JP2009296349A - Surveillance camera apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided a panning mechanism which has high precision in a long-period continuous use environment for a universal head of a surveillance camera, and to provide a panning rotational angle detecting mechanism with simple constitution which is free from an influence of the backlash and the hysteresis of a transmission mechanism, problems of scattering of fats and oils and abrasion powder from a driving mechanism, and the sticking of fats and oils, and a foreign matter during assembling, and has a high detection resolution and a detection error tolerance. <P>SOLUTION: A panning shaft is extended into an electromagnetic shield space of an electric component installed at a bottom, and an encoder mechanism is constituted near the end of the panning shaft to constitute an encoder mechanism using a large-diameter pattern plate in a space isolated from the driving mechanism. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  This is a technique related to the structure of a surveillance camera having a movable head.

  Surveillance cameras need to be operated continuously for a long period of time and ensure accurate operation for a long period of time. It is important that a surveillance camera with a movable pan head that monitors multiple locations with a single camera can guarantee the rotation stop position accuracy of panning and tilting for a long period of time. On the other hand, it is conceivable to use a method of guaranteeing the rotation stop position accuracy by using a servo-controlled motor in a drive system used in a machine tool and maintaining the motor rotation speed accurately.

On the other hand, as disclosed in Patent Document 1 and the like, there is disclosed a method for detecting an absolute rotational position of an object to be rotated by directly attaching an optical or magnetic encoder or the like to a rotating shaft for panning and tilting. Yes. This method has a simple circuit configuration and the like as compared with the method of monitoring the rotational speed of the motor. In addition, this is an excellent method that does not require correction for backlash and backlash of the power transmission mechanism from the motor to the rotation axis whose rotation angle is to be detected, such as the panning axis and tilting axis.
JP 2000-156855 A

  However, on the other hand, there is a problem that the detection resolution of the encoder itself must be increased because the rotation speed of the rotation angle detection target and the rotation speed magnification of the encoder are 1: 1.

  As a countermeasure, a method can be considered in which the pattern pitch on the encoder pattern plate (hereinafter referred to as pattern plate) is made fine, but higher pattern reading accuracy is required. As a result, a margin for reading errors is narrowed, and requirements for component accuracy and environmental change resistance become severe, and it is difficult to maintain detection quality.

  As a second countermeasure, a method of increasing the number of patterns per unit angle without increasing the pattern pitch by increasing the diameter of the pattern plate can be considered. The hurdle for maintaining detection quality is lower than the former measure. On the other hand, as shown in Patent Document 1, when the pattern plate is configured in the vicinity of the drive mechanism, the structure around the drive mechanism becomes large due to the large pattern plate.

  Furthermore, when an encoder is arranged around the drive mechanism, there is a problem of contamination of the pattern plate due to scattering of oil and grease applied to gears and bearings and wear powder when driving, and adhesion when applying oil and grease. Cannot be ignored as a cause of read errors.

  In the present invention, a mechanism is devised in which a pattern plate is directly connected to a rotating shaft to be rotated and contamination of the pattern plate is prevented during operation and assembly while maintaining sufficient rotation detection accuracy. This provides a surveillance camera device with a pan head that can maintain the rotational position accuracy of the pan head under long-term continuous use as a pan head for the surveillance camera.

  In order to achieve the above object, in the present invention, an encoder pattern plate having a diameter as large as possible is directly fixed to a rotating shaft, and at the same time, the drive mechanism and the pattern plate are arranged in separate spaces. I will decide.

  At present, there are trends in surveillance cameras, such as high-definition image shooting and high-speed image transmission as well as consumer-use digital image equipment. As a result, the processing speed of electrical signal processing for image processing and image transmission has been increased, and high-speed clock operation of electrical circuits has become prominent. For this reason, the radiated radio waves from the electric circuit for processing increase. In order to prevent this radiated radio wave, it is essential to form an electromagnetic shield space that shields the radiated radio wave around an electric circuit with a metal plate or the like.

  In the present invention, the panning shaft is extended into the electromagnetic shield space, and the pattern plate is fixed near the end thereof. With this configuration, the drive mechanism and the pattern plate can be arranged in separate spaces.

  Further objects and other features of the present invention will be made clear by the preferred embodiments described below with reference to the accompanying drawings.

  As described above, according to the present invention, it is possible to provide a monitoring camera device with a pan head that can maintain the rotational position accuracy of the pan head under long-term continuous use as a pan head for the monitoring camera with a simple configuration.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is an external view of a surveillance camera device with a movable head according to the present invention.

  The photographing lens unit 10 is installed in the camera unit 20.

  The panning base 30 is connected to the fixed portion 60 so as to be horizontally rotatable (panned) with respect to the fixed portion 60. A first support column 40 and a second support column 50 are erected on the panning base 30 so as to sandwich the camera unit case 20. Tilt shafts (not shown) are installed in portions facing the first support column and the second support column of the camera unit 20, and these are fitted to bearings provided on the first support column and the second support column. Is tiltable with respect to the panning base.

  The camera unit 20 has a camera casing cover 21, a first support column 40 with a first support column cover 41, and a second support column 50 with a second support column cover 51 detachably attached.

  FIG. 2 is an internal perspective view of FIG. 1 viewed from the A direction. A part of the cover and a part of the mechanism are shown as a cross section, and some of the known parts and parts that are not necessary for the explanation of the present invention and are complicated are not shown.

  The photographing lens unit 10 and the first electric circuit board 12 are fixed inside the camera unit 20 with a structure such as a sheet metal or a resin (not shown). The camera unit 10 includes a known photographing optical system and an image sensor, and is connected to the image sensor, the first electric circuit board 12 and the signal cable 11, and undergoes a known electric process via the first electric circuit board 12. Output the captured image.

  A first tilt shaft 14 and a second tilt shaft 15 are fixed on both sides of the camera unit 20, and a bearing portion of the bearing portion 42 of the first support column 40 standing on the panning base 30. 52 so as to be rotatable. A worm wheel 80 is fixed to the first tilt shaft 14 on the first support column 40 side with a screw 15 or the like. The worm wheel 80 is rotated by a worm 81 that is rotated by the power of the step motor 85 to rotate the first tilt shaft and the camera unit 20. Here, the motive power of the step motor 85 is transmitted from the motor pinion 84 to the pulley 82 coaxially formed with the worm 81 by the belt 83 to rotate the worm 81. The step motor 85 is supplied with electric power and control from the electric wire 103 connected to the second electric board 61 described later by known electric connection means (not shown). Note that a fixing structure for fixing the step motor 85, the worm 81, and the like to the first support column 40 is omitted in this figure, and details are shown in FIG.

  FIG. 3 shows the first support column 40 viewed from the side with the first support column cover 41 removed. The worm 81, the pulley 82, the belt 83, the motor pinion 84, and the step motor 85 are configured on the structural substrate 86 and fixed to the first support column 40 with screws 87 or the like.

  In FIG. 2, the second tilt shaft 15 is fitted on the second support column 50 side. The second tilt shaft 15 is hollow, and an electric wire 101 connected to a second electric circuit board 61 to be described later is passed through the camera unit 20 to be connected to the first electric circuit board 12 by the connector 13. Thereby, the first electric substrate and the second electric substrate are electrically connected. The electric wire 101 is introduced into the second tilt shaft after being wound around the second tilt shaft 15 in a spiral manner so as not to be disconnected by the rotation of the camera unit 20.

  A pattern plate 90 is fixed near the tip of the second tilt shaft by press fitting or the like. The pattern plate 90 is made of a transparent member, and black lines are printed at a predetermined interval such as 360 dpi on the peripheral surface. The sensor 91 includes a plurality of pairs of light emitting units and light receiving units arranged from one to the other, and is disposed so that the pattern plate 90 is sandwiched between the light emitting units and the light receiving units. It is possible to detect the rotation angle and rotation speed of the pattern plate 90 by counting how many times the light emitted from the light emitting unit is blocked by the black line for a predetermined time. The sensor 91 is mounted on the sensor electric board 92 and connected to the electric wire 102 connected to the second electric circuit board 61 described later via a connector 93 mounted on the same electric board 92. Accordingly, the sensor 91 receives power and control from the second electric circuit board 61, and the second electric circuit board 61 detects a signal from the sensor 91. FIG. 4 shows the second column 50 viewed from the side with the second column cover 51 removed. The sensor electric board 92 is fixed to the second support 50 with screws 94 or the like.

  In FIG. 2, a mechanism base 62 is fixed to the fixing portion 60 with screws 74 or the like. The panning base is fixed by a pan shaft 31 press-fitting or the like. The pan bearing 32 is fixed to the above-described mechanism base 62 with a screw 35 or the like, and the pan shaft 31 is rotatably fitted. Thereby, the panning base 30 is joined to the fixed portion 60 so as to be horizontally rotatable. The pan shaft 31 is prevented from coming off by a spring ring 33. The worm wheel 34 is fixed to the panning base 30 with screws 36 or the like so as to be coaxial with the pan shaft 31. The worm wheel 34 is rotated by a worm 67 that is rotated by the power of the step motor motor 71 to rotate the panning base 30. Here, the power of the step motor 71 is transmitted from the motor pinion 70 to a pulley 68 configured coaxially with the worm 67 by a belt 69 to rotate the worm 67. The step motor 71 is supplied with electric power and control from an electric wire 103 connected to a second electric circuit board 61 described later by known electric connection means (not shown) such as an electric board, a flexible board, and a connector. Note that a fixing structure for fixing the step motor 71, the worm 67, and the like to the mechanism base 61 is omitted in this figure, and details are shown in FIG. FIG. 3 shows the first support column 40 viewed from the side in a state where a part of the fixed portion 60 is transmitted. The worm 67, the pulley 68, the belt 69, the motor pinion 70, and the step motor 71 are configured on the structural substrate 72 and fixed to the mechanism base 61 with screws 73 or the like.

  A screw 75 is fixed to a second electric circuit board 62 on which a power source, a control circuit, an internal wiring connector, various external interfaces and the like are mounted on a mechanism base 61 fixed on the fixing portion 60. The control circuit includes a multiprocessor unit, a motor driver, a memory image processing unit, and the like. The external interface includes a power input terminal 115, an image output port 116, an external control communication port 117, and the like.

  The electric wire group 105 is installed in the electric wire case 76 in a state of being wound around the pan bearing 32 several times in a spiral shape so as not to be disconnected by the rotation of the panning base. The lower end of the electric wire group 105 is wired downward from the electric wire case 76 and connected to the second electric circuit board by a known electric connecting means (not shown). The upper end of the electric wire group 105 is wired upward from the electric wire case 76, and is branched into the electric wire 101, the electric wire 102, the electric wire 103, and the like, and is laid out in the above-described places.

  An electromagnetic shield upper case 66 and an electromagnetic shield lower case 67 are fixed to the mechanism base 62 and cover the second electric circuit board up and down. The electromagnetic wave shielding upper case 66, the electromagnetic wave, and the lower shielding case 67 have a function of shielding the electromagnetic wave generated from the second electric circuit board so as not to be emitted outside.

  The pan shaft 31 passes through a part of the upper case 66 of the electromagnetic wave shield and extends to the vicinity of the second electric circuit board, and the pattern plate 110 is fixed to the front end thereof by a screw 37 or the like.

  The pattern plate 110 is made of a transparent member in the same manner as the pattern plate 90 described above, and black lines are printed at a predetermined interval on the peripheral surface. The sensor 111 and the connector 113 mounted on the sensor electric board 112 fixed to the mechanism base 61 pass through a part of the electromagnetic shielding upper case 66 and protrude to the vicinity of the second electric circuit board. The sensor 110 is installed so as to sandwich the pattern plate similarly to the sensor 91 described above. The connector 113 is connected to the connector 77 on the second electric circuit board with the electric wire 106. The sensor 110 is connected to the second electric circuit board 61 via the connector 113 to receive power and control, and the second electric circuit board 61 detects a signal from the sensor 111. Thereby, the rotation angle and rotation speed of the panning base 30 are detected.

  An example of panning and tilting operations will be described with the above configuration.

  In FIG. 5, the MPU (main processor unit) 201 configured on the second electric circuit board 61 controls the motor driver 202 by a rotation control command received from the external control communication port 117 or an internally programmed control command. Then, the stepping motor 203 is driven by applying a predetermined number of power pulses. As a result, the detection pulse m of the sensor 91 or sensor 111 that detects the rotation of the tilt axis or pan axis is input to the MPU 204 and compared with the output pulse n of the motor driver. An example of rotation control by comparing the sensor detection pulse m with the motor driver output pulse n by the MPU 204 will be described with reference to FIG.

  In FIG. 6, the MPU 204 compares the output pulse n of the motor driver with the sensor detection pulse m, and when m = n (221), the output pulse n is written in the memory as the amount of movement of the motor assuming that the operation is normal (221). 222). When the value of m−n is smaller than the set predetermined amount a (223), the motor is driven until the sensor detection pulse m is reached (224), and the sensor detection pulse m is written to the memory as the motor movement amount. (222). When the value of mn is larger than the set predetermined amount a (223), it is determined that the above has occurred, the motor drive is stopped, and an alarm is issued (227-228).

  In the above, the drive mechanism is disposed on the first support column 40 side and the sensor structure is disposed on the second support column 50 side, but the reverse is also possible.

  The motor is not a step motor, but it is also possible to perform close control with an angle sensor using a DC or AC motor.

  The pattern plate 90, 110 is not a digital pattern such as black (shielded) -transparent (transmitted), but has a continuous density change, and the absolute position is detected by detecting a continuous change in transmittance. A potentiometer for detecting the above may be configured.

  FIG. 7 shows a variation of the structure of the fixing portion 60.

  The fixing part 60 is made of a metal material, and a pedestal for fixing the mechanism base 61 is formed on the bottom edge of the fixing part 60 as shown in the figure. If the mechanism base 61 is fixed here, the second electric circuit board 62 Electromagnetic shield space can be formed.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

1 is a schematic view of a monitoring camera with a carriage according to the present invention. The front perspective view of this invention apparatus. The right surface partial perspective view of this invention apparatus. The left surface partial perspective view of this invention apparatus. An example of the control system of the device of the present invention An example of pan / tilt control of the device of the present invention. The figure which shows the change form of the structure of the fixing | fixed part 60. FIG.

Claims (4)

A lens unit composed of an imaging optical system and an imaging element;
A first electric circuit board electrically connected to the lens unit; a second electric circuit board installed on the fixed part;
Connection means for electrically connecting the first electric circuit board and the second electric circuit board;
A monitoring camera device that outputs an image by electrically connecting the first electric circuit board and the second electric circuit board;
A panning movable part mounted with the lens unit and joined to the fixed part so as to rotate horizontally around a panning axis;
Panning rotation drive means for rotating the panning movable part;
Having a panning angle detection means fixed on the panning shaft;
A surveillance camera device comprising a movable pan head in which the panning angle detection means is disposed in a space isolated from the rotation driving means.   The surveillance camera device according to claim 1, wherein the isolated space is formed by an electromagnetic shield plate of the second electric circuit board.   The pattern detecting plate fixed to the tilt shaft and rotating together with the tilt shaft, and the angle detecting means for reading a specific pattern of dark / light or transparent / opaque drawn on the pattern plate with an optical sensor The surveillance camera device according to claim 1, further comprising:   The surveillance camera device according to claim 2, wherein the pattern plate is obtained by printing the specific pattern on a disc made of a transparent material.

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