JPH03123183A - Electronic still camera - Google Patents

Abstract

PURPOSE:To record an image signal and a sound signal is a memory card by a simple timing control by containing a semiconductor line memory of a small capacity in a camera. CONSTITUTION:The camera is provided with a memory card 10 which is provided so as to be freely attachable and detachable to and from a camera body, and stores a digital image signal and a digital sound signal, and a semiconductor line memory 14 for storing the digital sound signal, and the digital sound signal in a period in which the digital image signal is written in the card memory 10 is written in the line memory 14. Subsequently, after the digital image signal is written in the card memory 10, the digital sound signal is read out of the line memory 14 and written in the card memory 10. In such a way, while the digital image signal is being written in the memory card, the digital sound signal can be written in the card memory without being interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic still camera, and more particularly to an electronic still camera in which an audio signal is stored in a memory card in addition to an image signal.

[Prior Art] Conventionally, in electronic still cameras, systems are known in which video floppies are used as recording media to record image signals and audio signals. Among these, when recording an audio signal, the audio signal is recorded as a compressed analog signal on a plurality of tracks of a video floppy.

In this electronic still camera, in order to compress the audio signal, the analog audio signal is first A/D converted using a clock of about 10 kHz, then imported into a large capacity semiconductor memory, and then converted to a semiconductor memory using a high speed clock of about 7 MHz. A digital audio signal was read out from the computer, D/A converted, and recorded on a video floppy.

[Problems to be Solved by the Invention] In the above-mentioned conventional electronic still camera, images and audio are recorded and played back on a video floppy, so the video floppy rotation drive mechanism, large capacity semiconductor memory, and D/A are required. Since a converter and the like are required, the housing of the electronic still camera becomes larger, the weight increases, and power consumption increases. There were drawbacks such as cost I/up.

Furthermore, the digital image signal and analog audio signal must be recorded on separate tracks of the video floppy. Therefore, when recording image signals and audio signals simultaneously, it is necessary to move the recording head that writes to the video floppy and write to separate tracks, which requires complex timing control. There was a problem.

This invention was made in view of these conventional problems. By incorporating a small-capacity semiconductor line memory into a camera, it is possible to record image signals and audio signals on a memory card with simple timing control. The purpose is to obtain an electronic still camera with a

[Means for Solving the Problems] In order to solve the above problems, the electronic still camera of the present invention includes a first A/D converter that converts an analog image signal obtained from an image sensor into a digital image signal; It has a second A/D converter that converts an analog audio signal obtained from a microphone into a digital audio signal, and a memory card that is detachably attached to the camera body and stores digital image signals and digital audio signals. It has a semiconductor line memory for storing digital audio signals.

[Function] When writing a digital image signal to the card memory while writing a digital audio signal to the card memory,
By writing a digital audio signal to the line memory during the period when the digital image signal is being written to the card memory, and after the digital image signal is written to the card memory, reading the digital audio signal from the line memory and writing it to the card memory. , While a digital image signal is being written to a memory card, a digital audio signal can be written to the card memory without interruption.

[Example] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic block diagram showing an embodiment of an electronic still camera of the present invention. In FIG. 1, 1 is an imaging lens, 2 is a CCD image sensor, 3 is a preprocessing circuit that preprocesses an analog image signal output from the CCD image sensor 2, and 4
is an A/ that converts an analog image signal into a digital image signal.
A D converter 5 is a switch for switching the input to the frame memory 6. Further, the frame memory 6 is composed of a dual port type memory having a storage capacity for one frame. The output of this frame memory 6 is connected to a D/A converter 7 and a contact a of a changeover switch 8. The output of this D/A converter 7 is the built-in LC
The output of the switch 8 is connected to a D monitor 9, and the output of the switch 8 is connected to a pass line B that leads to a memory card 10 that is removably provided in this electronic still camera. Further, the output of the switch 8 is connected to the contact a of the switch 5.

11 is a microphone that picks up audio, 12 is microphone 1
1 is a preprocessing circuit that performs preprocessing such as amplifying an input analog audio signal; 13 is an A/D converter for converting the analog audio signal into a digital audio signal; 1
A line memory 4 temporarily stores the digital audio signal input from the A/D converter 13, and the output of this line memory 14 is connected to a path line B leading to the memory card 10. The line memory 14 is a dual-port type small-capacity memory that has a storage capacity of one line, that is, one byte, and performs serial in/serial out operations in units of one byte. The output of this line memory 14 is connected to contact C of the changeover switch 8 mentioned above. 15 is a data generation circuit that generates various data such as date according to the digital image signal and digital audio signal recorded in the storage area of the memory card 10.

Next, the operation will be explained.

First, as a CCD image sensor 2, for example, 768 pixels horizontally, 490 pixels vertically (nominal 380,000 pixels), drive frequency 4
-fsc (fsc: color subcarrier transmission frequency.

f 5c = 3.579545 MHz) is used.

The output from the CCD image sensor 2 passes through a preprocessing circuit 3 that performs gamma correction, etc., and is converted into a digital signal by an A/D converter 4 with an operating frequency of 4.t'sc and a resolution of 8 bits. When the contact of the switch 5 is turned on, the output of the A/D converter 4 is passed through the switch 5 to the frame memory 6.
Enter. The output of this frame memory 6 then branches into two paths. One output is input to the D/A converter 7, where the digital image signal that is the memory content is converted into an analog image signal, and the recorded image is confirmed on the LCD monitor 9. When the contact a of the switch 8 is turned on, the other output is manually recorded in the memory card 10 attached to the electronic still camera via the switch 8.

In this way, the sequence of recording the digital image signal on the memory card 10 while checking the quality of the photographed image on the LCD monitor 9 is completed. However, if you simply want to check the recorded contents of the memory card 10, you can output the digital image signal of the desired frame from the memory card 10 by operating a playback switch or a recording screen selection switch (not shown). When the contact a of the switch 5 is turned on, the signal is input to the frame memory 6 through the switch 5. At this time, if the switch 8 is switched so that the contact is turned on, the digital image signal output from the frame memory 6 is supplied only to the D/A converter 7, so that the reproduced signal converted to an analog image signal is is confirmed on the LCD monitor 9.

When recording an audio signal, the analog audio signal that has passed through the microphone 11 and preprocessing circuit 12 is converted into an 8-bit digital audio signal by an A/D converter 13 with a conversion frequency of about 10 kHz. , line memory 1
4 are input consecutively.

The line memory 14 uses this 10kHz write clock.
The digital audio signal written to the same <10kHz
(1024/(IOXIO3) #0.
After 1 sec), the audio information is read out continuously from the line memory 14, and when the contact C of the switch 8 is turned on, the audio information is recorded on the memory card 10 via the switch 8 as audio information.

Next, details of the timing during the above-mentioned recording operation will be explained with reference to FIGS. 1 to 4.

In FIG. 1, CLKI is the conversion clock of the A/D converter 4, CLK2 is the write clock of the frame memory 6, CLK3 is the read clock of the frame memory 6, CLK4 is the conversion clock of the D/A converter 7, and CLK
5 is a write or read clock to the memory card 10, CLK6 is a conversion clock of the A/D converter 13, C
LK7 is the write clock of the line memory 14, CLK
8 is a read clock of the line memory 14.

Next, referring to FIGS. 2 to 4 showing the operation timings of switching the contacts of switch 5.8 and changing the frequency of each clock signal in FIG. (3) Audio 9-image interval time recording operations will be explained in order. Also, in Figs. 2 to 4, the clocks CLKI to CL
It is assumed that no clock signal is applied to the section where the frequency is not described in K8, and the section where the contact point is not described in Sui-Sochi5°8 may be connected to any one.

(1) Image recording Figures 2 (a) and (b) show the switching states of the contacts of switches 5 and 8, and Figures 2 (C) to (g) show the frequencies of the clocks CLKI- to CLK5. FIG. In Figure 2, T1 is Shirtsui 7chi (
After the button (not shown) is pressed, it is the time when the analog image signal is actually output from the CCD image sensor 2, and various processes actually start from this time. Further, in this embodiment, a case will be described in which the operation speed during writing of the memory card 10 follows only up to the clock frequency 2·f'sc. First, an analog image signal for one frame is output from the CCD image sensor 2 between times T1 and T2,
During this time, the A/D converter 4 converts the analog image signal into a digital image signal using the conversion clock CL K1 (frequency: 4 fsc), and transmits this digital image signal to the frame memory 6 via the switch 5 whose contact is on. The data is recorded using the write clock CLK2 (frequency 4·fsc). On the other hand, at time T1, the read clock C [, K3 frequency = 2 fsc) is read from the frame memory 6 and the time axis is expanded twice, and the write clock C is sent to the memory card 10 via the switch 8 whose contact is switched to a. K 5 (
Frequency = 2 fsc) and 2 frame period or time T
Writing ends at 3. After this, confirmation of the recorded image is continued on the built-in LCD monitor 9 until time T4. Time T3~
'During F4, read clock CL of frame memory 6
The frequency of K'3 is changed from 2.fsc to 4.fsc, and the conversion clock CLK of the D/A converter 7 is changed from 2.fsc to 4.fsc.
4 is also set to 4·t'sc, and the digital image signal is converted into an analog image signal and output to the monitor 9.

Note that since the audio signal is not recorded, the clock signal CLK6
~8 is not applied.

Furthermore, it goes without saying that when the write clock CLK5 is applied to the memory card 10, the memory card 10 is in the recording mode.

Further, following recording of this image signal, the data generation circuit 15
The data created in , for example, the date, photographing number, photographing conditions, etc., are simultaneously recorded in the data block provided in the memory card 10 corresponding to the image block in which the image signal is recorded.

(2) Checking the contents of the memory card Figures 3 (a) and (b) show the contact switching states of switches 5 and 8, and Figures 3 (c) to (g) show the clock CL.
FIG. 5 is a timing diagram showing frequencies of K1 to CLK5. In FIG. 3, when a recording screen selection switch (not shown) installed on the camera is pressed at time T, the memory card 10 goes into the read mode in response to this and the two frames up to time T6 are pressed. During the period, data for one screen is written to the frame memory 6 by the read clock CLK5 (frequency = 2 fsc) through the switch 5 whose contact a side is on.
・fsc). At this time, the switch 8 is switched to the contact side to prevent a short circuit between the outputs. At time T6, the writing of one screen worth of digital image signals read from the memory card 10 into the frame memory 6 is completed, so that the read clock CLK is then
3 (frequency: 4.fsc) is supplied to the frame memory 6 to read out the digital image signal, and the conversion clock CL K4 (frequency: 4.fsc) is supplied to the D/A converter 7.
The video signal is confirmed on the LCD monitor 9 by converting the digital image signal into an analog image signal.

Furthermore, if the block on the memory card 10 selected by the recording screen selection switch is an audio recording block, an indication is displayed on the LCD monitor 9 that the block is a block for recording audio signals. It is supposed to be done. Note that a method for determining whether the block records an image signal or an audio signal will be described later.

] 3 4 Note that in the case of the content confirmation operation of the memory card 10 described above, since no image signal or audio signal is recorded, the clock signals CLK1, CLK6 to CLK8 are not applied.

(3) Simultaneous recording of 9 audio images. Figures 4(a) and 4(b) show the switching states of the contacts of switch 5.8, and Figures 4(C) to (j) show the clock C.
Frequencies of LKI to CLK8, (k) and (1) are timing charts showing the write address and read address of the line memory 14, respectively. FIG. 4 shows a case where audio is recorded at an arbitrary time. It is equipped with an IK byte line memory 14 that characterizes this invention for audio recording, and always uses a fixed clock CL.
Line memory 1 with K7 (frequency = 10kHz)
Continuously write digital audio signals to 4, usually about 1
Time delayed by line minutes (1024/(IOXIO3)”i
o.

The digital audio signal is read out continuously from 1 sec later) and recorded on the memory card 10, and at the moment the shutter switch (not shown) is pressed, the digital audio signal of one line before is read out from the high-speed clock CLK8. (Frequency: 2
・f, , ), and the remaining time is used to record the digital image signal on the memory card 10.

In FIG. 4, recording is started by pressing the recording start switch (not shown) of the electronic still camera at time T7, and then the recording shutter switch (not shown) is pressed at time T9. CC at time T11 due to
It is assumed that an analog video signal is read out from the D image sensor 2.

First, from time T7 when the recording start switch was pressed, the A/D
The converter 13 uses a conversion clock CLKO (frequency f: 10k
At the same time, the operation of converting the audio analog signal into a digital signal is started at a frequency of 7 (frequency f) at a writing clock CL of the line memory 14. Then, the write address of the line memory 14 is the maximum I
Time T at the moment when address K, that is, address 1024 is reached.
8 supplies the read clock CLK8 (frequency: f) to the line memory 14 to start reading out the digital audio signal, and starts recording the digital audio signal to the memory card 10 via the switch 8 whose contact C side is on. do.

From time T8, a write clock CLK5 (frequency: f) is applied to the memory card 10. Next, from time T1o, the frequency of the read clock CLK8 of the line memory 14 is changed from f to 2·f'sc. As a result, after the time T9 when the recording shutter was pressed, the time T
The period of one line up to lo, that is, Fig. 4(k)
, In (j), the digital audio signal of the period corresponding to the B2 period from write address +1 to address 1024 of the line memory 14 and the 01 period from write address 1 to address 143usec (1024/
The information is written to the memory card 10 in a short period of time (2·fsc>). At this time, it goes without saying that the frequency of the write clock CLK5 to the memory card 10 is switched from f to 2·f5°.

Next, from time T1□ when writing of the digital audio signal for the period corresponding to the B2 and C1 periods to the memory card 10 is completed, two frames are written in the same procedure as in the case of "(1) Image recording" described above. period (2/30'; 0.067s
ec) The digital image signal is transferred to the memory card 10.
will be written to.

During this image recording period, the line memory 14
A digital audio signal is continuously written in. Remaining digital audio signal (line memory address +
1.~1024 02 period onwards) is 1 from time TIo.
After time TI3, which is delayed by a line, the data is read from the line memory 14 at the read clock CLK8 (frequency: f) and written to the memory card 10 at the write clock CLK5 (frequency: f).

As mentioned above, the memory card 10 for digital audio signals
When the recording shutter is pressed during the writing operation to the memory card 10 to instruct the writing operation of the digital image signal to the memory card 10, the digital audio signal for one line written to the line memory 14 at that point is written to the memory card 10 with a faster write clock than usual. Then, at the same time as writing of the digital audio signal for one line is completed, a digital image signal is subsequently written to the memory card 10. Since the digital audio signal is written to the line memory 14 during the writing operation of the digital image signal to the memory card 10, the recording operation of the audio signal is not interrupted. That is, the line memory 14 has a storage capacity capable of storing the digital audio signal during the period when the digital image signal is being written to the memory card 10.

Note that in order to mix and efficiently record digital audio signals and digital image signals on the memory card 10, the storage area of the memory card 10 is divided in advance into blocks of the first field. Therefore, digital image signals and digital audio signals are recorded in blocks, and these blocks are called image blocks and audio blocks, respectively.

Furthermore, the following data outputted from the data generation circuit 15 is added to the image block and the audio block and recorded at the same time.

■ Identification data that identifies whether the data recorded in the block is an audio signal or an image signal, ■ Data that identifies that audio is recorded continuously in the block, ■ Simultaneous recording of images and audio. In this case, the block No. 17 of the audio block corresponding to the image block, and the block No. 0 of the image block corresponding to the audio block.Next, other embodiments will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing another embodiment, and the same reference numerals as in FIG. 2 indicate the same parts. Also, Figure 6 shows the 5th
2 is a timing diagram corresponding to the embodiment shown in the figure, and the same reference numerals as in FIGS. 2 and 3 indicate the same parts.

The difference between FIG. 5 and FIG. 2 is that a switch 16 is added in FIG. recorded. However, when a shutter switch (not shown) is pressed, a digital image signal is written to the memory card 10 and, in parallel, a digital audio signal is written to the line memory 14.

Then, at the same time as the recording of the digital image signal is finished, the switch 16 is switched to the contact a side, and the digital audio signal written in the line memory 14 is read out using a high-speed clock signal and written to the memory card 10, and the writing for one line memory is completed. When the process is finished, the switch 16 is switched from the contact a side to the contact side, and from then on, the digital audio signal is written to the memory card 10 again in real time.

The operation shown in FIG. 5 will be explained based on the timing diagram shown in FIG. 6. FIGS. 6(a) to (j) show the switching states of the contacts of the switch 5.8 and the frequencies of the clocks Ct, K1 to CLK8, similar to FIGS. 4(a) to (j), and FIG. (
k) shows the switching state of the contacts of the switch 16. As shown in FIG. 6, switch 5.8 and clock C
The operations of LKi to CLK4 are the same as those shown in FIG.

First, when a recording start switch (not shown) is pressed at time T4, the A/D converter 13 starts using the conversion clock CLK6.
(Frequency: r) to start converting an analog audio signal to a digital audio signal. Then, the digital audio signal is transmitted to the memory card 10 via the switch 16 whose contacts are on.
Data is written in real time using a write clock CLK5 (frequency: f). Thereafter, at time] 15, the shutter switch (not shown) was pressed, and the CCD
Analog image signals begin to be read out from the image sensor 2.

In this example, the storage of the image signal into the memory card 10 ends at time 'r16 after two frame periods.

On the other hand, from time T15 when the reading of the image signal from the CCD image sensor 2 starts, the line memory 14 starts writing the digital audio signal at the write clock CI-, at a frequency of 7 (frequency: "), and starts writing the digital audio signal at the Nth address. The rewriting continues until time TI7 when 1 2 is written. Also, at time T1, which is two frame periods after time TI5,
6. In other words, from time T16 when writing of the digital image signal to the memory card 10 is completed, the line memory 14
is read clock CF, K8 (frequency: 2・f, c)
The reading of the digital audio signal is started at , and the write clock CLK5 (frequency=2·f, c ) to write the digital audio signal.

Therefore, the following two times indicating the time from time T15 when reading out the image signal from the CCD image sensor 2 starts to time T1 when writing of the Nth address of the line memory 14 and reading end are equal. Become.

■Clock CLK7 (frequency:
The time required to write to the line memory 14 at f = 10 kt (z): ■ Time for 22 frames (2/30 sec) and clock CLK8 (frequency: 2 ・f
, c=2・3. 58M) Iz) and the time required to read from the line memory 7.

From the above relationship, in this embodiment, line memory 1
4 becomes address N-667, which is time T17 when the write address and the read address match. Therefore, switch 16 is switched to the contact side at this time, and from then on, the digital audio signal is sent to memory card 10 again in real time. Load into.

In addition, in the electronic still camera of the present invention, if the memory card can operate by following the driving frequency of 4 f Ac of the CCD image sensor, the frame memory can be omitted, which saves space and power in the camera body. It is possible to significantly reduce consumption.

In addition, if the digital information of digital image signals and digital audio signals is compressed using compression techniques such as orthogonal exchange, it will be possible to significantly reduce the number of memory storage customers, and the number of video frames that can be recorded on a memory card will be reduced. It becomes possible to significantly increase both audio signals.

[Effects of the Invention] As explained above, according to the electronic still camera of the present invention, when a digital image signal is written to the card memory while a digital audio signal is being written to the card memory, the digital image signal is Writes the digital audio signal while it is being written to the memory to the line memory,
After the digital image signal is written to the card memory, the digital audio signal is read from the line memory and written to the card memory, thereby interrupting the digital audio signal during the period in which the digital image signal is being written to the memory card. It can be written to the card memory without any need to write to the card memory.

In this way, digital image signals and digital audio signals can be recorded on the memory card, so unlike conventional methods, there is no need for large-capacity semiconductor memory or D/A converters for audio compression, so electronic still cameras It is possible to downsize the casing and reduce power consumption.

Also, unlike the conventional method, since a video floppy is not used, there is no need for complicated timing control for moving the recording head.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of an electronic still camera of the present invention, FIGS. 2, 3, and 4 are timing diagrams in the embodiment, and FIG. 5 is a block diagram showing another embodiment. , FIG. 6 is a timing diagram in another embodiment. 4... A/D converter (first A/D converter), 10.
- Memory card, 13 - A/D converter (second A
/D converter), 14... line memory (semiconductor line memory).

Claims (4)

[Claims] (1) A first A/D converter that converts an analog image signal obtained from an image sensor into a digital image signal, and a second A/D converter that converts an analog audio signal obtained from a microphone into a digital audio signal. and a memory card that is detachably attached to the camera body and stores the digital image signal and the digital audio signal, the electronic still camera having a semiconductor line memory that stores the digital audio signal. electronic still camera. (2) The electronic still camera according to claim 1, wherein the semiconductor line memory is of a dual port type. (3) In claim 1, the frequency of the read clock supplied to the semiconductor line memory is determined depending on whether only a digital audio signal is recorded on the memory card or when a digital audio signal and a digital image signal are recorded on the memory card. An electronic still camera characterized by being able to change. (4) In claim 1, 2, or 3, the operation of writing the digital audio signal to the semiconductor line memory is started simultaneously with the start of the recording operation of the digital image signal to the memory card, and An electronic still camera characterized in that after a recording operation is completed, the recording operation is continued until a predetermined time when a write address and a read address of a semiconductor line memory match, and is stopped for other periods.