JP2004153588A - Coding device and coding record reproducing system using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coding device capable of suppressing image deterioration even if resolution is changed, and a coding record reproducing system using the device. <P>SOLUTION: The coding device comprises an input means for inputting an image signal, a resolution conversion means for converting resolution of the image signal inputted by the input means, an image coding means capable of encoding the image signal outputted from the resolution conversion means using a plurality of encoding methods, and a control means for controlling switch-over among encoding methods in the image coding means according to the resolution of the image signal changed by the resolution conversion means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an encoding device and an encoded recording / reproducing system.
[0002]
[Prior art]
MPEG (Moving Picture Expert Group) is known as an image signal encoding method, and there are MPEG2 Video (ISO / IEC13818-2) and MPEG4Video (ISO / IEC14496-2) standards.
[0003]
In the compression processing of image information in MPEG2 Video, DCT (Discrete Cosine Transform), quantization, variable length coding, and the like are performed. In this DCT processing, processing suitable for each input image can be selected depending on whether the input image has a field structure by interlaced scanning or a frame structure by progressive scanning.
[0004]
In a device that performs MPEG2 encoding, when encoding either a progressive image or an interlaced image, DCT processing according to an input image may be selected. However, in a device that performs MPEG encoding of an input image including both a progressive image and an interlaced image, if encoding is performed for one of the two, there is a problem that the image quality deteriorates when the other is an input.
[0005]
An apparatus for solving such a problem is disclosed in, for example, Reference 1. Document 1 relates to a telecine apparatus that encodes an input image including a progressive image (film material) and an interlaced image (video material). In this apparatus, it is determined whether an input image is a progressive image or an interlaced image. If the input image is a progressive image, encoding is performed by a DCT processing method using a frame DCT, and if an input image is an interlaced image, encoding is performed using a field DCT. In addition, control is performed such that the scan order of DCT coefficients is zigzag scan for an image by progressive scanning, and alternate scan for an image by interlace scanning.
[0006]
[Patent Document 1]
Re-published patent WO00 / 13418
[0007]
[Problems to be solved by the invention]
In the above document 1, when encoding image data by interlaced scanning, the scan order of DCT coefficients is fixed to alternate scan, and the DCT method is fixed to field DCT. However, in order to change the resolution of the output image after encoding, for example, a VGA (Video Graphics Array) having a first resolution (hereinafter, referred to as an image size), however, the image size of the VGA is several lines due to signal processing. Is possible, the encoding is performed after the number of vertical lines of the image is converted to the SIF (Source Input Format) size of the second image size which is approximately half the number of lines of the first image size. In this case, the image data to be encoded may not include an interlace component, and there is a problem that the image quality is deteriorated by fixing the DCT encoding method.
[0008]
Therefore, an object of the present invention is to provide an encoding device capable of suppressing image degradation even when the resolution is changed, and an encoded recording / reproducing system using the same.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an encoding apparatus according to the present invention comprises: an input unit that inputs an image signal; a resolution conversion unit that converts a resolution of an image signal input by the input unit; An image encoding unit capable of encoding the output image signal by a plurality of encoding systems; and an encoding system of the image encoding unit according to a resolution of the image signal converted by the resolution conversion unit. And control means for controlling the switching.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An encoding device according to an embodiment of the present invention will be described.
[0011]
FIG. 1 is a block diagram of an encoding device according to an embodiment of the present invention. In the first embodiment, an image signal input from an external imaging device is encoded by the encoding device.
[0012]
In FIG. 1, 100 is an external input terminal, 101 is an image signal analog / digital converter, 102 is an image size conversion circuit, 103 is an image encoding circuit, 104 is a microphone, 105 is an audio signal analog / digital converter, and 106 is audio encoding. A circuit, 107 is a system encoder, 108 is an external input / output interface circuit, and 109 is a control circuit.
[0013]
An image signal input from the external input terminal 100 is converted into a digital signal in an image signal analog / digital converter 101 and input to an image size conversion circuit 102. The image size conversion circuit 102 converts the size (resolution) of the input image signal into VGA or SIF based on a user instruction input via the external input / output I / F 108 and inputs the converted signal to the image encoding circuit 103. I do.
[0014]
The image encoding circuit 103 generates, for example, compressed encoded image data conforming to the ISO / IEC13818-2 (commonly known as MPEG2 Video) MP @ ML (Main Profile @ Main Level) standard as the image compression encoding method, and the system encoder 107. To enter.
[0015]
An audio signal input from the microphone 104 is subjected to analog / digital conversion at a predetermined sampling rate in an audio signal analog / digital converter 105. The audio signal converted to the digital signal is input to the audio encoding circuit 106. The audio encoding circuit 106 generates, for example, a bit stream that conforms to the ISO / IEC13818-1 (commonly known as MPEG2 Audio) standard as an audio compression encoding system. The generated compression-encoded audio data is input to the system encoder 107. The audio compression encoding method is not limited to the MPEG2 Audio, but may be another encoding method.
[0016]
The control circuit 109 controls the image size conversion circuit 102, the image encoding circuit 103, and the like. The control operation of the image encoding circuit 103 performed by the control circuit 109 in the control will be described with reference to the flowchart of FIG.
[0017]
First, a case where an external imaging device outputs image data including an interlace component by interlace scanning or the like will be described. Step 200 is a step of inputting the image data after the image size conversion. Step 201 is to determine the image size after the image size conversion. If the image size is VGA, the DCT processing is performed as field DCT as shown in step 202, and the scan order of the DCT coefficients is controlled to be the alternate scan order. If the image size is SIF, control is performed so that the DCT processing is performed as the frame DCT as shown in step 203 and the scan order of the DCT coefficients is the zigzag scan order.
[0018]
Next, a case will be described in which image data that does not include an interlace component is output from an external imaging device by progressive scanning. The control circuit 109 controls the image encoding circuit 103 so that the DCT processing is performed as the frame DCT and the scan order of the DCT coefficients is the zigzag scan order even if the image size is VGA or SIF.
[0019]
The compression-encoded image data and the compression-encoding audio data are input to the system encoder 107, multiplexed, and output via the external input / output I / F.
[0020]
As a method of determining whether an input image signal is an image signal that does not include an interlace component by progressive scanning or an image signal that includes an interlace component by interlace scanning, the user determines whether the input signal is progressive scanning or interlace scanning. Of the input image signal, a method of adding a marker to the input image signal to identify whether the scanning is progressive scanning or interlaced scanning, and a method of determining the input image signal by using the marker. It is possible to determine whether the scanning is progressive scanning or interlaced scanning based on the temporal correlation between them.
[0021]
As described above, even when the image size of the image signal input from the external input terminal 100 is converted, by switching the DCT coefficient scanning order according to whether the image size is VGA or SIF, the optimal code can be obtained. Therefore, it is possible to improve the image quality at the time of encoding. For example, even when encoding a low-quality image signal having a small number of horizontal lines such as SIF and not including an interlace component, it is possible to improve the image quality.
[0022]
Next, a second embodiment will be described with reference to FIG. In FIG. 3, reference numeral 300 denotes a lens, and 301 denotes an image sensor. The image sensor 301 outputs an image signal containing no interlace component by progressive scanning or an image signal containing an interlace component by interlace scanning or the like. 302 is an image signal analog / digital converter, 303 is an image size conversion circuit, 304 is an image encoding circuit, 305 is a microphone, 306 is an audio signal analog / digital converter, 307 is an audio encoding circuit, and 308 is a system encoder. , 309 are external input I / F circuits, and 310 is a control circuit.
[0023]
The encoding device according to the second embodiment is different from the encoding device according to the first embodiment in that an image sensor is built-in, and an image signal output from the image sensor is interlaced by progressive scanning. The control is performed depending on whether the image signal contains no component or an image signal containing an interlace component by interlace scanning or the like.
[0024]
When the image sensor 301 outputs image data that does not include an interlace component by progressive scanning, the control circuit 310 sends a DCT process to the image encoding circuit 304 as a frame DCT and a DCT coefficient to the image encoding circuit 304 as in the first embodiment. Are controlled so that the scan order is the zigzag scan order. When the image sensor 301 outputs image data including an interlaced component by interlaced scanning, the control circuit 310 performs DCT processing on the image encoding circuit 304 in the same manner as in the first embodiment, and performs DCT processing as field DCT. Control is performed so that the scan order of the DCT coefficients is the alternate scan order.
[0025]
The other control regarding the encoding is the same as that of the first embodiment, and the description is omitted. In addition, the encoding method of the audio signal input from the microphone 305 is the same as that of the first embodiment, and the description is omitted. The image data and audio data thus compressed and encoded are input to the system encoder 308, multiplexed, and then output via the external input / output I / F.
[0026]
As described above, according to the second embodiment, when performing the image size conversion of the image signal input from the image sensor 301, the DCT coefficient of the DCT coefficient is determined according to whether the image size of the image signal to be encoded is VGA or SIF. By switching the scan order as in the above control, even when encoding a low-quality image signal with a small number of horizontal lines such as SIFs and no interlace component is performed, image degradation is suppressed. be able to. In the present embodiment, whether an image to be coded is progressive or interlaced is determined by the image sensor, so that it is not necessary to provide a device for determining whether an image is progressive or interlaced.
[0027]
Next, an encoded recording / reproducing apparatus according to a third embodiment of the present invention will be described with reference to FIG. The present embodiment is characterized in that it has one or more image signal input terminals and a switching circuit capable of switching the input. Further, it is characterized by comprising a recording / reproducing unit for recording and reproducing the compression-encoded data.
[0028]
In FIG. 4, reference numeral 701 denotes a switching circuit having one or more input terminals for image signals and capable of switching the input; 702, an image signal analog / digital converter; 703, an image size conversion circuit; Circuit, 705 is an audio signal input circuit, 706 is an audio signal analog / digital converter, 707 is an audio encoding circuit, 708 is a system encoder, 709 is a first control circuit, 710 is an external input / output I / F, 711 Is a control interface such as operation buttons, 712 is a buffer such as a semiconductor memory, etc., 713 is a buffer control circuit, and 714 is a storage medium. 715 is a system decoder, 716 is a second control circuit, 717 is an image decoding circuit, 718 is an audio decoding circuit, 719 is an OSD (On Screen Display) circuit, 720 is an image signal digital / analog converter, and 721 is audio. It is a signal digital / analog converter.
[0029]
In the present embodiment, a method of determining whether an input image signal is an image signal that does not include an interlace component by progressive scanning or an image signal that includes an interlace component by interlace scanning or the like is the same as in the first embodiment. . Further, similarly to the first embodiment, control is performed such that the DCT processing and the scan order of the DCT coefficients are changed according to the type of the input image signal.
[0030]
The control of the image encoding circuit 704 and the audio encoding circuit 707 relating to other encoding is the same as in the first embodiment, and the compression-encoded image and audio data are input to the system encoder 708 and multiplexed. Later, it is packetized.
[0031]
The packets multiplexed by the system encoder 708 are input to the buffer control circuit 713 and temporarily stored in the buffer 712. At the time of recording, the buffer control circuit 713 records the packet stored in the buffer 712 on the storage medium 714. The storage medium 714 is composed of, for example, a hard disk or a DVD.
[0032]
The buffer 712 is formed of a ring-shaped memory circuit, and when packets to be stored are full, the packets stored first are sequentially overwritten. Alternatively, the packets recorded on the storage medium 714 are sequentially deleted.
[0033]
When reproducing the packet recorded in the storage medium 714, the packet read from the storage medium 714 is supplied to the system decoder 715 by the buffer control circuit 713. The system decoder 715 separates the packet into compressed and coded image data and compressed and coded audio data, and supplies them to the image decoding circuit 717 and the audio decoding circuit 718, respectively. After being subjected to the decoding process, the image signal is superimposed on character information or the like by the OSD circuit 719, supplied to the image signal digital / analog converter 720, and output to the outside as an analog image signal. The audio signal is supplied to an audio signal digital / analog converter 721, and an analog audio signal is output.
[0034]
As an example of an encoded recording / reproducing system using the encoded recording / reproducing apparatus, a system as shown in FIG. 5 is considered.
[0035]
In FIG. 5, reference numerals 601 to 603 denote cameras, 604 denotes an encoding / reproducing apparatus, 605 denotes a monitoring display, and 606 denotes a speaker. A group of cameras 601 to 603 connected to the encoding / reproducing apparatus 604 transmit information to the encoding / reproducing apparatus 604 by using analog signals to transmit images and sounds taken from the respective installation locations, and the encoding / reproducing apparatus 604 encodes the information. And record. Then, the image and the sound reproduced by the encoded recording / reproducing device 604 are output by the display 605 and the speaker 606.
[0036]
As described above, according to the present embodiment, even if image size conversion is performed on an input image signal, the DCT coefficient is determined according to whether the image size of the image signal to be encoded is VGA or SIF. By switching the scan order of the above-mentioned control as in the above-described control, it is possible to realize an improvement in image quality when encoding a low-quality image signal having a small number of horizontal lines such as SIF and not including an interlace component.
[0037]
【The invention's effect】
According to the present invention, it is possible to provide an encoding device capable of suppressing image degradation even when the resolution of an image is changed, and an encoded recording / reproducing device and system using the same.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an encoding device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an encoding method.
FIG. 3 is a block diagram illustrating a configuration of an encoding device according to an embodiment of the present invention.
FIG. 4 is a block diagram illustrating a configuration of an encoding recording / reproducing apparatus according to an embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of an encoded recording / reproducing system according to an embodiment of the present invention.
[Explanation of symbols]
100 external input terminals 101, 302, 702 image signal analog / digital converters 102, 303, 703 image size conversion circuits 103, 304, 704 image coding circuits 104, 305 microphones 105, 306, 706 audio signals Analog / Digital converters 106, 307, 707 Speech encoding circuits 107, 308, 708 System encoders 108, 309, 710 External input / output I / F
109, 310 ... Control circuit 300 ... Lens 301 ... Imaging elements 601-603 ... Camera 604 ... Encoding / reproducing device 605 ... Display 606 ... Speaker 701 ... Switching circuit 705 ... Sound signal input circuit 709 ... First control circuit 711 ... Control I / F
712 buffer 713 buffer control circuit 714 storage medium 715 system decoder 716 second control circuit 717 image decoding circuit 718 audio decoding circuit 719 OSD
720, 721 ... DAC

Claims (15)

Input means for inputting an image signal,
Resolution conversion means capable of converting the resolution of the image signal input by the input means to the first resolution or the second resolution,
Image encoding means capable of encoding the image signal output from the resolution conversion means by a plurality of encoding schemes,
Control means for controlling to switch the encoding method of the image encoding means according to the resolution of the image signal converted by the resolution conversion means,
An encoding device comprising: Input means for inputting an image signal,
Resolution conversion means capable of converting the resolution of the image signal input by the input means,
An image encoding unit that encodes the image signal output from the resolution conversion unit; and an external input / output I / O that outputs the image signal encoded by the image encoding unit to the outside and inputs a resolution change instruction. An F circuit,
Control means for controlling the resolution conversion means and the image encoding means according to the input change instruction;
An encoding device comprising: 3. The encoding device according to claim 2, wherein the resolution conversion unit converts the resolution of the image signal into a first resolution or a second resolution according to a change instruction received by the external input / output I / F. An encoding device comprising: 4. The encoding device according to claim 1, wherein the control unit is configured to control the image signal input from the input unit to be an image signal obtained by interlaced scanning, and that the resolution of the image signal output from the resolution conversion unit be the same as the resolution of the image signal. If the resolution is one, the encoding apparatus controls the image encoding means to perform DCT processing using field DCT. 4. The encoding device according to claim 1, wherein the control unit is configured to control the image signal input from the input unit to be an image signal obtained by interlaced scanning, and that the resolution of the image signal output from the resolution conversion unit be the same as the resolution of the image signal. If the resolution is one, the image encoding unit is controlled to scan the DCT coefficients using an alternate scan. 4. The encoding apparatus according to claim 1, wherein the control unit is configured to control the image signal input by the input unit to be an image signal obtained by interlaced scanning, and that the resolution of the image signal output from the resolution conversion unit be the same as the resolution of the image signal. If the resolution is two, the image encoding means is controlled to perform DCT processing using frame DCT. 4. The encoding apparatus according to claim 1, wherein the control unit is configured to control the image signal input by the input unit to be an image signal obtained by interlaced scanning, and that the resolution of the image signal output from the resolution conversion unit be the same as the resolution of the image signal. If the resolution is two, the image encoding means is controlled to scan DCT coefficients using zigzag scanning. Imaging means for outputting an image signal;
Resolution conversion means for converting the resolution of the image signal output from the imaging means, image coding means for coding the image signal output from the resolution conversion means, and an image coded by the image coding means An external input / output I / F circuit that outputs a signal to the outside and inputs a resolution change instruction;
Control means for controlling the resolution conversion means and the image encoding means according to the input change instruction;
An encoding device comprising: 9. The encoding device according to claim 8, wherein the resolution conversion unit converts the resolution of the image signal into a first resolution or a second resolution according to a change instruction received by the external input / output I / F. An encoding device comprising: 10. The encoding apparatus according to claim 9, wherein the control unit is configured to control the image signal output from the imaging unit to be an image signal obtained by interlaced scanning, and that the resolution of the image signal output from the resolution conversion unit be the first signal. An image encoding means for controlling the image encoding means to perform DCT processing using field DCT when the resolution is. 10. The encoding device according to claim 9, wherein the control unit is configured to output an image signal from the imaging unit by an interlaced scanning, and to change the resolution of the image signal output from the resolution conversion unit to the first image signal. If the resolution is the resolution, the encoding apparatus controls the image encoding means to scan the DCT coefficients using an alternate scan. 10. The encoding device according to claim 9, wherein the control unit is configured such that an image signal output from the imaging unit is an image signal by interlaced scanning, and a resolution of the image signal output from the resolution conversion unit is the second signal. If the resolution is a resolution, the encoding apparatus controls the image encoding means to perform DCT processing using a frame DCT. 10. The encoding device according to claim 9, wherein the control unit is configured such that an image signal output from the imaging unit is an image signal by interlaced scanning, and a resolution of the image signal output from the resolution conversion unit is the second signal. If the resolution is determined, the encoding apparatus controls the image encoding unit to scan the DCT coefficients using zigzag scanning. 9. The encoding apparatus according to claim 1, wherein the first resolution is 720 waterside lines, and the second resolution is half the number of horizontal lines of the first resolution. An imaging device that outputs an image signal, the encoding device according to any one of claims 1 to 7, a recording / reproducing device that records / reproduces an image signal encoded by the image encoding device, and the recording / reproducing device. And a display device for displaying an image signal output from the playback device.

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