Patent Publication Number: US-8537076-B2

Title: Video circuit

Description:
PRIORITY CLAIMS/RELATED APPLICATIONS 
     This application is a 371 U.S. national stage filing of (and claims the benefit and priority to under 35 U.S.C. 119 and 120) PCT/IB03/03324 filed on Jul. 24, 2003, which in turn claims the benefit of and priority under 35 U.S.C. 119 to European Patent Application Serial No. 02078419.5 filed on Aug. 19, 2002, both of which are incorporated herein by reference. 
     The invention relates to a video circuit for processing video signals which show images on a display panel with linear light transition, comprising a gamma correction circuit, a quantizer and a sub-field generator circuit. 
     From U.S. Pat. No. 6,097,368 is known that video signals for showing images on a display panel of a television set comprise a red, a green and a blue signal, which is 3 times 8 bits of video data. Plasma display panel or PDP for short have a linear light transition. Therefore, the video signals subjected to a gamma function are to be corrected and the video signals converted into luminance data. Plasma display panels are limited as regards the number of luminance stages that can be displayed, a quantization process therefore reduces the number of bits. For generating red, green or blue light for a pixel, sub-fields are addressed which make a red, green or blue light source of the pixel light up for the definite period. This technique is also referred to as sub-field generation or SFG for short. Processors are provided for these methods. The conversion of video signals into luminance signals, the quantization method and the addressing of sub-fields are methods requiring time and implemented successively for a plasma display panel. If a movement occurs from one picture to the next, artefacts may occur. 
     Therefore it is an object of the invention to save computing time and improve the picture quality. 
     This object is achieved in accordance with the characteristic features of the coordinated claims  1 - 3 . 
     In a first embodiment, in a first random-access memory a coarse adjustment of the quantization is effected and in a second random-access memory a fine adjustment. Time is saved with the quantization effected in a random-access memory. The splitting up into two parts provides that the necessary memory size for a 12-bit input is significantly reduced. 
     In a second embodiment most significant bits are quantized in a first random-access memory and least significant bits are quantized in a second random-access memory. Time is saved with the quantization effected in a random-access memory. Here too, the splitting-up into two parts significantly reduces the necessary memory size for a 12-bit input. 
     In a third embodiment a random-access memory replaces the quantizer. Digital data signals are applied to a random-access memory as addresses and associated values are issued from an output. This saves time compared to a computer that carries out calculations in a plurality of steps. 
     The random-access memory advantageously replaces a dequantizer. The formerly quantized signal is reconverted and a comparison with the input values can be made. Quantizers and dequantizers are realized in a random-access memory. A quantization error can be detected and an error scattering method can be performed by means of a filter. 
     The random-access memory advantageously replaces a gamma correction circuit. If a gamma correction function and a quantization are carried out in a single random-access memory, the computing time is also saved. Based on the linear light transition the video signals subjected to a gamma function are to be corrected and video data are converted into luminance data. A corresponding gamma correction function reads x=y n  with n=2.4. In order to achieve a sufficiently high resolution for dark areas, at least 3 times 12 bits are to be used. Plasma display panels are limited as to the number of luminance stages that can be displayed which are typically 32 (=2 5 ) to 256 (=2 8 ) discrete stages. A quantization process reduces the number of bits and an error scattering method reduces the occurring quantization noise. The quantization process and the error scattering method are also referred to as dithering. 
     An inverse gamma correction circuit is advantageously included downstream of the dequantizer. If the correction in the gamma correction circuit is not converted with equidistant values, the inverse gamma correction circuit is necessary between the dequantizer and the filter. The quantizer, the dequantizer, the gamma correction circuit and the inverse gamma correction circuit are then realized in a single random-access memory. 
     The random-access memory advantageously replaces a sub-field generator. If the quantizer, dequantizer and sub-field generator are collectively realized in a single random-access memory, computer time is also saved. 
     A gamma function, a quantization, a sub-field generation circuit and a partial line doubling are advantageously achieved by means of two random-access memories. Least significant bits of sub-fields of two neighboring lines are identical and time is saved then. The sub-field generator circuit of a first random-access memory outputs a bit sample with which a plasma display panel can be driven directly and furthermore outputs data via a converter, a quantizer and a filter to the input signal of the neighboring line and via a second converter, a second dequantizer also to the input signal. With sub-fields that are spread non-equidistantly by the bit sample of the least significant bits is output directly to the quantizer of the second random-access memory. 
    
    
     
       For a better understanding of the invention, an example of embodiment will be explained hereinafter with reference to the drawing in which: 
         FIG. 1  shows a block circuit diagram comprising a random-access memory for a quantization process and subsequent dequantization process, 
         FIG. 2  shows a display panel section with neighboring pixels, 
         FIG. 3  shows the display panel section with correction values for the neighboring pixels, 
         FIG. 4  shows a filter with delay elements, 
         FIG. 5  shows a block circuit diagram with two random-access memories for a coarse and a fine adjustment of a quantization process, 
         FIG. 6  shows a block circuit diagram with two random-access memories for most significant and least significant bits of a quantization process, 
         FIG. 7  shows a block circuit diagram with a random-access memory which replaces a gamma correction function and a quantization process for equidistant values, 
         FIG. 8  shows a block circuit diagram with a random-access memory which replaces a gamma correction function and a quantization process and their reverse functions for non-equidistant values, 
         FIG. 9  shows a diagram for the representation of quantization noise with a classification in equidistant values, 
         FIG. 10  shows a diagram for the representation of quantization noise for a classification in non-equidistant values, 
         FIG. 11  shows a block circuit diagram with a random-access memory which replaces a gamma correction function, a quantizer and their reverse functions and a sub-field generator, 
         FIG. 12  shows a block circuit diagram for a partial line doubling, 
         FIG. 13  shows a block circuit diagram with two random-access memories for processing pixel values of a first and a second line for equidistant sub-line codings, 
         FIG. 14  shows a block circuit diagram with two random-access memories for processing pixel values of a first and a second line for non-equidistant sub-field codings, 
         FIG. 15  shows a timing diagram with sub-fields for the operation of a plasma display panel and 
         FIG. 16  shows a second timing diagram with sub-fields for the operation of a plasma display panel in which a partial line doubling is used. 
     
    
    
       FIG. 1  shows a video circuit  1  having an input  2 , a gamma correction circuit  3 , an adder  4 , a memory  5 , a rounding circuit  6 , a random-access memory  7 , a sub-field generator circuit  8  also called sub-field generation or SFG circuit for short, an output  9  and a filter  10 . The memory  7  replaces a multiplier circuit  11 , a rounding circuit  12 , a second multiplier circuit  13  and an adding circuit  14 . The random-access memory  7  is also referred to as allocation table or look-up table, LUT for short. For defined values on m-defined lines the initial values which are present as a result of the functions combined in the memory  7  are calculated and stored in the memory  7 . 
       FIG. 2  shows a display section with neighboring pixels x−1, y−1 and x, y−1 and x+1, y−1 and x−1, y and x, y. Then x is a substitute for the number of the column and y is a substitute for the number of the line. 
       FIG. 3  shows absolute values by which a quantization error QE which occurs at the respective spot is multiplied for the generation of a value to be displayed for a current value in a pixel x, y. The quantization error, QE for short, is also referred to as quantization noise. 
       FIG. 4  shows the filter  10  comprising delay elements  15 - 18  and multiplier elements  19 - 22  and adders  23 ,  24 ,  25 . The elements  15 ,  17  and  18  each delay by one pixel and have a memory location for the value of one pixel, the delay element  16  delays by the number of pixels of one line, subtracts two pixels and accordingly has many memory locations. 
     The function of the video circuit  1  can be described as follows: in the gamma correction circuit  3  a red, green or blue signal is converted into a red, green or blue luminance signal under the influence of a gamma function. A typical gamma function is non-linear and reads as follows x=y n  with n=2.4. In order to achieve a sufficiently high resolution for dark areas, at least 3 times 12 bits are to be used. The converted red, green or blue luminance signal is applied to the adder  4  over a parallel data line comprising m or 12, respectively, lines. A value ½ from the memory  5  and a further value which is the sum of quantization noise from previous pixels are added to the luminance signal in the adder  4 . With the constant value ½ it is definitely feasible for the rounding circuit  6  to perform a rounding function. The sum of the pixel values preceding the quantization noise is formed in a filter  10 , as described in  FIG. 4 . A luminance value of a pixel value to be displayed is thus calculated as the sum of a current pixel value X (x,y)  which is present at input  2  and of the pixel values neighboring the quantization noise values, which neighboring pixel values are calculated in the filter  10  and are added to the current value. The following equation which is satisfied after the rounding circuit  6  is the result thereof:
 
pixel value to be displayed=rounded ( X   (x,y) +½+ 1/16QE (x−1,y−1) + 5/16QE (x,y−1) + 3/16QE (x+1,y−1) + 7/16QE (x−1,y) )
 
with the current pixel value X (x,y) .
 
with the value ½ from the memory  5  and
 
with the values 1/16QE (x−1,y−1) + 5/16QE (x,y−1) + 3/16QE (x+1,y−1) + 7/16QE (x−1,y)  as a total sum from filter  10 .
 
     The quantizer is defined by the following function
 
 F ( x )=( x/S )
 
where S is the quantization factor that is calculated as follows
 
 S =number of input stages/number of output stages=1024/256=4
 
The dequantization function is predefined by
 
 F ( y )= y*S  
 
The influence on the current pixel value X (x,y)  by the filter values is also known as the Floyd-Steinberg algorithm. The random-access memory  7  replaces the two multiplications  11  and  13 , the rounding function  12  and the addition  14 . This means that for m addresses memory values are available for n outputs to the SFG circuit  8  and m+1−n outputs to the filter  10 , which are all in all 2 m * (m+1)  memory locations.
 
       FIG. 5  shows a second video circuit  31  having an input  2 , the gamma correction circuit  3 , the adder  4 , the memory  5 , the rounding circuit  6 , the SFG circuit  8 , the output  9 , the filter  10  and a circuit  32 . The circuit  32  has a coarse-value random-access memory  33 , a fine-value random-access memory  34  and two adders  35  and  36 . The coarse-value random-access memory  33  performs a coarse adjustment in the quantization for the output and the fine-value random-access memory  34  a fine adjustment in the quantization for the output and a feedback loop  37 . As a result, the look-up table is split up into two sub-memories  33  and  34  and the necessary memory size is significantly reduced by 0.8 kbyte for a 12-bit input. 
       FIG. 6  shows a further video circuit  41  having the input  2 , the gamma correction circuit  3 , the adder  4 , the memory  5 , the rounding circuit  6 , the SFG circuit  8 , the output  9 , the filter  10  and a circuit  42 . The circuit  42  has an MSB random-access memory  43 , an LSB random-access memory  44  and two adders  45  and  46 . MSB is the abbreviation of most significant bits, thus high-order bits, LSB stands for least significant bits, low-order bits. The input data stream of the parallel data is divided into two halves, where m-k parallel data, which corresponds to m-k parallel lines, flow as MSB into the first memory  43  and 2 m-k  addresses are detected there. A second half k of parallel data, which corresponds to k parallel lines, flows into the memory  44 . A quantization error is further subtracted in the adder  46  from the LSB data. 
     The function of the circuit  42  is explained for simplicity with values from the decimal system and is as follows. 
     After the adder  45  the value  41  should be present on the output of circuit  41 . In the MSB random-access memory  43  output values for MSB input values are issued in tens, thus in steps of ten and in the LSB random-access memory  44  output values for LSB input values are issued in steps of one. If, however, the MSB memory  43  cannot supply the value  40 , but only  39 , a quantization error QE occurs on the output of the MSB memory  43 , which also flows into the LSB memory  44  via the adder  46 . The quantization error would be −1 as absolute value, the addition of the negated value to the LSB value which is 1 is then:
 
LSB−(−1)=LSB+1=2.
 
     Thus the necessary memory size is reduced by 0.25 kbyte for a 12-bit input. In this architecture the random-access memory is divided into two parts, one part generates an MSB quantization and an associated quantization error on a first output and the other part generates the LSB quantization and an associated quantization error on a second output. If the two output signals are added together, this will lead to the new quantized value. The size of the MSB random-access memory is 2 m/2+(m+1)    
     The size of the LSB random-access memory is 2 (m+1)/2+(m+1)    
     The contents of the Table can be easily generated with the following algorithm: 
     Rounded off:
 
( X   (x,y) +½+ 1/16QE (x−1,y−1) + 5/16QE (x,y−1) + 3/16QE (x+1,y−1) + 7/16QE (x−1,y) )
 
X is the value of the newly arriving pixel and QE is the quantization error of previously generated pixel values.
 
     The new quantization output signal is:
 
Rounded (½ n +1 /S *rounded ( X   (x,y) +½ m + 1/16QE (x−1,y−1) + 5/16QE (x,y−1) + 3/16QE (x+1,y−1) + 7/16QE (x−1,y) ))
 
     The new quantization error is:
 
Rest (½ n +1 /S *rounded ( X   (x,y) +½ m + 1/16QE (x−1,y−1) + 5/16QE (x,y−1) + 3/16QE (x+1,y−1) + 7/16QE (x−1,y) ))
 
       FIG. 7  shows a video circuit  51  comprising a random-access memory  52  in which a gamma correction function  53  and a quantization function  54  are combined. The gamma correction function  53  is converted with equidistant values, so that the error spreading in the luminance area is effected by means of a forward controller  55 . A current value from the luminance area is added to the filter value from the filter  10  in an adder  57 . 
       FIG. 8  shows a video circuit  61  comprising a random-access memory  62  for values converted with non-equidistant values. The memory  62  replaces a gamma correction circuit  63 , a quantizer  64 , a dequantizer  65 , an inverse gamma correction circuit  66  and an adder  67 . Since the gamma-corrected values in the gamma correction circuit  63  have been converted with non-equidistant values, an inverse gamma correction circuit  66  is included in a feedback loop  68 . A rounding circuit  69  is inserted between the filter  10  and the adder  4 . 
       FIG. 9  shows a gamma curve  71  which is converted with equidistant values. The result is a quantization noise curve  72  with a high quantization error in a dark area between the absolute values 1 and 22. Especially in dark areas the perception by the human eye is better than in bright areas. The high quantization error is thus perceived by a viewer. This provides a discrepancy between sampling and perception. 
       FIG. 10  shows a gamma curve  81  which is sampled with non-equidistant values. The non-equidistant values are shown as curve  82 . A quantization noise curve  83  with a rather large quantization noise in a dark area between the absolute values 1 and 22 is smaller than the QE in values converted equidistantly. The first value in the dark area has a small quantization error. In bright areas the quantization noise is larger. The quantization noise in bright areas, however, can be perceived less by a viewer. The sample values thus correspond to the observation. 
       FIG. 11  shows a video circuit  101  comprising a random-access memory  102  which replaces the gamma correction circuit  63 , the quantizer  64 , the dequantizer  65 , the inverse gamma correction circuit  66 , the addition  67  and the sub-field generator  8 . 
       FIG. 12  shows a circuit  111  comprising a line delay  112 , a min/max detection circuit  113 , a first substitution circuit  114 , a partial line doubling circuit  115  and a second substitution circuit  116 . The line of a television picture is delayed by one line in the delay circuit  112 . Then values of two pixels lying beside each other in one column are compared in the detection circuit  113 . The respective larger value is defined and applied to a first or second input of the doubling circuit  115 . If the lines are then substituted in the substitution circuit  114 , a re-substitution is made in the second substitution circuit  116 . 
       FIG. 13  shows a first partial line doubling circuit  120  for equidistant sub-field codings which circuit can be used for the partial line doubling circuit  115 , comprising a first gamma correction circuit  121 , an adder  122 , an inverse gamma correction circuit  123 , a memory  124 , a 2D filter  125 , a further gamma correction circuit  126 , a further adder  127 , an inverse gamma correction circuit  128 , a further memory  129  and a one-dimensional filter  130 . The memory  124  replaces a gamma correction circuit  131 , a quantizer  132 , an SFG and a PLD circuit  133 , a converter  134 , a dequantizer  135 , a second converter  136 , a second dequantizer  137  and an adder  138 . The SFG and PLD circuit  133  includes an MSG circuit  139 , an LSG circuit  140 , an LSG light circuit  141  and a QE circuit  142 . The memory  129  replaces a gamma correction circuit  143 , a quantizer  144 , an SFG and PLD circuit  145 , a further converter  146 , a dequantizer  147  and an adder  148 . The SFG and PLD circuit  145  includes an MSG circuit  149  and a QE circuit  150 . Signals are present on inputs  151  and  152  and output signals are output via the outputs  153 ,  154 ,  155  and  156 . This partial line doubling circuit  120  can be used instead of the partial line doubling circuit  115 . 
       FIG. 14  shows a second partial line doubling circuit  159  for non-equidistant sub-field codings, which circuit  159  can be used instead of the partial line doubling circuit  115 , with an adder  160 , a memory  161 , a 2D filter  162 , a further adder  163 , a further memory  164  and a one-dimensional filter  165 . The memory  161  replaces a gamma correction circuit  166 , a quantizer  167 , an SFG and PLD circuit  168 , a converter  169 , a dequantizer  170 , an inverse gamma correction circuit  171  and an adder  172 . The SFG and PLD circuit  168  includes an MSG circuit  173 , an LSG circuit  174  and a QE circuit  175 . The memory  164  replaces a gamma correction circuit  176 , a quantizer  177 , an SFG and PLD circuit  178 , a converter  179 , a dequantizer  180 , an inverse gamma correction circuit  181  and an adder  182 . The SFG and PLD circuit  178  includes an MSG circuit  183  and a QE circuit  184 . Signals are present on inputs  185  and  186  and output signals are output via outputs  187 ,  188 ,  189  and  190 . 
       FIG. 15  shows eight sub-fields  201  to  208 , SF for short. Each sub-field has an erasing time  209 , an addressing time  210  and a sustaining time  211 . The eight sub-fields cover a picture duration  212 . The sub-fields  201  to  204  represent least significant bits of a group or LSB for short of a least significant group or LSG for short. The sub-fields  205  to  208  represent most significant bits or MSB of a most significant group or MSG. 
     If the LSB for two successive lines are identical, there is a time-saving  213  as shown in  FIG. 16 . The doubling of partial ranges of a line is called partial line doubling in English, PLD for short. Only during the stop period are emitted light pulses from the red, green or blue light sources of a pixel. 
     The function of the circuit  120  is as follows: pixel values are present on the input of the memory  124  and are converted in the gamma correction circuit  131  into the luminance area, therefore, an 8-bit data word becomes an 12-bit data word to achieve a sufficiently high resolution in dark areas. In the subsequent quantizer the 12-bit data word is adapted to a data word that is necessary for the sub-field generation. The latter data word is applied to the SFG and PLD circuit  133  and an associated bit sample of sub-fields is generated in this circuit. 
     To avoid artefacts, other sub-fields are addressed in boundary areas than the sub-fields that are responsive of the pixel value to be displayed. A typical example is to address only the sub-field  208  instead of the sub-fields  201  to  207 . In addition to the quantizing error an addressing error will then occur. This error is applied by the QE circuit  142  to a converter  134  which converts the light value signal into a luminance signal and eliminates any occurring addressing error. From the converter  134  the signal is conveyed to the dequantizer  135  which cancels the quantization. The value generated now is compared with the signal from the correction circuit  131  and the actual quantization error is determined in the adder  138 . The quantization error is applied to the 2D filter  125  and filtered in accordance with the Floyd-Steinberg algorithm. Since the filtered quantization error is situated in the luminance area and is to be applied to the input signal, the input signal is transformed into the luminance area by the gamma correction circuit  121 . This transformation is cancelled in the inverse gamma correction circuit  123 . 
     Since the filtered quantization error also influences pixel values of pixels of the neighboring line, the filter  125  is connected via an electrically conductive line to the adder  127 . Thus an output signal of the 2D filter is added for further processing to an input signal which represents pixel values of the neighboring line. 
     If an addressing error occurs, a respective correction signal is transported from the LSG circuit  141  via the converter  136 , the dequantizer  137  to the adder  127  and thus the input signal is corrected which represents pixel values of pixels of the neighboring line. 
     The video signals in the gamma correction circuit  143  in the memory  129  are transformed from the video area into the luminance area, then quantized in the quantizer  144  and conveyed to an SFG and PLD circuit  145  which generates the bit sample for the sub-fields of the PDP. Only the MSG are generated then. A light value signal is reconverted in the converter circuit  146  into a luminance signal and a possible addressing error is eliminated. The luminance signal is dequantized in the dequantizer  147  and applied to the adder  148 . In the adder is determined an actual quantization error and applied to the filter  130 . The quantization error has no effect on neighboring lines, so that only a one-dimensional filter  130  is used. 
     Since here too the processing takes place in the luminance area, the adder  127  is surrounded by a gamma correction circuit  126  and an inverse gamma correction circuit  128  which convert the values of the current pixel of the second neighboring line. 
     The function of the circuit  159  can be described as follows: pixel values are present on an input  185  of the circuit  159  and are converted into the luminance area in the gamma correction circuit  166  and for this purpose an 8-bit data word becomes a 12-bit data word to achieve a sufficiently high resolution in dark areas. In the subsequent quantizer  167  the 12-bit data word is adapted to a data word that is necessary for the sub-field generation. This data word is applied to the SFG and PLD circuit  168  and in this circuit an associated bit sample of sub-fields is generated which is output via the outputs  187  and  188 . 
     To exclude artefacts, different sub-fields are addressed in boundary areas than the sub-fields that are responsive to the picture value to be displayed. An addressing error then occurs in addition to the quantization error. This addressing error is applied by the QE circuit  175  to a converter  169  which converts the light value signal into a luminance signal and cancels any occurring addressing error. From the converter  169  the signal is conveyed to the dequantizer  170  which cancels the quantization. The downstream inverse gamma correction circuit  171  converts luminance data into video data so that a value in the video area is present on an output of the inverse gamma correction circuit  171 , which video area value corresponds to the output value on the outputs  187  and  188 . This value is compared in the adder  172  to the input signal and an actual quantization error is determined. The quantization error is filtered in the filter  162  and the actual pixel values of a first line are added to the input  185 . 
     Since the filtered quantization error also influences pixel values of pixels of the neighboring line, the filter  162  is connected to the adder  163  via an electrically conducting line. Thus an output signal of the 2D filter is added to an input signal for further processing which input signal represents pixel values of the neighboring line. 
     In the memory  164  the video signals in the gamma correction circuit  176  are transformed from the video area to the luminance area, then quantized in the quantizer  177  and conveyed to an SFG and PLD circuit  178  which generates the sub-fields for the PDP. Only the MSG are generated then. In the converter circuit  179  a light value signal is reconverted into a luminance signal and a possible addressing error is eliminated. The luminance signal is dequantized in the dequantizer  180  and applied to the inverse gamma correction circuit  181 . In the adder  182  is detected an actual quantization error and this error is applied to the filter  165 . The quantization error has no effect on neighboring lines so that only a one-dimensional filter  165  is used. 
     The LSB on the output  188  are directly applied to the quantizer  177  and are thus taken into account when the most significant bits of the neighboring line available on output  189  are formed. 
     REFERENCE LIST 
     
       
         
           
               
               
               
               
             
               
                   
               
             
            
               
                 1 
                 video circuit 
                 32 
                 circuit 
               
               
                 2 
                 input 
                 33 
                 coarse-value random-access 
               
               
                   
                   
                   
                 memory 
               
               
                 3 
                 gamma correction circuit 
                 34 
                 fine-value 
               
               
                   
                   
                   
                 random-access memory 
               
               
                 4 
                 adder 
                 35 
                 adder 
               
               
                 5 
                 memory 
                 36 
                 adder 
               
               
                 6 
                 rounding circuit 
                 37 
                 feedback loop 
               
               
                 7 
                 random-access memory 
                 38 
               
               
                 8 
                 sub-field generator circuit 
                 39 
               
               
                 9 
                 output 
                 40 
               
               
                 10 
                 filter 
                 41 
                 video circuit 
               
               
                 11 
                 multiplier circuit 
                 42 
                 circuit 
               
               
                 12 
                 rounding circuit 
                 43 
                 MSB random-access memory 
               
               
                 13 
                 second multiplier circuit 
                 44 
                 LSB random-access memory 
               
               
                 14 
                 adder circuit 
                 45 
                 adder 
               
               
                 15 
                 delay element 
                 46 
                 adder 
               
               
                 16 
                 delay element 
                 47 
               
               
                 17 
                 delay element 
                 48 
               
               
                 18 
                 delay element 
                 49 
               
               
                 19 
                 multiplier element 
                 50 
               
               
                 20 
                 multiplier element 
                 51 
                 video circuit 
               
               
                 21 
                 multiplier element 
                 52 
                 random-access memory 
               
               
                 22 
                 multiplier element 
                 53 
                 gamma correction circuit 
               
               
                 23 
                 adder 
                 54 
                 quantizer 
               
               
                 24 
                 adder 
                 55 
                 forward controller 
               
               
                 25 
                 adder 
                 56 
                 delay element 
               
               
                 26 
                   
                 57 
                 adder 
               
               
                 27 
                   
                 58 
               
               
                 28 
                   
                 59 
               
               
                 29 
                   
                 60 
               
               
                 30 
                   
                 61 
                 video circuit 
               
               
                 31 
                 video circuit 
                 62 
                 random-access memory 
               
               
                 63 
                 gamma correction circuit 
                 94 
               
               
                 64 
                 quantizer 
                 95 
               
               
                 65 
                 dequantizer 
                 96 
               
               
                 66 
                 inverse gamma 
                 97 
               
               
                   
                 correction circuit 
               
               
                 67 
                 adder 
                 98 
               
               
                 68 
                 feedback loop 
                 99 
               
               
                 69 
                 rounding circuit 
                 100 
               
               
                 70 
                   
                 101 
                 video circuit 
               
               
                 71 
                 gamma curve 
                 102 
                 random-access memory 
               
               
                 72 
                 quantization noise curve 
                 103 
                 sub-field generation 
               
               
                 73 
                   
                 104 
               
               
                 74 
                   
                 105 
               
               
                 75 
                   
                 106 
               
               
                 76 
                   
                 107 
               
               
                 77 
                   
                 108 
               
               
                 78 
                   
                 109 
               
               
                 79 
                   
                 110 
               
               
                 80 
                   
                 111 
                 circuit 
               
               
                 81 
                 gamma curve 
                 112 
                 line delay 
               
               
                 82 
                 curve 
                 113 
                 Min/Max detection circuit 
               
               
                 83 
                 quantization noise curve 
                 114 
                 substitution circuit 
               
               
                 84 
                   
                 115 
                 partial line doubling circuit 
               
               
                 85 
                   
                 116 
                 second substitution circuit 
               
               
                 86 
                   
                 117 
               
               
                 87 
                   
                 118 
               
               
                 88 
                   
                 119 
               
               
                 89 
                   
                 120 
                 partial line doubling circuit 
               
               
                 90 
                   
                 121 
                 gamma correction circuit 
               
               
                 91 
                   
                 122 
                 adder 
               
               
                 92 
                   
                 123 
                 inverse gamma 
               
               
                   
                   
                   
                 correction circuit 
               
               
                 93 
                   
                 124 
                 memory 
               
               
                 125 
                 2D filter 
                 157 
               
               
                 126 
                 gamma correction circuit 
                 158 
               
               
                 127 
                 adder 
                 159 
                 second partial line 
               
               
                   
                   
                   
                 doubling circuit 
               
               
                 128 
                 inverse gamma 
                 160 
                 adder 
               
               
                   
                 correction circuit 
               
               
                 129 
                 memory 
                 161 
                 memory 
               
               
                 130 
                 one-dimensional filter 
                 162 
                 2D filter 
               
               
                 131 
                 gamma correction circuit 
                 163 
                 adder 
               
               
                 132 
                 quantizer 
                 164 
                 memory 
               
               
                 133 
                 SG ad PLD circuit 
                 165 
                 one-dimensional filter 
               
               
                 134 
                 converter 
                 166 
                 gamma correction circuit 
               
               
                 135 
                 dequantizer 
                 167 
                 quantizer 
               
               
                 136 
                 converter 
                 168 
                 SFG and PLD circuit 
               
               
                 137 
                 second dequantizer 
                 169 
                 converter 
               
               
                 138 
                 adder 
                 170 
                 dequantizer 
               
               
                 139 
                 MSG circuit 
                 171 
                 inverse gamma 
               
               
                   
                   
                   
                 correction circuit 
               
               
                 140 
                 LSG circuit 
                 172 
                 adder 
               
               
                 141 
                 LSG light circuit 
                 173 
                 MSG circuit 
               
               
                 142 
                 QE circuit 
                 174 
                 LSG circuit 
               
               
                 143 
                 gamma correction circuit 
                 175 
                 QE circuit 
               
               
                 144 
                 quantizer 
                 176 
                 gamma correction circuit 
               
               
                 145 
                 SFG and PLD circuit 
                 177 
                 quantizer 
               
               
                 146 
                 inverse luminance circuit 
                 178 
                 SFG and PLD circuit 
               
               
                 147 
                 dequantizer 
                 179 
                 converter 
               
               
                 148 
                 adder 
                 180 
                 dequantizer 
               
               
                 149 
                 MSG circuit 
                 181 
                 inverse gamma 
               
               
                   
                   
                   
                 correction circuit 
               
               
                 150 
                 QE circuit 
                 182 
                 adder 
               
               
                 151 
                 input 
                 183 
                 MSG circuit 
               
               
                 152 
                 input 
                 184 
                 QE circuit 
               
               
                 153 
                 output 
                 185 
                 input 
               
               
                 154 
                 output 
                 186 
                 input 
               
               
                 155 
                 output 
                 187 
                 output 
               
               
                 156 
                 output 
                 188 
                 output 
               
               
                 189 
                 output 
                 221 
               
               
                 190 
                 output 
                 222 
               
               
                 191 
                   
                 223 
               
               
                 192 
                   
                 224 
               
               
                 193 
                   
                 225 
               
               
                 194 
                   
                 226 
               
               
                 195 
                   
                 227 
               
               
                 196 
                   
                 228 
               
               
                 197 
                   
                 229 
               
               
                 198 
                   
                 230 
               
               
                 199 
                   
                 231 
               
               
                 200 
                   
                 232 
               
               
                 201 
                 sub-field 
                 233 
               
               
                 202 
                 sub-field 
                 234 
               
               
                 203 
                 sub-field 
                 235 
               
               
                 204 
                 sub-field 
                 236 
               
               
                 205 
                 sub-field 
                 237 
               
               
                 206 
                 sub-field 
                 238 
               
               
                 207 
                 sub-field 
                 239 
               
               
                 208 
                 sub-field 
                 240 
               
               
                 209 
                 erasing time 
               
               
                 210 
                 addressing time 
               
               
                 211 
                 sustaining time 
               
               
                 212 
                 duration of image 
               
               
                 213 
                 time saving 
               
               
                 214 
               
               
                 215 
               
               
                 216 
               
               
                 217 
               
               
                 218 
               
               
                 219 
               
               
                 220