JP4861352B2 - Head separation type camera device - Google Patents

Description

  The present invention relates to a head-separated camera device, and more particularly to a head-separated camera device that can optimally exchange various signals between a camera head unit and a camera control unit unit.

  The head-separated camera is a camera head unit that amplifies or outputs a signal (hereinafter referred to as a video information signal) obtained from an image sensor, and a final video signal (hereinafter simply referred to as a video signal based on the signal from the camera head unit). A camera control unit section (hereinafter also referred to as a CCU) having a signal processing circuit capable of obtaining a video signal), which is connected by a dedicated camera cable for connecting the camera head section and the CCU. This is a general configuration. As described above, since the CCU has a part or most of the signal processing circuit in the head separation type camera, the configuration of the camera head unit can be reduced in size.

  In addition, the camera head portion thus miniaturized has less restrictions on the installation location (high degree of freedom) because it requires less space for installation, and the CCU portion can be operated easily. It is possible to install in a place having a sufficient size that can be performed (for example, a place that is easy to work without being restricted by a posture or the like for operation). For this reason, in general, it is often used in applications (places) that are difficult to use with an integrated camera.

  In a head-separated type camera in which the head unit and the CCU are separated, each other is connected by a dedicated camera cable. Usually, camera cables of various lengths and types are prepared, but the analog video signal wiring length in this camera cable may vary due to individual differences in the camera cable, and varies depending on the cable material. The delay time is about 5ns / m. As a result, a difference occurs in the delay time of each color signal, and the image quality is deteriorated due to the phase shift between the clock and the video signal at the time of AD conversion.

  As a countermeasure, there is a method of generating a signal from the CCU side and looping back (for example, Patent Document 1). However, although the length of the camera cable can be confirmed, the variation of each color signal cannot be confirmed, and the number of the cables is doubled. There was a demerit that the cable becomes thick because it becomes necessary.

On the other hand, a pulse generation circuit for generating a pulse in the camera head unit is provided, and this pulse signal is transmitted to the CCU via the camera cable, and the detection rate is detected on the CCU side to control the amplification factor. It has been broken. (For example, Patent Document 2)
Japanese Patent Laid-Open No. 9-181936 JP 11-98493 A

  In this case, the camera cable can be made thinner than when performing loopback. However, in a 3CCD head separation camera having three CDDs, which has been used recently to improve image quality, RGB video signals are transferred by separate cables. In this case, although it differs depending on the material of the cable, the delay time due to the cable length is generally about 5 ns / m, and the difference in the camera cable is about 200 to 300 ps / m. If a simple calculation holds, a difference of 4 to 6 ns is obtained with a 20 m cable. On the other hand, with a 1080p60 video signal, the pixel clock is equivalent to 150 MHz and is 6.67 ns, which greatly affects the image quality.

  For this reason, there is an error in the cable, so even if these deviations are fine-adjusted at the time of shipment from the factory, the same cable is not necessarily packed in the product, and it will be fine when it is replaced as a service part after shipment. The adjustment itself is wasted.

  The present invention has been made in view of the above problems, and detects a difference in length of each video signal line in a camera cable section connecting a camera head section and a CCU (camera control unit). An object of the present invention is to provide a head-separated camera device that can be controlled according to the difference.

The head-separated camera device according to the present invention is a head-separated camera device comprising a camera head unit, a camera controller unit, and a camera cable unit connecting the camera head unit and the camera controller unit. An imaging means; a pulse generating means for generating a test signal; and a switching means for switching a transmission signal to the test signal , wherein the camera controller section receives the test received via a video signal line of the camera cable section. characterized by comprising phase difference detection means for detecting a phase difference between the signals as an electric potential, and a phase difference compensating means for compensating a phase difference the detection.

  According to the present invention, the signal generator provided in the camera head unit is used to detect the delay amount of each video signal line in the camera cable unit, thereby correcting the delay amount of the video signal. Therefore, the image quality of the captured image can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the overall configuration of a first embodiment of a head-separated camera device according to the present invention.
As shown in FIG. 1, the head-separated camera device includes a camera head unit 1 that is an imaging unit, and a CCU (camera control unit unit) 3 that receives an original signal (video information signal) imaged by the imaging device. And a camera cable unit 2 for transmitting various signals between the camera head unit 1 and the CCU unit, and roughly three functional units.

  First, the camera head unit 1 serving as an image capturing unit switches between a CCD 11 serving as an image capturing unit, a signal generator 12 that generates a test pattern for measuring a delay amount between cables, and a signal output to the cable unit 2. And a switch circuit 13.

  Here, the CCD 11 serving as an image pickup device is a three-plate CCD, and is output by three video signal lines as image signals of R, G, and B components of images picked up by the respective CCDs. The signal generator 12 is a circuit that outputs a predetermined test pattern used in the test mode. The generated test pattern is output as the same pulse signal of three systems through the equal length wiring. The switch circuit 13 is switched by the control of the CCU 3 so as to output a CCD image signal in the video mode and a test pattern from the signal generator 12 in the test mode.

  The cable unit 2 transmits various signals between the CCU 3 and the camera head unit 1, and includes various video information signal lines 21, control lines 22, power supply lines 23, and the like composed of three RGB lines. Consists of cables. In the following description, the length of the cable portion 2 can be arbitrarily selected depending on the application.

  The CCU 3 outputs video signals picked up by three image pickup devices (CCD) of the camera head unit 1 as digital image signals and outputs various control signals for the camera head unit 1. The CCU 3 detects the phase difference from the CPU 31 that controls the entire CCU 3 and also transmits a control signal to the camera head unit 1 and the test pattern transmitted from the signal generation circuit 12 of the camera head unit 1 in the test mode. A phase detection circuit 32, an A / D converter 33 that converts an analog video signal transmitted from the camera head unit 1 into a digital signal while compensating for the phase difference detected by the phase difference detection circuit, and an A / D converter 33 When the video signal digitized by the DSP 34 that performs necessary processing for outputting as a video signal and the signal transmitted through the camera cable unit based on the control from the CPU 31 are in the normal video mode A switch circuit 35 that switches to the A / D converter 33 and switches to the phase detection circuit 32 side in the test mode; It consists source unit 36 and the like.

The operation in such a configuration will be described.
The head-separated camera according to the present embodiment has a video mode for outputting a captured video as a video signal and a test mode for detecting variations between three video signal lines for RGB. The CCU can switch between a video signal from the CCD 11 and a pulse signal which is a test signal from the signal generator 12 according to two types of operation modes, a video mode and a test mode. Both signals are input to the CCU 3 via the RGB video signal lines 21.

An example of a pulse signal as a test signal output from the signal generator 12 is shown in FIG. It is assumed that a pulse signal as shown in FIG. 2 is used, and is divided into three systems by equal-length wiring and connected to the respective video signal lines for RGB.

In the case of the video mode, the video signal that has reached the CCU 3 via the respective video signal lines is digitized by the AD converter 33, and then subjected to appropriate image processing by the DSP 34 and output in a predetermined format. The

Next, how to enter the test mode will be described.
When the camera is activated after the camera is turned on and the CPU 31 operates, the test mode is automatically set for a certain period.
The CPU 31 outputs a control signal so that the switch circuit 13 of the camera head unit 1 is switched to the signal generator side and the switch circuit 35 of the CCU is switched to the phase detection circuit side. Thereafter, output of a predetermined signal pattern is started from the signal generator 12 of the camera head unit 1.

The phase detection circuit 32 of the CCU 3 detects a phase difference for each video signal line when the video information signal from the CCD 3 reaches the CCU 11 via the camera cable.

Here, a method of detecting the phase difference will be described with reference to FIG.
The test signal generated by the signal generator 12 is input from the camera head unit 1 side to the three video signal lines in the camera cable unit 2 in phase. On the CCU 3 side, the phase detection circuit 32 receives pulse signals from the RGB video signal lines, compares R and B, B and G, and G and R, respectively, and detects a phase difference. In the example of FIG. 2, since the B video signal line is slightly short, only the B pulse is shifted to the left. Then, the B pulse and the CLK signal are compared to generate a differential pulse, and the differential pulse is integrated to detect the phase difference to be adjusted as a voltage.

  When detecting the phase difference, the phase detection circuit 32 outputs a control signal to the A / D converter 33. The configuration of the A / D converter 33 in the first embodiment will be described with reference to FIG.

  As shown in FIG. 3, a path 332 provided with a delay circuit is provided in the preceding stage of the A / D converter 331 so that the delay amount of each video signal is different. Based on the phase difference detected by the phase difference detection circuit 32, the microcomputer 333 calculates a necessary delay amount. As an example of the delay calculation method, the phase difference is determined as follows: no delay when the detected phase difference time is 0 to 20 ms, delay amount 1 for 21 to 40 ms, and delay amount 2 for 41 ms or more. Then, the delay circuit 332 of each video signal line is switched so that this delay amount is obtained. In the case of FIG. 2, only the delay amount B is switched, and R and G are switched so that there is no delay.

  As described above, the phase difference is compensated by switching the delay amount, and when a certain time has elapsed and the phase determination and adjustment are completed, the CPU 31 switches the switch circuit 13 of the camera head unit 1 and the switch circuit of the CCU 3. 35 to switch from the test mode to the normal video mode.

Therefore, the RGB video signals transmitted via the camera cable unit 2 are digitized and input to the DSP 34 because the video signals are input in a state where the RGB phases are aligned in the AD converter 331. Therefore, a normal video signal is output.

  In the first embodiment described above, the transition from the video mode to the test mode is automatically set to the test mode for a certain period after the camera is turned on. Absent.

  For example, the test mode may be automatically entered when the CCU 3 side detects a synchronization signal transmitted by being superimposed on the video signal and determines that the synchronization signal is not received.

Further, the way to exit from the test mode to the video mode is not limited to this.
FIG. 4 is a diagram showing another example of a pulse signal which is a test signal. For example, as shown in FIG. 4 (a), a pulse signal that is a test signal may be a pulse having a different number of pulses. In this case, after the transmission of the three pulses is completed, the CCU 3 may detect the phase difference and control the delay amount, and then return to the video mode.

  As another method, as shown in FIG. 4B, signals with different pulse widths are sent in order, the number of pulses (start / end) is recognized, and the test mode is automatically changed to the normal mode (video). A method of shifting to the output state may be used.

  As another method, if the pulse is not detected within a certain time despite the CCU 3 transitioning to the above test mode, it is determined that the camera cable unit 2 is not connected and the video signal is output. It can also be superimposed as OSD and output as an error message.

Next, a second embodiment will be described.
In the present embodiment, as a method of compensating the phase difference detected by the phase difference detection circuit 32 by the A / D converter 33, there is a method of performing phase control of the pixel clock. This method will be described with reference to FIG.

Similar to the first embodiment, after shifting to the test mode by a procedure such as after power-on, the phase difference detection circuit 32 of the CCU 3 detects the phase difference of the video signal lines between RGB.
The phase difference detection circuit 32 converts the detected phase difference into a voltage, as will be described with reference to FIG. Based on the phase difference detected by the microcomputer 333, the delay amount of the pixel clock signal applied to each video signal is calculated. The clock shift circuit 334 generates a pixel clock obtained by adding a necessary delay to each of RGB with respect to the reference clock, and inputs the pixel clock to the corresponding A / D converter 331. For this reason, the digitized video signal is latched by the reference clock inside the DSP 34, is subjected to predetermined processing, and is output as a video signal.

As described above, by shifting the pixel clock based on the detected phase difference, it is possible to absorb the variation between the video signal lines.
Next, a third embodiment will be described with reference to FIG.
In the first and second embodiments, the example in which the mode is changed to the test mode when the predetermined condition is satisfied has been described. In the present embodiment, the mode switching unit from the video mode to the test mode is used. An operation key 37 is provided on the CCU 3.

  In such a configuration, when the user operates the operation key 37 provided on the CCU 3 side, the CPU 31 detects this and controls the switch circuit 35 on the CCU 3 side and the switch circuit 13 on the camera head unit 1 side to Transition from mode to test mode.

As a result, a test signal is sent from the camera head unit 1 side to the CCU 3 side, and the phase difference detection circuit 32 of the CCU 3 detects the phase difference between the RGB video signal lines. The detected phase difference is compensated for by the method of either the first embodiment or the second embodiment described above.

  As a method of exiting from the test mode, the video signal may be automatically returned, but the transition from the test mode to the video mode may be performed again by the key operation described above.

As described above, by providing the operation key for changing the mode, the user can change to the test mode at an arbitrary timing.
Next, a fourth embodiment will be described with reference to FIG.
In the present embodiment, in addition to the operation key 37 on the CCU 3 side, the mode switching operation key 14 is also provided on the camera head unit 1 side.
When transitioning from the video mode to the test mode, both can enter the test mode by pressing both the operation key 14 of the camera head unit 1 and the operation key 37 of the CCU 3 unit. Similarly, when the test mode is exited to the video mode, the mode can be switched by pressing both the operation key 14 of the camera head unit 1 and the operation key 37 of the CCU 3 unit.

For this reason, the control line 22 regarding the mode switching in the camera cable unit 2 can be omitted.
Next, a fifth embodiment will be described with reference to FIG. In this embodiment, connectors 40 and 41 that can recognize that the camera cable unit 2 is attached to the CCU 3 and the camera head unit 1 are used.

An example of the configuration of the connector 40 on the CCU 3 side is shown in FIG. In addition, about the structure of the connector 41 by the side of the camera head part 1, since it is the same structure, description is abbreviate | omitted.
The CCU side of the connector 40 has 8 pins as connection terminals, whereas the camera cable side has 6 pins. The two on the CCU 3 side are short-circuited inside the connector, and one of the two pins is connected to the CPU 31 and the other is connected to the ground terminal. The remaining six lines are connected to the respective camera cables (in FIG. 9, horizontal synchronizing signal H, vertical synchronizing signal V, clock signal CKL, video signal lines R, G, and B).

  Due to such a configuration, when the camera cable unit 2 is connected to the CCU 3 via the connector 40, the potential of the terminal connected to the CPU 31 becomes 0. Therefore, the CPU 31 detects this and the camera cable unit 2 Recognize that connected.

In this embodiment, switching between the video mode and the test mode may be performed by the procedure described in each of the above embodiments, but the test is performed when the CPU 31 recognizes that the camera cable unit 2 is attached. You may comprise so that it may switch to a mode.

In this case, for example, when the camera cable unit 2 is replaced, it is convenient to automatically switch to the test mode when the camera cable unit 2 is connected.
As a method for exiting the video mode from the test mode, any of the procedures described in the above embodiments may be used. For example, if a pulse is not detected within a certain time despite the transition to the test mode described above, it is determined that the camera cable unit 2 is not connected and an error message is superimposed on the OSD and output. In some cases, when the cable is actually attached, it can be determined that the signal line portion is disconnected or the head portion is malfunctioning.

Each of the embodiments described above is merely an example and is not limited thereto. Therefore, various modifications can be made without departing from the spirit of the present invention.
Moreover, although the above-mentioned description was performed about each Example, you may combine several Example suitably.

The block diagram which shows the whole structure of 1st Embodiment. The figure which shows an example of the pulse signal as a test signal. The figure which shows the structure of the A / D converter in 1st Embodiment. The figure which shows the other example of the pulse signal which is a test signal. The figure which shows the structure of the A / D converter in 2nd Embodiment. The block diagram which shows the whole structure of 3rd Embodiment. The block diagram which shows the whole structure of 4th Embodiment. The block diagram which shows the whole structure of 5th Embodiment. It is a block diagram which shows the structure of the connector of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Camera head part 2 ... Camera cable part 3 ... CCU (camera control unit part)
11 ... CCD
DESCRIPTION OF SYMBOLS 12 ... Signal generator 13 ... Switch circuit 14 ... Operation key 21 ... Video signal line 22 ... Control line 23 ... Power supply line 31 ... CPU
32 ... Phase detection circuit 33 ... A / D converter 34 ... DSP
35 ... Switch circuit 36 ... Power supply circuit 37 ... Operation keys 40, 41 ... Connector

Claims (6)

In a head-separated camera device comprising a camera head unit, a camera controller unit, and a camera cable unit connecting the camera head unit and the camera controller unit,
The camera head unit includes imaging means, pulse generation means for generating a test signal, and switching means for switching a transmission signal to the test signal ,
The camera controller section includes a phase difference detecting means for detecting a phase difference between the test signal received via the video signal lines of the camera cable portion as potential, and a phase difference compensating means for compensating a phase difference the detected A head-separated camera device comprising:   2. The head-separated camera device according to claim 1, wherein the pulse generator generates three systems of pulses.   2. The head-separated camera device according to claim 1, wherein the phase difference compensation unit compensates for the phase difference by changing a delay amount given to each signal line.   2. The head-separated camera device according to claim 1, wherein the phase difference compensation unit compensates for the phase difference by changing a phase of a clock signal used in the digitization process.   The head-separated camera device has a mode switching unit in either one or both of the camera controller unit and the camera head unit, and changes the video mode and the test mode by operating the switching unit. The head-separated camera device according to claim 1. The head-separated camera device has detection means for detecting the presence or absence of the cable connection in either one or both of the camera controller unit and the camera head unit,
2. The head-separated camera device according to claim 1, wherein when the detection unit detects that a camera cable is connected, the mode switching from the video mode to the test mode is performed.

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