graphic, and these are not the blocks including the empty area portion.
[0020]
Therefore, the region specifier 46, indicated by oblique lines in FIG. 3, as well as specify the block containing the outline of the object, the object picture coder to generate a block designating signal for designating a block of free space portion 43 To supply. Based on the block designation signal, the object image encoder 43 interpolates the encryption information input from the encryption generator 45 into the block of the empty area portion of the object image input via the input terminal 41. After that, the whole is encoded in units of blocks, and the input object image and the encoded data of the encryption information are output.
[0021]
The multiplexer 47 encodes the object image encoded data interpolated with the encryption information extracted from the object image encoder 43 and the shape plane encoded data extracted from the shape plane encoder 44. Are multiplexed, and the multiplexed data is sent to the transmission line via the terminal 48.
[0022]
The decoding unit in FIG. 2 receives the multiplexed data transmitted through the transmission path via the terminal 51, and separates the encoded data of the object image and the encoded data of the shape plane by the separator 52. The separated encoded data of the shape plane is supplied to the shape plane decoder 54 and decoded into the shape plane information.
[0023]
The area detector 55 detects a block including the contour portion of the object image based on the shape plane information extracted from the shape plane decoder 54, and determines whether or not the block contains encryption information. A feedback signal is generated and supplied to the object image decoder 53. Based on the feedback signal from the area detector 55, the object image decoder 53 is a block in which the encoded data of the encryption information of the encoded data of the object image separated and input by the separator 52 is interpolated. , And the encoded data of the encryption information of the block is supplied to the encryption / decryption device 56, and the encoded data of the other blocks is decoded to obtain an object image. The encryption / decryption device 56 decrypts the input encryption information.
[0024]
In addition, for each block corresponding to the object image decoder 53 and the shape plane decoder 54 synchronously, the respective input encoded data is decoded, and the shape plane block is determined by the region detector 55, The object image decoder 53 may receive the detection signal from the area detector 55 and supply the encryption information obtained by decrypting the block of the empty area portion to the encryption / decryptor 56.
[0025]
Further, the object image extracted from the object image decoder 53 and the shape plane information extracted from the shape plane decoder 54 are respectively supplied to the display synthesizer 57, and here based on the shape plane information. Then, as shown in FIG. 7C, an image in which only the outline and the inner part of the object are displayed is output to the terminal 58.
[0026]
As described above, in this embodiment, a block of an empty area that is not an object image is selected from blocks surrounding an object, and encryption information is interpolated and transmitted in the block of the empty area. Encryption information can be easily transmitted without degrading the object image.
[0027]
In the above-described embodiment, the encryption information is described as being directly interpolated and transmitted to the block including the outline of the object, but the present invention is limited to the above-described embodiment. For example, when an image signal is decomposed into frequency components at the time of encoding, the image quality deterioration is less noticeable in a relatively high frequency region, so that encryption information is interpolated in the frequency component in the high frequency region. May be transmitted.
[0028]
In this case, since the contour portion of the image contains a lot of high frequencies, the encryption information is interpolated and transmitted in the high frequency component of the contour portion of the image (the portion with the empty area), and the decryption unit In the same manner as in the embodiment, the block including the image is detected by detecting the block including the contour portion of the image, sending the detection signal to the object image decoder, and extracting the encryption information from the frequency component before the decryption to perform the decryption. The remaining frequency components are decoded and an object image is obtained.
[0029]
Also, a block for interpolating encryption information may be designated according to the area (number of pixels) occupied by the object image in each block, and the encryption information may be interpolated in an area other than the image data of the designated block. I do not care. In this case, the encoding unit detects whether the number of pixels of the image of each block exceeds (or is less than) the set threshold value, and blocks in which the number of pixels exceeds (or is less than) the set threshold value. The cryptographic information is interpolated in the free space of.
[0030]
On the other hand, on the decoding side, based on the decoded information on the shape plane, the block of the contour portion (the portion with the empty area) of the object image is detected by the area detector, and the pixels of the image of the block are encoded in advance. If it is a block that exceeds (or is less than) the threshold value set to a fixed value that is consistent with the part, the encryption information is stored in the free area of the block other than the image detected based on the shape plane information. Is determined to be interpolated, the object image decoder determines that the free space information is extracted and input to the encryption / decryption device.
[0031]
In addition, a threshold value is described in the block having the first free space, and the subsequent block is detected based on the threshold value as to whether or not the encryption information is interpolated. Also good. Alternatively, not only the first but also the threshold value may be inserted into the free area of the block irregularly as a signal different from the encryption information, and the threshold value may be changed each time. In this case, it is necessary to set a description format in which the decryption unit can determine whether the cipher information contained in the empty area is true cipher information or a threshold value. As an example of this setting, if the first two bits of the encryption information are “11”, the encryption information is indicated, and if not, the threshold value is indicated.
[0032]
In addition, regarding the above threshold value, in the example in which encryption information is interpolated and transmitted in the frequency component of the high frequency region, the position where the encryption information is interpolated in the frequency component of the high frequency region is identified. Is the same. The cipher information output from the cipher generator 45 can use any data such as characters, sounds, and images. Further, as to the encryption method in the cipher generator 45, it goes without saying that any method may be used as long as consistency with the encryption / decryption device 56 in the decryption unit is obtained.
[0033]
【The invention's effect】
As described above, according to the present invention, the encoding unit detects a block including an empty area portion in an object image extracted in an arbitrary shape, and encodes the empty area portion by interpolating encryption information. When decrypting this, the encryption information is extracted and only the inside of the contour of the object image is displayed. Therefore, not only the image but also the encryption information can be easily transmitted. Further, according to the present invention, since the encryption information is interpolated in an area that is not recognized when the object image is actually displayed, it is possible to substantially eliminate the information missing of the object image information.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of an encoding unit of an image transmission method according to the present invention.
FIG. 2 is a block diagram of an embodiment of a decoding unit of an image transmission method according to the present invention.
FIG. 3 is a diagram illustrating an example of a block including an empty area portion.
FIG. 4 is a block diagram illustrating an example of a conventional image transmission method.
FIG. 5 is a block diagram illustrating an example of an encoding unit of a conventional image transmission method.
FIG. 6 is a block diagram of an example of a decoding unit of a conventional image transmission method.
FIG. 7 is a diagram illustrating an example of a display of a shape plane of an object extracted in an arbitrary shape.
[Explanation of symbols]
41 Object Image Input Terminal 42 Shape Plane Input Terminal 43 Object Image Encoder 44 Shape Plane Encoder 45 Cryptographic Generator 46 Region Designator 47 Multiplexer 51 Multiplexed Data Input Terminal 52 Separator 53 Object Image Decoder 54 Shape plane decoder 55 Region detector 56 Cryptographic decoder 57 Display synthesizer

Claims (3)

A shape plane encoder that encodes information of a shape plane representing the shape of the object image extracted in an arbitrary shape;
A cryptographic generator for generating cryptographic information;
An area designation for generating an area designation signal for designating a block including an outline portion of the object image having an empty area portion based on the information on the shape plane, wherein the object image and the shape plane information are input in synchronization with each other. And
An object image input to the area designator and an area designation signal from the area designator are received as inputs, and the encryption is added to the empty area portion in the block designated by the area designation signal in the object image. An object image encoder that encodes the object image in units of blocks after interpolating encryption information from the generator;
The object data encoded data extracted from the object image encoder and interpolated with encryption information and the shape plane encoded data extracted from the shape plane encoder are multiplexed and multiplexed. A multiplexer for sending data to the transmission line;
A separator that receives the multiplexed data through the transmission path and separates the encoded data of the object image in which the encryption information is interpolated and the encoded data of the shape plane;
A shape plane decoder for decoding the encoded data of the shape plane separated by the separator;
Based on the shape plane information extracted from the shape plane decoder, a block including the outline portion of the object image having the empty area is detected, and it is determined whether or not the encryption information is an interpolated block. An area detector for generating a feedback signal;
The encoded data of the object image in which the encryption information separated by the separator is interpolated and the feedback signal are received as input, and the encoded data of the object image in which the encryption information is interpolated are converted into the feedback signal. An object image decoder for extracting the encoded information encoded based on the data and decoding the encoded data of the object image;
An encryption / decryption device for decoding the encoded encryption information extracted by the object image decoder;
An image transmission system comprising: a display synthesizer that sets a display area of an object image extracted from the object image decoder based on information on a shape plane extracted from the shape plane decoder. A shape plane encoder that encodes information of a shape plane representing the shape of the object image extracted in an arbitrary shape;
A cryptographic generator for generating cryptographic information;
An area designation for generating an area designation signal for designating a block including an outline area of the object image having a vacant area portion based on the information on the shape plane, the object image and the shape plane information being input in synchronization with each other. And
An object image input to the area designator and an area designation signal from the area designator are received as inputs, and the encryption is added to the empty area portion in the block designated by the area designation signal in the object image. An object image encoder that encodes the object image in units of blocks after interpolating encryption information from the generator;
The object data encoded data extracted from the object image encoder and interpolated with encryption information and the shape plane encoded data extracted from the shape plane encoder are multiplexed and multiplexed. An image transmission system comprising: a multiplexer for sending data to a transmission line. Encoding data of an object image in which encryption information is interpolated in the empty area portion and encoded in units of blocks of a block including an outline portion of an object image having an empty area portion, and a shape representing the shape of the object image the multiplexed data and the plane of encoded data are multiplexed, is input through the transmission path, a separator for separating the coded data of the object image, the encoded data of the planar shape,
A shape plane decoder for decoding the encoded data of the shape plane separated by the separator;
Based on the shape plane information extracted from the shape plane decoder, a block including the outline portion of the object image having the empty area is detected, and it is determined whether or not the encryption information is an interpolated block. An area detector for generating a feedback signal;
The encoded data of the object image in which the encryption information separated by the separator is interpolated and the feedback signal are received as input, and the encoded data of the object image in which the encryption information is interpolated are converted into the feedback signal. An object image decoder for extracting the encoded information encoded based on the data and decoding the encoded data of the object image;
An encryption / decryption device for decoding the encoded encryption information extracted by the object image decoder;
An image transmission system comprising: a display synthesizer that sets a display area of an object image extracted from the object image decoder based on information on a shape plane extracted from the shape plane decoder.

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