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Description  |
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FIELD OF THE INVENTION
The present invention generally relates to an electronic imaging system
such as an electronic still camera system and, more particularly, to an
electronic still camera system for converting an electronically
sensed/input electronic still image into a digital image signal and
recording the image signal by using an inexpensive magnetic recording
medium such as a magnetic disk.
DESCRIPTION OF THE RELATED ART
With a decrease in size and an increase in performance of solid-state image
sensing devices, various types of electronic cameras using these
solid-state image sensing devices have been developed. A home video camera
is one of them. Recently, various electronic still cameras for
electronically sensing and recording an object image instead of recording
an object image by using a silver chloride film have been developed.
An electronic still camera of this type is basically designed to
electronically sense/input an object image formed on the image sensing
surface of a solid state image pickup device such as a CCD (charge coupled
device) through an optical lens and to record it in a magnetic floppy disk
or a magnetic tape upon predetermined image signal processing, as
disclosed in, e.g., Published Unexamined Japanese Patent Application No.
56-43884. In an electronic still camera designed to convert an object
image into a digital signal, a sensed/input electronic still image is
converted into a digital signal, and the digital signal is recorded in a
so-called semiconductor memory card or the like.
The electronic still image sensed/recorded in this manner is read out from
the recording medium by using a reproduction apparatus and is converted
into a television signal of, e.g., the NTSC (National Television Standard
Committee) scheme so as to be reproduced as an image on a TV receiver
(monitor).
In the above-described recording of an electronic still image using a
magnetic floppy disk or a magnetic tape, a recording format and the like
are standardized according to the EIAJ (Electronic Industries Association
of Japan) standards or the like. In electronic still cameras of this type,
therefore, various attempts have been made to record/reproduce an image
signal with high quality while satisfying the standards of this type.
In contrast to this, in electronic still cameras designed to convert an
electronic still image into a digital signal and record the digital signal
on a semiconductor memory card, no significant movement toward
standardization is present. In such a type of camera, various studies have
been made on efficient recording/reproduction of an image signal with high
quality. However, the serious problem of electronic still cameras of this
digital recording scheme is that semiconductor memory cards used for
digital recording of image signals are very expensive.
If digital recording of image signals is performed by using the
above-mentioned magnetic disk or magnetic tape in place of such an
expensive memory card, the cost of recording can be reduced to, for
example, 1/50 that of recording using the memory card, thus allowing users
to very easily use the camera.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a new and
improved electronic imaging system such as electronic still camera system
with high quality image recording/reproduction functions in which digital
recording of electronic still images can be effectively performed by using
an inexpensive, easy-to-use magnetic floppy disk, magnetic tape or hard
disk of small size as a recording medium, and high-quality image
reproduction can be performed, thereby greatly increasing the practical
value of the system.
According to one aspect of the present invention, an electronic imaging
system is provided for recording or reproducing a picture utilizing an
applied recording device or media comprising. An imaging main system
includes a data processing means and one-side connector means, with the
data processing means generating a data signal to be recorded in the
recording device or media inclusive of a digital image data signal
corresponding to a previously picked-up image, or generating a signal of a
form adapted to display an image on a display means based on a reproduced
signal from the recording device or media. The one-side connector means
connects any one of several predetermined imaging sub-systems applicable
to the electronic imaging system with the imaging main system. A plurality
of first imaging sub-systems has each one being formed as a unit and
having a driver circuit means and an other-side connector means. The
driver circuit means drives a magnetic recording device or media so as to
record or reproduce the data signal supplied thereto or sent therefrom,
while such first imaging sub-system is connected to the imaging main
system by means of a connection between the one-side connector means of
the imaging main system and the other-side connector means of such imaging
sub-system. A plurality of second imaging sub-systems has each one being
formed as a unit and having an I/O controller means and an other-side
connector means, the I/O controller means controlling record and/or
reproduction operations for an applied semiconductor memory as to the data
signal supplied thereto or sent therefrom, while such second imaging
sub-system is connected to the imaging main system by means of a
connection between the one-side connector means of the imaging main system
and the other-side connector means of such second imaging sub-system. The
I/O controller means controls transmission of the data signal conveyed
through the other-side connector means of such second imaging sub-system
to be compatible with the data signal conveyed through the other-side
connector means of such first imaging sub-system.
The electronic imaging system embodied as an electronic still camera system
according to the present invention takes an effect that after an
electronically sensed electronic still image signal is digitized and is
processed by predetermined error correction coding, the obtained signal is
subjected to predetermined recording modulation and is recorded on a
predetermined magnetic recording medium.
Especially an electronic still camera, as the imaging main system, for
electronically sensing an object image is characterized in that the camera
includes a video processor for performing predetermined video signal
processing for an electronic still image signal electronically sensed by
an image sensing device, an A/D converter for performing digital
conversion of the electronic still image signal processed by the video
processor according to the predetermined video signal processing, and a
data compressor for data-compressing the digital electronic still image
signal, and a mechanism for performing predetermined error correction
coding and recording modulation for the data-compressed electronic still
image signal and recording the obtained signal on a magnetic recording
medium which is disposed in a detachably mounted attachment circuit unit
as the first imaging sub-system.
In the electronic imaging system embodied as a reproduction system, an
attachment circuit unit, as the first imaging sub-system, having a
mechanism for reading out and demodulating a signal recorded in a magnetic
recording medium and subsequently performing error correction processing
for the signal is detachably mounted to a reproduction apparatus, as the
imaging main system, and the apparatus includes a means for performing
data decoding of a reproduction signal output from the attachment circuit
unit, a D/A converter for performing predetermined image signal processing
for the data-decoded signal and subsequently restoring the signal to an
analog signal of the original form, and means for converting the analog
signal into a signal having a predetermined monitoring signal form.
In addition, the electronic still camera is characterized in that the
electronic still image signal is recorded by arbitrarily using recording
tracks and sectors set on a magnetic recording medium in accordance with,
e.g., the form of error correction coding for the electronic still image
signal, and corresponding recording management information is recorded on
a predetermined specific track of the magnetic recording medium.
Furthermore, the electronic still camera is characterized in that the
camera includes a function for testing the characteristics of the
recording tracks and sectors set on the predetermined magnetic recording
medium and allowing only recording tracks and sectors of the magnetic
recording medium which pass the test to be used for recording of the
electronic still image signal. Moreover, the electronic still camera is
characterized in that the camera includes a means for reproducing the
electronic still image signal from the predetermined magnetic recording
medium immediately after the electronic still image signal is recorded on
the magnetic recording magnetic medium and testing quality of the
electronic still image signal recorded on the magnetic recording medium,
thereby realizing highly reliable recording of the electronic still image
signal on the magnetic recording medium.
According to the present invention, when digital recording of an
electronically sensed electronic still image signal is to be performed,
error correction coding is performed for the digital image signal. For
this reason, even if a burst-like error such as dropout is caused in the
digital image signal recorded on a magnetic floppy disk or a magnetic
tape, the error can be effectively compensated to ensure sufficiently high
signal quality.
In addition, since the digital signal processed by error correction coding
is subjected to recording modulation and is recorded on a magnetic
recording medium, DC components contained in the recorded data can be
effectively suppressed, and problems associated with, e.g., the DC
blocking characteristics of the magnetic head or the like can be
effectively prevented. This allows high-quality recording/reproduction of
the image signal.
In addition, an error correction coding circuit, a recording modulation
section, and the like are formed into an attachment circuit unit, and the
unit is used after it is mounted in the electronic still camera as needed.
With this system arrangement, the electronic still camera can be applied
to various different purposes by interchanging attachment circuit units,
thus improving the applicability. More specifically, a semiconductor
memory card is prepared as the second imaging sub-system of the present
invention, recording/reproduction of an image signal can be performed in
accordance with various types of recording media by simply selecting the
corresponding circuit unit.
Furthermore, since recording of electronic still images is performed by
arbitrarily using empty areas of the recording tracks and sectors of a
magnetic recording medium in accordance with, e.g., the form of error
correction coding for electronic still image signals, more specifically a
data amount or the like, a large number of electronic still image signals
can be recorded by effectively using the limited storage capacity of the
magnetic recording medium.
Moreover, only recording tracks and sectors which pass quality tests in
advance are used for recording of the electronic still images, and an
electronic still image signal recorded on the magnetic recording medium is
immediately read out to test its recording quality. Therefore, the
recording quality can be made sufficiently high in spite of the fact that
the inexpensive magnetic recording medium is used.
Additional objects and advantages of the invention will be set forth in the
description which follows, and in part will be obvious from the
description, or may be learned by practice of the invention. The objects
and advantages of the invention may be realized and obtained by means of
the instrumentalities and combinations particularly pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part
of the specification, illustrate presently preferred embodiments of the
invention and, together with the general description given above and the
detailed description of the preferred embodiments given below, serve to
explain the principles of the invention, in which:
FIGS. 1 and 2 show an electronic imaging system according to an embodiment
of the present invention, in which
FIG. 1 is a block diagram showing a schematic arrangement of an electronic
still camera system as the electronic imaging system, and
FIG. 2 is a block diagram showing a schematic arrangement of a reproduction
system as the electronic imaging system;
FIG. 3 is a block diagram showing an arrangement of an attachment circuit
unit, as the first imaging sub-system, including recording/reproduction
functions with respect to a magnetic recording medium;
FIG. 4 is a block diagram showing a semiconductor memory card formed into
an attachment circuit unit as the second imaging sub-system;
FIG. 5 is a block diagram showing a schematic arrangement of an electronic
still camera having a frame memory and a data-compressing means built in
one body;
FIG. 6 is a view showing a recording format of recording management
information applied to the camera in FIG. 5;
FIG. 7 is a block diagram showing a schematic arrangement of an electronic
still camera having a ROM test data contained therein; and
FIG. 8 is a block diagram showing a schematic arrangement of an electronic
imaging system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the presently preferred embodiments
of the invention as illustrated in the accompanying drawings, in which
like reference characters designate like or corresponding parts throughout
the several drawings.
Electronic still camera systems according to several embodiments of the
present invention will be described below with reference to the
accompanying drawings.
FIG. 1 is a block diagram showing a schematic arrangement of an electronic
still camera system associated with an electronic imaging system according
to an embodiment of the present invention. FIG. 2 is a block diagram
showing a schematic arrangement of a reproduction system as the electronic
imaging system associated with the system in FIG. 1.
Referring to FIG. 1, an electronic still camera A includes an image sensing
system constituted by a controller 10 for controlling the overall
operations of the camera A, a solid-state image pickup device 11,
constituted by a CCD (charge coupled device) or the like, for
electronically sensing/inputting an object image, and an optical lens 12
for forming an object image on the image sensing surface of the
solid-state image pickup device 11. The electronic still camera A is
designed to input electronic still image signals electronically sensed by
the solid-state image pickup device 11 to a color video processor 13 so as
to perform predetermined video signal processing. Video signal processing
to be performed by the video processor 13 includes y correction processing
for the image system, color separation processing for separating each
image signal into a luminance signal component and a color difference
signal component, and the like.
The luminance signal component and the line sequential color difference
signal output upon color separation processing by the color video
processor 13 are respectively converted into digital signals by A/D
converters 14 and 15 and are supplied to a data compressing section 16. In
an electronic still camera using a semiconductor memory card (not shown)
as an image signal recording medium, digital image signals subjected to
predetermined data compression processing in the data compressing section
16 are sequentially and electronically recorded on the semiconductor
memory card upon addition of control information for the electronic still
images.
Note that in this electronic still camera A, audio information associated
with the electronic still images sensed/input in the above-described
manner is also acquired and recorded together with the electronic still
images.
More specifically, a microphone 17 acquires/inputs audio information
(including ambient sound information) associated with an object (to be
sensed) upon image sensing of an object image. The input audio information
is amplified to a predetermined input level by a preamplifier 18. The
audio information input/processed in this manner is converted into a
digital signal by an A/D converter 19 and is subjected to time axis
compression by re-sampling or the like in a time base converting section
20. The time-axis-compressed audio information is then subjected to
predetermined data compression processing in a data compressing section
21. When the electronic still image signal is to be recorded on the
semiconductor memory card, as the second imaging sub-system in the
above-described manner, the signal is recorded in association with a
corresponding recorded image signal.
The electronic still camera A according to this embodiment is characterized
in that, in place of the semiconductor memory card, an attachment circuit
unit 22, as the first imaging sub-system, including a magnetic recording
medium 27 such as a hard disk of small size, a magnetic floppy disk or a
magnetic tape as a signal recording medium is attached in place of the
semiconductor memory card.
More specifically, the attachment circuit unit 22 basically comprises a
frame memory 23 for receiving and buffering a one-frame image signal
data-compressed by the data compressing section 16, and an error
correction coding section 24 for reading out the data-compressed digital
image signal from the frame memory 23 in synchronism with a signal
recording operation with respect to the magnetic recording medium 27, and
reading out digital audio information data-compressed by the data
compressing section 21, thereby performing predetermined error correction
coding processing of the read signal and information.
Error correction coding processing by the error correction coding section
24 is performed by using Reed-Solomon product codes or the like which
exhibit high error correction performance with respect to, e.g.,
burst-like code errors, allow arbitrary selection of code lengths, and
allow hardware to be easily formed into an LSI. More specifically, a
one-frame image is divided into a large number of blocks, and Reed-Solomon
product coding is performed by doubly adding redundant bits for error
correction in horizontal and vertical directions.
In the attachment circuit unit 22, the digital signal (image signal and
audio information), which underwent error correction coding in this
manner, is further subjected to predetermined recording modulation
(recording coding) in a recording modulation section 25. This recording
modulation processing is performed by suppressing DC components contained
in the above-mentioned digital signal as an object to be recorded, because
a magnetic head and the like for recording signals in the magnetic
recording medium 27 have DC blocking characteristics, and performing
coding processing (modulation processing) for averaging inversion
intervals of bits. In this recording modulation processing, for example,
as a coding scheme, various techniques are used: scrambled NRZ (non return
to zero) coding, 8-10 block coding, and Miller square coding.
The signal subjected to recording modulation by such coding is magnetically
recorded on the magnetic recording medium 27 through a driver circuit 26.
The above-described error correction coding and recording modulation
processing required to digitize an electronic still image are performed by
the circuit portion integrated as the attachment circuit unit 22
independently of the main body portion of the electronic still camera A.
In addition, error correction coding processing and recording modulation
processing for burst-like signal errors due to dropout and for the DC
blocking characteristics, which tend to pose problems when digital signals
are recorded on the magnetic recording medium 27 such as a hard disk of
small size, a magnetic floppy disk or a magnetic tape, are executed in the
attachment circuit unit 22. As a result, inconveniences posed in magnetic
recording can be effectively eliminated, and magnetic recording of digital
image signals can be effectively performed by using the magnetic recording
medium 27 such as a hard disk of small size, a magnetic floppy disk or a
magnetic tape which are inexpensive and easy to handle.
Note that the above-mentioned magnetic recording medium 27 is detachably
mounted on the attachment circuit unit 22 and is replaced with another
medium as needed to be used for digital recording of image signals and
audio information.
The digital image signal magnetically recorded on the magnetic recording
medium 27 in the above-described manner is read and reproduced by a
reproduction apparatus B (FIG. 2) and is provided for image reproduction
by means of a TV monitor C in the following manner.
Referring to FIG. 2, the reproduction apparatus B, as the electronic
imaging system, is basically designed to read out the electronic still
image signal and the audio information recorded as digital data in the
semiconductor memory card, as the second imaging sub-system, and to
perform processing for image and sound reproduction. At the same time, the
reproduction apparatus B is designed to mount a circuit portion as an
attachment circuit unit 28, as the first imaging sub-system, in place of
the semiconductor memory card and to read out the digital image signal and
the audio information magnetically recorded on the magnetic recording
medium 27 so as to perform signal processing for image and sound
reproduction.
More specifically, the attachment circuit unit 28 to be mounted on the
reproduction apparatus B comprises a demodulator 29 for reading out image
signals from a magnetic recording medium set in the unit 28 and performing
demodulation processing of the readout image signals, and an error
correcting section 30 for detecting data errors from the signals read out
from the magnetic recording medium 27 by using the error correction codes
added by the error correction coding processing as described above, and
performing error correction of the detected errors. The demodulator 29 is
arranged in correspondence with the recording modulation section 25 (FIG.
1) and has a function of restoring the modulated signal, which is
recording-modulated by suppressing its DC components so as to compensate
for the DC blocking characteristics of the magnetic head, to the original
signal form. Error correction processing is performed for signals
demodulated by the demodulator 29 so that even if burst-like signal
omissions (signal errors) such as dropouts occur when signal
recording/reproduction is performed with respect to the magnetic recording
medium 27, these omissions can be effectively corrected.
The signals obtained by compensating for the problems associated with
digital signal recording on the magnetic recording medium 27 by using the
attachment circuit unit 28 are input to the main body portion, as the
imaging main system, of the reproduction apparatus B.
In the main body portion of the reproduction apparatus B, the image signal
components are data-compressed by the above-described data compression
pressing and are decoded by a data decoding section 31. The image signal
decoded by the data decoding section 31 is stored in a one-frame memory
incorporated in an image processing section 32. The image processing
section 32 performs predetermined signal processing with respect to the
one-frame image signal stored therein. For example, the image processing
section 32 separates the image signal into, e.g., luminance signal
components and color difference signal components and sequentially outputs
them. The luminance signal components and the color difference signal
components output from the image processing section 32 are restored to the
original analog signal form through D/A converters 33 and 34. The restored
analog signal is then supplied to, e.g., an NTSC converting section 35 to
be converted into an NTSC television signal and is output to a TV monitor
C so as to be reproduced as an image.
Meanwhile, in the reproduction apparatus B, decoding processing of the
audio information supplied from the attachment circuit unit 28 is
performed by a data decoding section 36 in the sam | | |
