Camera apparatus

High-resolution image data and large-capacity data are transmitted as transmission data. A camera apparatus includes a fixing part and a moving part rotating about a rotary axis. The fixing part includes at least a first wireless section, a first signal processing section, and a power source section. The moving part includes at least a camera section, a second signal processing section, a second wireless section, and a driver section for driving the camera section. The first wireless section is coupled with the second wireless section using a waveguide tube to propagate an electric wave. The waveguide tube includes a waveguide path aligned with a center of the rotary axis of the moving part.

INCORPORATION BY REFERENCE

The present application claims priority from Japanese application JP 2006-014694 filed Jan. 24, 2006, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

The present invention relates to a camera apparatus, and in particular, to an endless camera apparatus using wireless data transmission.

Monitor camera apparatuses using imaging devices have been actually employed in many cases to monitor an invader or an invading object (which will be referred to as an invading object hereinbelow) making an invasion upon, for example, a public building, a public place, a hospital, a bank, a shop such as a supermarket, or a zone which any unauthorized person is forbidden to enter such as a dam, a base, or an airport. When such monitor camera apparatus is employed to a remote monitor system, the monitor area to be monitored by the system can be easily confirmed by visually checking images produced by the monitor camera apparatus. It is therefore possible to construct a high-quality warning monitor system capable of appropriately and rapidly cope with various states according to situations monitored by the monitor camera apparatus.

However, to monitor the monitor target area for a long period of time by remote control, high reliability is required for such monitor camera system. Particularly, when the monitoring apparatus is installed in a place requiring high security such as a bank, a base, or an airport or a place at a high altitude or a remote place such as a dam or a port, maintenance of the apparatus is quite troublesome. There consequently exists a demand for a monitor camera apparatus in which the human power and time required for the maintenance and inspection thereof can be reduced to the maximum extent.

To fully achieve the monitoring function, the monitor camera apparatus requires a wide monitor zone depending on places. For this purpose, the monitor camera apparatus includes a driver module to drive the camera itself in a pan direction (horizontal direction) and in a tilt direction (direction of angle of elevation) to widely change the visual field range of the monitor camera apparatus. Particularly, there recently exists a demand for a camera apparatus which covers a wide monitor range to track an invading object by use of an endless rotation in a pan direction.

On the other hand, the camera apparatus generally includes a coaxial cable to transmit a video signal from a camera section to shoot an object as well as a camera control signal and to supply power for the operation of the camera section. The coaxial cable is connected to a fixing part and a moving part in the configuration. That is, a first end of the coaxial cable is connected to the fixing part and a second end thereof is connected to the moving part. For example, the camera section and the lightening device are configured to be united with each other onto a rotary axis which rotates together with the camera section so that the camera section and the lightening device move as one unit. However, the wiring cables of the camera section, the lightening device, and the like are disposed on the substrate of the fixing part which does not rotate together with the camera section. Therefore, in the monitor camera apparatus in which the visual field is to be frequently changed as described above, the wiring cables are twisted and are repeatedly expanded and contracted. This causes disconnection or connection failure of the wiring cables. In the camera apparatus connected by wiring cables as above, it is not possible to conduct the endless rotation in the pan direction.

Such camera apparatus to implement the endless rotation has already been put to practical uses.FIG. 5is a diagram showing an outline of the configuration of a camera apparatus of a conventional type using slip rings. The camera apparatus ofFIG. 5includes a moving part501and a fixing part502. The moving part501includes a camera section503to shoot an image of an object such as an invader or an invading object, a signal processing section504which appropriately processes the video signal of the image of the object shot by the camera section503and which converts the video signal into a signal for transmission, a camera driver section505to drive the camera section503in the pan and tilt directions, a power source section506to supply power to the camera section503, the signal processing section504, and the driver section505and so on. The moving section501can conduct endless rotation about a rotary axis, not shown.

The fixing part502includes a signal processing section508to appropriately process the video signal from the signal processing section504, an interface (I/F) section510, a power source section509and so on. The fixing part502is attached to a place at a high altitude, for example, on a wall or a ceiling. Reference numeral507indicates slip rings S1, S2, and S3each of which includes as well known a fixed conductor and a rotating conductor or a rotating (or a rotary brush), not shown. Reference numeral511is an input/output terminal for the video and control signals and reference numeral512is a power input terminal.

Operation of the configuration will be briefly described. Alternating-current (ac) power inputted from the power terminal512is converted by the power source section509into, for example, direct-current (dc) power to be supplied via the slip ring S3to the power source section506. Although not shown inFIG. 5, it is to be appreciated that power is supplied from the power source section506respectively to the camera section503, the signal processing section504, the driver section505and so on. Control signals for the camera section503and the driver section505are inputted from the input terminal511to be fed via the interface section510to the signal processing section508. The control signals are separated in the signal processing section508and are applied via the slip ring S2respectively to the camera section503and the driver section505. The control signals are used, for example, to adjust the focus and the color balance in the optical system of the camera section503and to adjust the pan and tilt angles in the driver section505. The video signal of the image of the object shot by the camera section503is appropriately processed by the signal processing section504to be supplied via the slip ring S1to the signal processing section508and is then outputted via the interface section510from the input/output terminal511.

As described above, in the camera apparatus employing slip rings, the moving part501including the camera section503can conduct endless rotation. It is therefore possible to configure a camera apparatus which covers a wide range as a monitor device. However, as can be seen fromFIG. 5, when the video data and the control data from the camera section are supplied via the slip rings, the transmission data is limited to analog data of low resolution or control data with a small amount of information. For example, to transmit image data of high resolution and data of a large capacity, it is required to use digital signals in a range from about several megahertz (MHz) to about 30 MHz. This consequently leads to a problem that the digital signals of such high frequency cannot be transmitted via the slip rings. There hence exists a demand for the implementation of a camera apparatus which can conduct the endless rotation and which can transmit image data of high resolution and data of a large capacity.

The technique described above are described in, for example, JP-A-9-284612.

SUMMARY OF THE INVENTION

According to the conventional method using slip rings, only analog data of low resolution or control data including a small amount of information can be transmitted, namely, it is not possible to transmit image data of high resolution and large-capacity data.

It is therefore an object of the present invention to provide a camera apparatus enabling transmission of high-resolution and high-quality image data and the like.

Another object of the present invention is to provide a camera apparatus capable of conducting the endless rotation and capable of transmitting digital data and the like.

Still another object of the present invention is to provide a camera apparatus employing wireless transmission.

In accordance with the present invention, a camera apparatus is configured to include a fixing part and a moving part which rotates about a rotary axis. The fixing part includes at least a first wireless section, a first signal processing section, and a power source section. The moving part includes at least a camera section, a second signal processing section, a second wireless section, and a driver section for driving the camera section. The camera apparatus further includes a waveguide tube which propagates an electric wave and which couples the first wireless section with the second wireless section. The waveguide tube includes a waveguide path aligned with a center of the rotary axis of the moving part.

The camera apparatus is configured that either one of the first and second wireless sections is fixed onto a first end of the waveguide tube and other one of the first and second wireless sections is supported with a predetermined gap between the other one wireless section and a second end of the waveguide tube.

The camera apparatus is configured to further includes a shielding cylinder for preventing leakage of the electric wave. The shielding cylinder includes an axis thereof aligned with an axis of the waveguide path and covers the gap.

In the camera apparatus, the shielding cylinder has a length set to at most about a quarter of a wavelength λ of the electric wave in the waveguide tube, the electric wave propagating through an inside of the waveguide tube.

The camera apparatus is configured that the fixing part further includes a power source section. The camera apparatus further includes a slip ring on the waveguide tube. Power from the power section is fed via the slip ring to at least to the camera section, the second signal processing section, the second wireless section, the second wireless section, and the driver section for driving the camera section of the moving part. A video signal from the camera section disposed in the moving part is obtained via the second wireless section and the waveguide tube from the first wireless section.

Moreover, the camera apparatus of the present invention further is configured to include a control signal input section such that the control signal is obtained via the first wireless section and the waveguide tube from the second wireless section. The carrier frequency to transmit the control signal via the waveguide tube is different from the carrier frequency to transmit the video signal via the waveguide tube.

According to the present invention described above, by using the camera apparatus capable of conducting the endless rotation, it is possible to construct a high-resolution and high-quality camera apparatus.

Another object of the present invention is to provide a camera apparatus capable of transmitting high-resolution and high-quality image data. Since digital data can be transmitted using the wireless transmission, it is possible to construct a high-resolution and high-quality camera system.

DESCRIPTION OF THE EMBODIMENTS

Referring toFIG. 1, description will be given of an embodiment of the present invention.FIG. 1shows an outline of the configuration of the embodiment of the present invention. The configuration ofFIG. 1includes a support section101(also called a fixing section) of a monitor camera apparatus and is fixed onto, for example, a ceiling102. Reference numeral103is a protective cover in the contour of a dome formed of transparent or semi-transparent glass or resin and is fixed onto the support section101.

Reference numeral104is a cabinet (also called a moving section) constituting the moving section and is rotably coupled via a coupling shaft105with the support section101. Specifically, in the configuration, the cabinet104constituting the moving section is coupled via a bearing129with the coupling shaft105to conduct the endless rotation by the driver section127.

The cabinet104includes a camera section120to produce an image of an invading object, a zoom lens121to magnify the image of the object, a signal processing section122which appropriately processes the video signal produced by the camera section120and which transmits the processed signal therefrom, a wireless section123to transmit through wireless transmission the video signal using a carrier of, for example, a millimeter band; a shielding cylinder124to prevent leakage of electric waves, a driver section128to drive the camera section120, and a slip ring rotary conductor (or a rotary brush)130. These constituent components arranged in the cabinet104are fixed onto the cabinet according to necessity and rotate together with the cabinet104about an axis200(shown inFIGS. 2A and 2B) of the coupling shaft105. The constituent components disposed in the cabinet104are only representatively shown. That is, other parts and members are also disposed therein according to necessity.

Reference numeral126is a circular waveguide tube. The carrier of the millimeter band propagates through the inside of the waveguide tube126. The waveguide tube126is fixed onto the fixing part101. Reference numeral125is a fixed conductor of slip rings and is fixed onto an outer circumference of the waveguide tube126.

The support section101includes a wireless section110to receive the carrier signal of the millimeter band propagating through the waveguide tube126, a signal processing section111to appropriately process the signal from the wireless section110, and a power source section112. Reference numeral113is a video signal input/output terminal, reference numeral114is a power input terminal, and reference numeral115is a control signal input/output terminal. The support section101naturally includes other parts according to necessity.

Description will now be given of operation of the monitor camera apparatus shown inFIG. 1. For example, an ac voltage supplied to the power input terminal114is converted into a dc voltage by the power source section112and is fed via the fixed conductor125of the slip ring and the rotary conductor (or rotary brush)130of the slip ring to the camera section120, the signal processing section122, the wireless section123, the driver sections127and128and so on. In the embodiment, although the power source section112converts the ac voltage into a dc voltage, the conversion may be conducted in the cabinet104. InFIG. 1, only part of the power supply operation is shown. The slip ring is employed for the power supply operation for the following reason. It is possible to supply large power, and the frequency is low for the direct current and the alternating current, and hence the transmission is not hindered.

The video signal produced by the camera section120is processed through a predetermined operation by the signal processing section122and is fed to the wireless section123. The wireless section123converts the video signal into a carrier signal of the millimeter band, which will be described later, and the signal is transmitted via the waveguide tube126to the wireless section110. The wireless section110converts the carrier signal received as above into a baseband signal, which is then delivered to the signal processing section111. The signal processing section111executes predetermined signal processing for the signal from the wireless section110to send the signal from the video signal output terminal113to a transmission path in the subsequent stage or to display a monitor image on a monitor, not shown.

If a control signal from, for example, a monitor center is inputted to the control signal input/output terminal115, the control signal is appropriately processed by the signal processing section111to be supplied to the wireless section110. The wireless section110converts the control signal into a carrier signal of the millimeter band, which will be described later, and the signal is transmitted via the waveguide tube126to the wireless section123. The wireless section123converts the carrier signal received as above into an Intermediate-Frequency (IF) signal and amplifies the signal to deliver the signal to the signal processing section122. The signal processing section122converts the IF signal into a baseband signal and separates the control signal to thereby control the camera section120and the zoom lens121. The control signal is also fed to the driver sections127and128to adjust the pan and tilt directions.

Referring now toFIGS. 2A and 2B, description will be given in detail of the wireless sections110and123, the waveguide tube126, and the shielding cylinder (having a cylindrical contour)124.FIG. 2Ashows a cross-sectional view of the wireless sections110and123, the waveguide tube126, and the shielding cylinder124.FIG. 2Bis a plan view ofFIG. 2Aalong line B-B. The wireless sections110and123are only partially shown inFIGS. 2A and 2B. Specifically, only part thereof coupled with the waveguide tube126are shown. InFIGS. 2A and 2B, the wireless section110is appropriately fixed onto the support section101. The wireless section123is constructed to rotate about a central axis200. InFIGS. 2A and 2B, reference numeral201is a metallic cabinet, reference numeral202is a semiconductor circuit element section constituting a high-frequency module of the wireless section, which will be described later, reference numeral203is a dielectric substrate, reference numeral204is an electrode leading airtight pin disposed on a side surface of the metallic cabinet201, and reference numeral205is wiring (a wire piece of metal or the like) to connect an electrode of the semiconductor circuit element section202to the airtight pin204. Reference numeral207is a metallic cap to keep the metallic cabinet201airtight. Reference numeral208is a stripline constituting an antenna for the millimeter band. Reference numeral206is wiring (a wire piece of metal or the like) to connect the stripline to the semiconductor circuit element section202.

Reference numeral209is a metallic electrode and reference numeral210is a throughhole disposed in the metallic cabinet201to couple a waveguide path or line212of the waveguide tube126with the stripline208. Reference numeral211is a transmission line including a metallic electrode. In the metallic electrode211, there is disposed an opening having a contour and a size which are substantially equal to those of the waveguide path212of the waveguide tube126or an opening having a contour in a size expressed by a product between the size of the waveguide path212and a reciprocal number of the square root of the relative dielectric constant of the dielectric substrate203. InFIG. 2A, there is disposed a circular opening substantially equal in size to the throughhole210. Thanks to the configuration, it is possible that a high-frequency signal is obtained from the stripline208constituting an antenna and is fed to the waveguide path212. The high-frequency signal can be supplied from the waveguide path212via the stripline208to the semiconductor circuit element section202.

Also, the wireless section123is configured in almost the same way as for the wireless section110. That is, inFIGS. 2A and 2B, reference numeral221is a metallic cabinet and reference numeral222is a semiconductor circuit element section constituting a high-frequency module of the wireless section, which will be described later. Reference numeral223is a dielectric substrate, reference numeral224is an electrode leading airtight pin disposed on a side surface of the metallic cabinet221, and reference numeral225is wiring (a wire piece of metal or the like) to connect an electrode of the semiconductor circuit element section222to the airtight pin224. Reference numeral227is a metallic cap to keep the metallic cabinet221airtight. Reference numeral228is a stripline constituting an antenna for the millimeter band. Reference numeral226is wiring to connect the stripline to the semiconductor circuit element section222.

Reference numeral229is a metallic electrode and reference numeral230is a throughhole disposed in the metallic cabinet221to couple a waveguide path212of the waveguide tube126with the stripline228. Reference numeral231is a transmission line including a metallic electrode. In the metallic electrode231, there is disposed an opening having a contour and a size which are substantially equal to those of the waveguide path212of the waveguide tube126or an opening having a contour in a size expressed by a product between the size of the waveguide path212and a reciprocal number of the square root of the relative dielectric constant of the dielectric substrate223. InFIG. 2A, there is disposed a circular opening substantially equal in size to the throughhole230. The configuration is possible that a high-frequency signal is obtained from the stripline228constituting an antenna and is fed to the waveguide tube126. The high-frequency signal can be supplied from the waveguide tube126via the stripline228to the semiconductor circuit element section222.

Next, description will be given of the circular waveguide tube126and the shielding cylinder124to transmit the millimeter-band carrier signal. In this situation, the frequency of the millimeter band ranges, for example, from about one gigahertz (GHz) to about 60 GHz. In the description of the embodiment, there is employed, for example, a millimeter wave of 2.4 GHz. The shielding cylinder124having a cylindrical contour is fixed onto the metallic cabinet221and rotates together with the metallic cabinet221as one unit about the rotary axis200. The metallic cabinet221and the shielding cylinder124are separated from the waveguide tube126with a gap232therebetween. It is therefore likely depending on cases that unnecessary electric waves leak from the gap232to exert adverse influence upon other electronic devices. Or, unnecessary electric waves enter the gap232to exert adverse influence upon the video signal. To cope with the difficulty, there is arranged the shielding cylinder124to prevent the leakage of the unnecessary electric waves from the gap232and to prevent the unnecessary electric waves from entering the gap232. Height H of the shielding cylinder124and width of the gap232are determined as below. The wavelength λ of the 2.4 GHz millimeter wave in the tube is expressed as follows.
λ=v/f=3.0×1011(mm/s)/2.4×109Hz=125 mm   (1)

To prevent the leakage of the electric waves from the gap232, it is required that height H and gap width R are equal to or less than λ/4. That is, according to expression (1), height H and gap width R are set to values equal to or less than 31 millimeters (mm). Therefore, in the embodiment, height H is set to, for example, 30 mm and gap width R is set to about five millimeters also in consideration of prevention of dust. As the waveguide tube126, there is employed a circular waveguide tube126having an inner diameter Ø ranging from about 30 mm to about 40 mm. The length of the waveguide tube126is set to nλ/4 (n is a positive integer).

The size of each section described is only an example. It is hence to be appreciated that the value of the size of each section is appropriately changed depending on the wavelength of the millimeter waves and the construction of the camera apparatus.

In the description of the configuration of the embodiment, the waveguide tube126is fixed onto the wireless section110and is separated from the wireless section123by the gap232. However, since the electric wave propagates through the waveguide tube126in an symmetric way, it is also possible to fix the waveguide tube126onto the wireless section123. In this situation, the wireless section110is naturally separated from the waveguide tube126by a gap. Therefore, the shielding cylinder124is fixed onto the wireless section110. However, if the waveguide tube126is fixed onto the wireless section123, since the waveguide tube126is driven together with the cabinet104as one unit, it is required to increase the driving force.

Next, description will be given of the signal transmission from the camera section120to the wireless section123by referring toFIG. 3.FIG. 3shows video signal processing in a block diagram. A video signal produced in the camera section120by shooting an object is converted therein into video signals conforming to National Television System Committee (NTSC) or is divided into a Y signal (luminance signal) and a C signal (color signal). The resultant signals are supplied to the signal processing section122.

The signal processing section122includes an encoder module301, an Internet Protocol (IP) module302, and a demodulator module304. The encoder module301converts the video signal from the camera section120into a compressed signal in the Joint Photographic Experts Group (JPEG) system, the Moving Pictures Experts Group (MPEG) system, or the like to deliver the compressed signal to the IP module302. The IP module302converts the video signal compressed by the encoder module301, into a signal in the packet format suitable for the transmission and then delivers the signal to the modulator module304. The modulator module304converts the signal into a signal of an intermediate frequency suitable for the wireless Local Area Network (LAN) to deliver the signal to the wireless section123. The wireless section123includes a high-frequency module305and an antenna306. The high-frequency module305includes a Radio Frequency (RF) unit and an amplifier unit and corresponds to the semiconductor circuit element section222shown inFIGS. 2A and 2B. The RF unit converts the signal into a carrier signal of the millimeter band as described above and delivers the carrier signal to the antenna306. The antenna306corresponds to the stripline228shown inFIGS. 2A and 2B. Therefore, the video signal from signal processing section122propagates through the waveguide path212as the carrier signal of the millimeter band from the stripline228of the wireless section123and is then delivered to the stripline208of the wireless section110.

Referring now toFIG. 4, description will be given of the wireless section110and the signal processing section111. InFIG. 4, the wireless section110includes an antenna401and a high-frequency module402and corresponds to the stripline208shown inFIGS. 2A and 2B. The high-frequency module402includes an amplifier unit and an RF unit and corresponds to the semiconductor circuit element section202shown inFIGS. 2A and 2B. The carrier signal of the millimeter band received by the stripline208is converted by the IF module into a signal of an intermediate frequency to be fed to the signal processing section111.

The signal processing section111includes a demodulator module403, an IP module404, and a decoder module405. The video signal converted by the wireless section110into a signal of the intermediate frequency is demodulated to be converted by the demodulator module403into a baseband signal. The base band signal is then fed to the IP module404. The IP module404converts the video signal converted by the IP module302described above into a signal of the packet format into the original video signal and supplies the video signal to the decoder module405. The decoder module405decodes the video signal thus converted into the compressed signal of the JPEG or MPEG system as described above, to produce the original video signal and outputs the video signal from the output terminal113.

Next, description will be given of the control signal supplied to the control signal input/output terminal115. The control signal fed to the input/output terminal115is converted by the signal processing section111into signal suitable for the transmission and is delivered to the wireless section110. The control signal fed to the wireless section110is converted into a carrier signal of the millimeter band and is supplied via the waveguide tube126to the wireless section123. The wireless section123converts the carrier signal into an IF signal and supplies the IF signal to the signal processing section122. The signal processing section122converts the IF signal into a baseband signal and separates each control signal to thereby adjust the zooming unit of the optical system of the camera section and the pan and tilt directions. On the other hand, information items of the results of the control operations associated by the respective control signals, for example, the zooming magnification factor of the optical system and the setting values of the pan and tilt angles are outputted via the signal processing section122, the wireless section123, the waveguide tube126, the wireless section110, and the signal processing section111from the input/output terminal115to be displayed on the monitor or the like.

Referring now toFIG. 6, description will be given of the mode of transmitting the video and control signals.FIG. 6shows transmission and reception signal waves of the carrier signal of the millimeter band in which the f axis represents the frequency and the t axis represents time. According to the present invention, a frequency of the 2.4 GHz band is employed as the carrier frequency. For example, a carrier frequency of Tx is employed in the forward direction (the direction from the wireless section123to the wireless section110) and a carrier frequency of Rx is employed in the reverse direction (the direction from the wireless section110to the wireless section123). The forward carrier frequency Tx is about ten megahertz apart from the reverse carrier frequency Rx. Each of the carrier frequencies Tx and Rx includes a plurality of time-division channels, i.e., channels1,2,3, and so on to transmit mutually different signals. For example, in the forward direction, the video signal produced by the camera section120is converted by the signal processing section122into a signal of a format required for the transmission and is then transmitted by the wireless section123using, for example, channel1of the carrier frequencies Tx. The information items of the zooming magnification factor of the camera section and the pan and tilt directions are converted by the signal processing section122into signals of a format required for the transmission and are then transmitted by the wireless section123using, for example, channel2of the carrier frequencies Tx. Therefore, the wireless section110having received the carrier frequencies Tx converts the received signal into an IF signal and supplies the IF signal to the signal processing section111. The signal processing section111converts the video signal transmitted through channel1into the original video signal and outputs the video signal from the output/input terminal113. The information items regarding control transmitted through channel2are converted into the original signals and are outputted from the output terminal115.

On the other hand, the control signal from the control signal input/output terminal115is amplitude-modulated, frequency-modulated or multivalue-modulated by the signal processing section111to be converted into a signal of a format required for the transmission. The signal is then transmitted by the wireless section110using, for example, channel1of the carrier frequencies Rx. The wireless section123converts the received signal into an IF signal to supply the IF signal to the signal processing section122. the signal processing section122demodulates the received signal of channel1to obtain the original control signal to thereby conduct the necessary control operations for the zooming magnification factor of the camera section and the pan and tilt directions.

According to the present invention described above, although the power is supplied using the slip ring, large-capacity data such as the video data or the control data is transmitted via the waveguide tube using the carrier wave of the millimeter band. Moreover, the camera apparatus of the present invention can conduct the endless rotation. Therefore, it is possible to implement a camera apparatus capable of transmitting high-resolution and high-quality image data and the like.

Description has been given in detail of the present invention. However, the present invention is not restricted by the embodiment of the camera device described above. It is to be appreciated that the present invention is applicable to camera apparatuses other than the camera apparatus described above.