JP3311007B2 - Electronic still 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 still camera having a moving picture monitor function.

[0002]

2. Description of the Related Art Conventionally, there has been known an electronic still camera having a moving image monitor function, that is, an electronic still camera provided with a monitor such as an electronic viewfinder. In such an electronic still camera, a video signal obtained by a CCD is subjected to predetermined processing by an imaging circuit or the like, and then output as a moving image on a monitor. The charge accumulation time in the CCD is usually 1/60 second or less, and therefore, the imaging circuit or the like must output a video signal to the monitor within 1/60 second or less. Therefore, 1/60
For a low-speed shutter that is slower than a second, it is conceivable to temporarily store an output signal from a CCD in a memory, read out the signal, and output it to a monitor. Such a configuration has been proposed for a movie camera.

[0003]

The operation of writing a video signal to a magnetic disk after temporarily storing the video signal in a memory will be described with reference to FIG. Exposure is performed in synchronization with the vertical synchronization signal, and the video signal is transferred from the imaging circuit to the video memory. At the same time, a video signal is output from the video memory to the monitor, and a moving image is displayed. During this time, if a release signal is output by a shutter release operation, the spindle motor starts to rotate and a PG pulse is output, and the start of this motor causes the transfer of the video signal from the imaging circuit to the video memory. Interrupt. Thereafter, when the rotation of the spindle motor is stabilized and the lock-in state is established, the video signal of the video memory is recorded on the magnetic disk in synchronization with the PG pulse. As described above, since the storage of the video signal in the video memory is interrupted between the start of the spindle motor and the start of recording on the magnetic disk (about 1 second), there is a problem that the video on the monitor is stopped during this period. . SUMMARY An advantage of some aspects of the invention is that an electronic still camera having a moving image function prevents a moving image on a monitor from being stopped by a shutter release operation and always displays the moving image on the monitor.

[0004]

An electronic still camera according to the present invention includes an imaging circuit for generating a video signal corresponding to a captured video, and a video signal obtained by the imaging circuit and output to a video monitor. A first video memory for storing;
A second video memory for storing a video signal obtained by the imaging circuit after a shutter release, and a first video memory
Transfers the video signal stored in the memory to the second video memory and stores it
First transfer means for causing the image data to be stored in the second video memory.
A second transfer means for transferring the video signal to the recording medium, another
First and second synchronizing signals that output synchronizing signals independently of each other.
Signal generation means , and an image for output to a video monitor.
Read when a signal is read from the first video memory
Is a first synchronization signal generated by the first synchronization signal generation means.
Based on the second video in the first transfer means
Writing of the video signal to the memory is based on the first synchronization signal.
The second video memo in the second transfer means.
The video signal is read from the second synchronization signal generating means.
The control is performed based on a second synchronization signal generated by the stage .

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
FIG. 1 shows a control circuit built in an electronic still camera according to one embodiment of the present invention.

A system control circuit 11 is a conventionally known microcomputer for controlling the entire camera, and includes a CPU,
It has an OM and a RAM. The system control circuit 11 includes an operation unit 12 having various operation switches.
And a display unit 13 for displaying a setting state of the camera and the like.

The magnetic disk D is rotated by a spindle motor 21, and the spindle motor 21 is driven and controlled by a spindle servo circuit 22. The PG coil 23 detects the rotation timing of the magnetic disk D, and outputs this detection signal to the spindle servo circuit 22. The spindle servo circuit 22 is the system control circuit 1
1 to rotate the spindle motor 21 at a constant rotation speed (for example, 3600 rpm). The magnetic head 24 is displaced in the radial direction of the magnetic disk D by the tracking motor 25,
5 is controlled by the system control circuit 11 via the tracking motor drive circuit 26. That is,
While the magnetic disk D is rotating, the magnetic head 24 is positioned on a predetermined track of the magnetic disk D and records a video signal and an ID code on this track, or a video signal and an ID code recorded on this track. Is read.

An image of a subject is formed on a solid-state image pickup device (CCD) 32 by an aperture and a lens 31. CC
D 32 is connected to the imaging circuit 33, and the image formed on the CCD 32 is read out by the imaging circuit 33. The horizontal synchronization signal and the vertical synchronization signal are input from the first synchronization signal generation circuit 34 to the imaging circuit 33 for controlling the driving of the CCD 32 and controlling the reading of the video signal by the imaging circuit 33. The image signal is divided into a color difference signal and a luminance signal in the imaging circuit 33, and two color difference signals (R-
Y, BY) are alternately arranged every 1H (horizontal scanning period). The color difference signal and the luminance signal are output to the imaging circuit 3
3 and is AD-converted by the AD converter 35.

The AD converter 35 is connected to a first video memory 37 via a switch 36. First video memory 37
Are connected to the second video memory 38. Each of the first and second video memories 37 and 38 has a storage capacity sufficient to store video signals for at least one screen. The switch 36 is switched to the AD converter 35 side (R) during a photographing operation.
Side (P).

The second video memory 38 is connected to a DA converter 42, and the DA converter 42 is connected to an FM modulation circuit 43. The FM modulation circuit 43 is connected to a recording amplifier 45,
The recording amplifier 45 is connected to the magnetic head 24 via the switch 46.
Connected to. During the shooting operation, the switch 46 is switched to the recording amplifier 45 side (R). Therefore, after the video signal stored in the second video memory 38 is DA-converted,
The signal is FM-modulated, amplified by the recording amplifier 45, and recorded on a predetermined track of the magnetic disk D via the magnetic head 24.

The first video memory 37 is connected to the AD converter 51 via the switch 36, and the AD converter 51
The M demodulation circuit 52 is connected. The FM demodulation circuit 52 is connected to a reproduction amplifier 53, and the reproduction amplifier 53 is connected to a switch 46.
Is connected to the magnetic head 24 via the. Magnetic disk D
When reproducing the video signal recorded in the A / D converter 51, the switch 36 is on the AD converter 51 side (P), and the switch 46 is on the reproduction amplifier 5
It is switched to each of the three sides (P). Therefore, a video signal recorded on a predetermined track of the magnetic disk D is amplified by the reproduction amplifier 53, FM-demodulated, AD-converted, and stored in the first video memory 37.

The first video memory 37 is connected to a video signal processing circuit 54. The video signal processing circuit 54 is connected to a DA converter 55, and an electronic viewfinder 56 is connected to the DA converter 55. During shooting operation, switch 36
Is switched to the AD converter 35 side (R). Therefore, the video signal output from the imaging circuit 33 is subjected to A / D conversion by the A / D converter 35 and then to the first video memory 37.
Is stored once. The video signal is subjected to a predetermined process by a video signal processing circuit 54, then DA converted, and output as a moving image by an electronic viewfinder 56. That is, an image which is obtained by the lens 31 and changes every moment is observed through the electronic viewfinder 56.

On the other hand, when reproducing a video signal recorded on the magnetic disk D, the switch 36 is switched to the AD converter 51 side (P). Therefore, the video signal read from the magnetic disk D is temporarily stored in the first video memory 37, subjected to predetermined processing by the video signal processing circuit 54, DA-converted, and converted into a NTSC signal as a display device or the like. Is output to

The horizontal synchronizing signal and the vertical synchronizing signal included in the video signal output from the FM demodulation circuit 52 are separated from the video signal by a synchronization signal separating circuit 61. The synchronization signal separation circuit 61 is connected to a write sampling pulse generation circuit 63 via a switch 62. Switch 6
2 is also connected to a first synchronizing signal generating circuit 34, which is switched to the first synchronizing signal generating circuit 34 side (R) during a photographing operation, and a synchronizing signal separating circuit 61 during video signal reproduction.
Side (P). The write sampling pulse generating circuit 63 generates a sampling pulse based on the horizontal synchronizing signal and the vertical synchronizing signal output from the synchronizing separation circuit 61 or the first synchronizing signal generating circuit 34 and writes the generated sampling pulse with the AD converters 35 and 51. Output to the address generation circuit 64. The AD converters 35 and 51 AD-convert the video signal in synchronization with the sampling pulse. The write address generating circuit 64 synchronizes the first video memory 37 with the sampling pulse for writing to the first video memory 37.
The address of the video memory 37 is controlled.

The first synchronizing signal generation circuit 34 is connected to a read sampling pulse generation circuit 65. The read sampling pulse generation circuit 65 generates a sampling pulse based on the horizontal synchronization signal and the vertical synchronization signal output from the first synchronization signal generation circuit 34,
The signals are output to the A converters 42 and 55 and the read address generation circuit 66. The DA converters 42 and 55 perform DA conversion of the video signal in synchronization with the sampling pulse. The read address generation circuit 66 controls the address of the first video memory 37 in synchronization with the sampling pulse for reading from the first video memory 37.

The first synchronizing signal generation circuit 34 is connected to a write sampling pulse generation circuit 83. The write sampling pulse generation circuit 83 generates a sampling pulse based on the horizontal synchronization signal and the vertical synchronization signal output from the first synchronization signal generation circuit 34, and outputs this to the write address generation circuit 84. The write address generation circuit 84 controls the address of the second video memory 38 in synchronization with the sampling pulse for writing to the second video memory 38.

The second synchronizing signal generating circuit 73 generates a vertical synchronizing signal and a horizontal synchronizing signal similarly to the first synchronizing signal generating circuit 34.
The output timing of the vertical synchronizing signal output from is determined according to the reset pulse output from the spindle servo circuit 22. The second synchronization signal generation circuit 73 is connected to the read sampling pulse generation circuit 85. The read sampling pulse generation circuit 85 generates a sampling pulse based on the horizontal synchronization signal and the vertical synchronization signal output from the second synchronization signal generation circuit 73, and outputs this to the read address generation circuit 86. The read address generating circuit 86 synchronizes with the sampling pulse for reading from the second video memory 38.
The address of the video memory 38 is controlled.

Write sampling pulse generation circuit 6
3, 83 and read sampling pulse generating circuit 6
5 and 85 are controlled by the system control circuit 11, respectively.

During the photographing operation, the switch 36 is set to the AD converter 3
On the fifth side (R), the switch 62 is connected to the first synchronization signal generation circuit 34.
Side (R). Therefore, the video signal output from the imaging circuit 33 is AD-converted in the AD converter 35 in synchronization with the sampling pulse output from the write sampling pulse generation circuit 63 based on the control of the first synchronization signal generation circuit 34. You. This video signal is stored in the first video memory 37 at an address determined by the write address generation circuit 64 based on the control of the first synchronization signal generation circuit 34, and based on the control of the first synchronization signal generation circuit 34. The data is read from the address determined by the read address generation circuit 66. As described above, the video signal read from the first video memory 37 is subjected to predetermined processing by the video signal processing circuit 54, and is then D / A-converted.
6 is output as a moving image.

In this photographing operation, when a shutter release is performed, the video signal read from the first video memory 37 is transferred to the second video memory 38. The address of the second video memory 38 to which this video signal is written is specified by the write address generation circuit 84 as described above. After the shutter release, the spindle motor 21
Is stabilized, a reset pulse is output from the spindle servo circuit 22, whereby the output timing of the synchronization signal from the synchronization signal generation circuit 73 is controlled. Then, based on the timing determined by the synchronization signal, the read address generation circuit 86 specifies the address of the second video memory 38 and reads the video signal as described above. This video signal is DA-converted by a DA converter 42, FM-modulated by an FM modulation circuit 43, amplified by a recording amplifier 45, and recorded on a predetermined track of a magnetic disk D via a magnetic head 24.

When reproducing a video signal, the switch 36 is connected to the AD converter 51 (P), and the switch 62 is connected to the synchronous signal separating circuit 6.
Each is switched to the first side (P). Therefore, the video signal read from the magnetic disk is supplied to the AD converter 51.
In the above, AD conversion is performed in synchronization with the sampling pulse output from the write sampling pulse generation circuit 63 based on the control of the synchronization signal separation circuit 61. This video signal is supplied to the write address generation circuit 64 based on the control of the synchronization signal separation circuit 61 in the first video memory 37.
Are stored at an address determined by the first synchronization signal generation circuit 34, and the read address generation circuit 66
Is read from the address determined by.

In this embodiment, both the first and second synchronizing signal generating circuits 34 and 73 output the vertical synchronizing signal, but their output timings are different. That is, the output timing of the vertical synchronizing signal from the first synchronizing signal generating circuit 34 is always at a constant interval, but the second synchronizing signal generating circuit 73
The output timing of the vertical synchronizing signal is determined according to the reset pulse output from the spindle servo circuit 22 when the rotation speed of the spindle motor 21 is controlled to the set value.

Next, the operation of this embodiment will be described with reference to FIG. In FIG. 2, the first vertical synchronizing signal is output from the first synchronizing signal generation circuit 34, and the output timing is always constant. Exposure is performed in synchronization with the first vertical synchronization signal, and a video signal is transferred from the imaging circuit 33 to the first video memory 37 and stored at a predetermined address. The video signal is output from the first video memory 37 to the electronic viewfinder 56 to display a moving image.

When the shutter release is performed by the operation switch of the operation unit 12, the spindle motor 21 starts and the magnetic disk D starts rotating. Thus, one PG pulse is output from the PG coil 23 every time the magnetic disk D makes one rotation. The video signal obtained by the exposure performed immediately after the shutter release is transferred and stored in the first video memory 37, and is also transferred from the first video memory 37 to the second video memory 38 and stored at a predetermined address. Is done. During this time, the exposure is performed in synchronization with the first vertical synchronizing signal output from the first synchronizing signal generation circuit 34, and the moving image is displayed by the electronic viewfinder 56 as before the shutter release. The second synchronizing signal generating circuit 73 also outputs the second vertical synchronizing signal at a constant timing, similarly to the first synchronizing signal generating circuit 34.

Thereafter, when the rotation of the spindle motor 21 is stabilized and the lock-in state is attained, a reset pulse is output from the spindle servo circuit 22 after a lapse of a predetermined time (for example, 7H (H is a horizontal scanning period)) from the output of the PG pulse. You. As a result, the second synchronization signal generation circuit 73
The output timing of the vertical synchronization signal is synchronized with the reset pulse. As a result, the rotation timing of the magnetic disk D becomes predetermined, and in this state, the second video memory 3
8 is recorded on the magnetic disk D. The recording period starts after the output of the second vertical synchronization signal (one period of the vertical synchronization signal−7H), and the length of the recording period is the same as the length of one period of the PG pulse.
That is, the writing of the video signal to the magnetic disk D is performed by PG
This is performed in synchronization with the pulse.

As described above, in the present embodiment, the image obtained immediately after the shutter release is stored in the second image memory 38, and is stored in the first image memory 37 on a moving image monitor such as the electronic viewfinder 56. It is configured to output a video signal. Therefore, the spindle motor 2
The video signal is always stored in the first video memory 37 during the photographing operation, including the period from the start of the recording No. 1 to the start of recording on the magnetic disk D (about 1 second). Will not stop.

In this embodiment, the first vertical synchronizing signal used for controlling the operation of the imaging circuit 33 and the second vertical synchronizing signal used for controlling the reading from the video memory 38 are generated independently. The output timing of the first vertical synchronizing signal is not affected by the reset pulse output when the rotation speed of the spindle motor 21 is stabilized. Therefore, since the imaging circuit 33 is not affected by the reset pulse, the output of the moving picture monitor is not disturbed during the shooting operation.

In this embodiment, the video signal is transferred from the first video memory 37 to the second video memory 38 immediately after the shutter is released.
The image signal may be directly transferred from the imaging circuit 33 to the second image memory 38.

[0029]

As described above, according to the present invention, in an electronic still camera having a moving image function, the moving image on the monitor is prevented from being stopped by the shutter release operation, and the moving image can be always displayed on the monitor. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a control circuit of an electronic still camera to which an embodiment of the present invention has been applied.

FIG. 2 is a diagram illustrating a shooting operation according to the embodiment.

FIG. 3 is a diagram showing a conventional photographing operation.

[Explanation of symbols]

 D Magnetic disk

Claims (2)

(57) [Claims] An imaging circuit for generating a video signal corresponding to a captured video; a first video memory for storing a video signal obtained by the imaging circuit and output to a video monitor; a second image memory for storing the video signal obtained by the circuit, the first video signal stored in the video memory the second movies
A second transfer means for transferring a first transfer means for storing transferred to the image memory, the image signal stored in the second image memory to the recording medium, first for outputting a synchronization signal independently of each other And the second one
And a video signal for outputting to the video monitor.
When reading from the image memory, the first
Based on the first synchronization signal generated by the synchronization signal generation means
Is controlled, and the second video image in the first transfer means is controlled.
The writing of the video signal to the memory is performed according to the first synchronization signal.
And the second transfer means controls the
The reading of the video signal from the second video memory is performed by the second
Based on the second synchronization signal generated by the synchronization signal generation means
An electronic still camera characterized by being controlled . 2. The electronic still according to claim 1, wherein the second transfer means transfers the video signal stored in the second video memory to the recording medium after the rotation of the recording medium is stabilized. camera.