JPH03267863A - Recorder - Google Patents

Abstract

PURPOSE:To store information continuously in a storage means as required by providing the storage means storing in advance the information to be stored in a recording means in response to the comparison between an unrecored quantity of the recording means and a code quantity to be recorded. CONSTITUTION:A control section 7 stores a video signal converted into a digital signal to a picture memory 4, reads a picture signal and compressed by a coding circuit 5, a counter circuit 16 counts a data subject to compression coding, the compressed code quantity and an idle capacity of a recording medium in a recorder 6 are compared and when the idle capacity is enough, the picture signal is read again from the memory 4 and the compression coding is implemented, the data is outputted to the recorder 6 and a gate 18 is controlled for the recording. Thus, the stable recording to the recording medium estimating the total code quantity is warranted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image recording apparatus that converts an image signal into digital data, compresses and encodes the data, and records the data.

[Conventional technology]

Conventional image recording devices, such as still video cameras, record analog data on floppy disks,
Digital image data compressed using a fixed length encoding method was recorded on a semiconductor memory card. Fixed length encoding is a method of compressing and encoding so that the amount of compressed codes for one screen becomes a fixed value.

[Problem that the invention is trying to solve]

In such conventional image signal recording systems, the capacity of the recording medium required to record one screen of image data is fixed, so the total number of recording media can be guaranteed.

However, in a digital still video camera that compresses image data using a fixed length encoding method, there are limits to guaranteeing the image quality of the compressed image for various image data. In total, it can only be compressed to about 8 bits/pixel. On the other hand, if the encoding method is variable length, image quality can be guaranteed and compression can be performed efficiently. Variable length encoding is an encoding method that allows the length of the generated code to change depending on the image, and after guaranteeing the image quality empirically, the length of the generated code is, for example, 2 to 4 bits/pixel+ including brightness and color information. A coding rate of is obtained. However, since the total code amount changes depending on the image at this time, stable recording on the recording medium cannot be guaranteed.

The present invention aims to solve this problem.

[Means to solve the problem]

In order to achieve the above-mentioned objects, the present invention provides a generating means for generating information about the storage capacity of a storage means, a holding means for holding in advance data to be stored in the storage means, and a variable length storage means for storing data held in the holding means. It has means for generating a signal indicating the amount of data when encoded, and means for controlling the holding means in accordance with a comparison between the information generated by the generating means and the amount of data.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Note that other parts of the camera that are not directly related to the present invention, such as an aperture and a shutter, are of course provided. In FIG. 1, the optical image of the subject captured by the lens 1 is captured by an imaging device 22 located at the rear, such as a Charge-Co
It is converted into a video electrical signal by an upgraded device (CCD). The imaging device 2 stores charges corresponding to an optical image of a subject and reads out a video signal in response to a control signal given by a control section 7. The read video signal is converted into a digital signal by the A/D converter 3. Note that the imaging device 2 and A/D converter 3
Although not shown, means for adjusting the video signal, such as forming and separating gamma-corrected color signals and performing white balance processing, is provided between the two.

The video signal converted into a digital signal is stored in the image memory 4.

The compression encoding device 5 compresses and encodes the image data read from the image memory 4 and outputs it to the recording device 6. The control unit 7 is configured to control recording and reproduction through the recording device 6 using, for example, MS-DOS commands. As a compression method, for example, "Unpublished Patent Publication 1986-124"
For example, a compression method that generates a variable length code such as that described in "No. 680 Encoding Method" or a variable length code that performs DCT transformation on an image signal and then performs entropy encoding is executed.

It also has a function of counting the amount of compressed codes without outputting the compressed codes to the recording device 6. For such a function, the circuit shown in FIG. 1 includes a counting circuit 16 for counting the amount of code before outputting the compression-encoded data to the recording device 6.

The recording device 6 has, for example, a semiconductor memory or a tape-shaped recording medium, and can exchange information with a control section, and can write and read arbitrary digital data to and from an arbitrary physical address on the recording medium. It also has a function to count the free space on the recording medium.

The control unit 7 controls the functions of the devices 2 to 6 and integrates the overall functions. In particular, image data files on a recording medium can be managed through the recording device.

That is, the control unit 7 is a DO3 (Disk Operating) implemented in the computer system.
It functions to link file information to a physical address on a recording medium, similar to what the System does. Therefore, the control unit 7 stores a file (=image compressed data) on the recording medium.
You can manage how your data is recorded, and therefore you can also manage your free space. If it is necessary to divide the compressed code into multiple small recording units and store them, the control unit specifies the physical address and data length on the medium for each recording unit and records the compressed code in the recording device 6. let

When one image file is placed at a plurality of positions on the recording medium, the control unit 7 also causes information indicating how the image file is placed to be recorded on the recording medium.

The MMIF (man-machine interface) 8 includes an operating member 9 for operating the release (SWI, 5W2) and other switches described below, a display in the Finder, and an external L.
It includes a display device 10 such as a CD display and a buzzer.

The number of shots that can be taken during actual shooting is displayed in the following steps.

This procedure will be explained using the flowchart shown in FIG.

(2) First, at the beginning of the flowchart, the control unit 7 outputs commands DIR and CHKDSK to the recording device 6 to cause the recording device to output the free space (Sl).

When taking a picture, press the shutter button halfway SWI O
N), the control unit drives the lens 1 to focus, operates the diaphragm, shutter, etc., exposes the imaging device (S5), and captures the image information into memory (S7), compresses and encodes it ( Have them perform the work up to S9).

Then, the compression code counting circuit 16 counts the code amount of the image data. On the other hand, the free space is counted by the recording device, and from both values, the number of images that can be taken from now on is calculated (S11). For example, the number of images that can be taken is calculated by dividing the free space by the code amount of image data. The value obtained by the calculation is then notified to the user through the display device 10 provided in the finder (S13). This display continues while the SWI is turned on (S15, 517). Of course, the images that are actually taken and recorded will change from S17 to S19 when the shutter button is pressed even further. S21. The flow branches to S23, and the above-mentioned 85. S7. A step similar to S9 is executed and the data is imported again.

■If continuous shooting mode is not selected, the flow branches from S25 to S3; if it is selected, as continuous shooting progresses, the free space on the recording medium will decrease, and the amount of code for one screen of image data will change. Therefore, after recording the first frame of continuous shooting, each time the recording of one screen is completed, the free space and the amount of image code to be recorded next are counted (S23), and the number of possible shots decreases. are displayed continuously in the finder (S29).

That is, in this embodiment, when SW2 is kept pressed and the continuous recording mode is selected, images are exposed one after another, taken into the memory, encoded, and recorded. At that time, the remaining recordable number is calculated from the code amount of the image recorded immediately before and the free space of the recording medium at that time, and the reduced remaining recordable number is continuously displayed in the finder.

Next, S21 in FIG. A detailed flowchart of step S23 will be explained using FIG. 4.

FIG. 4 shows the operation performed after S23 in FIG. 1, that is, the image data is stored in the memory 4.

In FIG. 4, first, the image signal written in the memory 4 is read out and compressed and encoded by the encoding circuit 5, and the compression encoded data is counted by the counting circuit 16 (S41). and the free space of the recording medium in the recording device 6 (S43), and if there is enough free space, the image signal is read out from the memory 4 again, compressed and encoded, and the data is output to the recording device 6. The gate 18 is controlled to perform recording.

In this case, the control unit 7 instructs the image memory 4 to read the image data, the compression encoding circuit 5 to output the compressed code, the recording device 6 to record the compressed code, and the gate 18 to open the gate. The recording device 6 is configured to record a compression code by specifying a physical address on the medium and a data length for each recording unit. Since the recording device 6 does not request the compression encoding circuit 5 to output data unless there is a recording instruction from the control section 7, the operations of the compression encoding circuit 5 and the image memory 4 are interrupted. Therefore, the control unit 7 specifies the physical address and data length on the medium for each recording unit according to the file format, and instructs the recording device to perform the recording operation, thereby controlling the compression encoding circuit 5 and the image memory 4. You can record while controlling the movements of the

The recording operation is completed when all compressed codes are recorded.

Incidentally, FIG. 2 is a diagram showing a communication procedure between the control section 7 and the recording device 6 described above.

In FIG. 2, D-Reg is a data output request from the recording device 6 to the control unit 7, and D-Ack indicates that the data being output from the compression encoding circuit 5 to the recording device 6 is valid. This signal is output from the control section 7 to the recording device 6.

Data Do-Dl is 8-bit parallel data output from the compression encoding circuit 5 to the recording device 6.

In FIG. 2, the control unit 7 and the recording bag M6 are mutually D-
This shows a state in which data is output byte by byte while exchanging ReqSD-Ack.

In FIG. 2, the side that receives and receives data, that is, the recording device 6 (
Below, Receiver) sets the signal - Req to High.
By setting the signal to Low, the data output side, that is, the encoding circuit 5 (hereinafter referred to as a transmitter) is requested to output data. Transmi t t
When e r detects that DReq becomes Low, it outputs data on the data bus (Do to D?), and changes D-Ack from High to Low when the value is determined.

The Receiver takes over the signal on the data bus when D-Ack goes Low, and sets D-Req High.
Return to h. The trans-mitter stops outputting onto the data bus when D-Req becomes high, and returns DAck to high.

By the above Req-Ack handshake, Tra
Data transfer is performed according to the convenience of both the nsmitter and the receiver.

Therefore, the compression encoding circuit 5 does not need to generate compression codes at a fixed transfer rate (and the fact that the code length changes depending on the content of the image does not cause any problems).

Further, when the flow branches to 847 in S43, the control unit notifies the finder display warning device 10 of the man-machine interface 8 that recording is not possible due to insufficient free space on the recording medium. Display it,
Prompt the user to select one of the following three processes.

That is, (1) stop the recording operation, (2) replace the recording medium, and (3) erase one of the image files on the currently installed recording medium.

For this reason, the control unit 7 performs S49. S51. Execute step S53.

If (1) is selected by the user, all operations are stopped from S49.

If (2) is selected by the user, that is, if the recording device 6 detects the replacement of the medium and reports it to the control unit 7, the process returns to S43.

When (3) is selected by the user, the control unit 7 displays how many images are present on the display device 10 555
), prompting the user to enter which image to delete. When the user inputs the number of the image to be deleted using the operation switch (S57), the control unit 7 deletes the image file (559), and returns to S43.

In order to detect that the medium has been replaced, a method may be used in which the recording section mechanically detects whether or not the medium has been replaced, as disclosed in Japanese Patent Application Laid-Open No. 182669/1983. The control unit 7 can access information on the presence/absence of such information via the recording device 6.

According to the control shown in the flowchart of FIG. 4 explained above, even if a compression method that generates variable length codes is used, image recording is guaranteed for the user in some way, so a system that is easy to use and can guarantee image quality is created. Can be provided.

Next, using FIG. 5, a method of displaying the number of shots that can be taken, which is executed in Sll and S13 in FIG. 3, will be explained.

The control unit 7 outputs, for example, the above-mentioned command for detecting free space, causes the recording device 6 to count the free space of the recording medium (S61), and performs compression using the variable length encoding method stored in advance. Calculate how many more pieces of image data can be recorded on the recording medium from the representative value of the rate and the free space (S
63).

For example, the encoding method is
680 encoding method, the code length is on average 2 bits/pixel, at worst about 4.5 bits/pixel, so in S65 the average code length is 2 bits/pixel.
The number of shootable images calculated by /pixel is set as the standard remaining number of images, and the number of shootable images calculated by 4.5 bits/pixel is set as the minimum guaranteed number of images, and both are displayed on the display device 8.

Of course, such display may be performed by performing only one display. The display device 8 is, for example, Liquid Crystal.
Display (LCD) and Light-Emitt
It is preferable to use an LED (LED) or the like, which can be displayed on the top of the camera, in the viewfinder, or both.

The present embodiment described above has means for counting the free space of the recording medium, and by storing the representative value of the compressed code amount in variable length encoding, the counted free space and the representative value of the code amount can be calculated from the counted free space and the representative value of the code amount. By having a function that can calculate the number of shots that can be taken by a recording medium, and by having a means to display information on the number of shots that can be taken by the calculation, it is possible to determine whether the number of shots that can be taken by a recording medium is the standard value or the minimum guaranteed value. A variable length encoded digital image recording device is shown that can display either or both.

Furthermore, according to the embodiment described above, after the free space of the recording medium is detected at 81 in FIG. 3, the details are shown in the fifth row. Since the free space of the recording medium is detected again in steps Sll and S13, the free space of the recording medium can be checked not only when SW1 is turned on, but also even during continuous recording.

Furthermore, according to this embodiment, even if the variable length encoding compression method is used, it is possible to guarantee and notify the user of the amount of recorded images, that is, the number of remaining images that can be taken on the recording medium.
It is easy to use and can guarantee image quality.

In the embodiment described above, a so-called still video device that records still images on a medium has been described as an example, but the present invention is not limited to such a device, but can also be applied to, for example, a facsimile device or an image electronic file device.

Furthermore, various other methods may be used as the variable length encoding method of the compression encoding method in this embodiment.

For example, entropy encoding may be performed on DCT encoded data.

Further, in this embodiment, the recording device 16 is an MS-DO.
Although the data storage device is driven by the S OS system, the present invention is not limited to this, and other types of media may be used, such as semiconductors or tape-shaped media.

Note that when considering a floppy disk as a recording medium, it is quite possible to realize a capacity of 5 MB with a 2-inch floppy disk using the perpendicular magnetization recording method. In this case, this embodiment can guarantee a standard 55 to at least 22 TV field images to the floppy disk.

Further, in this embodiment, the memory 4 is used as a holding means for holding data to be stored in the storage means in advance. Further, in this embodiment, the means for generating a signal indicating the amount of data when the data held in the holding means is variable-length encoded is photoelectrically converted into a subject image as a target image prior to recording by the recording device 6. The amount of coded data after encoding is calculated by actually variable-length encoding the image signal stored in the memory 4, but the present invention is not limited to this. It is also possible to obtain the amount of coded data without any processing.

For this purpose, for example, it is within the scope of the present invention to predict the amount of data by performing simplified encoding.

The means for controlling the holding means in accordance with the comparison between the information generated by the generating means and the amount of data is the control section 7 that executes the flow shown in FIG. 4.

〔Effect of the invention〕

As explained above, according to the present invention, the holding means for holding the information to be stored in the storage means in advance is controlled according to the comparison between the unrecorded amount of the storage means and the code amount to be recorded, so when necessary. The information can be continued to be held in the holding means.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the device according to the embodiments of the present invention, FIG. 2 is a timing chart showing the operation of the device shown in FIG. 1, and FIG. 3 is a block diagram showing the operation of the device shown in FIG. 1. Flowcharts FIGS. 4 and 5 each show details of a part of the flowchart in FIG. 3. Flowchart 1: Lens 2: CCD 3: A/D converter 4: Image memory 5: Compression encoding circuit 6: Recording device 7: Control unit 8: Display device 9: Operation switch

Claims (2)

[Claims] (1) Generating means for generating information about the storage capacity of the storage means, holding means for holding data to be stored in the storage means in advance, and amount of data when the data held in the holding means is variable-length encoded. A recording device comprising: means for generating a signal indicating the amount of data; and means for controlling the holding means in accordance with a comparison between the information generated by the generating means and the amount of data. (2) The recording apparatus according to claim 1, wherein the control means causes the holding means to continue holding the data to be stored when the amount of data is larger than the storable capacity.