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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to an electronic still camera, which uses,
for example, a semiconductor memory card as a recording medium, for
recording still images on the recording medium.
DESCRIPTION OF THE RELATED ART
Electronic still cameras which use a solid state imaging device such as a
CCD (charge coupled device) for photographing still images of subjects and
recording the still images on rotatable magnetic recording medium, that
is, a video floppy, are considered to replace conventional still cameras
for photographing and recording still images by use of the
photosensitivity of silver salt films, that is, photographic films using
silver salt photosensitive material, and they have been merchandized.
However, since this type of electronic still camera uses the rotatable
magnetic recording medium, a driving unit for driving the rotatable
magnetic recording medium relative to the recording head must be provided
inside the camera, thus making it difficult to reduce the size of the
camera. A solid state electronic still camera system for recrding image
information on a memory card using a semiconductor memory (that is,
storing image information in a semiconductor memory of a memory card), as
a system which has no driving unit and is suitable for small sized
cameras, has been considered by the same applicant (U.S. application Ser.
No. 073,160, Minoru Sasaki). A typical example of this type of electronic
still camera is shown in FIG. 13.
An image of the subject is transmitted via lens 121, diaphragm 122 and
color filter 120, and formed on CCD 126 which is used as the imaging
device in which the optical image is subjected to a photoelectric
conversion. An output signal of CCD 126 is subjected to a predetermined
process in preprocessing circuit 127, converted into a digital signal by
means of analog-to-digital (A/D) converter 128, and then recorded on
memory card 115. In this case, a signal from each picture element of the
imaging device is recorded in the digital form on memory card 115. The
signal of each picture element of the imaging device is subjected to a
predetermined process such as the amplification, white-balance correction
and .gamma. correction as the pre-processing. Picture element data, which
has been subjected to the pre-processing in a sequence according to the
picture element array, is recorded on memory card 115. In the reproduction
mode, memory card 115 is set in a reproducing unit, and data stored in
memory card 115 is subjected to a predetermined signal processing and
digital-to-analog (D/A) conversion, and then supplied to a TV (television)
monitor which in turn displays the data as an image. In FIG. 13, case 110,
release switch 111 for triggering the imaging operation, battery 123 used
as a power source, shutter control circuit 124 for controlling diaphragm
122 and electronic shutter operation, CCD driving circuit 125, and
monitoring unit 130 are also shown. CCD driving circuit 125 is used to
control and drive shutter control circuit 126, pre-processing circuit 127,
A/D converter 128 and memory card 115. Monitoring unit 130 displays the
photographed image based on signals transmitted via pre-processing circuit
127 at the time of photographing and is used as a view finder.
As described above, wherein data corresponding to each picture element of
the solid state imaging device is recorded on the memory card, the signal
processing is simple and the device is simple in construction. However, if
the recording conditions such as the number of picture elements and the
arrangement of color filters of the solid state imaging device of the
electronic still camera are changed, for example, the arrangement of data
recorded on the memory card or the amount of data per frame will be
changed accordingly. Therefore, the recorded memory card is not
interchangeably used for another type of electronic still camera system,
that is, an electronic still camera having the number of picture elements
and arrangement of color filters different from those of the electronic
still camera used for recording the image data on the memory card.
If a single electronic still camera is designed so as to record image under
different recording conditions, the recorded memory card may be
interchangeably used to some extent. However, in this case, the memory
capacity required for recording one frame of image data of the
photographed still image varies depending on the recording conditions
(recording modes) set at the time of photographing. Therefore, in a case
where new image data is written into a recording area in which one frame
of image data has been previously recorded and erased, the memory capacity
may sometimes be insufficient for recording the new image data, thus
making it impossible to record the new image data.
SUMMARY OF THE INVENTION
An object of this invention is to solve the aforementioned disadvantages
and provide a new electronic still camera and an image recording method by
which the memory capacity required for recording one frame of data can be
changed as required, the number of images to be recorded on one recording
medium can be efficiently changed according to the image quality, and
which can flexibly cope with a shortage in residual amount of the
recording medium mounted at the time of photographing and the
non-coincidence of the recording area when a suitable frame is erased and
a new image is recorded.
In an electronic still camera of this invention, a recording medium for
recording a photographed image data, for example, a memory card is
detachably provided. The electronic still camera comprises a data
compression unit for compressing an image data to be recorded, a mode
selection unit provided in association with the data compression unit to
select a recording mode, that is, a compression mode, a buffer memory for
temporarily storing an image data compressed in the compression mode
selected by the mode selection unit, and a determination unit for
determining whether or not the image data stored in the buffer memory can
be recorded on the recording medium. In the electronic still camera, when
"NO" is determined by the determination unit, the image data stored in the
memory is stored in the buffer memory of the camera until the recording
medium assumes a recordable state, that is, until a new memory card is
mounted, for example. Preferably, the compression mode includes an
uncompression mode not applied with the data compression by the data
compression unit.
In the electronic still camera according to a preferred embodiment of the
present invention, an image signal subjected to photoelectric conversion
by a solid state imaging device is digitalized by a signal processing
circuit and coded, and the coded digital data is recorded on a memory
card. In the electronic still camera, an image signal is converted into a
brightness signal and two color-difference signals by a signal processing
circuit and recorded on a memory card. In the electronic still camera, the
image data can be compressed and the total bit capacity for recording one
frame of image data can be reduced by changing the number of samples and
by non-linear quantitizing an error with an expected signal to reduce the
number of bits required to express one sample data, and the brightness
signal and two color-difference signals can be written into the memory
card as the recording medium. Also, the number of frames of images written
into a memory card can be changed as desired accordingly. In the
electronic still camera, the memory of the memory card is divided into
blocks of fixed capacity, a number or name is set to each block, data in
each frame is divided into several blocks and recorded, and the number of
blocks used for each frame and the number or name of the first block are
recorded whereby even if the memory of different capacity is used every
frame, writing, reading, erasing or rewriting can be easily made.
In the electronic still camera according to the present invention, there
are a plurality of compression modes having different compressibility, and
an user can suitably select any of these modes. In the electronic still
camera as described, even if the capacity of the recording medium or the
data amount of one frame is determined so that the capacity capable of
being recorded by one recording medium, for example, a memory card, is the
natural number times of the data amount of one frame in all the recording
modes, when a plurality of different compression modes are selected for
one recording medium, for example, the memory card, a surplus of the
memory capacity less than one frame inevitably sometimes occurs. In other
words, there sometimes occurs a case where a shortage of capacity not
capable of recording an image of one frame on the memory capacity finally
left occurs. In the light of this, in the electronic still camera of the
present invention, when a shortage in capacity of the memory card attached
occurs for photographed image data, and the transfer of the photographed
image data to the memory card is effected for the first time when a new
memory card is attached and the image data assumes a state capable of
being recorded. Accordingly, the user can suitably select and photograph
the compression mode without being troubled by the residual capacity of
the recording medium or the kind of compression modes when the compression
mode is selected.
In the electronic still camera according to the present invention, the
number of images capable of being recorded on the recording medium for
example memory card, can be efficiently changed depending on the image
quality, and even if plural kinds of image data processed according to
different modes are mixed and recorded on a single recording medium, no
inconvenience occurs. Moreover, in the electronic still camera, it is
possible to erase only data of one frame to record a new image data in an
easy manner. Furthermore, in the electronic still camera, even in the case
where the shortage in capacity of the recording medium attached has been
found after imaging had been made, the imaging content can be recorded on
another recording medium. Accordingly, the present invention can provide
an electronic still camera and an image recording method which can be
conveniently used as a system including the recording medium.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an appearance of an electronic still
camera according to a first embodiment of this invention;
FIG. 2 is a diagram schematically showing the construction of the
electronic still camera shown in FIG. 1;
FIG. 3 is a perspective view illustrating the basic construction of a
semiconductor memory card used in the electronic still camera shown in the
embodiment of FIG. 1;
FIG. 4 is a diagram illustrating the detail construction of the memory card
shown in FIG. 3;
FIG. 5 is a diagram showing the modeled construction of a CCD array used in
the embodiment shown in FIG. 1;
FIGS. 6A and 6B are diagrams showing the detailed construction of the
electronic still camera shown in FIG. 2;
FIGS. 7 and 8 are views illustrating the sampling points of the image data
in the embodiment shown in FIG. 1 on the assumption that the positions
thereof lie on a 2-dimensional plane;
FIGS. 9A to 9E are views illustrating the recording formats of the memory
card used in the embodiment shown in FIG. 1;
FIG. 10 is a flowchart showing the process in detail at the time of
photographing effected by the embodiment shown in FIG. 1;
FIG. 11 is a block diagram showing the schematic construction of a
reproducing unit for reproducing an image from the memory card recorded by
the camera of this invention;
FIGS. 12A and 12B are block diagrams showing the detailed construction of a
second embodiment of this invention;
FIG. 13 is a diagram showing the construction of the conventional
electronic still camera;
FIGS. 14A and 14B are block diagrams showing the detailed construction of a
third embodiment of this invention;
FIG. 15 is a flowchart showing the process in detail at the time of
photographing in the embodiments shown in FIGS. 14A and 14B;
FIGS. 16A and 16B are block diagrams showing the detailed construction of a
fourth embodiment of this invention;
FIG. 17 is a view for explaining a format of a directory within a memory
card in the embodiments shown in FIGS. 16A and 16B; and
FIGS. 18A and 18B are views illustrating examples of mode switch.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
There will now be described an electronic still camera according to an
embodiment of this invention with reference to the accompanying drawings.
An electronic still camera system, as used hereinafter is defined as
including an electronic still camera and a reproducing unit. The
electronic still camera is used to take a picture of a subject and record
the image on a semiconductor memory card used as recording medium, and the
reproducing unit is used to read out image information from the memory
card and transfer the image information to TV receiver or the like for
display.
FIG. 1 is a perspective view of the electronic still camera as viewed from
the rear upper point thereof, and the explanation for portions thereof
which have the same functions as those of an ordinary still camera (using
a photographic film) is omitted. Electronic still camera 10 includes reset
switch 9, release 11, photographing mode switch 12 and photographed
picture number displaying unit 13. Further, insertion slot 14 is provided
for permitting insertion of semiconductor memory card 15 on the right side
of electronic still camera 10. Shutter speed selection dial 18 is disposed
on the electronic still camera 10. These elements will be described more
in detail later.
FIG. 2 schematically shows the basic construction of electronic still
camera 10. In the photographing operation, focusing is effected by lens
system 21 and the shutter speed is adequately set by operating shutter
speed selection dial 18 in the same manner as in the ordinary still
camera. Diaphragm 22 is controlled by control circuit 24, and the shutter
speed is adjusted by a so-called electronic shutter. The electronic
shutter adjusts the shutter speed by controlling the charge storing time
in CCD array 26 used as an image device. An image of a shutter is formed
on CCD array 26 via lens system 21.
When the photographing operation is started and release 11 is set into the
halfway position (the release button is depressed halfway) by an operator
or user, the power source voltage from power source 23 using a battery is
supplied to the respective electronic circuit sections (that is, when the
power source switch not shown is turned on, the power source voltage is
supplied only to a portion required in the preparation stage of
photographing, and the power source voltage is supplied to other portions
required for photographing for the first time when the release 11 assumes
the halfway position). The amount of incident light is measured by
exposure sensor 19, and control circuit 24 controls diaphragm 22 according
to the measured amount of incident light. The external color temperature
is measured by white balance sensor 17, and control circuit 24 generates a
white balance control signal according to the measured color temperature.
When release 11 is further depressed from the half-way position to the
fully depressed position (the release button is fully depressed), control
circuit 24 produces a shutter pulse. In response to the shutter pulse,
driving circuit 25 supplies control signals to CCD array 26,
pre-processing circuit 27, A/D conversion circuit 28 and signal processing
31 which are in turn operated in response to the respective control
signal. An image information signal formed of an analog signal from CCD
array 26 is supplied to A/D conversion circuit 28 via pre-processing
circuit 27 and is converted into a corresponding digital signal. The image
information signal thus converted into the digital form is subjected to a
predetermined signal processing in signal processing circuit 31. A digital
image information signal from signal processing circuit 31 is supplied to
semiconductor memory card 15 together with a control signal with an
address signal. In this way, the image information signal corresponding to
the photographed still image is stored in semiconductor memory card 15.
Prior to the photographing, the user can selectively set the format of data
to be stored in semiconductor memory card 15 by operating mode switch 12.
Mode switch 12 is used to select and set a desired one of a plurality of
modes for different image qualities. Mode selection by mode switch 12
makes it possible to change the amount of digital data required for
storing one frame image (i.e., the number of image frames which can be
stored in one memory card 15). For example, when high quality mode is set,
one frame image is stored as digital data of 640 Kbytes with the highest
image quality. When mode "B" is set, one frame image is stored as digital
data of 320 Kbytes with the second highest image quality, and when mode
"C" is set, one frame image of 160 Kbytes is stored with the third highest
image quality. Further, when mode "D" or low image quality mode is set,
one frame image of 80 Kbytes corresponding to the smallest memory space
for one frame is stored. If memory card 15 is provided with a memory of
2.56 Mbytes, for example, it is possible to store 4, 8, 16 and 32 frames
into one memory card 15 in modes "A", "B", "C" and "D", respectively. The
selection of the recording modes by the mode switch 15 is effected every
frame. The details of a method for storing data into the memory card 15
will be described later.
In the above description, the data amount in one frame is set by selecting
one of the invariable modes. However, the compression rate of data amount
may be set freely set by the user. In the case of the former (i.e.,
selecting one mode), for example, a dial-type switch 12A, wherein modes
(A) to (D) correspond to four selections of a dial 12A1, as shown in FIG.
18A, can be used as the mode switch 12. In this type of mode switch, the
dial 12A1 is rotated to select one of the modes (A) to (D). In the case of
the latter (i.e., freely setting the compression rate of data amount), a
switch 12B, which comprises, as shown in FIG. 18B, a pair of triangular
button switches 12B1 and 12B2 arranged in opposite directions and a
display 12B3 for displaying the compression rate, can be used. In the mode
switch 12, the compression rate 1/N (N: an integer having a predetermined
value or less that determines the limit of compression) is displayed on
the display 12B3. Upon operation of the button switches 12B1 and 12B2, the
value N is increased or decreased to set a desired compression rate.
FIG. 3 shows the basic construction of memory card 15. Memory card 15 is
constituted by a printed circuit board having a plurality of random access
memory (RAM) chips 36 mounted thereon. External terminals 32 including
data terminals, address terminals and control terminals, and power source
terminals 33 are provided on one side of memory card 15. For use of memory
card 15, it is inserted into electronic still camera 10 or a reproducing
unit. Supply of the power source voltage to memory card 15 is achieved via
power source terminals 33, and transfer of signals with respect to memory
card 15 is effected via external terminals 32. Exclusive battery 34 used
for holding stored data is built in memory card 15. Further, memory card
15 includes power source switching circuit 35 which switches the power
source of RAM chip 36 from built-in battery 34 to power source 23 of
electronic still camera 10 or the power source of the reproducing unit
when memory card 15 is inserted into electronic still camera 15 or the
reproducing unit, respectively.
FIG. 4 shows an example of memory card 15 having 20 1 M-byts RAM chips
36.sub.1 to 36.sub.20. External terminals 32.sub.1 to 32.sub.3 and power
source terminals 33 are provided on one side of memory card 15. External
terminals 32.sub.1 to 32.sub.3 include 8-bit data terminals 32.sub.1,
address terminals 32.sub.2 for receiving address information A0 to A20 and
control terminals 32.sub.3. Memory card 15 of FIG. 4 has a memory capacity
of 20 Mbytes (2.56 Mbytes). Control terminals 32.sub.3 include terminal CS
for selection of RAM chips 36, write pulse terminals WP and card selection
terminals CE for selecting one of cards when a plurality of cards are
used. One of decoders 121.sub.1 and 121.sub.2 is selected by an input
supplied to terminals CS. Decorders 121.sub.1 and 121.sub.2 respectively
correspond to RAM chips 36.sub.1 to 36.sub.10 and 36.sub.11 to 36.sub.20.
CCD array 26 which is a solid state imaging device is used as an imaging
device for photographing still frame images, for example. A frame
interline transfer type CCD may be suitable for the CCD array 26 used in
the electronic still camera of this invention, for example.
FIG. 5 shows the modeled construction of one example of a frame interline
transfer type CCD solid state imaging device.
The CCD array has image receiving portions 51 formed of photoelectric
conversion elements such as photodiodes arranged in a matrix form.
Vertical transferring portions 52 are arranged along and adjacent to the
columns of image receiving portions 51. Charges in each of image receiving
portions 51 are transferred to a corresponding one of the vertical
transferring portions 52 in response to field shift pulse .phi.vl, and the
transferred from one end thereof to charge storage section 54 acting as a
frame memory section via transfer gate 53. Signal charges in charge
storage section 54 are transferred to output circuit 56 via horizontal
transferring section 55 and then output as an electrical signal. Drain
portion 57 is arranged adjacent to the other ends of vertical transferring
sections 52.
In a case where only one CCD array of this type is used to derive out a
color image signal, an optical color filter for separating light
components of red (R), green (G) and blue (B) is disposed on each image
receiving portion 51. Various types and arrangements of the optical color
filters are known in the art, and any type and arrangement may be used in
the electronic still camera of this invention.
Referring to FIGS. 6A and 6B, electronic still camera 10 of this invention
is explained in more detail.
The user can select a desired mode by operating mode switch 12 prior to the
operation of release 11 by taking the quality of image stored in the
memory card and the number of frames stored in the memory card into
consideration. Modes may be individually selected for each frame of still
images to effect photographing. The reason why the mode can be changed for
each frame will be described later. A selected mode signal is supplied
from central processing unit (CPU) 24.sub.1 to switch 31.sub.5. When the
memory card 15 is set to the camera body, CPU 24.sub.1 reads information
(a file number, a number of using blocks, etc. which will be described
later) of the memory card 15, and in case of a new card, it is initially
set.
When release 11 is depressed halfway, information of external color
temperature and the information of light exposure are supplied from white
balance sensor 17 and exposure sensor 19 to CPU 24.sub.1 via interface
(I/F) 24.sub.2. CPU 24.sub.1 controls diaphragm driving circuit 24.sub.5
in response to the information of light exposure so as to drive diaphragm
22. Further, CPU 24.sub.1 controls CCD driving circuit 25.sub.2 via I/F
24.sub.3 and signal generator 25.sub.1 according to the information of
white balance and light exposure so as to drive CCD array 26. Flash
driving circuit 24.sub.4 is controlled by a signal supplied from CPU
24.sub.1 via I/F 24.sub.3, and it is determined whether or not flash 16
such as an electronic flash should be driven by flash driving circuit
24.sub.4 at the photographing time. Amplifier circuit 27.sub.1 and color
separation.multidot..gamma. correction.multidot.white balance circuit
27.sub.1 are each controlled by a signal supplied from CPU 24.sub.1 via
I/F 24.sub.3 and a signal supplied CPU 24.sub.1 via I/F 24.sub.3 and
signal generator 25.sub.1.
When release 11 is further depressed to a fully depressed position, signal
generator 25.sub.1 supplies respective driving signals to CCD array 26,
amplifier 27.sub.1, color separation.multidot..gamma.
correction.multidot.white balance circuit 27.sub.2, A/D conversion circuit
28, signal processing circuit 31.sub.1, filter 31.sub.2, sub-sampling
circuit 31.sub.3, data compression circuit 31.sub.4, switch 31.sub.5, and
memory interface (memory I/F) 31.sub.7.
An image information signal is output from CCD array 26 in response to the
above described operation of release 11. The image information signal is
amplified to a preset level by amplifier 27.sub.1, and R, G and B signals
are supplied in parallel to A/D conversion circuit 28 via color
separation.multidot..gamma. correction.multidot.white balance circuit
27.sub.2 including a color separation circuit, white balance circuit and
.gamma. correction circuit. R, G and B digital signals output in parallel
from A/D conversion circuit 28 are converted into luminance signal Y1 and
color difference signals CR1 and CB1 by signal processing circuit
31.sub.1, and color difference signals CR1 and CB1 are supplied to
low-pass filter 31.sub.2 after the sampling number thereof is reduced to
one half. In this case, luminance signal Y1 is supplied to low-pass filter
31.sub.2 with the sampling number kept unchanged. Thus, luminance signal
Y1 and color difference signals CR1 and CB1 are obtained as linearly
quantized data with each sampled value represented by 8 bits. FIG. 7 shows
the relation between the sampling points of luminance signal Y1 and those
of color difference signals CR1 and CB1. Low-pass filter 31.sub.2 is a
pre-low-pass filter for sub-sampling. Luminance signal Y1 and color
difference signals CR1 and CB1 are supplied to sub-sampling circuit
31.sub.3 via low-pass filter 31.sub.2. In sub-sampling circuit 31.sub.3,
luminance signal is subjected to a line-offset sampling process and
converted into luminance signal Y2 whose sampling number is reduced to one
half, and color difference signals CR1 and CB1 are sampled in every other
line and converted into color difference signals CR2 and CB2 whose
sampling number is reduced to one half. FIG. 8 shows the relation between
the sampling data points of the signals. Luminance signal Y2 and color
difference signals CR2 and CB2 are supplied to data compression circuit
31.sub.4. As described before, luminance signal Y2 and color difference
signals CR2 and CB2 are linearly quantized using 8 bits for each sampled
value, but the data bit number for each sampling value is reduced in data
compression circuit 31.sub.4. In this embodiment, differential pulse code
modulation (DPCM) is used, for example, as the data compression system to
effect the data compression. The data compression by DPCM is well known in
the art, each sampling data is quantized by nonlinearly compressing a
difference between the sampling data and receding sampling data. For
example, in the case of luminance signal Y12 of FIG. 8, a difference
between luminance signals Y11 and Y12 is nonlinearly quantized, and each
sampling value is represented by 4 or 2 bits. Likewise, color difference
signals CR1 and CB1 are compressed and each sampling value is represented
by 4 or 2 bits. The luminance signal thus compressed is denoted by Y3, and
the color difference signals thus compressed are denoted by CR3 and CB3.
Switch 31.sub.5 is used to select the luminance signal and color difference
signals according to the set mode. In a case where mode (A) is set, for
example, signals Y1, CR1 and CB1 supplied from signal processing circuit
31.sub.1 are selected by switch 31.sub.5 and stored into memory card 15
via buffer memory 31.sub.6. Likewise, in mode (B), signals Y2, CR2 and CB2
supplied from sampling circuit 31.sub.3 are selected by switch 31.sub.5,
in mode (C), signals Y3, CR3 and CB3 compressed by data compression
circuit 31.sub.4 to represent each sampling value by 4 bits are selected
by switch 31.sub.5, and in mode (D), signals Y3, CR3 and CB3 compressed by
data compression circuit 31.sub.4 to represent each sampling value by 2
bits are selected by switch 31.sub.5. The signals selected by switch
31.sub.5 are stored in memory card 15 via buffer memory 31.sub.6.
In addition to image data, information relating to the selected mode is
also stored into memory card 15 together with the image data. (For
example, in modes (A) and (B), "001" and "010" are stored in the form of
binary code indicating the selected mode numbers).
For example, it is also possible to store in memory card 15 imaging data
such as data relating to use of the flash, white balance control data,
exposure data (or aperture data) and shutter speed data in the form of
binary code as well as the selected mode. The imaging data is displayed on
display unit 13 by the control of CPU 24.sub.1, thereby permitting the
user or operator to recognize the imaging data by observing display unit
13.
A method of storing data into memory card 15 is explained in detail with
reference to FIGS. 9A to 9E. In this example, a memory card of 20 Mbits or
2.56 Mbytes which has 20 RAMs or static RAMs (SRAM) of 1 Mbits mounted
thereon as shown in FIG. 4 is used.
As shown in FIG. 9A, all the memory space is divided into directory area, a
file allocation table (FAT) and a data area. As shown in FIG. 9B, there
are stored in the directory area various items of 1-byte information which
include information indicating a file number or image (frame) number in
the case where the file is image data; information indicating data
classification or the classification of image data, voice data or other
data; information indicating the imaging system, that is, the 525
(lines)/60 (fields) system or 625 (lines)/50 (fields) system in the case
of image data; information indicating the imaging mode or image
compression method (indicating the case where no data compression is
effected); information indicating the voice mode or compression method in
the case of voice data; information indicating the year in which the
recording or photographing was effected; information indicating the month
in which the recording was effected; information indicating the date on
which the recording was effected; information indicating the hour at which
the recording was effected; and information indicating the minute at which
the recording was effected. Further, the entry block number of the file
(image data file) and the number of data blocks used for storing the file
are stored into the directory area. The directory area has 16 bytes for
each file, and 256 f | | |
