KR20000039949A - Apparatus for compressing/depressing image separately according to the characteristics of input image and method thereof - Google Patents

Abstract

PURPOSE: An apparatus for compressing/depressing image separately according to the characteristics of input image and a method thereof are provided to divide input image signal into image signal for a reference and image signal for a teacher. CONSTITUTION: An apparatus for compressing/depressing image separately according to the characteristics of input image includes image divider(102), a temporal subsampler(103), a reference image encoder(104), a reference image packeting machine(105), a volume subsampler(106), a teacher image encoder(107), a teacher image packeting machine(108), and a multiplexor(109). The image divider(102) divide input image signal into a reference image signal and a teacher image signal. The temporal subsampler(103) subsamples the input image according to the output from the image divider(102). The reference image encoder(104) and the teacher image encoder(107) encodes corresponding images. The reference image packeting machine(105) and the teacher image packeting machine(108) packet the encoded image from the encoders(104,107).

Description

Compression / restoration device and method for separating and processing images according to characteristics of input image

The present invention relates to a compression / restoration apparatus for separating and processing images according to characteristics of an input image, and a method and a computer-readable recording medium recording a program for realizing the method. The present invention relates to a compression / restoration apparatus for separating and processing a lecturer image and a textbook image separately for efficiently compressing a lecture video image including a method, and a computer-readable recording medium having recorded thereon a program for realizing the method. .

In the conventional digital compression method of analog lecture video images, analog video images are digitized and compressed using the same method without distinguishing the lecturer image portion and the textbook image portion that constitute the lecture video image.

However, the uniform method is very inefficient because the instructor image part and the teaching material image part have different spatiotemporal characteristics and different spatiotemporal visual importance.

In other words, the textbook image part is almost unmovable, but because of the characteristics of the application of the lecture must be represented very spatially clear, even if the frame rate is low, large and clear images are required. On the other hand, the instructor video portion requires a relatively high frame rate to express the movement of the instructor's hand or mouth, rather than a large or very clear image.

However, since the conventional method uses the same frame rate, the same image size, and the same compression method without distinguishing between the instructor image portion and the text image portion, the size of the image is increased and the frame rate is increased to accurately represent the text image portion. If you lower it, the intermittent movement will be very intermittent in the instructor's video area, which will be very annoying to the eye, and if you increase the frame rate, reduce the image size, or reduce the sharpness of the picture, you will not be able to read the text part properly.

As a result, in the conventional method, both the frame rate, the image size, and the sharpness have to be increased in order to proceed the remote lecture properly, and as a result, a very high bit rate is required, which makes it impossible to apply to most homes having a small bandwidth. There was this.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the present invention provides a compression / restoration apparatus, a method and the method for separating and restoring a compressed image according to the characteristics of the input image, and receiving and restoring the compressed image on the receiving side. Its purpose is to provide a computer readable recording medium having recorded thereon a program.

In addition, the present invention, in order to effectively compress the lecture video image by separating the lecture video image into the instructor image and the teaching material image instructor image instead of maintaining a relatively high frame rate to reduce the image size (or sharpness), the teaching material image Instead of maintaining a large image size, a compression / restore device capable of compressing a lecture video image at a very low bit rate by compressing and transmitting and restoring a textbook image and an instructor image using different compression methods, and reducing the frame rate. It is an object of the present invention to provide a computer-readable recording medium storing a method and a program for realizing the method.

1 is a block diagram of an embodiment of a digital compression apparatus for analog lecture video image according to the present invention.

2 is a configuration diagram of an apparatus for restoring a lecture video image according to the present invention;

3 is a flowchart illustrating a digital compression method of an analog lecture video image according to the present invention.

4 is a flowchart illustrating a method for reconstructing a lecture video image according to the present invention.

* Explanation of symbols for the main parts of the drawings

101: A / D converter 102: classifier

103: temporal abbreviation 104: textbook image encoder

105,108: Packetizer 106: Spatial Abbreviator

107: lecturer video encoder 109: multiplexer

111: demultiplexer 112,113: depacketizer

114: text picture decoder 115: lecturer video decoder

116,117 display

According to an aspect of the present invention, there is provided a compression apparatus for compressing a lecture video image, comprising: image classification means for determining and classifying whether an input image frame is a textbook image frame or an instructor image frame; Temporal condensing means for condensing the input image frame in time according to the teaching material image classification signal of the image classification means; Teaching material image compressing means for compressing the teaching material image condensed temporally in said temporal contracting means; Teaching material image packetizing means for packetizing the teaching material image bit stream compressed by the teaching image compression means and displaying the teaching material image in its header; Spatial reduction means for spatially contracting the input image frame according to the instructor image classification signal of the image classification means; Instructor image compression means for compressing a spatially reduced instructor image in the spatial reduction means; Instructor image packetization means for packetizing the instructor image bit string compressed by the instructor image compression means and displaying the instructor image in its header; And multiplexing means for transmitting the lecture image packet sequence by multiplexing the teaching image packet sequence of the teaching material image packetization means and the lecturer image packet sequence of the lecturer image packetization means.

The compression apparatus may further include analog / digital converting means for receiving an analog lecture video image from the outside and converting the video into a digital image frame and transmitting the image classification means and the temporal or spatial reduction means. It is done.

The reconstruction device of the present invention is a reconstruction device for reconstructing a compressed lecture video image, and receives a compressed lecture video packet string from a transmitting side and examines the packet header to determine whether the teaching material video packet is an instructor video packet. Demultiplexing means for classification; Teaching image depacketization means for receiving a teaching image packet sequence from the demultiplexing means and removing the packet header to restore the teaching image bit sequence; Teaching image decoding means for decoding the teaching image bit string from the teaching image depacketization means; First display means for displaying the teaching material image decoded by the teaching image decoding means according to teaching material / instructor image determination information from the demultiplexing means; Instructor image depacketization means for receiving an instructor image packet sequence from the demultiplexing means and removing the packet header to restore the instructor image bit sequence; Instructor image decoding means for decoding an instructor image bit string from the instructor image depacketization means; And second display means for displaying the instructor image decoded by the instructor image decoding means according to the teaching material / instructor image determination information from the demultiplexing means.

On the other hand, another compression apparatus of the present invention, a compression apparatus for compressing an image, comprising: image classification means for determining and classifying characteristics of an input image frame; A plurality of image reduction means for respectively shortening the input image frames classified and input according to the image classification signal of the image classification means; A plurality of image compression means for respectively compressing the reduced images corresponding to the plurality of image reduction means; A plurality of image packetizing means for packetizing the compressed image bit stream corresponding to the plurality of image compression means and displaying an image type according to an input image characteristic in a header thereof; And multiplexing means for multiplexing and transmitting each video packet string from the plurality of video packetizing means.

The other compression apparatus may further include analog / digital converting means for receiving an analog video image from the outside and converting it into a digital image frame and transmitting the image classification means and the plurality of image reduction means. .

Another reconstruction device of the present invention is a reconstruction device for reconstructing a compressed video image. Multiplexing means; A plurality of image depacketization means for receiving an image packet sequence classified by the demultiplexing means and removing the packet header, respectively, to restore the image bit sequence; A plurality of image decoding means for decoding the reconstructed image bit stream corresponding to the plurality of image depacketization means; And display means for displaying the decoded image corresponding to the plurality of image decoding means according to the image type determination information from the demultiplexing means.

On the other hand, the compression method of the present invention, a compression method applied to the compression device for compressing a lecture video image, the first step of determining whether the teaching material image or instructor image by reading the frame of the input lecture video image; A second step of, as a result of the determination in the first step, compressing and compressing the image data in time if the text is a text image, and packetizing the text image bit string to display the text image in the header; A third step of, if the instructor image is a lecturer image, condensing and compressing the image data in a contemporaneous manner and then packetizing the instructor image bit string and displaying the instructor image in its header; And a fourth step of repeating the process of reading the video frame of the first step for all the frames after multiplexing the compressed teaching material video packet sequence and the instructor image packet sequence.

The compression method may further include a fifth step of reading analog video image data and converting the image data into digital image data to input the lecture video image.

In addition, the reconstruction method of the present invention is a reconstruction method applied to a reconstruction device for reconstructing a compressed lecture video image, and reads a packet from a multiplexed packet sequence and examines a packet header to determine whether the packet is a text image or an instructor image. Determining a first step; A second step of decoding and displaying the text image bit string after restoring the text image bit string by removing the header of the text image packet if it is a text image; A third step of decoding and displaying the instructor image bit string after restoring the instructor image bit string by removing the header of the instructor image packet if the instructor image is determined as the first step; And a fourth step of repeatedly performing the first step on all packets.

On the other hand, another compression method of the present invention, a compression method applied to a compression device for compressing an image, comprising: a first step of reading the frame of the input video image to determine the type of the image according to the input image characteristics; A second step of compressing the image data in time and compressing the image bit stream after packetizing the image bit stream if the image has a temporal compression characteristic as a result of the determination in the first step; A third step of condensing and compressing the image data temporally and compressing the image bit stream if the image has a spatial compression characteristic as a result of the first step, and displaying the type of image in the header thereof; And a fourth step of repeating the process of reading the video frame of the first step for all the frames after multiplexing the compressed video packet streams.

The method may further include a fifth step of reading analog video image data and converting the image data into digital image data to input the video image.

Another reconstruction method of the present invention is a reconstruction method applied to a reconstruction device for reconstructing a compressed video image, the method comprising: a first method of determining a type of a read packet by reading a packet from a multiplexed packet sequence and examining a packet header; step; A second step of decoding and displaying a video bit stream having a temporal compression characteristic after reconstructing the video bit string by removing a header of the video packet as a result of the determination of the first step; A third step of decoding and displaying the image bit string having the spatial compression characteristic after restoring the image bit string by removing the header of the image packet if the image having the spatial compression characteristic is determined as the first step; And a fourth step of repeatedly performing the first step on all packets.

On the other hand, the present invention, the compression device having a processor, a first function for determining whether the teaching material image or the lecturer image by reading the input frame of the lecture video image; A second function of compressing and compressing the image data in time as a result of the determination in the first function, compressing the image data in time, and packetizing the text image bit string to display the text image in its header; A third function of compressing and compressing the video data in a timely manner if the instructor image results in the instructor image, compressing the instructor image bit stream, and displaying the instructor image in its header; And a program for realizing a fourth function of repeatedly performing the process of reading the image frame of the first function for all frames after multiplexing the compressed teaching material image packet sequence and the instructor image packet sequence. Provide the medium.

The present invention also provides a decompression device including a processor, comprising: a first function of reading a packet from a multiplexed packet sequence and examining a packet header to determine whether the read packet is a teaching material image or an instructor image; A second function of decoding and displaying the text image bit string after restoring the text image bit string by removing the header of the text image packet if it is a result of the determination in the first function; A third function of decoding and displaying the instructor image bit string after reconstructing the instructor image bit string by removing the header of the instructor image packet if the instructor image is determined as the first function; And a computer-readable recording medium having recorded thereon a program for realizing a fourth function of repeatedly performing the first function for all packets.

In addition, the present invention provides a compression device having a processor, comprising: a first function of reading a frame of an input video image and determining a type of an image according to an input image characteristic; A second function of compressing and compressing the image data in time and then packetizing the image bit string and displaying the type of image in the header if the image has a temporal compression characteristic as a result of the determination in the first function; A third function of condensing and compressing the image data in a temporal manner if the image has a spatial compression characteristic and then compressing the image data to packetize the image bit string and displaying the type of image in the header thereof; And a computer-readable recording medium having recorded thereon a program for realizing a fourth function of repeatedly performing the process of reading the image frame in the first function for all frames after multiplexing the compressed image packet streams. .

The present invention also provides a decompression device including a processor, comprising: a first function of reading a packet from a multiplexed packet sequence and examining a packet header to determine the type of the read packet; A second function of decoding and displaying an image bit string having a temporal compression characteristic after reconstructing the image bit string by removing a header of the image packet as a result of the determination in the first function; A third function of decoding and displaying an image bit string having a spatial compression characteristic after reconstructing the image bit string by removing a header of the image packet as a result of the determination in the first function; And a computer-readable recording medium having recorded thereon a program for realizing a fourth function of repeatedly performing the first function for all packets.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an embodiment of a digital compression device for analog lecture video image according to the present invention.

As shown in the figure, in the compression apparatus according to the present invention, an analog lecture video image (image 1), which is input from the outside, is converted into digital by the analog-to-digital converter 101. The classifier 102 receives the converted digital image frame (image 2) and determines whether the frame is a textbook image frame or an instructor image frame. According to the determination result (signal 1), the digitally converted image frame (image 2) is compressed in different ways via the temporal condenser 103 or the spatial condenser 106.

That is, if the frame is a textbook image frame, it is temporally subsampled, and this temporally reduced textbook image (image 3) is compressed through the textbook image encoder 104, and the resulting textbook image bit stream (bit) The column 1) is packetized in the packetizer 105 to form a teaching material video packet sequence (packet sequence 1).

On the other hand, if the current frame is an instructor image frame, it is spatially subsampled, and this spatially reduced instructor image (image 4) is compressed through the instructor image encoder 107, and the resulting instructor image bit string ( Bit string 2) is packetized in packetizer 108 to form an instructor video packet string (packet string 2).

The spatial condenser 106 spatially condenses each input frame, and the temporal condenser 103 selects only one input frame for each frame and passes them to the input of the teaching material image encoder 104, and the remaining frames Throw away. The packetizers 105 and 108 of the teaching material image and the instructor image have a function of including information indicating whether each packet corresponds to the teaching material image or the instructor image in the packet header.

Subsequently, the text image packet sequence and the instructor image packet sequence are multiplexed through a multiplexer 109 to be configured as a lecture image packet sequence (packet sequence 3) and transmitted to the receiver.

On the other hand, in the compression device of the present invention, the analog-to-digital converter 101 is not an essential component of the present invention. That is, the digital image (image 2) may be directly input to the input image (image 1).

On the other hand, in the compression apparatus of the present invention, when the bandwidth is further lowered due to congestion of the network, it is easy to apply an adaptive transmission technique such as transmitting only a teaching material image without transmitting an instructor image.

2 is a configuration diagram of an apparatus for restoring a lecture video image according to the present invention.

As shown in the figure, the operation of the decompression device according to the invention takes place in the reverse order of the compression device. First, the demultiplexer 111 receives a compressed lecture video packet sequence (packet sequence 4) from the transmitting side and examines the packet header to determine whether each packet is a textbook image packet or an instructor image packet. 112, 113). This determination information (signal 2) is also used as an input to the displayers 116 and 117 of the teaching material image and the instructor image as will be described later.

As a result of the determination, if the current packet is a teaching image packet, the packet header is removed by the teaching packet depacketizer 112 to restore the teaching image bit sequence (bit sequence 3), and the teaching image image decoder (text teaching image decoder) The textbook image, which is decoded and decoded by using the reference numeral 114, is displayed on the text image display 116.

On the other hand, if the current packet is the instructor video packet, the packet header is removed through the instructor video depacketizer 113 to restore the instructor video bit string (bit string 4). The instructor image decoded and decoded by the decoder 115 is displayed through the instructor image display 117.

At this time, the instructor image portion is freeze while the teaching material image is displayed, and the teaching material image portion is freeze while the instructor image is displayed. This freeze operation is controlled by the teaching material / instructor image determination information (signal 2) from the demultiplexer 111. The display materials 116 and 117 for the teaching image and the lecturer image may be physically different hardware, or may be implemented by using different windows on the same monitor. In addition, the present invention may be implemented in various forms such as displaying an instructor video window at a corner of the textbook video window.

3 is a flowchart illustrating a digital compression method of an analog lecture video image according to the present invention.

As shown in the figure, the compression apparatus according to the present invention first reads analog video image data (201) and converts it into digital image data (202). Thereafter, after reading the digitally converted lecture video image by one frame (203), it is determined whether the read frame is a textbook image or an instructor image (204).

As a result of the determination (204), if the read frame is a text image, the video data is temporally reduced (205), and then the temporally reduced textbook image is compressed with a text image encoder (206). Packetize (207).

On the other hand, the determination result 204, if the read frame is an instructor image, after condensing the image data in time (208), the spatially reduced instructor image is compressed with the instructor image encoder (209) and the resulting instructor The video bit string is packetized (210).

Thereafter, the text image packet sequence and the instructor image packet sequence are multiplexed with each other (211), and if there are further remaining image frames, the digital image data of one frame is read (203) and the process of determining whether the read frame is a text image or instructor image The process is repeated from 204 and if there is no more image frame remaining, the compression process ends (212).

On the other hand, in the compression method of the present invention, the step 202 of reading the analog image data (201) and converting it into digital data is not an essential component of the present invention. That is, the digital image may be directly received as the input image.

On the other hand, in the compression method of the present invention, when the bandwidth is further lowered due to congestion of the network, it is easy to apply the adaptive transmission technique such as transmitting only the teaching material image without transmitting the instructor image.

4 is a flowchart illustrating a method of reconstructing a lecture video image according to the present invention.

As shown in the figure, the restoration method according to the present invention is performed in the reverse order of the above-described compression process. First, the decompression device reads one packet from the multiplexed packet sequence (221), and determines whether the read packet is a textbook image or an instructor image by looking at the packet header of the read packet (222).

As a result of the determination (222), if the read packet is a text image, the header of the text image packet is removed to restore the text image bit string (223), and the text image bit string is decoded (224) to decode the decoded text image. The display for the teaching material image is displayed and the display for the instructor image is frozen (225).

On the other hand, when the determination result 222, if the read packet is the instructor image, the header of the instructor image packet is removed to restore the instructor image bit string (226), and the instructor image bit string is decoded (227) to be decoded. The image is displayed on the instructor image display and the text image display is frozen (228).

Subsequently, if there are any remaining packets, the packet is read from the multiplexed packet sequence (221) and repeated from the process of determining whether the read packet is a textbook image or an instructor image (222), and the remaining packets are no longer present. If no, the restoration process is terminated (229).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

As described above, the present invention can effectively compress lecture video images at a low bit rate, thereby enabling remote lectures through a low bandwidth transmission path, and saving more lecture video images in a given database. It is effective to implement realistic distance education system.

In addition, when the bandwidth is further lowered due to congestion of the network, the present invention is easy to apply an adaptive transmission technique such as transmitting only a teaching material image without transmitting an instructor image. Remote lecture progress is also possible.

In addition, the present invention compresses the lecture video image at a higher compression rate to provide higher image quality compared to the prior art, thereby maximizing the distance education effect, and replaces a large part of the existing group training, which is a time required for group training. This has the effect of reducing economic costs.

In addition, the present invention has the effect of reducing the cost for rewriting new digital lecture content by enabling the efficient transmission of the analog lecture video image already made through a digital network such as the Internet / intranet.

Claims (29)

In the compression device for compressing lecture video images, Image classification means for determining and classifying whether the input image frame is a teaching material image frame or an instructor image frame; Temporal condensing means for condensing the input image frame in time according to the teaching material image classification signal of the image classification means; Teaching material image compressing means for compressing the teaching material image condensed temporally in said temporal contracting means; Teaching material image packetizing means for packetizing the teaching material image bit stream compressed by the teaching image compression means and displaying the teaching material image in its header; Spatial reduction means for spatially contracting the input image frame according to the instructor image classification signal of the image classification means; Instructor image compression means for compressing a spatially reduced instructor image in the spatial reduction means; Instructor image packetization means for packetizing the instructor image bit string compressed by the instructor image compression means and displaying the instructor image in its header; And Multiplexing means for transmitting the lecture image packet sequence by multiplexing the teaching material image packet sequence of the teaching material image packetization means and the instructor image packet sequence of the instructor image packetization means Compression device comprising a. The method of claim 1, Analog-to-digital conversion means for receiving an analog lecture video image from the outside and converting it into a digital image frame and transmitting it to the image classification means and the temporal or spatial reduction means. Compression device further comprising. The method according to claim 1 or 2, Demultiplexing means for receiving the compressed lecture video packet sequence from the multiplexing means and examining the packet header to determine whether the teaching material video packet or the lecturer video packet is classified; Teaching image depacketization means for receiving a teaching image packet sequence from the demultiplexing means and removing the packet header to restore the teaching image bit sequence; Teaching image decoding means for decoding the teaching image bit string from the teaching image depacketization means; First display means for displaying the teaching material image decoded by the teaching image decoding means according to teaching material / instructor image determination information from the demultiplexing means; Instructor image depacketization means for receiving an instructor image packet sequence from the demultiplexing means and removing the packet header to restore the instructor image bit sequence; Instructor image decoding means for decoding an instructor image bit string from the instructor image depacketization means; And Second display means for displaying the instructor image decoded by the instructor image decoding means according to teaching material / instructor image determination information from the demultiplexing means; Compression device further comprising. The method of claim 3, wherein The first and second display means, Controlled by the teaching material / instructor image determination information from the demultiplexing means, the instructor image is frozen while the teaching material image is displayed, and the teaching material image is frozen while the instructor image is displayed, Compressor comprising a physically different hardware, using a different window on the same monitor, or displaying the instructor image window in the text image window. The method of claim 3, wherein The compression device, Compression device, characterized in that to apply the adaptive transmission method that transmits only the textbook image without transmitting the instructor image when the bandwidth is lowered due to network congestion. A decompression device for reconstructing a compressed lecture video image, Demultiplexing means for receiving a compressed lecture video packet sequence from a transmitting side and examining a packet header to determine whether to classify a teaching material video packet or a lecturer video packet; Teaching image depacketization means for receiving a teaching image packet sequence from the demultiplexing means and removing the packet header to restore the teaching image bit sequence; Teaching image decoding means for decoding the teaching image bit string from the teaching image depacketization means; First display means for displaying the teaching material image decoded by the teaching image decoding means according to teaching material / instructor image determination information from the demultiplexing means; Instructor image depacketization means for receiving an instructor image packet sequence from the demultiplexing means and removing the packet header to restore the instructor image bit sequence; Instructor image decoding means for decoding an instructor image bit string from the instructor image depacketization means; And Second display means for displaying the instructor image decoded by the instructor image decoding means according to teaching material / instructor image determination information from the demultiplexing means; Restore device comprising a. The method of claim 6, The first and second display means, Controlled by teaching material / instructor image determination information from the demultiplexing means, the instructor image is frozen while the teaching material image is displayed, and the teaching material image is frozen while the instructor image is displayed, A reconstructing apparatus comprising physically different hardware, using different windows on the same monitor, or displaying an instructor image window in a textbook image window. In the compression device for compressing an image, Image classification means for determining and classifying characteristics of the input image frame; A plurality of image reduction means for respectively shortening the input image frames classified and input according to the image classification signal of the image classification means; A plurality of image compression means for respectively compressing the reduced images corresponding to the plurality of image reduction means; A plurality of image packetizing means for packetizing the compressed image bit stream corresponding to the plurality of image compression means and displaying an image type according to an input image characteristic in a header thereof; And Multiplexing means for multiplexing and transmitting each video packet sequence from the plurality of video packetizing means Compression device comprising a. The method of claim 8, Analog-to-digital conversion means for receiving an analog video image from the outside and converting it into a digital image frame and transmitting it to the image classification means and the plurality of image reduction means. Compression device further comprising. The method according to claim 8 or 9, Demultiplexing means for receiving a compressed video packet sequence from the multiplexing means and examining a packet header to determine and classify the type of video packet; A plurality of image depacketization means for receiving an image packet sequence classified by the demultiplexing means and removing the packet header, respectively, to restore the image bit sequence; A plurality of image decoding means for decoding the reconstructed image bit stream corresponding to the plurality of image depacketization means; And Display means for displaying the decoded video corresponding to the plurality of video decoding means according to the image type determination information from the demultiplexing means; Compression device further comprising. The method of claim 10, The display means, It is controlled by the image type determination information from the demultiplexing means to freeze another image while one image is displayed, Compressor comprising a physically different hardware, using a different window on the same monitor, or displays another video window in a certain video window. In the decompression device for restoring a compressed video image, Demultiplexing means for receiving a compressed video packet sequence from a transmitting side and examining a packet header to determine and classify the types of video packets; A plurality of image depacketization means for receiving an image packet sequence classified by the demultiplexing means and removing the packet header, respectively, to restore the image bit sequence; A plurality of image decoding means for decoding the reconstructed image bit stream corresponding to the plurality of image depacketization means; And Display means for displaying the decoded video corresponding to the plurality of video decoding means according to the image type determination information from the demultiplexing means; Restore device comprising a. The method of claim 12, The display means, It is controlled by the image type determination information from the demultiplexing means to freeze another image while one image is displayed, A reconstructing device comprising physically different hardware, using different windows on the same monitor, or displaying another video window within a certain video window. A compression method applied to a compression device for compressing lecture video images, A first step of determining whether a teaching material image or an instructor image is read by reading the input lecture video image frame; A second step of, as a result of the determination in the first step, compressing and compressing the image data in time if the text is a text image, and packetizing the text image bit string to display the text image in the header; A third step of, if the instructor image is a lecturer image, condensing and compressing the image data in a contemporaneous manner and then packetizing the instructor image bit string and displaying the instructor image in its header; And A fourth step of repeating the process of reading the image frame of the first step for all the frames after multiplexing the compressed teaching material image packet sequence and the instructor image packet sequence Compression method comprising a. The method of claim 14, A fifth step of inputting the lecture video image by reading analog video image data and converting the image into digital image data Compression method comprising more. The method according to claim 14 or 15, A sixth step of reading a packet from the multiplexed packet sequence and examining a packet header to determine whether the read packet is a textbook image or an instructor image; A seventh step of decoding and displaying the text image bit string after restoring the text image bit string by removing the header of the text image packet if it is the text image; An eighth step of decoding the instructor image bit string by restoring the instructor image bit string by removing the header of the instructor image packet if the instructor image is determined as the result of the sixth step; And A ninth step of repeating the sixth step for all packets Compression method comprising more. A restoration method applied to a restoration apparatus for restoring a compressed lecture video image, A first step of reading a packet from the multiplexed packet sequence and examining a packet header to determine whether the read packet is a textbook image or an instructor image; A second step of decoding and displaying the text image bit string after restoring the text image bit string by removing the header of the text image packet if it is a text image; A third step of decoding and displaying the instructor image bit string after restoring the instructor image bit string by removing the header of the instructor image packet if the instructor image is determined as the first step; And A fourth step of repeating the first step with respect to all packets Restoration method comprising a. In the compression method applied to a compression device for compressing an image, A first step of reading a frame of an input video image and determining a type of the image according to an input image characteristic; A second step of compressing the image data in time and compressing the image bit stream after packetizing the image bit stream if the image has a temporal compression characteristic as a result of the determination in the first step; A third step of condensing and compressing the image data temporally and compressing the image bit stream if the image has a spatial compression characteristic as a result of the first step, and displaying the type of image in the header thereof; And A fourth step of repeating the process of reading the first image frame for all frames after multiplexing the compressed image packet streams Compression method comprising a. The method of claim 18, A fifth step of inputting the video image by reading analog video image data and converting the image data into digital image data; Compression method comprising more. The method of claim 18 or 19, A sixth step of reading a packet from the multiplexed packet sequence and examining a packet header to determine the type of the read packet; A seventh step of decoding the image bit string having the temporal compression characteristic after decoding the header of the image packet to restore the image bit string if the image has the temporal compression characteristic as a result of the sixth step; An eighth step of decoding and displaying an image bit string having a spatial compression characteristic after restoring the image bit string by removing the header of the image packet as a result of the determination of the sixth step; And A ninth step of repeating the sixth step for all packets Compression method comprising more. In the decompression method applied to a decompression device for restoring a compressed video image, A first step of reading a packet from the multiplexed packet sequence and examining a packet header to determine the type of the read packet; A second step of decoding and displaying a video bit stream having a temporal compression characteristic after reconstructing the video bit string by removing a header of the video packet as a result of the determination of the first step; A third step of decoding and displaying the image bit string having the spatial compression characteristic after restoring the image bit string by removing the header of the image packet if the image having the spatial compression characteristic is determined as the first step; And A fourth step of repeating the first step with respect to all packets Restoration method comprising a. In a compression device equipped with a processor, A first function of determining whether the teaching material image or the instructor image is read by reading the input lecture video image frame; A second function of compressing and compressing the image data in time as a result of the determination in the first function, compressing the image data in time, and packetizing the text image bit string to display the text image in its header; A third function of compressing and compressing the video data in a timely manner if the instructor image results in the instructor image, compressing the instructor image bit stream, and displaying the instructor image in its header; And A fourth function of repeating the process of reading the image frame of the first function for all frames after multiplexing the compressed teaching material image packet sequence and the instructor image packet sequence A computer-readable recording medium having recorded thereon a program for realizing this. The method of claim 22, A fifth function of inputting the lecture video image by reading analog video image data and converting the image into digital image data The computer-readable recording medium having recorded the program further comprising. The method of claim 22 or 23, A sixth function of reading a packet from the multiplexed packet stream and examining a packet header to determine whether the read packet is a textbook image or an instructor image; A seventh function of decoding and displaying the teaching material image bit string after removing the header of the teaching material packet by restoring the teaching material image bit string as a result of the determination in the sixth function; An eighth function of removing the header of the instructor video packet by restoring the instructor video bit string if the instructor image determines that the instructor video bit is decoded, and then decoding and displaying the instructor video bit string; And 9th function which repeats from said 6th function with respect to all the packets The computer-readable recording medium having recorded the program further comprising. In a restoration device having a processor, A first function of reading a packet from the multiplexed packet sequence and examining a packet header to determine whether the read packet is a textbook image or an instructor image; A second function of decoding and displaying the text image bit string after restoring the text image bit string by removing the header of the text image packet if it is a result of the determination in the first function; A third function of decoding and displaying the instructor image bit string after reconstructing the instructor image bit string by removing the header of the instructor image packet if the instructor image is determined as the first function; And A fourth function for repeating the first function with respect to all packets A computer-readable recording medium having recorded thereon a program for realizing this. In a compression device equipped with a processor, A first function of reading a frame of an input video image and determining a type of the image according to an input image characteristic; A second function of compressing and compressing the image data in time and then packetizing the image bit string and displaying the type of image in the header if the image has a temporal compression characteristic as a result of the determination in the first function; A third function of condensing and compressing the image data in a temporal manner if the image has a spatial compression characteristic and then compressing the image data to packetize the image bit string and displaying the type of image in the header thereof; And A fourth function of repeating the process of reading the image frame in the first function for all the frames after multiplexing the compressed image packet streams A computer-readable recording medium having recorded thereon a program for realizing this. The method of claim 26, A fifth function of inputting the video image by reading analog video image data and converting the analog video image data into digital image data; The computer-readable recording medium having recorded the program further comprising. The method of claim 26 or 27, A sixth function of reading a packet from the multiplexed packet sequence and examining a packet header to determine the type of the read packet; A seventh function of decoding and displaying an image bit string having a temporal compression characteristic after reconstructing the image bit string by removing a header of the image packet as a result of the determination in the sixth function; An eighth function of decoding and displaying an image bit string having a spatial compression characteristic after restoring the image bit string by removing a header of the image packet as a result of the determination in the sixth function; And 9th function which repeats from said 6th function with respect to all the packets The computer-readable recording medium having recorded the program further comprising. In a restoration device having a processor, A first function of reading a packet from the multiplexed packet sequence and examining a packet header to determine the type of the read packet; A second function of decoding and displaying an image bit string having a temporal compression characteristic after reconstructing the image bit string by removing a header of the image packet as a result of the determination in the first function; A third function of decoding and displaying an image bit string having a spatial compression characteristic after reconstructing the image bit string by removing a header of the image packet as a result of the determination in the first function; And A fourth function for repeating the first function with respect to all packets A computer-readable recording medium having recorded thereon a program for realizing this.