JP3096683B2 - Electronic camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera having a moving image recording mode which is driven by a battery and records image information for a plurality of screens continuously obtained by imaging on a recording medium such as a memory card.

[0002]

2. Description of the Related Art Conventionally, in a digital electronic still camera, an image is captured by an image sensor such as a CCD imager, and still image information obtained by performing predetermined signal processing is compressed and recorded as digital data. Various types of batteries, such as batteries, are used as a power source. The remaining battery level is constantly monitored based on the output voltage of this battery, and the user is notified of the remaining battery status. In particular, if the battery level is significantly reduced and the battery voltage falls below a preset lower limit, signal processing and recording operation cannot be guaranteed, and the still image information obtained by shooting is recorded on a recording medium. A configuration has been adopted in which storage is prohibited or shooting is disabled by forcibly turning off the power of the camera body.

On the other hand, recent electronic cameras do not record only still images, but use motion JPEG or MPEG.
In accordance with the standards such as, a series of a plurality of imaging screens obtained continuously are recorded for a predetermined time as moving image information on a recording medium, and during reproduction, these moving image information are sequentially reproduced for a predetermined time. A type of camera that can reproduce minute moving images has also been developed.

In a normal moving image recording mode of such a camera supporting moving images, a maximum recordable time is defined in advance so that a series of processes can be guaranteed. For example, 1998
In the digital camera (DSC-X100) introduced in the Dempa Shimbun on September 10, 1998, 60 seconds is set as the maximum recordable time for one moving image recording, and 15 frames of image data are captured per second. Then 15
Frames / second × 60 seconds = 900 frames of image data and 60 seconds of audio data can be recorded on a recording medium as a moving image file, and continuous moving image recording longer than 60 seconds is impossible. .

Therefore, when the user selects the moving image recording mode, it is indispensable to guarantee moving image recording for the predetermined maximum recording time. That is, if the user is 6
Despite recording a movie for 0 seconds, the remaining power of the battery falls below the lower limit in the middle of this movie recording, the camera power is forcibly shut off, and movie recording for 60 seconds is interrupted. Therefore, it is necessary to avoid a situation where desired moving image recording cannot be completed.

Therefore, conventionally, immediately before moving to the moving image recording mode and starting moving image recording, the remaining battery level is detected, and the power consumption required for moving image recording for the maximum recordable time of 60 seconds is stored in the battery. If it is left, the start of moving image recording is permitted, and if it is not left, the start of moving image recording is forcibly blocked even if the release button is operated, so that during the recording operation of moving image recording for a preset predetermined time, To prevent interruption of recording due to battery exhaustion.

[0007]

As described above, the remaining amount of the remaining battery is detected before the start of moving image recording, and according to the remaining amount, whether or not to start moving image recording immediately thereafter is selected. The following problem arises in the case where the decision is made in an appropriate manner. That is, when the maximum recordable time is short, there is no particular problem. However, with the increase in the capacity of the recording medium, the maximum recording time conventionally defined as 60 seconds is extended to 120 seconds or 180 seconds. In this case, the remaining amount of the battery that guarantees the movie recording with the extended recordable time is required more, and even if the conventional 60-second movie recording has the remaining amount that can be sufficiently guaranteed. For example, it cannot be guaranteed that it will be 180 seconds,
A situation in which video recording is disabled will occur.

[0008]

According to the present invention, an image pickup means for photoelectrically converting incident light, a signal processing means for subjecting an output of the image pickup means to predetermined signal processing and outputting as image information, are obtained continuously. Image recording means for recording image information for a plurality of screens on a recording medium for a screen corresponding to a preset recordable time, a battery serving as a drive power supply source, and a battery remaining amount detecting a remaining battery level It is characterized by comprising detecting means and changing means for changing the recordable time in accordance with the remaining battery power, and further displaying the recordable time on the display means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall block diagram of an electronic camera which is the apparatus of the present embodiment, and FIG. 2 is a flowchart for explaining an operation focusing on a system controller.

Reference numeral 1 denotes a CCD imager which photoelectrically converts incident light incident through a lens (not shown) into an image signal. The image signal output from the CCD imager 1 is a noise signal which is well-known by a CDS / AGC circuit 2. After removal and level adjustment, the image data is converted into digital image pickup data by the A / D converter 3. The subsequent signal processing circuit 4 performs well-known signal processing, such as color separation processing and YUV conversion, on the imaging data to create image data composed of luminance data and two types of color difference data, This image data is transferred to the SDRAM 5 by the control circuit 22.
Is temporarily stored in the image data storage area 5a.

The NTSC encoder 6 encodes image data read from the image data storage area 5a of the SDRAM 5 via the bus 7 into an NTSC format to produce a video signal. The image data is supplied to the monitor 9 at the subsequent stage mounted on the main body, and the image data is displayed on the monitor 9.

When specific character data is input from a character generator 10 to be described later, the mixer 8 superimposes the character data on a video signal input from the encoder 6 and mixes the data. When no character data is input, the video signal is output to the monitor 9 as it is.

The image compression / expansion circuit 11 receives the image data stored in the image data storage area 5a via the bus 7 when receiving a compression command from the system controller (sys-con) 12 at the time of image recording, and executes JPEG. Image compression is performed in accordance with the format, and the obtained compressed image data is once again stored in the compressed data storage area 5b of the SDRAM 5 via the bus 7, and thereafter, as will be described later, together with audio data, a memory as a recording medium Card 14
Will be recorded.

The image data storage area 5a and the compressed data storage area 5b are set in completely different areas in the SDRAM 5, and the system controller 12 is constituted by a microcomputer.

The mode changeover switch 15 is a switch by which a user can manually select any one of a still image recording mode and a moving image recording mode. The selected mode is a system control signal as a mode selection signal. 12
Is input to

Reference numeral 17 denotes a battery composed of a plurality of batteries, which outputs a voltage of 3 V in a fully charged state. This battery output is supplied to an analog power supply circuit 19, a digital power supply circuit 20, and an output voltage detection circuit at the subsequent stage. 18.

The analog power supply circuit 19 supplies the necessary drive power to the drive circuit for the CCD imager 1 and the analog processing section such as the CDS / AGC circuit 2 which performs signal processing in the analog stage. Is composed of a DC / DC converter that changes a 3V battery voltage to a plurality of DC voltage levels required for the analog processing unit.

The digital power supply circuit 20 is necessary for a digital processing unit which receives a battery output and performs signal processing at a stage after digitally converting an image pickup signal of the signal processing circuit 4, the image compression / expansion circuit 11, and the like. And a DC / DC converter for changing the battery voltage to a plurality of DC voltage levels required for each unit constituting the processing unit, similarly to the analog power supply circuit 19.

The output voltage detecting circuit 18 detects the output voltage value of the battery 17 and notifies the system controller 12 of the detected battery voltage value.

The system controller 12 has a mode changeover switch 15
In response to a mode selection signal input from the camera, each part of the camera is set to a desired mode, and recording control in each mode is executed in response to an instruction from the release button 16. Further, the level of the battery voltage value from the output voltage detection circuit 18 is compared with a plurality of preset threshold values, and various controls in the moving image recording mode are executed based on the comparison result.

The audio signal processing circuit 25 performs predetermined processing on the audio signal input through the microphone 26, and converts the processed audio signal into digital audio data.
Is output to the memory control circuit 22 together with the write command from the SDRAM 5, and is written in a specific area 5c different from the storage areas 5a and 5b in the SDRAM 5.

Next, the operation of each unit will be described with reference to the flowchart of FIG. First, when a power button (not shown) of the camera is turned on and the camera is operated in a recordable mode in which an image can be recorded instead of a reproduction mode, the battery 17
Then, the drive voltage is applied to the analog power supply circuit 19 and the digital power supply circuit 20, and the respective parts become operable, and the system controller 12 instructs the respective parts to display a through image (step S1).

When the camera is activated, the CCD imager 1 starts imaging, activates the signal processing circuit 4 in response to a command from the system controller 12, and creates the first screen image data in the image data storage area. The data in the image data storage area 5a is updated by the sequentially obtained image data. At the same time, the data in the image data storage area 5a is transmitted to the monitor 9 via the NTSC encoder 6 and the mixer 8. Since the image is displayed, a moving image captured by the CCD imager 1 is displayed on the monitor 9. In this embodiment, the image data output from the CCD imager 1 to the signal processing circuit 4 is:
It is assumed that 15 frames are obtained in one second.

In the state where the live view display is instructed, no character data output command is issued from the system controller 12 to the character generator 10, so that only a moving image is displayed on the monitor 9 and the system controller 12 compresses the image. Since no command is issued and the image compression circuit 11 performs no operation, the moving image is only displayed on the monitor 9 and is not compressed and recorded on the memory card 14.

During the live view display, the system controller 12 determines which of the still picture recording mode and the moving picture recording mode is selected by the mode selection signal from the mode switch 15 (step S2).

If it is determined in step S2 that the still image recording mode has been selected, the release button 16
Is determined (step S3). When the button is pressed, the system controller 12 issues an instruction for a still image recording mode to each unit, and converts image data from the CCD imager 1 into image data. When the image data is stored in the image data storage area 5a of the SDRAM 5 and the storage of the image data for one screen, that is, one frame is completed, an image data storage completion signal is input from the memory control circuit 22 to the system controller 12, and
The system controller 12 instructs the memory control circuit 22 to read out the image data and issues a compression instruction to the image compression / expansion circuit 11 (step S4). Also, the memory control circuit 22
Is the SD of the image data newly obtained from the signal processing circuit 4.
Block input to RAM5.

In response to the compression command, the image compression / decompression circuit 11 performs image compression on the image data stored in the image data storage area 5a, and compresses the compressed image data obtained from the system controller 12 to the memory control circuit 22. Is instructed to be stored in the compressed data storage area 5b. Thus, S of the compressed image data for one frame
When the storage in the DRAM 5 is completed, a compressed data storage completion signal is input from the memory control circuit 22 to the system controller 12, and in response thereto, the system controller 12 fetches the compressed data, adds index information and adds the index information to the memory card 14 as a JPEG file. Is executed (step S5).

When the recording for one frame is completed, the system controller 12 again instructs the display of a through image, the memory control circuit 22 allows the storage of new image data from the signal processing circuit 4, and the image compression / decompression circuit. 11 is in a non-operation state. In the still image recording mode, the updating of the image data in the image data storage area 5a is prevented during the compression and the writing, so that the image data in the image data storage area 5a is displayed on the monitor 9 as a frozen image. .

On the other hand, if the moving image recording mode has been selected in step S2, the process proceeds to step S6. In this step S6, the moving image recordable time Tm that can be continuously recorded is set to a predetermined initial value, for example, 12
Initially, it is automatically initialized to 0 seconds. Then, in step S7, the system controller 12 supplies a display command to the character generator 10 to monitor and display a character corresponding to the initially set recordable time Tm.
0 receives this command and inputs a display character of "120 seconds" to the mixer 8, where it is superimposed on the through image,
As shown in FIG. 3, "120 seconds" and the time Tm are displayed on the upper right portion of the monitor 9.

Next, the system controller 12 detects the remaining amount of the battery by comparing the value of the output voltage Vb of the battery 17 inputted from the output voltage detecting circuit 18 with a plurality of thresholds R1, R2, R3, R4. (Step S8). Here, the threshold value R1 is set to a value that can be taken by the battery voltage when the remaining amount is 50% of the fully charged state. Similarly, the threshold value R2 is set when the remaining amount is 20%, and the threshold value R3 is set when the remaining amount is 10%. , The threshold value R4 is set to a value that can be taken when the remaining amount is 5%, and both are determined in advance based on experimentally measured values.

In the relationship between the battery voltage Vb and each of the threshold values, if Vb ≧ R1, it is determined that the first remaining state is sufficient and there is no problem in recording a moving image, and V1> Vb
In the case of ≧ V2, there is a considerable remaining amount, and it is determined to be the second remaining amount state in which the initially set moving image recording for 120 seconds is possible,
When R2> Vb ≧ R3, the remaining amount is less than 20%, but 10% exists, and it is difficult to record a moving image for 120 seconds, but it is possible to record a moving image for 60 seconds. When R3> Vb ≧ R4, the remaining amount is less than 10%, but there is 5%, and it is difficult to record a moving image for 60 seconds.
It is determined that the moving image recording for 0 seconds is the fourth remaining state in which recording is possible,
In the case of R4> Vb, the remaining amount is less than 5% and almost zero, so that it is determined that the fifth remaining amount state is difficult even for the moving image recording for 30 seconds. In other words, the minimum remaining amount required to realize 120 seconds of moving image recording set in step S6 is 20%, and the minimum remaining amount required to realize 60 seconds of moving image recording is 10%. Each threshold value is determined after experimentation has confirmed that the minimum remaining amount required to realize moving image recording for 30 seconds is 5%.

When the remaining amount detecting operation is completed in this way, in step S9, the moving image recordable time T is calculated based on the remaining battery amount.
m is updated. More specifically, when the remaining amount is determined to be the first or second remaining amount state, the time Tm is maintained at the initial setting of 120 seconds, but in the third remaining amount state. It is updated to Tm = 60 seconds, Tm = 30 seconds in the fourth remaining state, and Tm = 0 seconds in the fifth remaining state.

Next, in step S10, the converted value K in the number of recordable frames corresponding to the time Tm from the time Tm.
Performs conversion to. That is, in the moving image recording mode of this digital camera, 15 frames of image data are recorded per second, so that the conversion formula is calculated by K = 15 × Tm, and when the time Tm = 120 seconds, K = 15. × 120 =
1800 frames, or 18 in a JPEG image file
It means that 00 images can be recorded, and the time T
When m = 60 seconds, K = 15 × 60 = 900 frames, and when Tm = 30 seconds, K = 15 × 30 = 45.
0 frame, time Tm = 0 second, K = 15 × 0 =
That is, it is converted that an image of 0 frame can be recorded.

Next, in step S11, the system controller 1
2 inputs a display command for displaying a character corresponding to the moving image recordable time Tm updated in step S9 on the monitor 9 to the character generator 10 and superimposes the corresponding character on the through image by the mixer 8; It is displayed on the upper right part of the monitor 9. For example, when the time Tm is from 120 seconds to 6
When it is updated to 0 seconds, the display state of FIG. 3 is changed to the display state of FIG. The display of the updated time Tm is set in advance so that the output of the character from the character generator 10 is stopped three seconds after the display command is issued in step S11. Is displayed only for 3 seconds.

Next, at step S12, it is determined whether or not the time Tm is 0 second, that is, if the battery is in the fifth remaining state where the remaining battery level is so small that the recording of a moving image of the minimum recording unit of 30 seconds cannot be guaranteed. Moves to step S13 and forcibly turns off the power of the camera assuming that movie recording is impossible.
F, specifically, the analog and digital power supply circuits 19 and 20 are deactivated.

On the other hand, the time Tm is not 0 second, ie, 1
If it is any of 20 seconds, 60 seconds, and 30 seconds, the process proceeds to step S14, where the recording frame counter FR that counts the number of frames recorded on the memory card 14
Is cleared, and in step S15, the system controller 12 determines whether or not the release button 16 has been operated. If the release button 16 has not been operated, the process returns to step S8 to repeat a series of processes. If the release button 16 has been operated, Then, the process shifts to step S16 to clear the compression frame counter FP for counting the number of frames of the compressed data stored in the compressed data storage area 5b, and then shifts to step S17 to create from the imaging signal output from the CCD imager 1. And processed by the signal processing circuit 4, and further processed by the SDRAM
The system controller 12 instructs the memory control circuit 22 to read the image data so as to execute image compression for one frame, that is, one screen of image data stored in the image data storage area 5a of FIG. The image compression / decompression circuit 11 issues an image compression command to the image compression / decompression circuit 11, and the image compression / decompression circuit 11 converts the image data sequentially supplied from the SDRAM 5 into compressed image data and stores it in the compressed data storage area 5b of the SDRAM 5.

When the image compression for one frame is completed, the counter FP is incremented by "1" in step S18, and the count value of the counter FP can be set to one second in the moving image recording mode of the camera in step S19. Compare with “15” which is the number of frames. In other words, it is determined whether or not the compressed data stored in the compressed data storage area 5b has reached one second.

If the count value of the counter 5b does not reach "15", that is, if it is determined that the storage of the compressed data for 15 frames in the compressed data area 5b is not completed, the process returns to step S17.

Here, in the image data storage area 5a,
When the output of the stored image data to the image compression circuit 11 is completed, the storage of the image data of the new frame output from the signal processing circuit 4 is restarted. While the release button 16 is kept ON, every time a compression command is issued from the system controller 12 in step S17,
Similar compression processing is performed on image data of a new frame stored in the memory area 5a, and compressed image data is sequentially accumulated in the storage area 5b.

If the count value of the counter FP has reached "15" in step S19 and it is determined that 15 frames of compressed data have been stored in the compressed data storage area 5b, the process proceeds to step S20.

Although omitted in the flowchart of FIG. 2, the audio signal processing circuit 25 performs a predetermined process on the audio signal input through the microphone 26, and then performs a built-in SR
A predetermined amount of audio data is stored in the AM, a write command is periodically issued from the system controller 12 to the memory control circuit 22, and the audio signal temporarily stored in the SRAM is sent to the memory control circuit 22 via the bus 7. The memory control circuit 22 stores the transmitted audio data in the audio data storage area 5c of the SDRAM 5.

Therefore, at the time when the compressed image data for one second is stored in the compressed data storage area 5b, the audio data for one second collected by the microphone 26 is stored in the audio data storage area 5c. Will be.

In step S20, the system controller 12 instructs the memory control circuit 22 to output audio data and compressed image data to the system controller 12, and records the sequentially input audio data and compressed image data on the memory card 14. Let it.

Here, the system controller 12 responds to the operation of the first release button 16 and stores the MO on the memory card 14.
A header portion of a well-known AVI (Audio Video Interleave) file, which is a moving image file conforming to the TION JPEG standard, is newly created.
The audio data and the compressed image data supplied from are written in the header portion and thereafter. As a result, as shown in FIG.
Image chunks composed of compressed image data for frames are alternately formed.

When the recording of the voice and compressed image data for one second on the memory card is completed, step S21 is performed.
In step S22, the number of frames newly stored, that is, "15" is added to the count value of the recording frame counter FR, and the number of recorded frames is constantly monitored. In step S22, the count value of the counter FR and the recordable time Is compared with the converted value K for the number of frames.

If the count value has not reached the converted value K, it is determined that the recording time recorded on the memory card 14 by the moving image recording has not reached the maximum possible time, and step S
At 23, it is determined whether or not the release button 16 has been kept ON, and if the ON state has been continued, the process returns to step S16, where a series of moving image recording has been continued, and the ON state has been continued. If not, the process returns to step S8 to end a series of moving image recording. If it is determined in step S22 that the count value of the counter FR has reached the converted value K, it is determined that it is difficult to guarantee the operation of moving image recording after that with the current remaining battery level, and the process proceeds to step S8. Return and end a series of moving image recording.

Since it is necessary to form an index chunk at the last position of the AVI file in FIG.
When a series of moving image recording is completed by moving from step S19 and S20 to step S8, the system controller 12 causes the memory card 14 to record the index chunk following the chunk of the last recorded compressed image data.

As described above, the AVI file recorded on the memory card 14 is transferred as data by attaching the memory card to a computer, and is reproduced as a moving image with sound by a known application such as “QuickTime 3.0”. It is possible to do.

Also, if the camera body is set to the playback mode,
Movie playback is also possible on the camera side. That is, in the reproduction mode, the compressed image data is sequentially read from the AVI file, stored in the storage area 5b of the SDRAM 5, the image is expanded by the image compression / expansion circuit 11 in the reverse of the recording, and the expanded image data is stored. If the data is expanded on the storage area 5a of the SDRAM 5 and displayed on the monitor 9 via the NTSC encoder 6 and the mixer 8, a moving image can be reproduced. Further, a speaker is provided in the camera, and voice data is also read from the memory card 14 to the area 5c of the SDRAM 5, and
If a process opposite to the process in the audio signal processing circuit 25 is performed and output to the speaker, the reproduced sound can be heard.

In the above embodiment, the image data created from the imaging data obtained from the CCD imager is described as being 15 frames per second, but the invention is not limited to this. For example, the frame rate may be 30 frames / sec. In this case, the formula for calculating the conversion value K from the recording time to the number of frames also needs to be changed to K = 30 × Tm.

Although the unit of recording the compressed image data on the memory card is one second, the present invention is not limited to this, and the recording may be performed every several frames. Furthermore,
The recording of the audio data is additional and may handle only the image data. The recording file format on the memory card 14 is not limited to the AVI file. Na M
It may be a PEG file. Similarly, the memory card 14 is only an example of a recording medium, and a magneto-optical disk or hard disk can record a moving image for a longer time.

In the block diagram of FIG. 1, data transfer via the bus 7 is normally executed by DMA.

The projection of the image data on the monitor 9 is as follows.
Although the description has been made so as to be always executed at the same time when the power of the camera is turned on, it goes without saying that a monitor ON / OFF switch may be provided and executed by the user's selection.

[0054]

As described above, according to the present invention, an optimum one is automatically selected from a plurality of maximum recording times prepared in advance for recording a moving image in accordance with the remaining amount of the battery. Even if the maximum recording time is lengthened and the battery has a considerable remaining amount, it is possible to avoid the inconvenience of being unable to record a moving image, and to realize both the moving image recording and the efficient use of the battery.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electronic camera according to an embodiment of the present invention.

FIG. 2 is a flowchart of one embodiment of the present invention.

FIG. 3 is a diagram illustrating a monitor display state maintained in step S7 according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a monitor display state according to an instruction in step S11 according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a structure of an AVI file according to an embodiment of the present invention.

Claims (2)

(57) [Claims] 1. An image pickup means for photoelectrically converting incident light, a signal processing means for subjecting an output of the image pickup means to predetermined signal processing and outputting it as image information, and a plurality of types of time which have different lengths and are prepared in advance. Recording time selecting means for selecting one of the following as a recordable time of a series of image information of a plurality of screens continuously obtained from the signal processing means; and recordable time selected by the recording time selecting means. Image recording means for recording image information as moving image information on a recording medium for a screen corresponding to time, a battery serving as a drive power supply source, battery remaining amount detecting means for detecting the remaining amount of the battery, and the battery Determining means for determining whether or not recording of the moving image information in the recordable time selected by the recording time selecting means can be completed with the remaining amount detected by the remaining amount detecting means; When it is determined that the recording of the moving image information cannot be completed in the recordable time selected by the recording time selecting means by the step, the recordable time is set to a length capable of completing the recording in the plurality of types of time. An electronic camera provided with a change unit that automatically changes at a certain time. 2. The electronic camera according to claim 1, further comprising display means for displaying the recordable time.