JP3197733B2 - Information recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a VTR, an electronic still camera, or the like having a digital image signal processing unit, and means for compressing an image signal and recording the image signal on a recording medium. And an information recording / reproducing apparatus having means for reproducing.

[0002]

2. Description of the Related Art Conventionally, a desired screen is selected from image signals continuously inputted, image data of the screen is recorded as still image data on a recording medium, and information capable of reproducing a still image is selected. There is a recording and reproducing device. In this information recording / reproducing apparatus, various methods for recording and reproducing a still image have been proposed and implemented.

In the still image recording apparatus disclosed in Japanese Patent Application Laid-Open No. 2-51983, a screen to be recorded as a still image generally has
Paying attention to a screen different from the previous scene as in a so-called cut scene, it detects that the image signal that has been continuously input has greatly changed over a plurality of screens, and the detection output outputs one of the image signals. Image data for a screen (frame) is recorded as still image data on a recording medium, so that no human operation is required.

[0004]

In the still image recording apparatus, when an image having a large change and an image having a small change are input at random, a difference in a time scale between recording and reproduction causes uncomfortable feeling when reproduced as it is. When a certain playback screen is obtained and audio is recorded at the same time, there is a problem that the playback screen and the audio cannot be matched during the playback.

Further, since the detection reference level of the detecting means for detecting a large change in the screen is not variable, and there is no means for setting an image data area for detecting a change in the screen, it is necessary to meet the purpose of use. There is a problem that image data is not recorded.

SUMMARY OF THE INVENTION An object of the present invention is to provide an information recording / reproducing apparatus which can perform good reproduction, can select image data according to a purpose of use, and can use a memory efficiently.

[0007]

In order to achieve the above object, an information recording / reproducing apparatus according to the present invention comprises means for compressing an image signal and recording the compressed image signal on a recording medium, and decompressing image data recorded on the recording medium. A still image recording mode for recording only one frame of image data by one recording command using a DCT algorithm as a compression method of an image signal during recording, and an image recording mode;
Alternatively, a recording control means for switching to any one of continuous image recording modes in which image data for several frames are continuously recorded by one recording command; Comparison area setting means for setting an area for comparing the data of the two quantized DCT coefficients, comparison means for comparing the data in the area set by the comparison area setting means, and an output of the comparison means. A memory control unit for setting the recording start address of the next frame to the recording start address of the immediately preceding frame when the recording level is equal to or lower than a predetermined set level.

The comparison area setting means specifies the address of the area to be compared in units of 8 × 8 blocks, specifies the start address of the start block by the horizontal address and the vertical address as the start address of the area to be compared, and a material obtained by each adding a predetermined value to the horizontal address and the vertical address of the starting block as an address, characterized in that specified.

[0009] said comparing means takes the difference between two data corresponding to each block in the region of the image, the specified value of the difference the block by adding a few minutes, was determined and the sum value preset It is characterized by comparing with the level.

In the continuous image recording mode, the continuous image recording mode is set when the comparison result by the comparing means is equal to or higher than the set level, and when the comparison result is equal to or lower than the set level, the recording start address of the immediately preceding frame is added to the next frame. A memory control means for setting a recording start address, switching to a recording mode for recording image data of the next frame, and recording.

[0011] Further, the present invention is characterized in that a set level serving as a reference for comparison by the comparing means is set variable.

[0012] Further, a memory control means for recording, as attribute information, information on the output level of the comparing means and information on the number of frames in which the state of the level continues continuously.

Further, at the time of image reproduction, a still image reproduction mode in which only one frame of image data of the image data recorded in the still image recording mode is continuously reproduced, or an image data recorded in the continuous image recording mode. A reproduction control means for switching to any one of a continuous image reproduction mode for continuously reproducing several frames is provided.

A decoding means for decoding the two pieces of attribute information; and, if the decoding result indicates that the output information of the comparison means is equal to or less than the set level, the image data being reproduced is repeated by a predetermined number of frames. A reproduction control unit that reproduces and, when the output information of the comparison unit is equal to or higher than a set level, performs continuous image reproduction.

[0015]

According to the information recording / reproducing apparatus having the above-described configuration, in the still image recording mode, only one frame of image data is recorded on the recording medium, and in the continuous image recording mode, the designated data in the frame to be recorded is designated. Only when it is determined that the data of the area that has been set is different from the data of the area corresponding to that of the immediately preceding frame, the data of the new frame is recorded, and the image data regarded as substantially the same is not recorded.

The area to be compared has an address of 8 ×
8, the DCT coefficient data is specified based on the horizontal address and the vertical address of the block, the difference between the DCT coefficient data is obtained for each block in the corresponding area of the two images, and the difference value and a predetermined setting In the continuous image recording mode, it is determined whether the level is equal to or lower than the set level in the continuous image recording mode.

When the level is higher than the set level, the image data of each frame is continuously recorded as a state where the image change is large. When the level is lower than the set level, substantially the same image is continuous. To record image data of only one frame.

By changing the set level, the switching between recording one frame of image data and switching to the continuous image recording mode is arbitrarily set according to the purpose of use.

Further, at the time of reproduction, the information relating to the set level and the information relating to the number of frames in which the state below the set level continues continuously are recorded together with the image data recorded as the attribute information. By using the attribute information, even when image data having a large change and image data having a small change are input at random, it is possible to reproduce the image data on the same time scale as at the time of recording.

Further, at the time of reproduction, recording is performed in the still image recording mode, or in the continuous image recording mode,
If only the frame image data is recorded,
The image data of the frame is reproduced continuously for a predetermined number of frames.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a main part according to an embodiment of the present invention. Reference numeral 1 denotes a DCT processing section for executing a DCT (Descrate Cosine Transform) on an input image signal; A memory controller, which is a memory control unit having a start address preset circuit 5 described below;
Reference numeral 6 denotes recording / recording of image data by the memory controller 4.
It is a recording medium such as a video tape, a magnetic disk, and a memory card to be reproduced.

A decoding processing unit 7 receives and decodes image data of the recording medium 6 via the memory controller 4, and 8
Denotes an inverse quantization processing unit, and 9 denotes an IDCT processing unit that executes inverse DCT and outputs a reproduced image signal.

10 is a buffer connected to the quantization processing unit 2, 12 and 13 are a first buffer memory and a second buffer memory connected to the buffer 10 and the frame pulse output unit 14,
15 is an inverter connected between the second buffer memory 13 and the frame pulse output unit 14, and 16 is a first buffer memory.
A differentiator receiving the outputs of 12 and the second buffer memory 13, 17
Is an adder, 18 is a comparison level setting unit, 19 is an analog / digital which digitizes a setting signal of the comparison level setting unit 18
An (A / D) converter 20 is a comparator as comparison means such as a digital comparator that receives data from the adder 17 and the A / D converter 19, and the output data of the comparator 20 is the memory controller. 4 is input.

Reference numeral 21 denotes a CPU (central processing unit) which receives various setting key inputs and transmits / receives signals to control the above-mentioned units, and 22 denotes a dot clock, HD (horizontal synchronization signal), VD (vertical synchronization signal). And a timing signal generation unit that receives a signal such as the above and supplies a timing signal to each unit.

In this embodiment having the above-described configuration, the image recording mode is set to one by a recording command such as one key input.
It is possible to set a still image recording mode in which only frame image data is recorded and a continuous image recording mode in which image signals for several frames are continuously recorded by one recording command. Switching of these modes is controlled by the CPU 21 having the function of the recording control means.

In the still image recording mode, an input image signal for one frame is converted into an 8 × 8
DCT processing is performed for each block of pixels, and each block is converted into 64 DCT coefficients. This DCT coefficient is quantized by the quantization processing unit 2 and then encoded by the encoding processing unit 3
And becomes encoded data, which is recorded on the recording medium 6 by the memory controller 4.

Image data read from the recording medium 6 by the memory controller 4 at the time of reproduction is decoded by the decoding processing unit 7, inversely quantized by the inverse quantization processing unit 8, and then decoded by the IDCT processing unit 9. It is subjected to inverse DCT processing and output as a reproduced image signal.

Next, the continuous image recording mode will be described.

When the mode is set, as described above, the quantized data quantized by the quantization processing unit 2 passes through the buffer 10 when the buffer 10 is on, and the first buffer memory 12
, And the quantized data at the time of recording the next frame is stored in the second buffer memory 13. ON / OFF of each of the buffer memories 12 and 13 is controlled by a signal synchronized with a frame pulse.

The data stored in each of the buffer memories 12 and 13 is stored in a differentiator 16 for each data in the pixel block.
, A difference value is calculated, and the result is added by the adder 17. The result of addition in one frame is compared with a reference level set in advance in the comparison level setting unit 18 by the comparator 20. If the comparison result is "H", the output of the adder 17 is In response to this output, the memory controller 4 continues the recording operation on the recording medium 6. That is, the memory controller 4
It is determined that the difference between the data of the immediately preceding frame and the data of the current frame is large and the image change is large, and the normal continuous image recording is continued.

On the other hand, if the comparison result is "L", it is determined that the output of the adder 17 is smaller, the image change is small, and substantially the same image continues, and the memory control means A certain memory controller 4 sets the address of the memory to be recorded next to the recording start position of the current frame, which has just finished recording, at the end of the recording of the current frame, and further as attribute information of the image data. ,
The number of frames in which “L” occurs continuously is added to the attribute information recording section of the recording medium 6.

That is, the memory controller 4 determines that the difference between the image data of the current frame and the image data recorded immediately before is small, and overwrites the current frame data with the image data of the next frame.

In this way, in the continuous image recording mode, the continuous image recording mode is executed based on the output of the comparator 20, or the memory address is reset to the current frame position to execute the recording. Can be switched automatically.

Next, the designation of the block area to be compared will be described.

The timing signal generator 22 also has a function as comparison area setting means for designating an address of data for comparing quantized DCT coefficients centering on the horizontal address generator and the vertical address generator. ing. As is well known, the horizontal area can be specified by setting the start address in each register as the dot clock count number from the HD start position and the end address as the same count number up to the count end position. On the other hand, the vertical area has VD as the start address.
And the end address as the same count number up to the count end position can be designated by setting each register. By specifying this address in block units, a block area to be compared can be specified.

The difference unit 16, adder 17, comparator 20
The timing of the operation of FIG.
It is controlled by a control signal from U21.

Next, the operation during continuous image reproduction will be described.

At the time of reproduction and recording, the attribute information recorded in the attribute information recording section is decoded by a decoder function in the CPU 21 or a decoding circuit such as a data coincidence detecting circuit comprising a comparator and a register. Is the L level and the number of frames for which the L level is detected continuously is n (integer), the CPU 21 having the function of the reproduction control means outputs the data of the frame currently being reproduced. Is repeated for n frames, and each unit is controlled so as to perform continuous reproduction. On the other hand, when it is at the H level, normal continuous image reproduction is executed.

FIG. 2 is a block diagram showing a configuration of the start address preset circuit 5 in the memory controller 4. Reference numeral 30 denotes an address generation circuit, 31 denotes an address latch circuit, 32 denotes a preset register, and 33 denotes an AND circuit. It is.

FIG. 3 is a timing chart when a start address is preset at the time of recording. In FIGS. 2 and 3, A is a VD (vertical synchronization signal), B is a frame pulse, C is a comparison timing signal, and D is a comparison timing signal. The comparison output of the comparator 20, E is a comparison output after latching, F is a start address signal, G is a start address signal after latching, H
Is a preset address signal, I is a preset address load pulse, and J is an output address signal. .., A, b, c,... Are frame start addresses, which usually change in the order of a → b → c →... → j → k →.

The address latch circuit 31 has an input LE
Latches the input address data at the rising edge of
And holds its output until the next rise of the LE. The preset register 32 stores the input data during a period when the input Load (= frame pulse) is “L”, and outputs the stored data when the Load next becomes “L”.

That is, when the comparison output D of the comparator 20 becomes "L", the start address of the immediately preceding frame stored in the preset register 32 at the timing when the next frame pulse B becomes "L". The signal F is preset in the address generation circuit 30, and normal frame recording is executed from this address.

The operation timing at the time of reproduction is the same as that at the time of recording. When the level of the comparison output D of the comparator 20 in the attribute information decoded as described above is "H", normal continuous reproduction is performed. In the case of "L", the reproduction start address is preset to the address reproduced immediately before, so that the data of the same frame is transmitted until the level of the comparison output D of the comparator 20 becomes "H". Play back n times based on the attribute information. At this time, the reproduction time is the same as the time recorded at the time of recording.

[0045]

As described above, according to the first aspect of the present invention, the information recording / reproducing apparatus of the present invention does not record substantially the same image data even in the continuous image recording mode. The memory efficiency is improved, the memory capacity can be reduced, and the data transfer efficiency can be improved.

According to the second aspect of the present invention, the determination as to whether or not the image data is substantially the same can be made by comparing the data of the designated area between the immediately preceding frame and the current frame. The area can be appropriately designated and set according to the purpose of use, and efficient use of the memory becomes possible.

According to the third aspect of the present invention, the determination as to whether or not the image data is substantially the same is automatically performed by comparing the image data with a set level based on a data difference of a designated area.

According to the fourth aspect of the present invention, the mode is automatically switched to the continuous image recording mode or the recording mode for recording only one screen, depending on whether the set level is equal to or higher than the reference or lower than the reference.

According to the fifth aspect of the present invention, the setting of the set level can be appropriately changed according to the purpose of use.
Efficient use of memory becomes possible.

According to the invention of claim 6, by recording the information on the set level and the time information thereof, the image data of the set level or more and the set level or less is recorded at random. Even in such a case, by using the information, it is possible to perform good reproduction without a sense of incongruity at the same time scale as at the time of recording at the time of reproduction.

According to the invention of claim 7, at the time of reproduction,
The reproduction mode is automatically switched so that the image data recorded in the still image recording mode or the continuous image recording mode is reproduced in a state suitable for those modes.

According to the eighth aspect of the present invention, when the image data recorded in the continuous image recording mode is reproduced, when it is determined that only one image data is recorded by the attribute information, the image data is recorded. By repeating the reproduction for the number of frames of the time information, the reproduction is performed on the same time scale as the continuous image reproduction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part in an embodiment of an information recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram showing a configuration of a start address preset circuit.

FIG. 3 is a timing chart when a start address is preset during recording.

[Explanation of symbols]

1 DCT processing unit 2 Quantization processing unit 3 Encoding processing unit 4 Memory controller (memory control means)
5: start address preset circuit, 6: recording medium, 7: decoding processing unit, 8: inverse quantization processing unit,
9 IDCT processing unit, 10 buffer, 12, 13 buffer memory, 14 frame pulse output unit, 15 inverter, 16 difference unit, 17 adder, 18 comparison level setting unit, 19 A / D Converter, 20 comparator (comparison means), 21 CPU (recording control means, reproduction control means, decoding means), 22 timing signal generator (comparison area setting means), 30 address generating circuit, 31 address・ Latch circuit, 32 ... Preset register.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI // H04N 101: 00

Claims (8)

(57) [Claims] 1. A means for compressing an image signal and recording it on a recording medium, a means for expanding and outputting image data recorded on the recording medium, and using a DCT algorithm as a compression method of the image signal during recording. And a still image recording mode in which only one frame of image data is recorded by one recording instruction, or a continuous image recording in which several frames of image data are continuously recorded by one recording instruction. Recording control means for switching to any one of the modes, and two quantized DCTs of the immediately preceding frame and the current frame in the continuous image recording mode.
Comparison area setting means for setting an area for comparing coefficient data; comparison means for comparing the data in an area set by the comparison area setting means; and an output of the comparison means being equal to or less than a predetermined set level. An information recording / reproducing apparatus comprising: a memory control unit for setting a recording start address of the next frame to a recording start address of the immediately preceding frame. 2. The comparison area setting means specifies an address of an area to be compared in units of 8 × 8 blocks, and specifies a head address of a start block by a horizontal address and a vertical address as a start address of the area to be compared. each information recording and reproducing apparatus according to claim 1, wherein a material obtained by adding a predetermined value, characterized in that specify the horizontal address and the vertical address of the starting block as the end address. Wherein said comparing means takes the difference between two data corresponding to each block in the region of the image, the adding block number of the value specified for the difference, defined the additional value previously 2. The information recording / reproducing apparatus according to claim 1, wherein the information is compared with a set level. 4. In the continuous image recording mode, when the result of the comparison by the comparing means is equal to or higher than the set level, the continuous image recording mode is set. 4. The information recording / reproducing apparatus according to claim 1, further comprising a memory control unit for setting a recording start address of the first frame and switching to a recording mode for recording image data of a next frame. 5. The information recording / reproducing apparatus according to claim 1, wherein a setting level serving as a reference for comparison by said comparing means is variable. 6. A memory control means for recording, as attribute information, information on an output level of the comparing means and information on the number of frames in which the state of the level continues continuously. The information recording / reproducing apparatus according to claim 1, 3, 4, or 5. 7. A still image reproduction mode for continuously reproducing only one frame of image data of image data recorded in the still image recording mode during image reproduction, or image data recorded in the continuous image recording mode. 2. The information recording / reproducing apparatus according to claim 1, further comprising: a reproduction control means for switching to any one of a continuous image reproduction mode for continuously reproducing a plurality of frames. 8. A decoding means for decoding the two pieces of attribute information according to claim 6, wherein, if the decoding result indicates that the output information of the comparing means is lower than the set level, the image data currently reproduced is converted to a predetermined level. 8. The information according to claim 1, further comprising: playback control means for performing playback repeatedly for the number of frames, and performing continuous image playback when output information of the comparison means is equal to or higher than a set level. Recording and playback device.