Abstract:
The present invention relates to an image processing system and data modulation/demodulation method thereof which compresses level of an input image information to that of an audio information to transfer them through conventional telephone liens after reproducing the stored data stored in a memory. This invention makes it possible to compress or reconstruct the image data without loss. The input image data are compressed to audio data level by factorial-code-conversion, cubic-code-conversion, and FASCM conversion, and are again reconstructed to an original image data by inverse.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an image processing system and data modulation/demodulation method thereof and, more particularly, to an image processing system which compresses an input image data to an audio signal level and then transfers the data through conventional telephone lines after reproducing the image data stored in a memory. Such a system also makes it possible to compress or reconstruct the image data without loss. 
     Generally, in the image processing system such as a video tape recorder (VTR), the image data are sorted in a magnetic recording media, and played back again if desired. However, there is a problem in that in order to play back the stored image data, a drum is always required, since tapes and disks are usually used as the magnetic recording media. Further, the image data are extended over a high frequency band and they are impossible to transfer. Therefore, a frequency band of 108 Hz is required for digital image processing and the capacity of a memory must be very large. 
     Conversely, a recording wavelength λ is the ratio of a tape velocity υ to a frequency f. That is, λ=υ/f. In order to record the image signal of a high frequency band, rotary-head drums which are able to play back the recorded signal beyond the predetermined wavelength λ by increasing a relative velocity have been proposed, but these drums have some limitations in minimizing the size of the video tape recorder. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an image processing system and a data modulation/demodulation method thereof which replaces the rotary had drum with a fixed-head drum, or removes the drum itself by compressing the input image data of a high frequency band to an audio data level of a low frequency band, eliminating data loss and transferring the input image data through the conventional telephone lines. The object can be achieved in such a manner that the input image data of a certain range are compressed and incorporated with new input image data to be compressed again repeatedly. 
     The present invention is comprised of a transmitter including an image processing circuit which provides input image data to a single information channel, an analog-to-digital converter connected to an output stage of the image processing circuit, a data compression device connected to an output stage of the analog-to-digital converter for compressing the input image data to audio data level, a first memory connected to an output stage of the data compression device for storing the compressed data, and a transmitting circuit connected to the output stage of the first memory for transmitting the data through the conventional communication network, a receiver, including a receiving circuit for receiving the data transmitted from the transmitting circuit in the transmitter, a second memory connected to the output stage of the receiving circuit for storing the transmitted data, a data reconstruction device connected to the output stage of the second memory for reconstructing an original data from the compressed data, and a data processing circuit connected to the data reconstruction device for displaying the data on a screen. 
     According to the present invention there is also provided a data modulation/demodulation method comprising: a data compression process including a factorial-code-conversion routine for converting an input digital data to factorial-codes, a cubic-code-conversion routine for converting the factorial weight form provided from the factorial-code-conversion routine to cubic-codes, a factorial-adaptive-size-comparison-method (FASCM) routine for comparing the magnitude of the cubic data and providing internal and adaptive bits, ; a data reconstruction process including an inverse factorial-adaptive-size-comparison-method routine for converting the compressed data to the factorial weight form which are comparable with each other, an inverse cubic-code-conversion routine for extracting the factorial-codes from the data of the inverse FASCM routine, and an inverse factorial-code-conversion routine for reconstructing the factorial-codes to original data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, features, and advantages of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings, in which: 
     FIGS. 1(A) and (B) are block diagrams of a transmitter and a receiver in an image processing system according to the present invention, respectively; 
     FIGS. 2(A) and (B) are main flowcharts illustrating an data modulation/demodulation method according to the present invention; and 
     FIGS. 3(A)˜(G) are subroutine flowcharts illustrating an data modulation/demodulation method according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described below with reference to the accompanying drawings. 
     FIGS. 1(A) and (B) show block diagrams each illustrating a transmitter and a receiver in an image processing system according to the present invention. The transmitter, which compresses and transmits an data to be inputted, comprises an image processing circuit 1, an A/D converter 2, a data compression device 3, a first memory 4, and a transmitting circuit 5. The receiver, which reconstructs the received image data and displays it on a screen, comprises a receiving circuit 6, a second memory 7, a data reconstruction device 8, and a data processing circuit 9. 
     To describe the transmitter of FIG. 1(A) in detail, the A/D converter 2 is connected to the image processing circuit 1 which processes the image data received through a tuner T. Subsequently, the data compression device 3 connected to the A/D converter 2 compresses the level of the input image data to that of audio data. The first memory 4 is connected to the data compression device 3 to store the compressed data. The transmitting circuit 5 connected to the first memory 4 transmits the data stored in the first memory 4 through the conventional telephone lines. 
     In the receiver of FIG. 1(B), the second memory 7 connected to the receiving circuit 6 receives the image data transmitted from the transmitting circuit 5 in the transmitter through the conventional telephones lines, and the data reconstruction device 8 is connected to the second memory 7. 
     Subsequently, the data processing circuit 9 connected to the data reconstruction device 8 displays the reconstructed data on a screen. The image processing circuit 1 in the transmitter includes a tuner T, a demodulator DEMO, a low pass filter LPF, a decoder DEC, and a multiplexer MUX. 
     To describe the image processing circuit 1 in more detail, the demodulator DEMO for demodulating the image signal is connected to the tuner T for extracting the image data and to both the decoder DEC for separating the demodulated signal into color difference signals, and the low pass filter LPV. Subsequently, the multiplexer MUX for selecting one signal from a luminance signal Y provided from the low pass filter LPF, color difference signals R-Y, B-Y provided from the decoder DEC, and an audio signal provided from the demodulator DEMO, for transmitting the selected data to a single information channel, is connected to the A/D converter 2. 
     Conversely, a first telephone TEL1 is connected to the first memory 4, and a first modulator/demodulator MODEM1 and a first microcomputer MICOM1 are connected to each other through the first telephone TEL1 in the transmitting circuit 5. The receiving circuit 6 in the receiver has a second telephone TEL2, a second modulator/demodulator MODEM2 and a second microcomputer MICOM2, similar to the transmitting circuit 5. Also, the data processing circuit 9 includes a demultiplexer DEMUX for distributing the data transmitted through a single information channel to many channels, four digital-to-analog (D/A) converters DAC 1-DAC4 for converting digital to analog signals luminance signal Y, digital color difference signals R-Y, B-Y, a digital audio signal provided from the demultiplexer DEMUX to each analog signal, and an encoder ENC for incorporating the analog brightness signal Y with analog color difference signals R-Y, B-Y provided from the D/A converters DAC1-DAC3 to yield pictorial image data. Accordingly, the encoder ENC produces the image data and the D/A converter DAC4 displays an audio signal A on the screen. 
     FIGS. 2(A) and (B) represent main flowcharts showing the data compression process and data reconstruction process according to the present invention. The data compression process comprises a factorial-code-conversion routine L1 for converting input digital data to a factorial weight form, a cubic-code-conversion routine L2 for converting the factorial-code to a cubic-code and a factorial adaptive size comparison method(FASCM) routine L3 for comparing the cubic-codes and for providing internal and adaptive bits, as shown in FIG. 2(A). Next, the data reconstruction process comprises an inverse FASCM routine L4 for converting the data provided from the second memory 7 to the factorial weight form, an inverse cubic-code-conversion routine L5 for converting the factorial weight form provided by the inverse FASCM routine L4 to the factorial-code, and an inverse factorial-code conversion routine L6 for converting the factorial-code to original data. FIGS. 3(A)˜(D) represent the subroutines to be executed in the data compression process according to the present invention. 
     In the data compression process the input digital data of 40 kbits stored in aRAM(Random Access Memory) is compressed to 20 kbit data, and this data of 20 kbits is incorporated with a new input data of 20 kbits, and this incorporated 40 kbit data is again compressed. This compression is repeated until the image data level is transferred to the audio data level. For example, if the image data level is 10 bits/sec the data compression is 10 K times repeated so that the audio data level is 10 4  bits/sec. FIGS. 3(E)-(G) represent subroutines to be used in the data reconstruction method. 
     In an embodiment of the present invention described above, if the image data are extracted by the tuner T of the image processing circuit 1 in the transmitter, the extracted data are separated into an audio signal A and an image signal by the demodulator DEMO. The separated audio signal A is then applied to the multiplexer MUX, while the image signal is applied to both the low pass filter LPF and to the decoder DEC. Next, the brightness signal Y is provided from the low pass filter LPV and the color difference signals R-Y, B-Y are provided from the decoder DEC. The color difference signals are applied to the multiplexer MUX to be transmitted through a signal information channel. The output signal of the multiplexer MUX is converted to digital data by the A/D converter 2, and then this data is compressed by the data compression device 3. 
     Now, the data compression method will be described. First, it is assumed that the level of the image data of 108 bits/sec is compressed to that of the audio data of 10 4  bits/sec. The digital data of 40 kbits provided from the A/D converter 2 is stored in the RAM and the stored data is converted to the factorial-code Q 1 , Qn by the steps S1 to S4 for the factorial-code-conversion routine L1 in FIG. 3(A). The digital data D is converted to a factorial-code Qn Qn-1 . . . Q1, by the following relationship: D=Qn×n! +Qn-1×(n-1)!+. . . Q2×2!+Q1×1!. . . (1) 
     For example, input digital data 08H corresponds to the factorial-code 0110 by using the above mentioned formula(1). 
     
         08H=0×4!+1×3!+1×2!+0×a! 
    
     Such a factorial-code QnQn-1 . . . Q1 is converted to the factorial weight form D1 to DN. The rule of the cubic conversion is illustrated in FIG. (3(B). For the factorial-code 0110 and N=5, since Q1=0, A=N-(Q1-1)=6 and A=N+1=6 so that a reference data 12345 is provided without the cubic-conversion. Next, since Q2=1, then A=N-(Q2-1)=5 and A(=5)≠N+1=6 so that the reference code is changed to a cubic code `15342`, that is, the positions of 2 and 5 are exchanged. Next, since Q3=1, A=N-(Q3-1)=5 and A≠N=1=6 so that the once changed cubic-code 15342 is again changed to 15243, that is, the positions of 3 and 2 are exchanged. 
     In other words, if the cubic condition, that is, A≠N+1, is satisfied, the cubic bit corresponding to the present position is exchanged with the lowest bit. To summarize this cubic-code-conversion rule, it is given by Table 1. 
     
                       TABLE 1______________________________________level  factorial code               reference data                           cubic code______________________________________1      Q1(0)        12345       123452      Q2(1)        12345       153423      Q3(1)        15342       152434      Q4(0)        15243       15243______________________________________ 
    
     Table 2 shows the relationship between factorial-code Q 1  ˜Qn outputted by the input digital data and factorial weight form D 1  ˜Dn converted to the cubic code by the factorial-code. 
     
                                           TABLE 2__________________________________________________________________________INPUT DATA   FACTORIAL NO             LEVEL 1(Q1)                     LEVEL 2(Q2)                             LEVEL (Q3)                                    LEVEL (Q4)__________________________________________________________________________0 0H    12345     0       0       0      00 1H    12354     0       0       0      10 2H    12543     0       0       1      00 3H    12534     0       0       1      10 4H    12435     0       0       2      00 5H    12453     0       0       2      10 6H    15342     0       1       0      00 7H    15324     0       1       0      10 8H    15243     0       1       1      00 9H    15234     0       1       1      10 AH    15432     0       1       2      00 BH    15423     0       1       2      10 CH    14325     0       2       0      00 DH    14352     0       2       0      10 EH    14523     0       2       1      00 FH    14532     0       2       1      11 0H    14235     0       2       2      01 1H    14253     0       2       2      11 2H    13245     0       3       0      01 3H    13254     0       3       0      11 4H    13542     0       3       1      01 5H    13524     0       3       1      11 6H    13425     0       3       2      01 7H    13452     0       3       2      1 .      .         .       .       .      . .      .         .       .       .      . .      .         .       .       .      .7 7H    23151     4       3       2      1__________________________________________________________________________ 
    
     The factorial weight form D 1  ˜Dn is provided as internal bits in In- 1  . . . I 1  and adaptive bits A1˜AM by the FASCM routine 1.3, where the internal bit is produced by comparing the present bit with the previous data, while the adaptive bit is produced by comparing the cubic code with the previous internal bit. 
     Applying the FASCM routine 1.3 to permit the factorial weight form D1-D5 (15243) to be converted to the cubic code as an example, it is as follows. Since D1(=1)&gt;D2(=5), I 1  =1, and similarly since D2(=5)&gt;D3(=2), I 3  =0, and since D3(=2)&lt;D4(=4), I 3  =1, and since Dr(=4)&gt;D5(=3), I 4  =0. Thus, the internal bits corresponding to the factorial weight form 15243 are `1010`. 
     Conversely, there are three methods used o find the adaptive bits An An- 1  . . . A 1  The first method is to extract the adaptive bit by searching the data from the largest of the data up to the present data when the previous internal bit is 1, whereas to extract the adaptive bit by searching from the smallest of the data up to the present data when the previous internal bit is 0. 
     For example, when the factorial weight form 15243 is replaced by the internal bits I1I2I3I4=1010, to find A1, since I1=1 and the next bit I 2  =0, so that a(=1) is the smallest of the bits a and b up to the present position and is compared with the next factorial weight form D3. Since a&lt;c, A1=1. Similarly, to find A2, since I3=1, b which is the largest of the bits a˜c up to the present position is compared with d. Since b&gt;d, A2=0. Similarly, the other adaptive bits A3 and A4 become all 1. Generally, the total number T of the adaptive bits A 1  ˜An by the first method is given by formula (2) as follow. ##EQU1## 
     The second method is to find the adaptive bits by searching the data on the basis of the upper data up to the present data when the previous internal bit is 1, while searching the data from the center of the lower data up to the present data when the previous internal bit is 0. The total number T of the adaptive bits A 1  ˜An by the second method is given by formula (3) as follows. ##EQU2## 
     the first method produces the adaptive bit having the largest value as shown in Eq.(1) and thus the data compression ratio is more than 1. This means that there is no data compression effect. And in the second method, the data compression ratio is close to 1. 
     The third method is to find the adaptive bits by using the first method when the previous internal bit is 1 and by using the second method when the previous internal bit is 0. 
     To find the internal and adaptive bits from the factorial weight form abcdefghi(=764193258) according to the third method, by the FASCM conversion routine, a(=7)&gt;c(=6) so that A1=0. Similarly c(=6)&gt;d(=1) so that I3=0. Since I3=0, comparison begins from the lower data. Then, b(=4)&gt;d(=1), so that A2=0. Also, since d=(1)&lt;e=(9), I4=1. Then, the comparison is begun from the upper bits since a(=7)&lt;e(=9), A3=1. Similarly since d(=1)&lt;f(=3) and b(=4)&gt;f(=3), A4=1 and A5=0. 
     Subsequently, since d(=1)&lt;g(=2), I=1 and since e(=9)&gt;h(=5), a(=7)&gt;h(=5), c(=6)&gt;h(=5), A7˜A10 is 0001. Also, since e(=9)&gt;i(=8) and a(=7)&lt;i(=8), A11=0 and A12=1. Thus, if the factorial weight form DOD1 . . . DN is 746193258, the internal bits I1I2 . . . I8 becomes 01010011 by the steps S16˜S23, and the adaptive bits A1A2 . . . A12 001101000101 by the steps S24˜S32. The total number of the adaptive bits according to the third method is given by formula (4) as follows 
     
         T=1+4+4+. . . =4N                                          (4) 
    
     The factorial weight form D1D2 . . . Dn is provided as the internal bits and the adaptive bits by the FASCM routine 1.3 and the compressed data are again stored in the RAM. In the RAM, the data of 20 kbits are incorporated with new data of 20 kbits and this data of 40 kbits are again compressed by the data compression method. 
     For example, the data compression is 10 K times repeated to compress the image data level of 10 bits/sec down to the audio data level of 10 4  bits/sec. 
     Then, the final compressed data become 20 kbits and this data of 20 kbits are stored in the first memory 4. 
     The data stored in the first memory 4 is applied to the first modulator/demodulator MODEM 1 through the first telephone TEL1 in the transmitting circuit 5. 
     At this time, the image-transmission control signal is provided from the microcomputer MICOM 1. 
     Conversely, the transmitted data through the MODEM 1 in the transmitting circuit 5 are applied to the MODEM2 in the receiving circuit 6 and the output data of MODEM 2 are stored in the second memory 7 through the telephone TEL2. At this time, the image-reception control signal is provided from the MICOM 2. Then, the data stored in the second memory 7 are reconstructed to the original image data by the data reconstruction device 8. 
     Now, the data reconstruction method will be described in detail. The data stored in the second memory 7 are converted to the factorial weight form D1D2 . . DN by the inverse FASCM routine 1.4 in FIG. 3(D). In other words, the internal bits I1I2 . . . In-1 and the adaptive bits A1A2 . . . AM are arranged in sequence of the data magnitude by steps S100˜s101 and the arranged data are changed to the factorial weight form D 1  ˜Dn. 
     For example, if it is assumed that internal bits I1I2I3I4 are 1010, the adaptive bits A1A2A3A4 are 1011, and the reference data are a b c d e, respectively, the relationships a&lt;b, b&gt;c, c&lt;d and d&gt;e are satisfied according to the internal bits 1010, and also the relationships a&lt;c, b&gt;d, a&lt;e, and c&lt;e are satisfied according to the adaptive bits 1011. Thus, the data are arranged in sequence of a, b, c, d, e and so the factorial weight form D1D2 . . . D5 becomes 1 5 2 4 3. 
     As mentioned above, the data stored in the second memory 7 are reconstructed to the factorial weight form D1D2 . . . DN by the inverse FASCM routine 1.4, and the factorial weight form D 1  ˜Dn is reconstructed to the factorial-code Q1Q2 . . . QN by the inverse cubic-code-conversion routine 1.5 in FIG. 3(e). In the inverse cubic-code-conversion routine L5, the reference data (R(1)=1, R(2)=2, . . . , R(N)=N) are set by the steps S104˜S107, as shown in FIG. 3(F), and the default data (d1=1, d2=2, . . . , dN=N) corresponding to the factorial weight form D 1  D 2  . . . DN are also set. That is, for d1=1 and D1=5, R(D1)=R(5)=5. 
     At this point, if the default data di is proven to be identical to the reference data R(Di) by the steps S100˜S103, then the factorial-code Qi=0 by the step S108, but if not, the factorial-code Qi is satisfied at the formula (5) by the step S110. 
     
         Qi=N+1-Di                                                  (5) 
    
     Additionally, if the default data di is not identical to the reference data R(Di), R(di) becomes equal to R(Di) by the step S111. For example, if it is assumed that the factorial weight form D1D2D3D4D5=54123, the default data d1d2d3d4d5=12345, and R(1)=1, R(2)=2, R(3)=3, R(4)=4, and R(5)=5, then A1=N+1-D1=6-5=1 since R(D1)=5≠R(d1)=1 and R(di) (=R(1)) is changed to R(D1) (=5), namely, R(1)=5. Thus, the reference data R(1)R(2R(3)R(4)R(5) become 52345. In a similar manner, R(D2)=R(4)=4 and R(D2)=4≠R(d2)=2, and thus, Q2=N+1-D2=6-4=2. 
     Consequently, R(d2) is changed to R(D2) (=4) and then R(1)R(2) R(3)R(4)R(5)=52345. The extracted factorial-code Q1Q2 . . . Zn using the above method is converted to the original data by the steps S116˜S119. For example, if the factorial code is 0110, the original data is provided by the following equation 
     
         D=0×4!+1×3&#39;+1×2&#39;+0×1!=08H 
    
     The resulting reconstructed data are provided to the demultiplexer DEMUX in the data processing circuit 9 and by the demultiplexer DEMUX, the data are provided as the brightness signal Y, the color difference signals R-Y and B-Y, and the audio signal A through four channels. These signals, on the other hand, are converted to the analog signals by the digital/analog converter DAC1˜CAC4, and the image analog signals, that is, Y B-Y, and R-Y, are applied to the encoder ENC and so displayed on the screen as a single data. The audio analog signal is provided as before. 
     As described above, the audio and image data are provided through a single information channel by the multiplexer MUX in the image processing circuit. The output signal is converted to the digital signal by the A/D converter 2, and this digital signal is compressed from the image data level to the audio data level and is stored in the first memory 4 by the data compression device 3. The compressed data are then transmitted through the conventional transmitting circuit 5. The data transmitted from the transmitter are reconstructed by the data reconstruction device 8 and the reconstructed data are displayed on the screen by the demultiplexer DEMUX, the digital/analog converters DAC 1˜DAC4, and the encoder ENC in the data processing circuit 9. Each data conversion formula in the data compression method is as follows: 
     (i) factorial-code-conversion 
     
         digital data D=Qn×n!+Qn-1×(n-1)!+. . . +Q2×2&#39;+Q1×1! 
    
     (ii) cubic-code-conversion 
     
         data A=N-(Qn-1) 
    
     and if A=N+1, no cubic conversion, but if not A=B 
     (iii) FASCM 
     a) internal bit ##EQU3## 
     b) adaptive bit 
     If Ii-1=1, compare from the largest data up to the present one 
     If Ii-1=0, compare from the smallest data up to the present one 
     Also, each data conversion formula in the data reconstruction method is as follows: 
     (i) inverse FASCM 
     extract the factorial weight form D 1  ˜Dn by arranging the data stored in the second memory 7 according to the internal and adaptive bits. 
     (ii) inverse cubic-code-conversion 
     If default data di=factorial weight form Di, factorial-code Qi=reference data R(Di) 
     
         if di≠Di, Q8=N+1-Di and R(di)=R(Di) 
    
     (iii) inverse factorial-code-conversion 
     
         the digital data D=QN×N!+QN-1×(N-1)!+. . . +Q2×2!+Q1×1! 
    
     According to the present invention described above, the image processing system can transmit and receive the image data through the conventional communication network by compressing the digital image data down to the audio data level. Secondly, the data compression can be repeated without any data loss by the factorial-code-conversion, cubic-code-conversion, and FASCM processes. 
     Furthermore, according to the present invention, since the memory size for storing the image data becomes smaller and also the recording or playback of the image data can be performed by the memories, the rotary-head drum of the conventional VTR can either be replaced by the fixed drum or can be removed, thereby making it possible to reduce the size of the video tape recorder. 
     The present invention is in no way limited to the embodiment described hereinabove. Various modifications of the disclosed embodiment as well as other embodiments of the invention will become apparent to persons skilled in the art upon reference to the description of the present invention. It is therefore believed that the appended claims will cover any such modifications or embodiments which fall within the true scope of the present invention.