JP2001309222A - Portable imaging apparatus and its operation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system which can store preview image data to display its preview image, even if power supply is cut off when the preview image is displayed. SOLUTION: In a preview imaging mode, as the preview image data is stored in a buffer memory 6 and its preview image data are transferred to an image liquid crystal display 17, the preview image is displayed. When the power is cut off by the power switch 22, the preview image data, which is stored in the buffer memory 6 temporarily, are transferred and stored in the memory card 30. Thus, the erase of the preview image data can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image pickup means for picking up an image of a subject and outputting image data representing the image of the subject, a buffer memory for temporarily storing image data output from the image pickup means as preview image data, and a buffer memory. A display device for displaying a preview image represented by the preview image data temporarily stored in the main memory, and a preview image data temporarily stored in the buffer memory when a recording instruction is given. The present invention relates to a portable imaging device for recording on a recording medium as a recording medium and an operation control method thereof.

[0002]

2. Description of the Related Art A portable imaging device such as a digital still camera captures a subject and records image data representing the subject image on a recording medium such as a memory card. Some digital still cameras can display a preview image.

[0003] A digital
The still camera includes a volatile buffer memory, and image data obtained by imaging is temporarily stored in the buffer memory as preview image data. The preview image data stored in the buffer memory is read out and provided to the display device, so that a preview display is performed. The user checks the preview-displayed image, and if necessary, records the preview image data on the recording medium. If the preview-displayed image is unnecessary, the preview image data is not recorded on the recording medium.

In a digital still camera that can be previewed, when the power of the camera is shut down due to a power drop, or when the power of the camera is turned off, the data is temporarily stored in a buffer memory. The preview image data that has been erased disappears. Even if a good image is obtained, the same image cannot be obtained again.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to save preview image data temporarily stored in a buffer memory even when a power supply is reduced.

According to the present invention, an image pickup means for picking up an image of a subject and outputting image data representing the image of the subject, a buffer memory for temporarily storing image data output from the image pickup means as preview image data, A display device for displaying a preview image represented by the preview image data temporarily stored in the memory; and a display device for displaying the preview image data temporarily stored in the buffer memory when a recording instruction is given. A power supply circuit for supplying a power supply voltage to each circuit in a portable imaging apparatus for recording on a recording medium as image data, and a first detection means for detecting that an output voltage of the power supply circuit has become equal to or lower than a predetermined threshold value And when the output voltage of the power supply circuit falls below a predetermined threshold value by the first detection means. , Characterized in that it comprises a recording control means for controlling the preview image data that is temporarily stored in the buffer memory to record on the recording medium.

The present invention also provides a method suitable for the above device. That is, the method includes an imaging unit that captures an image of a subject and outputs image data representing the subject image; a buffer memory that temporarily stores image data output from the imaging unit as preview image data; A display device for displaying a preview image represented by the preview image data temporarily stored in the buffer memory, and a preview image data temporarily stored in the buffer memory upon receiving a recording instruction. In a portable imaging apparatus that records data on a recording medium as data, it is detected whether an output voltage of a power supply circuit that supplies a power supply voltage to each circuit is equal to or less than a predetermined threshold value, and the output voltage of the power supply circuit is determined to be a predetermined value. The preview image temporarily stored in the buffer memory in response to the value being equal to or less than the threshold value. The data is intended to be recorded on the recording medium.

According to the present invention, it is detected whether or not the output voltage of the power supply circuit has fallen below the predetermined threshold voltage. When the voltage falls below a predetermined threshold voltage, the buffer
Preview image data temporarily stored in the memory is recorded on the recording medium.

[0009] Even when the output voltage of the power supply circuit becomes equal to or lower than a predetermined threshold value, the preview image data stored in the buffer memory is recorded and stored in the recording medium.

When a power switch for giving a power-off command is provided, the output voltage of the power circuit falls below a predetermined threshold voltage in response to the power-off command being given from the power switch. Will be detected. Even when the power is turned off by mistake, the preview image data can be recorded on the recording medium and saved.

Second detecting means for detecting that the output voltage of the power supply circuit has become larger than the predetermined threshold voltage (the second detecting means may be for detecting that a power switch which has been off has been turned on). It is also possible to detect that the power supply voltage such as a battery has been replaced and the power supply voltage has become equal to or higher than a predetermined threshold voltage.), And that the output voltage of the power supply circuit is changed to the predetermined voltage by the second detection means. A preview image data control means for providing the preview image data recorded on the recording medium to the buffer memory in response to the detection that the threshold voltage has become larger than the threshold voltage.

By providing the preview image data stored in the buffer memory to the display device, the preview image can be displayed on the display screen of the display device.

The preview image data recorded on the recording medium may be erased by giving an erase command. Unnecessary preview image data can be deleted from the recording medium, and the recording capacity of the recording medium having an upper limit can be effectively used.

[0014] The image processing apparatus may further include compression means for compressing the preview image data temporarily stored in the buffer memory. In this case, the recording control means will record the preview image data compressed by the compression means on the recording medium.

The preview image data can be recorded on the recording medium even if the free space of the recording medium is small.

When reading the compressed preview image data from the recording medium and displaying the preview image on the display device, it goes without saying that a circuit for expanding the data is provided in the portable imaging device.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention and is a block diagram showing an electric configuration of a digital still camera.

The digital still camera has a preview imaging mode. In the preview imaging mode, image data obtained by imaging a subject is temporarily stored in the buffer memory 6 as preview image data, and a subject image represented by the preview image data is displayed as a preview image on a display screen of a display device. Is displayed on the screen. In the digital still camera according to this embodiment, when the preview recording switch 21 is turned on, the preview image data temporarily stored in the buffer memory 6 is used as the main image data in the memory card 30. Will be recorded.

In the digital still camera according to the present embodiment, when the power switch 22 is turned off while the preview imaging mode is set, the preview temporarily stored in the buffer memory 6 is set. Image data is provided to the memory card 30 and recorded.
The loss of the preview image data can be prevented beforehand. More details will be apparent from the description below.

The overall operation of the digital still camera is controlled by the main CPU 14.

In the preview imaging mode described above,
A preview rec switch 21 for giving a command to record preview image data on the memory card 30, a power switch 22 for giving a digital still camera power ON / OFF command, an operation switch 23 for giving various operation commands,
A mode dial 24 and a shutter release switch 26 for setting various modes such as a preview imaging mode, a normal imaging mode, and a reproduction mode are provided. Various setting signals output from these switches and the like are input to the main CPU 14.

When the digital still camera according to this embodiment is turned off by the power switch 22, first,
The main CPU 14 is turned off, and then all other circuits are turned off.

The main CPU 14 controls an operation liquid crystal display device 20 for displaying the contents of an operation instructed by the operation switch 23. An EEPROM 25 for storing various data is connected to the main CPU.

The digital still camera includes a power supply circuit 18 for supplying a power supply voltage to each circuit. Further, a voltage detection circuit 19 for detecting whether or not the output voltage of the power supply circuit 18 has become equal to or lower than a predetermined threshold voltage is included. The signal detected by the voltage detection circuit 19 is input to the main CPU 14.

The digital still camera has a charging /
Strobe light emitting device 11 controlled by light emission control circuit 10
It is included. The charge / emission control circuit 10 is controlled by the photometry / distance measurement CPU 7.

A photometry / distance measurement CPU 7 and a main CPU
14 can communicate with each other.

CCD 3, white balance / gamma processing circuit 4
The analog / digital conversion circuit 5 is supplied with various timing clock pulses from the clock generator 8.

The lens position of the focusing lens 1 is adjusted by the photometry / distance measurement CPU 7 and the aperture of the aperture 2 is adjusted. The light image representing the subject image is formed on the light receiving surface of the CCD 3. The video signal output from the CCD 3 is subjected to white balance adjustment and gamma correction in a white balance / gamma processing circuit 4. The video signal output from the white balance / gamma processing circuit 4 is analog /
The digital conversion circuit 5 converts the image data into RGB digital image data. The digital image data is temporarily stored in a buffer memory (volatile memory) 6.

When the preview imaging mode is set, digital image data is read from the buffer memory 6 in response to the depression of the shutter release switch 26. The YC processing circuit 9 converts the RGB image data into YC image data (luminance data and color data). The converted YC image data is provided to the buffer memory 6 and is temporarily stored.

The YC image data is read from the buffer memory 6 and applied to the YC / RGB conversion circuit 15.
The YC / RGB conversion circuit 15 converts the image data into RGB image data. By providing the RGB image data to the image display liquid crystal display device 17 via the driver 16, a preview of the subject image obtained by imaging is displayed on the display screen of the display device 17.

When the preview recording switch 21 is pressed in the preview imaging mode, the preview image data temporarily stored in the buffer memory 6 is read out, and the data is compressed in the compression / decompression circuit 12. The compressed preview image data is recorded on the memory card 30 as main image data via the interface 13.

When the normal image pickup mode is set by the mode dial 24, the image data stored in the buffer memory 6 is read in response to the depression of the shutter release switch 26. The image data is provided to a removable memory card 30 via a compression / decompression circuit 12 and an interface 13 and recorded.

When the reproduction mode is set, the compressed image data recorded on the memory card is read out and given to the compression / decompression circuit 12 via the interface 13. The compressed image data is decompressed and supplied to an image display liquid crystal display device 17 via a buffer memory 6, a YC / RGB conversion circuit 15 and a driver 16. An image represented by the compressed image data recorded on the memory card 30 is displayed on the display screen of the image display liquid crystal display device 17.

FIG. 2 shows the file structure (data structure) of the memory card 30.

The memory card 30 includes a header recording area and an image data recording area.

The header recording area stores header information for managing the memory card 30. The header recording area also stores a preview image data storage completion flag described later. Furthermore, in the header recording area,
The paths of the main image data and the preview image data recorded in the image data recording area are also stored.

Image data is recorded in the image data recording area. The image data includes main image data, which is image data for storage, and preview image data. The preview image data temporarily stored in the buffer memory 6 is stored in the memory when the preview imaging mode is set as described later and the power switch 22 of the digital still camera is turned off. Recorded on the card 30. When the preview recording mode is set and the preview recording switch 21 is turned on, the preview image data temporarily stored in the buffer memory 6 is recorded on the memory card 30 as the main image data. Is done. When the imaging mode is set, image data obtained by imaging is recorded on the memory card 30 as main image data.

FIGS. 3 and 4 are flowcharts showing the processing procedure of the digital still camera when the preview imaging mode is set.

In the digital still camera according to this embodiment, when an off command is given from the power switch 22 as described above, the main CPU 14 is first turned off. After a certain period of time, the other circuits are turned off.

When an off command is not given to the digital still camera by the power switch 22, the main CPU
It is checked whether 14 is on (step
41).

If the main CPU 14 is on (step
If YES at 41), if any of the circuits constituting the digital still camera is off, the off circuit is turned on (step 42). continue,
The memory loaded in the digital still camera
It is determined whether a preview image data save flag is set in the header recording area of the card 30 (step 43).

If the preview image data storage flag is set (YES in step 43), the preview image data obtained in the preview imaging mode is recorded in the image data recording area of the memory card 30. Is shown. Conversely, if the preview image data storage flag is not set (NO in step 43),
No preview image data is recorded on the card 30.

It is assumed that the preview image data storage flag is not set in the memory card 30 and no preview image data is recorded (YE in step 43).
S).

In the preview imaging mode, it is determined whether or not the shutter release switch 26 has been turned on (step 44). Shutter release switch 26
Is turned on (NO in step 44), preview imaging is performed and an object is imaged (step 45). As described above, the digital image data representing the subject image is provided to the buffer memory 6 and is temporarily stored. The image data temporarily stored in the buffer memory 6 is read out, and the YC / RGB conversion circuit 15 and the driver 16 are read.
Is supplied to the image liquid crystal display device 17 via the interface (transfer of preview image data) to display a preview image representing the subject image (step 46).

In the preview imaging mode, when the shutter release switch 21 is not turned on (NO in step 44) but the preview recording switch 21 is turned on (YES in step 47), the shutter release switch 21 is obtained by preview imaging. It is determined whether the preview image data is being transferred from the buffer memory 6 to the image liquid crystal display device 17 as described above (step 48).

The preview image data is an image liquid crystal display device.
If the image is being transferred to 17 (YES in step 48), it indicates that the preview image is being displayed on the display screen of the image liquid crystal display device 17. By turning on the preview recording switch 21, the user has given the digital still camera a command to record the preview image data representing the preview image being displayed on the memory card as the main image data. The preview image data temporarily stored in the buffer memory 6 is given to the memory card 30 and is used as the main image data.
(Step 49).

The power switch 22 is turned off and the main CP
When U14 is turned off (NO in step 41), the memory card 30 loaded in the digital still camera is turned off.
It is confirmed whether or not the preview image data storage flag is set (step 50).

If the preview image data storage flag is set (YES in step 50), the memory card
Since the preview image data is recorded in 30, the preview image data is further stored on a memory card.
The process of recording in 30 is not performed. Needless to say, even when the preview image data storage flag is set and the preview image data is recorded on the memory card 30, the preview image data may be further recorded. .

If the preview image data storage flag is not set (NO in step 50), the digital
The preview image data is not recorded on the memory card 30 loaded in the still camera.
Then, it is determined whether the preview image data is being transferred from the buffer memory 6 to the image liquid crystal display device 17 (step 51). If the preview image data is being transferred (YES in step 51), the preview image is being displayed on the display screen of the image liquid crystal display device 17. When all circuits constituting the digital still camera are turned off, the preview image data temporarily stored in the buffer memory 6 is lost. In order to prevent the loss of the preview image data, the preview image data temporarily stored in the buffer memory 6 is given to the memory card 30 and recorded (step 5).
2).

The preview image data is stored in the memory card 30
Is recorded in the header recording area of the memory card 30 (step 53). It can be seen that the preview image data is recorded in the image data recording area of the memory card 30. Thereafter, all the circuits constituting the digital still camera are turned off (step 54).

When the power of the main CPU 14 is turned on (step 41) and the preview image data saving flag is set in the memory card 30 loaded in the digital still camera (YE in step 43).
S) As described above, it is understood that the preview image data is recorded on the memory card 30. The preview image data recorded on the memory card 30 is read, and the interface 13 and the compression / decompression circuit 12 are read.
And is stored in the buffer memory 6 via the memory (step 55).

The preview image data is read from the buffer memory 6 and applied to the image liquid crystal display device 17 via the YC / RGB conversion circuit 15 and the driver 16. The preview image represented by the preview image data recorded on the memory card 30 is displayed on the image liquid crystal display device 17.
(Step 56).

Since the preview image data is stored in the buffer memory 6 of the digital still camera,
The preview image data storage flag recorded on the memory card 30 is cleared (step 57). further,
The preview image data is deleted from the memory card 30 (step 58).

When it is desired to record the preview image data representing the preview image displayed on the image liquid crystal display device 17 on the memory card 30 as the main image data, the preview recording switch 21 is turned on as described above (step). YES at 47). The preview image data temporarily stored in the buffer memory 6 is recorded on the memory card 30 as the main image data (steps 48 and 49).

In the above-described embodiment, the power switch
When the CPU 22 is turned off and the main CPU 14 is turned off, the preview image data stored in the buffer memory 6 is recorded on the memory card 30. When the preview image data is being captured, May be recorded on the memory card 30. In this case, for example, a process of recording the preview image data on the memory card 30 after the process of step 46 will be performed.

In the above-described embodiment, the preview image data is recorded on the memory card in response to the power switch 22 being turned off. However, the output voltage of the power circuit 18 is lower than the threshold voltage. The preview image data may be recorded on the memory card 30 in response to the decrease. In this case, a process for determining whether or not the output voltage of the power supply circuit 18 has become equal to or lower than the threshold voltage will be performed instead of the process for determining whether or not the main CPU is turned on in step 41. . It goes without saying that the voltage detection circuit 19 checks whether the output voltage of the power supply circuit 18 has become equal to or lower than the threshold voltage.

Further, in the above-described embodiment, the image data storage flag is set in the memory card 30, but it may be set in the EEPROM 25. In that case, it is necessary to remember the memory card on which the preview image data is recorded in correspondence with the digital still camera.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a digital still camera.

FIG. 2 shows a file configuration of a memory card.

FIG. 3 is a flowchart showing a processing procedure of the digital still camera.

FIG. 4 is a flowchart showing a processing procedure of the digital still camera.

[Explanation of symbols]

 3 CCD 6 Buffer memory 12 Compression / expansion circuit 14 Main CPU 17 Image liquid crystal display 18 Power supply circuit 19 Voltage detection circuit 21 Preview rec switch 22 Power switch 24 Mode dial 26 EEPROM

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Claims (6)

[Claims] An image pickup means for picking up an image of a subject and outputting image data representing the image of the subject, a buffer memory for temporarily storing image data output from the image pickup means as preview image data, A display device for displaying a preview image represented by the temporarily stored preview image data, and a preview image data temporarily stored in the buffer memory when a recording instruction is given to the main image data A portable imaging device that records on a recording medium as a power supply circuit that supplies a power supply voltage to each circuit; When the output voltage of the power supply circuit falls below a predetermined threshold value by the first detection means, The portable image pickup apparatus provided with a preview image data in the file memory is temporarily stored recording control means for controlling so as to record on the recording medium. 2. A second detection means for detecting that an output voltage of the power supply circuit has become larger than the predetermined threshold voltage, and an output voltage of the power supply circuit is determined by the second detection means. 2. A preview image data control means for providing preview image data recorded on the recording medium to the buffer memory in response to detection that the voltage has become larger than a predetermined threshold voltage. Portable imaging device. 3. The portable imaging apparatus according to claim 1, further comprising an erasure control unit for erasing preview image data recorded on said recording medium when an erasure command is given. 4. A power supply switch for giving a power-off command, wherein the first detecting means adjusts an output voltage of the power supply circuit to a predetermined value in response to the power-off command being given from the power switch. The portable imaging device according to claim 1, wherein the portable imaging device detects that the voltage has become equal to or lower than a threshold voltage. 5. The recording apparatus according to claim 1, further comprising a compression unit configured to compress the preview image data temporarily stored in the buffer memory, wherein the recording control unit stores the preview image data compressed by the compression unit in the recording medium. The portable imaging device according to claim 1, which records. 6. An image capturing means for capturing an image of a subject and outputting image data representing the subject image, a buffer memory for temporarily storing image data output from the image capturing means as preview image data, and A display device for displaying a preview image represented by the temporarily stored preview image data, and a preview image data temporarily stored in the buffer memory when a recording instruction is given to the main image data In a portable imaging device for recording on a recording medium, whether or not the output voltage of a power supply circuit for supplying a power supply voltage to each circuit is equal to or lower than a predetermined threshold value is detected, and the output voltage of the power supply circuit is set to a predetermined threshold value. The preview image data temporarily stored in the buffer memory according to the threshold value or less. Recorded on the recording medium, the operation control method for a portable image pickup apparatus.