Television – Camera – system and detail – Combined image signal generator and general image signal...
Reexamination Certificate
1998-02-03
2002-08-20
Ho, Tuan (Department: 2612)
Television
Camera, system and detail
Combined image signal generator and general image signal...
C348S500000
Reexamination Certificate
active
06437824
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image pickup apparatus and system that photographs an object to output a video signal, and in particular, to an image pickup apparatus with a separated image pickup section in which the image pickup section and a signal processing section are connected together via a cable or by radio as well as an image pickup system using this apparatus.
FIG. 28
is a block diagram showing a system configuration of a conventional general image input apparatus. In this figure, numeral
301
denotes a system control section for controlling the entire system; numeral
303
denotes an optical lens system including a zoom lens, a zoom motor that drives the zoom lens, a focus lens, and a focus motor that drives the focus lens; numeral
304
denotes an iris that adjusts the amount of incident light passing through the optical lens system
303
; numeral
305
denotes a CCD that is an image pickup element; and numeral
306
denotes a timing generator (hereafter referred to as a “TG”) for controlling the CCD
305
.
Reference numeral
307
denotes an S/H&AGC circuit for performing a sampling and holding operation to reduce noise from stored charges in the CCD
305
and adjusting the gain of an image pickup signal; numeral
308
denotes an A/D converter for converting an analog signal from the S/H&AGC circuit
307
into a digital signal; numeral
309
denotes a signal processing circuit for executing required signal processing to convert a digital signal from the A/D converter
308
into a video signal to output various information required to control auto-focus (AF), auto-exposure (AE), and auto-white-balance (AW).
The image input apparatus is integral and comprises an image pickup section and a signal processing section that are integrated together. The system control section
301
comprises a control data sampling module for sampling control data from the signal processing circuit
309
, an AF control module, an AE control module, and an AW control module.
In such a conventional integral image input apparatus, the system control section
301
obtains various control data from the signal processing section
309
(the control data sampling module) and based on this information, controls the zoom control module for controlling the zoom lens in the system control section
301
, the AF control module for controlling the focus and the AE control module for controlling the iris
304
, TG
306
, and S/H&AGC circuit
307
to maintain the signal level at a constant level.
The present day is called the “multimedia age” and the image input apparatus is used for various applications. One example is a television conference system. Image input apparatuses used for such a system have different functions for different applications. For example, a single focus camera is sufficient to photograph a single person while a camera with a tripod head or a zoom lens is required to photograph several people.
In the above conventional example, however, since the camera section that is the image pickup section is integrated with the camera signal processing section, all components of the image input apparatus must be replaced when it is used for different applications.
In view of this point, for an image pickup apparatus using a charge coupled device (hereafter referred to as a “CCD”) as an image pickup element, an apparatus called a head-separated camera has been proposed in which an image pickup section including a CCD and a signal processing section for processing a video signal from the CCD to output it as a video signal are separated from each other and connected to each other via a cable.
With the improvement of recent electronic technology, the size and weight of camera apparatuses using the CCD are being reduced. In particular, the improvement of semiconductor technology has contributed to the development of apparatuses for executing the A/D conversion of a video signal at a high speed and using a DSP (a Digital Signal Processing circuit) to process and output the digitalized video signal.
Such conventional head-separated cameras, however, require a large number of signal lines used to transmit video signals, various synchronizing signals in synchronism with the video signals, and various control commands for panning, tilting, and zooming the camera, between the camera head section and the signal processing section. In addition, the camera head section typically has no power supply unit for supplying electric power, so these cameras require a power supply line for supplying power from the signal processing section as well as the signal line described above.
In addition, if an attempt is made to separate the image pickup section from the image processing section with the VCR circuit configuration unchanged, control data transmitted between a controller for the image pickup section and a controller for the signal processing section will leak into a video signal to degrade it.
To avoid this condition, tight shielding can be provided to prevent signals from affecting each other but this requires a thick and hard cable to connect these sections together, resulting in degraded usability.
FIG. 29
shows a configuration of a conventional camera section (an image pickup section)
1
.
In
FIG. 29
, the camera section
1
has a zoom lens
10
; an iris
11
; an optical lowpass filter and infrared cut filter
12
; a CCD
13
; a CDS circuit
14
; an AGC circuit
15
; an addition circuit
16
for adding a CCD signal, a composite synchronizing signal, and a burst clock together; a drive circuit
17
for driving, for example, a 75-&OHgr; coaxial line
2
: a synchronizing signal generator (SSG)
19
; an MPU micro processing unit
20
for controlling the entire camera section
1
; and a burst gate (BG) circuit
18
for applying a gate to add a burst clock to a video signal.
The cable
2
connects the camera section
1
to an image processing section (a signal processing section)
3
, which is described below.
Reference numeral
30
denotes a terminal for outputting a video signal to which a clock and a composite synchronizing signal are added; numeral
31
denotes a terminal for outputting a transmit signal used to communicate with the image processing section
3
; and numeral
32
denotes a terminal for inputting a receive signal used to communicate with the image processing section
3
.
The operation is described with reference to
FIGS. 29
to
31
. A CCD image pickup signal (a video signal) is obtained via the zoom lens
10
, iris
11
, optical lowpass filter and infrared cut filter
12
, CCD
13
, CDS circuit
14
, and AGC circuit
15
. The synchronizing signal generator
19
outputs various synchronizing pulses and composite synchronizing signals used for CCD photographing, burst gate pulses (BGP), and a clock used as a reference for photographing. Based on the BGP from the synchronizing signal generator
19
, the burst gate (BG) circuit
18
executes gating so as to change a continuously input clock into a burst clock suitable for addition to a video signal. The addition circuit
16
adds together a video signal output from the AGC control circuit
15
, a burst clock from the BG circuit
18
, and a composite synchronizing signal from the synchronizing signal generator
19
. After addition, the video signal is driven by the 75-&OHgr; drive circuit
17
and output to the image processing section
3
from an output terminal
30
.
FIG. 30
shows part of a video signal to which a burst clock and a composite synchronizing signal are added. “A” shows a composite synchronizing signal, “B” shows a burst clock, and “C” shows a video signal area. The MPU
20
uses an output terminal
31
and an input terminal
32
to communicate with an MPU in the image processing section
3
in order to drive the zoom and auto-focus lenses and to control the iris and AGC.
FIG. 31
shows a configuration of a conventional image processing section
3
. The image processing section
3
is shaped like an extension board of a computer and inserted into an extension board slot in the computer.
The ima
Kawai Hisashi
Komine Takayuki
Suzuki Yasuo
Tabei Kunihiko
Yasuda Hitoshi
Canon Kabushiki Kaisha
Ho Tuan
Morgan & Finnegan , LLP
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