JP2009111442A - Video transmission system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily determine a progressive conversion method. <P>SOLUTION: A field thinning-out circuit 12 converts a progressive video signal input from a video input terminal 10 into an interlaced video signal. A video encoding circuit 16 encodes the interlaced video signal generated by the field thinning-out circuit 12 by a known moving image compression system to generate a video stream. The generated video stream is recorded on a recording medium 18. An IP conversion auxiliary information generating circuit 14 compares the progressive video signal from the video input terminal 10 with the interlaced video signal from the field thinning-out circuit 12 to generate auxiliary information for IP conversion of the interlaced video signal. The auxiliary information shows which of in-field interpolation and inter-field interpolation of the IP conversion is suitable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video transmission system and method for transmitting, for example, recording and reproducing a progressive video signal.

  Advances in digital signal processing technology enable high-efficiency encoding of a large amount of digital information such as moving images, still images, and voices, enabling recording / reproduction to / from a small recording medium and data transmission via a communication medium. Applying such technology, video encoding devices that convert TV broadcast and video camera images into streams have been developed.

  In recent years, television receivers using thin flat panels such as plasma displays and liquid crystal displays have been rapidly spread and high-definition images can be reproduced at home. Many of these television receivers can display not only conventional interlace video signals but also progressive video signals, that is, progressive video signals. A television receiver that supports both an interlaced video signal and a progressive video signal generally includes an IP conversion circuit that converts the interlaced video signal into a progressive video signal. In addition, the video playback device may have an IP conversion circuit built-in, and may select interlaced output or progressive output. Note that the process of converting a progressive video signal into an interlaced video signal is called PI conversion.

  FIG. 7 shows a schematic block diagram of a conventional video reproduction apparatus having an IP conversion function.

  The video stream read from the recording medium 110 is supplied to the decoding circuit 112. This video stream is an ISO / IEC13818-2 standard or ITU-TH. The interlace video signal is compression-encoded by a compression method according to a known method defined in the H.264 standard. The decoding circuit 112 decodes the stream data from the recording medium 110 and generates an interlace video signal.

  FIG. 8 is a schematic diagram of an interlaced video signal. Every 1 / 60th of a second, field images with only odd lines (odd field images) and field images with only even lines (even field images) appear alternately. Therefore, a smooth video can be reproduced with half the amount of information. However, since vertical resolution is halved on each screen, problems such as flicker have been pointed out. IP translation is used to alleviate this flickering problem.

  The interlaced video signal output from the decoding circuit 112 is input to the IP conversion circuit 114, the IP conversion circuit 116, and the determination circuit 120. The IP conversion circuits 114 and 116 both convert an interlace video signal into a progressive video signal, but the modes are different. The IP conversion circuit 114 generates a progressive video signal, that is, a progressive video signal, for each field image constituting the input interlaced video signal by intra-field interpolation using lines in the same field. The IP conversion circuit 116 generates a progressive video signal by inter-field interpolation using adjacent field lines for each field image constituting the input interlaced video signal.

  9A shows a state of IP conversion by the IP conversion circuit 114, and FIG. 9B shows a state of IP conversion by the IP conversion circuit 116. The IP conversion circuit 114 generates an insufficient pixel line by filtering in the field. In the example shown in FIG. 9A, the average of the upper and lower pixel values is used as the pixel value of the interpolation pixel. The IP conversion circuit 116 uses adjacent field images for each field image constituting the input interlaced video signal. In the example shown in FIG. 9B, the shortage line of the previous field image is interpolated with the line of the adjacent field.

  In the IP conversion based on intra-field interpolation, insufficient lines are interpolated using adjacent pixels in the same screen, so that sufficient resolution cannot be obtained. On the other hand, since the IP conversion by inter-field interpolation is interpolating from fields with different times, blurring occurs in the case of a video with intense motion. That is, there are advantages and disadvantages.

  The determination circuit 120 determines video motion from the interlaced video signal supplied from the decoding circuit 112 and controls the selector 118 based on the determination result. Based on the determination result of the determination circuit 120, the selector 118 selects the output of the IP conversion circuit 114 for a video with a lot of motion, and selects the output of the IP conversion circuit 116 for a video that does not. The selector 118 outputs the selected progressive video signal to the output terminal 122. The determination in the determination circuit 120 may be performed in units of fields or in units of pixels to be interpolated.

In order to increase the definition of a progressive image, a progressive scan conversion device that uses motion information when generating a progressive video has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2006-304096

  In the conventional example, two types of IP conversion circuits are prepared, and the output is selected according to the presence or absence of motion of the video, thereby generating a video signal with less blur and high resolution. However, the determination result of the determination circuit 120 is not always correct, and an erroneous determination is likely to occur when the resolution is high, which is also greatly affected. Although there is little movement, it may be erroneously determined that there is movement because of the high resolution. On the other hand, it may be erroneously determined that there is little movement even though there is much movement. For example, it is very difficult to determine whether a fine horizontal stripe pattern in an interlaced image is really a horizontal stripe pattern or caused by movement.

  Some conventional video reproduction apparatuses try to reduce erroneous determinations by detecting motion using a very complicated circuit and analyzing motion history on the time axis by using a number of frame buffers. However, in spite of the fact that the scale of the apparatus becomes very large, it is difficult to determine the motion from the interlaced video in principle. As a result, the video quality of the obtained progressive video signal was not sufficient.

  Recently, a progressive video signal can be obtained by a video camera for progressive video output, digital terrestrial broadcasting, or the like. However, a transmission system capable of transmitting, for example, recording and reproducing the progressive video signal as it is, has not been sufficiently prepared. In that case, it must be transmitted as interlaced video through IP conversion, and converted to progressive video at the time of reproduction output or video display. Through the PI conversion and IP conversion, the image quality often deteriorates significantly.

  It is an object of the present invention to provide a video transmission system and method for reducing image quality deterioration due to these conversions when undergoing PI conversion and IP conversion.

  To achieve the above object, a video transmission system according to the present invention generates interlaced video signal generating means for generating an interlaced video signal from a progressive video signal, and auxiliary information for converting the interlaced video signal to a progressive format. Auxiliary information generating means, transmission means for transmitting the interlaced video signal generated by the interlaced video signal generating means and the auxiliary information generated by the auxiliary information generating means, and the interlaced video signal from the transmitting means And reproducing means for converting to a progressive format by a conversion method according to the auxiliary information from the transmission means.

  The video transmission method according to the present invention includes an interlaced video signal generating step for generating an interlaced video signal from a progressive video signal, an auxiliary information generating step for generating auxiliary information when the interlaced video signal is converted into a progressive format, A transmission step of transmitting the interlace video signal generated by the interlace video signal generation step and the auxiliary information generated by the auxiliary information generation step; and converting the interlace video signal into a progressive format by a conversion method according to the auxiliary information. And a reproducing step.

  According to the present invention, auxiliary information indicating a conversion method suitable for progressive conversion of an interlaced video signal is generated in advance and transmitted together with the video information, so that a progressive video signal with good image quality can be obtained. . The judgment burden of the progressive conversion method can be reduced and the circuit scale can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic block diagram of a recording system portion of an embodiment of a video transmission system according to the present invention. A progressive video signal is input to the video input terminal 10 from the outside. The input progressive video signal is supplied from the video input terminal 10 to the field thinning circuit 12 and the IP conversion auxiliary information generation circuit 14.

  The field thinning circuit 12 thins out odd lines or even lines for each field of the progressive video signal input from the video input terminal 10 and converts it into an interlaced video signal. The field thinning circuit 12 is an interlaced video signal generating unit. The video encoding circuit 16 encodes the interlace video signal generated by the field thinning circuit 12 using a known moving image compression method to generate a video stream. The generated video stream is recorded on the recording medium 18.

  The IP conversion auxiliary information generation circuit 14 compares the progressive video signal from the video input terminal 10 with the interlaced video signal from the field thinning circuit 12, and uses the auxiliary information for IP conversion of the interlaced video signal according to the comparison result. Generate.

  FIG. 2 shows a circuit configuration example of the IP conversion auxiliary information generation circuit 14. The IP conversion circuit 22 converts the interlaced video signal from the field thinning circuit 12 into a progressive format video signal by intra-field interpolation. The IP conversion circuit 24 converts the interlace video signal from the field thinning circuit 12 into a progressive format video signal by interpolation from the near field.

  The subtractor 26 subtracts the progressive video signal from the video input terminal 10 from the output progressive video signal of the IP conversion circuit 22. On the other hand, the subtractor 28 subtracts the progressive video signal from the video input terminal 10 from the progressive video signal output from the IP conversion circuit 24. The comparator 30 compares the output magnitudes of the differentiators 26 and 28 in the field screen unit, the interpolation line unit, or the pixel unit of each interpolation line, and outputs a signal indicating which is smaller. The output of the comparator 30 is auxiliary information. That is, the auxiliary information indicates whether to use intra-field interpolation or inter-field interpolation when the interlace video signal generated by the field thinning circuit 12 is progressively converted. The auxiliary information may be a field screen unit, an interpolation line unit in the field screen, or a pixel unit of the interpolation line, but higher image quality is obtained later.

  Of course, the transfer characteristic of the IP conversion circuit 22 is approximated or preferably matched with the transfer characteristic of the IP conversion circuit for intra-field interpolation in the IP conversion in the reproduction apparatus or the display apparatus. Similarly, the transfer characteristic of the IP conversion circuit 24 is approximated or preferably matched with the transfer characteristic of the IP conversion circuit for inter-field interpolation in the IP conversion in the reproduction apparatus or display apparatus.

  The auxiliary information encoding circuit 20 encodes the auxiliary information generated by the IP conversion auxiliary information generation circuit 14. The encoded auxiliary information is multiplexed into the video stream and recorded on the recording medium 18. Needless to say, the encoded auxiliary information may be referred to when the corresponding video stream is reproduced, and may be recorded on the recording medium 18 separately from the video stream. In this embodiment, the auxiliary information is 1-bit information indicating which one of the two interpolation methods is better in the field screen unit, the interpolation line unit, or the pixel unit of each interpolation line. Compared to that of the stream, it is much less.

  By replacing the video input terminal 10 with an imaging unit that outputs a progressive video signal, the embodiment shown in FIG. 1 uses a video camera or an imaging device that captures a subject with progressive video and records it on a recording medium with interlaced video. Constitute.

  FIG. 3 shows a schematic block diagram of the reproduction system. Similar to the recording medium 18, the recording medium 40 includes a video stream generated by the video encoding circuit 16, and auxiliary information generated by the IP conversion auxiliary information generation circuit 14 and encoded by the auxiliary information encoding circuit 20. Is recorded.

  The video decoding circuit 42 decodes the video stream read from the recording medium 40 and outputs a playback interlaced video signal. The IP conversion circuit 44 converts the reproduced interlaced video signal from the video decoding circuit 42 into a progressive signal by intra-field interpolation. The IP conversion circuit 46 converts the reproduced interlaced video signal from the video decoding circuit 42 into a progressive signal by interpolation from the near field. As described above, the transfer characteristic of the IP conversion circuit 44 approximates or preferably coincides with the transfer characteristic of the IP conversion circuit 22. Similarly, the transfer characteristic of the IP conversion circuit 46 approximates or preferably coincides with the transfer characteristic of the IP conversion circuit 24. The output progressive signals from the IP conversion circuits 44 and 46 are supplied to the selector 48.

  The auxiliary information decoding circuit 50 decodes the encoded auxiliary information read from the recording medium 40 and supplies it to the determination circuit 52. As described with reference to FIG. 2, the auxiliary information is a result of determining in advance which IP conversion result approximates the original progressive video. The determination circuit 52 controls the selector 48 in accordance with the auxiliary information from the auxiliary information decoding circuit 50 to select a progressive video signal with better image quality as viewed from the auxiliary information. The progressive video signal selected by the selector 48 is output from the video output terminal 54 to the outside.

  As described above, in this embodiment, a preferable IP conversion method for PI conversion at the time of recording is determined in advance, and an IP conversion method at the time of reproduction is selected with reference to the determination result (auxiliary information). As a result, it is possible to obtain a progressive image with good image quality close to the original image quality.

  FIG. 4 shows another circuit example of the IP conversion auxiliary information generation circuit 14. FIG. 5 shows a schematic block diagram of the reproducing apparatus for the auxiliary information generated by the circuit shown in FIG.

  The operation of the IP conversion auxiliary information generation circuit 14 shown in FIG. 4 will be described. The IP conversion circuit 60 converts the interlaced video signal from the field thinning circuit 12 into a progressive signal by intra-field interpolation. The IP conversion circuit 62 converts the interlaced video signal from the field thinning circuit 12 into a progressive signal by interpolation from the near field. Progressive video signals output from the IP conversion circuits 60 and 62 are supplied to the selector 64.

  The determination circuit 66 determines which of intra-field interpolation (IP conversion circuit 60) and inter-field interpolation (IP conversion circuit 62) is preferable from the interlaced video signal from the field thinning circuit 12. The determination circuit 66 controls the selector 64 in accordance with the determination result to supply a preferable progressive video signal to the differentiator 68 and an undesired progressive video signal to the differencer 70 among the output signals of the IP conversion circuits 60 and 62.

  The subtractor 68 subtracts the progressive video signal from the video input terminal 10 from the preferred progressive video signal from the selector 64. On the other hand, the subtractor 70 subtracts the progressive video signal from the video input terminal 10 from the undesirable progressive video signal from the selector 64. The comparator 72 compares the output magnitudes of the differentiators 68 and 70 in the field screen unit, the interpolation line unit, or the pixel unit of each interpolation line, and outputs a signal indicating which is smaller. The output of the comparator 72 becomes auxiliary information. This auxiliary information indicates the validity of the determination by the determination circuit 66, that is, whether it is correct. That is, when the output of the differencer 68 is smaller than the output of the differencer 70, the auxiliary information indicates that an interpolation method according to the determination result of the determination circuit 66 may be selected. On the contrary, when the output of the differentiator 70 is less than or equal to the output of the differentiator 68, the auxiliary information indicates that an interpolation method different from the determination result of the determination circuit 66 should be selected.

  With reference to FIG. 5, the reproduction operation will be described. In the recording medium 80, the video stream generated by the video encoding circuit 16 and the auxiliary information generated by the IP conversion auxiliary information generating circuit 14 having the configuration shown in FIG. 4 and encoded by the auxiliary information encoding circuit 20 are stored. Has been recorded.

  The video decoding circuit 82 decodes the video stream read from the recording medium 80 and outputs a playback interlaced video signal. The IP conversion circuit 84 converts the reproduced interlaced video signal from the video decoding circuit 82 into a progressive signal by intra-field interpolation. The IP conversion circuit 86 converts the reproduced interlaced video signal from the video decoding circuit 82 into a progressive signal by interpolation from the near field. As described above, the transfer characteristic of the IP conversion circuit 84 approximates or preferably matches the transfer characteristic of the IP conversion circuit 60. Similarly, the transfer characteristic of the IP conversion circuit 86 approximates or preferably coincides with the transfer characteristic of the IP conversion circuit 62. The output progressive signals of the IP conversion circuits 84 and 86 are supplied to the selector 88.

  The auxiliary information decoding circuit 90 decodes the encoded auxiliary information read from the recording medium 80 and supplies it to the determination circuit 92. Further, the reproduction interlaced video signal is input from the video decoding circuit 82 to the determination circuit 92. The determination circuit 92 determines the presence / absence of motion from the reproduced interlaced video signal from the video decoding circuit 82. The determination result at this stage is equal to the determination result of the determination circuit 52 at the time of recording. The determination circuit 92 further considers auxiliary information from the auxiliary information decoding circuit 90 and finally determines which of the outputs of the IP conversion circuits 84 and 86 should be selected. That is, an interpolation method to be applied to IP conversion is determined. The determination circuit 92 controls the selector 88 so as to select a playback progressive video signal by the determined interpolation method according to the final determination. The progressive video signal selected by the selector 88 is output from the video output terminal 94 to the outside.

  As described above, the auxiliary information indicates whether the determination result of the determination circuit 66 should be adopted or a result opposite to the determination result should be adopted. The determination circuit 92 can cause the selector 88 to select a more appropriate playback progressive video signal by referring to the auxiliary information. Specifically, the determination circuit 92 first selects the IP conversion circuit 84 when it is determined that there is movement in the movement determination, and selects the IP conversion circuit 86 when it is determined that there is no movement (less). When the auxiliary information indicates the adoption of the determination result of the determination circuit 66 for the primary determination result, the determination circuit 92 uses the primary determination result as the final determination result as it is. On the contrary, when the auxiliary information indicates that the determination result of the determination circuit 66 is not adopted, the determination circuit 92 sets the result opposite to the primary determination result as the final determination result. The determination unit (field, interpolation line, or pixel of the interpolation line) of the determination circuit 92 is the same as the determination unit of the auxiliary information. When auxiliary information is lost or reliability is lost due to a transmission error or the like, the determination circuit 92 controls the selector 88 according to the motion determination result of the reproduced interlaced video signal.

  FIG. 6 shows a schematic block diagram of a recording system according to the third embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals.

  The video decoding circuit 96 decodes the video stream encoded by the video encoding circuit 16 to generate an interlaced video signal, and supplies it to the IP conversion auxiliary information generation circuit 98. The IP conversion auxiliary information generation circuit 14 of the embodiment shown in FIG. 1 generates auxiliary information from a comparison between an interlaced video signal and a progressive video signal before encoding. On the other hand, the IP conversion auxiliary information generation circuit 98 compares the interlace video signal obtained by encoding / decoding with the progressive video signal to generate auxiliary information. Since the video signal that has undergone encoding and decoding is used, auxiliary information is generated by determination that takes into account deterioration due to encoding. That is, appropriate auxiliary information can be determined using the same interlaced video signal before IP conversion in the video playback device, and as a result, an appropriate IP conversion method can be adopted on the playback side.

  The configuration itself of the IP conversion auxiliary information generation circuit 98 is the same as that of the IP conversion auxiliary information generation circuit 14. The reproduction side has the configuration shown in FIG. 3 or FIG.

  In the configuration of each of the above embodiments, auxiliary information for determining the IP conversion method is generated from the progressive video signal before encoding, so that there are very few erroneous determinations of the IP conversion method. In addition, the circuit for determining the IP conversion method can be reduced in scale, and suitable progressive conversion can be realized with a small circuit scale.

1 shows a schematic block diagram of a recording system portion of an embodiment of the present invention. 2 shows a circuit configuration example of the IP conversion auxiliary information generation circuit 14. 1 shows a schematic block diagram of a reproducing system of the present embodiment. Another circuit example of the IP conversion auxiliary information generation circuit 14 is shown. FIG. 5 shows a schematic block diagram of a reproducing apparatus for auxiliary information generated by the IP conversion auxiliary information generating circuit shown in FIG. 4. FIG. 5 is a schematic configuration block diagram of a recording system according to a third embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a conventional video reproduction apparatus having an IP conversion function. A schematic diagram of an interlace video signal is shown. It is explanatory drawing of an IP conversion method, (a) shows inter-field interpolation, (b) shows inter-field interpolation, respectively.

Explanation of symbols

10: Video input terminal 12: Field thinning circuit 14: IP conversion auxiliary information generation circuit 16: Video encoding circuit 18: Recording medium 20: Auxiliary information encoding circuit 22, 24: IP conversion circuit 26, 28: Differentiator 30: Comparator 40: Recording medium 42: Video decoding circuit 44, 46: IP conversion circuit 48: Selector 50: Auxiliary information decoding circuit 52: Determination circuit 54: Video output terminal 60, 62: IP conversion circuit 64: Selector 66: Determination circuits 68 and 70: Difference unit 72: Comparator 80: Recording medium 82: Video decoding circuit 84, 86: IP conversion circuit 88: Selector 92: Determination circuit 94: Video output terminal 90: Auxiliary information decoding circuit 96: Video decoding circuit 98: IP conversion auxiliary information generation circuit 110: recording medium 112: decoding circuit 114, 116: IP conversion circuit 118: selector 120: determination time 122: output terminal

Claims (9)

Interlaced video signal generating means for generating an interlaced video signal from a progressive video signal;
Auxiliary information generating means for generating auxiliary information for converting the interlaced video signal into a progressive format;
Transmission means for transmitting the interlace video signal generated by the interlace video signal generation means and the auxiliary information generated by the auxiliary information generation means;
A video transmission system comprising: reproduction means for converting the interlaced video signal from the transmission means into a progressive format by a conversion method according to the auxiliary information from the transmission means. The transmission means is
Encoding means for encoding the interlaced video signal generated by the interlaced video signal generating means and the auxiliary information generated by the auxiliary information generating means and recording them on a recording medium;
The video transmission system according to claim 1, further comprising: a video decoding unit that reads the interlaced video signal encoded from the recording medium and decodes the interlaced video signal according to the auxiliary information. And further comprising decoding means for decoding the interlaced video signal encoded by the encoding means,
The video transmission system according to claim 2, wherein the auxiliary information generating unit generates the auxiliary information in accordance with an output of the decoding unit. The auxiliary information generating means includes
Two conversion means for converting the interlaced video signal into a progressive format by different conversion methods;
Comparing means for comparing each output of the two converting means with the progressive video signal,
The video transmission system according to claim 1, wherein the auxiliary information indicates a preferable conversion method according to a comparison result of the comparison unit. The reproducing means includes
Two IP conversion means for converting the interlaced video signal from the transmission means into a progressive format by different conversion methods;
5. The video transmission according to claim 1, further comprising a selection unit that selects one of the outputs of the two IP conversion units according to the auxiliary information from the transmission unit. system. The auxiliary information generating means includes
Two conversion means for converting the interlaced video signal into a progressive format by different conversion methods;
Determining means for determining movement of the interlaced video signal;
2. The apparatus according to claim 1, further comprising: means for comparing outputs of the two conversion means with the progressive video signal and outputting information indicating validity of a determination result of the determination means as the auxiliary information. The video transmission system according to any one of 5.   7. The video transmission system according to claim 1, wherein the auxiliary information is generated in units of pixels that are interpolated by the reproduction unit.   The video transmission system according to claim 1, wherein the auxiliary information is generated in units of fields. An interlaced video signal generating step for generating an interlaced video signal from the progressive video signal;
An auxiliary information generating step for generating auxiliary information when converting the interlaced video signal into a progressive format;
A transmission step of transmitting the interlace video signal generated by the interlace video signal generation step and the auxiliary information generated by the auxiliary information generation step;
A video transmission method comprising: a reproduction step of converting the interlaced video signal into a progressive format by a conversion method according to the auxiliary information.

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