JP2000333015A - Still image device - Google Patents

Abstract

(57) [Problem] To provide a still image device capable of recording on a recording medium by fixed-length encoding even when the capacity of a recordable area varies. An information amount reducing unit for reducing pixel information of still image data, a recording medium on which the reduced data can be written and read, and recording the reduced data from the information amount reducing unit. Recording means 2 for recording on the medium 3 and recording for giving an information amount reduction signal to the information amount reduction means 1 based on the capacity of the recordable area of the recording medium 3 and the reduced data amount to the information amount reduction means 1. It has a medium capacity management means 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a still picture apparatus capable of recording and reproducing still picture data.

[0002]

2. Description of the Related Art Generally, still image data is stored in a memory card,
When digital data is recorded on a recording medium such as a magnetic disk or a magnetic tape, the amount of data becomes enormous. Therefore, it is generally known that when many frame images are recorded in a limited recording capacity range, the obtained image signal data is recorded using highly efficient compression.

[0003] In an electronic still camera that has been rapidly spreading in recent years, a DCT compression system with fixed length encoding is used. This is because, when the variable length is maintained, the amount of encoded data significantly changes depending on the picture to be shot, and the number of shots per memory card is not determined.
In other words, while 20 pictures could be recorded when a picture was taken, fixed-length encoding was used to prevent the inconvenience of not being able to achieve the goal because only 5 pictures could be recorded if another picture was taken. Was needed.

[0004]

However, when the capacity of the recordable area is fluctuated, the code amount is fixed. In such a configuration, when the capacity of the recordable area is smaller than the fixed code amount, recording cannot be performed. There is a point.

The present invention solves the above-mentioned conventional problems, and provides a still picture apparatus capable of recording on a recording medium by fixed-length encoding even when the capacity of a recordable area fluctuates. The purpose is to do.

[0006]

The still picture apparatus of the present invention comprises:
Information amount reducing means for reducing pixel information of still image data;
A recording medium on which the reduced data can be written and read, a recording means for recording the reduced data from the information amount reducing means on the recording medium, a capacity of a recordable area of the recording medium and the reduction A recording medium capacity management means for providing an information amount reduction signal for changing the reduction amount to the information amount reduction means based on the subsequent data amount.

According to the present invention, even when the capacity of the recordable area of the recording medium fluctuates, the amount of information reduction is changed so that the recording data amount falls within the predetermined error range below the capacity of the recordable area. Therefore, it is possible to perform recording by fixed-length encoding using the recordable capacity of the recording medium effectively.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals are used for parts common to the embodiments.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a still picture apparatus according to Embodiment 1 of the present invention, and FIG.
FIG. 3 is an explanatory diagram of a recordable area in the still image apparatus according to the first embodiment of the present invention, and FIG. 3 is a block diagram illustrating a specific example of an information amount reducing unit in the still image apparatus according to the first embodiment of the present invention. In FIG. 1, 1 is an information amount reducing means, 2 is a recording means, 3 is a recording medium, 4 is a recording medium capacity managing means, 5 is a switch, and the information amount reducing means 1 is a piece of input still image data. , And outputs it to the recording medium capacity management unit 4. At this time, the switch 5 is selected in the direction shown in FIG. As shown in FIG. 2, the recording medium capacity management unit 4 controls the start address (Adr) of the recordable area of the recording medium 3.
By managing 1) and the last address (Adr2), the capacity of the recordable area is managed, and the reduced target data amount is set. In FIG. 2, still image data 1 and still image data 2
Indicates an area already recorded on the recording medium 3. The recording medium capacity management unit 4 compares the reduced data amount output from the information amount reduction unit 1 with the target data amount, and sends a reduction control signal to the information amount reduction unit 1 so as to approach the target data amount. To switch the amount of information reduction. The above processing is repeated, and when the data amount after the reduction is equal to or smaller than the target data amount and falls within the predetermined error range, the recording medium capacity management unit 4 moves the switch 5 in the direction opposite to the direction shown in FIG. A switching signal is given to make the selection, and the reduced data is input to the recording means 2. The recording unit 2 records the reduced data in the area from Adr1 to Adr2 managed by the recording medium capacity management unit 4.

Next, as an example of a concrete realizing means, a case where the present invention is applied to a compression process using DCT (discrete cosine transform) as an information amount reducing means will be described. In FIG. 3, the information amount reducing unit 1 includes a blocking unit 6, a DCT unit 7, a quantization unit 8, and an encoding unit 9. The blocking unit 6 divides the still image data into blocks of a predetermined size. The DCT unit 7 performs two-dimensional DCT (discrete cosine transform) as orthogonal transform on each of the divided luminance signal / color difference signal for each block. The quantization unit 8 has a DC
The quantization is performed by dividing the T result by the quantization table. The encoding unit 9 performs Huffman encoding on the quantized value as variable-length encoding. At this time, the difference value between the DC component and the DC component of the neighboring block is Huffman-coded. The AC component scans from a low frequency component to a high frequency component called a zigzag scan, and is a two-dimensional Huffman code based on the continuous number of invalid (value is “0”) components and the valid component values that follow. Perform the conversion. The still image data compressed by the above compression processing is recorded on the recording medium 3 by the recording means 2 in FIG.

Here, since only the above processing uses Huffman coding, which is variable length coding, the code amount changes due to recordable still image data, and a target recording capacity cannot be realized. Recording medium capacity management means 4 in FIG.
The encoding control is performed as follows, using the capacity of the recordable area of the recording medium 3 of FIG.

First, the above processing is performed to determine the total code amount of all the screens. Based on the output total code amount and the target code amount, an optimal quantization table for approaching the target code amount is predicted. Next, using the predicted quantization table, the quantization unit 8
The subsequent processing is repeated, and the optimal quantization table for approaching the target code amount again is predicted from the total code amount output this time, the total code amount output last time, and the target code amount. When the total code amount output by repeating the above processing is equal to or smaller than the target code amount and falls within the predetermined error range, the processing is terminated. The encoded data at the end is output to the recording means 2 of FIG. 1 and recorded on the recording medium 3. This allows the amount of recording data to be set from the capacity of the recordable area of the recording medium, so that even when the capacity of the recordable area fluctuates, recording can be performed on the recordable area of the recording medium.

As described above, according to this embodiment, even when the capacity of the recordable area of the recording medium varies, the amount of recording data can be reduced to a predetermined error or less by changing the information reduction amount. Within the range, recording on the recording medium is possible, and the recordable area of the recording medium can be effectively used.

(Embodiment 2) Embodiment 2 is a modification of the first embodiment shown in FIG. 3 in which the information amount reducing means is replaced with another realizing means, and the other blocks have the same configuration. The description is omitted because the same operation is performed, but the description will be made with reference to the case where necessary. FIG. 4 is a block diagram of an information amount reducing unit according to the second embodiment of the still image apparatus of the present invention, and FIG. 5 is a second embodiment of the still image apparatus of the present invention.
FIG. 2 is a schematic diagram showing a pixel configuration in FIG.

In FIG. 4, the information amount reducing means 1 includes a compression processing section 10 and a horizontal and vertical color difference signal thinning circuit 13.
And a first thinning-out processing section 11 comprising a switch 12. The compression processing unit 10 can be realized by, for example, the compression processing method using DCT described in the first embodiment. When the amount of data input to the compression processing unit 10 is reduced, the switch 12 is selected in the direction shown in FIG. 4 by the information amount reduction signal from the recording medium capacity management unit 4 in FIG. Data is input to the circuit 13. When still image data is input,
The horizontal and vertical color difference signal thinning circuit 13 thins out the color difference signals for each predetermined pixel unit to reduce the data amount. The data after the reduction is input to the compression processing unit 10 and performs the operation described in the first embodiment.

In this way, for example, as shown in FIG. 5A, the color difference signals corresponding to the luminance signals Y1 to Y2 are Cr1 to Cr4 and Cb1 to Cb2, respectively.
(Luminance signal): Cb (difference between luminance and blue level): Cr (difference between luminance and red level): When still image data composed of 4: 4: 4 is input, horizontal and vertical color difference signal thinning is performed. The circuit 13 converts the color difference signals corresponding to the luminance signals Y1 to Y2 into Cr1 of Cr1 to Cr4 and Cb1 to Cb2.
Y: Cb: Cr = 4:
Conversion to 1: 1 still image data (FIG. 5)
(B)). Therefore, the data amount input to the compression processing unit 10 in FIG. 4 can be reduced to 3/8. When the amount of still image data is not reduced, the switch 12 is selected in the opposite direction to the direction shown in FIG. 4 by the information amount reduction signal from the recording medium capacity management unit 4 in FIG. 1, and the still image data is compressed as shown in FIG. Processing unit 10
Will be output to

As described above, according to the present embodiment, the number of color difference signal pixels with respect to the number of luminance signal pixels can be switched according to the capacity of the recordable area according to the present embodiment. Is reduced, the amount of still image data input to the compression processing unit can be reduced, and the amount of recording data can be reduced even if the reduction amount in the compression processing unit is fixed. Therefore, data can be recorded even when the capacity of the recordable area is small, and the number of still images to be recorded on the recording medium can be increased. In particular, it is possible to suppress image quality deterioration due to block noise, mosquito noise, and the like that occur when the amount of reduction in the compression processing unit is increased to reduce the amount of recording data. Further, even when the composition ratio of the luminance signal and the color difference signal of the recording data is specified, recording can be performed by switching the composition ratio of the color difference signal to the luminance signal.

(Embodiment 3) This embodiment 3 is obtained by changing the information amount reducing means in the embodiment 1 shown in FIG. 3 to another realizing means, and the other blocks have the same configuration. The description is omitted because the same operation is performed, but the description will be made with reference to the case where necessary. FIG. 6 is a block diagram of an information amount reducing unit according to Embodiment 3 of the still image device of the present invention.

In FIG. 6, the information amount reducing means 1 comprises a compression processing unit 10 and a second thinning processing unit 14 comprising a horizontal and vertical pixel thinning circuit 16 and a switch 15. As an example, still image data composed of 640 (horizontal) × 480 (vertical) pixels is converted to 320 ×
A case where the image data is converted into still image data composed of 240 pixels will be described. The compression processing unit 10 can be realized by, for example, the compression processing method using DCT described in the first embodiment. When reducing the amount of still image data, the switch 15 is selected in the direction shown in FIG. 6 by the information amount reduction signal from the recording medium capacity management means 4 in FIG. The horizontal and vertical pixel thinning circuit 16 thins out one pixel in each of the adjacent horizontal and vertical directions for each pixel, and outputs it to the compression processing unit 10. As a result, the data can be converted into still image data composed of 320 × 240 pixels, so that the amount of data input to the compression processing unit 10 can be reduced to ４. When the amount of still image data is not reduced, the switch 15 is selected in the opposite direction to the direction shown in FIG. 6 by the information amount reduction signal from the recording medium capacity management unit 4 in FIG. 1, and the input still image data in FIG. This is output to the compression processing unit 10.

As described above, according to this embodiment, the number of pixels of still image data can be switched based on the capacity of the recordable area, so that the number of pixels of still image data input to the compression processing unit can be reduced. In this case, the recording data amount can be reduced even if the reduction amount in the compression processing unit is fixed, and data can be recorded even when the recordable capacity is small, so that the number of still images to be recorded on the recording medium can be increased. . In particular,
It is possible to suppress image quality deterioration due to block noise, mosquito noise, and the like that occur when the amount of reduction in the compression processing unit is increased to reduce the amount of recording data.

(Embodiment 4) Embodiment 4 is a modification of the first embodiment shown in FIG. 3 in which the information amount reducing means is changed to another realizing means, and the other blocks have the same configuration. The description is omitted because the same operation is performed, but the description will be made with reference to the case where necessary. FIG. 7 is a block diagram of an information amount reducing unit according to Embodiment 4 of the still image device of the present invention.

In FIG. 7, the information amount reducing means 1 comprises a compression processing unit 10, a horizontal and vertical pixel thinning circuit 16, a second thinning processing unit 14 comprising a switch 15 and a pixel adding unit 17. . The horizontal and vertical pixel thinning circuit 16 and the switch 15 have the same configuration as in FIG. Also, the compression processing unit 1
0 can be realized, for example, by the compression processing method using DCT described in the first embodiment. 640 (horizontal direction) ×
When reducing the number of pixels of still image data composed of 480 (vertical) pixels, the horizontal and vertical pixel thinning circuit 16 converts this still image data into three pixels as described with reference to FIG.
It is converted into still image data A composed of 20 × 240 pixels. Here, the still image data A is 480 × 360
When it is necessary to convert the still image data B into pixels, the pixel adding unit 17 complements pixels other than the still image data A in the number of pixels of the still image data B with fixed color data. The complemented still image data B is output to the compression processing unit 10.

As described above, according to the present embodiment, even if the number of pixels of the recording data is specified, the number of pixels can be increased by complementing the fixed color for realizing the specified number of pixels. The increase in the amount of recording data due to is minimized. Therefore, data can be recorded even when the recordable capacity is small, and the number of still images to be recorded can be increased.

[0024]

As described above, according to the present invention, when recording still image data on a recording medium, even if the capacity of the recordable area of the recording medium fluctuates, the information reduction amount is made variable, Since the recording data amount can be set within a predetermined error range below the capacity of the recordable area, there is obtained an advantageous effect that recording can be performed by fixed-length encoding using the recordable area of the recording medium effectively. Can be

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a still image device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a recordable area in the still image apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a specific example of an information amount reducing unit according to the first embodiment of the still image device of the present invention.

FIG. 4 is a block diagram of an information amount reducing unit according to a second embodiment of the still picture device of the present invention.

FIG. 5 is a schematic diagram illustrating a pixel configuration according to a second embodiment of the still image device of the present invention.

FIG. 6 is a block diagram of an information amount reducing unit according to a third embodiment of the still image device of the present invention.

FIG. 7 is a block diagram of an information amount reducing unit according to a fourth embodiment of the still image device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Information amount reduction means 2 Recording means 3 Recording medium 4 Recording medium capacity management means 5, 12, 15 Switch 6 Blocking unit 7 DCT unit 8 Quantization unit 9 Encoding unit 10 Compression processing unit 11 First thinning processing unit 13 Horizontal and vertical color difference signal thinning circuit 14 Second thinning processing unit 16 Horizontal and vertical pixel thinning circuit 17 Pixel addition unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) 9A001 F term (Reference) 5C022 AA13 AB68 AC69 5C053 FA08 GB26 GB34 GB36 5C057 AA11 AA19 DA03 EA02 ED08 EM09 EM13 EM16 5C059 LA00 MA23 PP01 PP14 SS15 TA58 TB08 TC15 5C078 AA09 CA02 CA27 DA01 DA02 DA22 DB04 EA00 9A001 BZ03 EE04 HH27

Claims (4)

[Claims] An information amount reducing unit configured to reduce pixel information of still image data, a recording medium capable of writing and reading the reduced data, and recording the reduced data from the information amount reducing unit. Recording means for recording on a medium, and a recording medium capacity for providing an information amount reduction signal for changing the reduction amount to the information amount reducing means from the capacity of the recordable area of the recording medium and the reduced data amount. A still image device comprising management means. 2. The information amount reducing unit includes: a first thinning processing unit that changes a composition ratio of a luminance signal and a color difference signal; and a compression processing unit that compresses output data of the first thinning processing unit. 2. The still image apparatus according to claim 1, wherein the first thinning processing unit changes a composition ratio between a luminance signal and a color difference signal of the still image data based on the information amount reduction signal. 3. The information processing apparatus according to claim 1, wherein the information amount reducing unit includes a second thinning processing unit that changes the number of pixels, and a compression processing unit that compresses output data of the second thinning processing unit. The unit, when the still image data is composed of L × M pixels, thins out N (N is an integer) adjacent pixels based on the information amount reduction signal from the recording medium capacity management unit, This is represented by L ′ × M ′ (L ′ = L / S,
2. The still picture apparatus according to claim 1, wherein the still picture data is converted into still picture data composed of pixels of L '= L / SS is an integer of 2 or more). 4. The still image according to claim 3, wherein the information amount reducing unit further includes a pixel adding unit that complements pixels other than the L ′ × M ′ still image data with fixed color data. apparatus.