JP4508603B2 - Electronic endoscope system with imaging device - Google Patents

Description

  The present invention relates to an electronic endoscope system including an imaging device in which an imaging unit and a control and signal processing unit are separated from each other and transmit a signal via a cable, and more particularly to a solid-state imaging device having a plurality of channel outputs. The present invention relates to an electronic endoscope system provided with an imaging device provided with an analog signal processing means provided in a control and signal processing unit.

  Conventionally, an imaging apparatus having a configuration shown in FIG. 10 is known as an imaging apparatus in which an imaging unit and a control and signal processing unit are separated and a signal is transmitted via a cable. That is, in this imaging apparatus, the imaging unit 1 is provided with a solid-state imaging device 104 (CCD here), and the control and signal processing unit 2 has a CCD driving means 111 for generating a pulse for driving the CCD 104, and the CCD 104. Output signal, an analog signal processing means 110 having a correlated double sampling circuit, and a timing signal generating means 112 for generating a timing signal necessary for signal processing in the analog signal processing means 110 are provided to drive the CCD 104 The pulse for this purpose is connected to the imaging unit 1 via the cable 3, and the output signal of the CCD 104 is connected to the control and signal processing unit 2 via the buffer 107 and the cable 3.

  Next, the operation of the imaging apparatus configured as described above will be described. A horizontal driving pulse φH, a vertical driving pulse φV, a reset pulse φRS and the like necessary for the operation of the CCD 104 are output from the CCD driving means 111 and supplied to the CCD 104 via the cable 3. A video signal corresponding to each pulse is output from the CCD 104, and this output video signal is given to the analog signal processing means 110 via the buffer 107 and the cable 3. The analog signal processing means 110 performs correlated double sampling (CDS) on the output signal of the CCD 104 using the timing signal from the timing signal generation means 112, and the reset signal and 1 / f noise contained in the output signal of the CCD 104 are removed. Is then processed into a signal that can be digitally processed (PGA, A / D conversion processing). Therefore, since the imaging unit 1 has no circuits other than the CCD 104 and the buffer 107, the imaging unit 1 can be reduced in size.

  Further, as another configuration example of the conventional imaging apparatus, a configuration shown in FIG. 11 is disclosed in Japanese Patent No. 2947663. As shown in FIG. 11, the image pickup apparatus includes a CCD 104, a CDS circuit 105 to which an output signal of the CCD 104 is input, a horizontal drive pulse φH, a reset pulse φRS, and a sampling pulse of the CDS circuit 105. And a timing signal generator 112 for generating a basic clock signal, a horizontal reference pulse and a vertical drive pulse, and an output signal of the CDS circuit 105 are input to the control and signal processor 2. Color separation circuit 113 and vertical drive pulse generation means 111 for generating a vertical drive pulse of CCD 104 are provided, and a basic clock signal, a horizontal reference pulse and a timing signal generation means 112 and vertical drive pulse generation means 111 are generated. The vertical drive pulse φV is connected to the CCD 104 and the timing pulse generation circuit 108 via the cable 3. , The output signal of the CDS circuit 105 has a configuration that is connected to a color separation circuit 113 via the buffer 107 and the cable 3.

Next, the operation of the imaging apparatus configured as described above will be described. A timing pulse generation circuit 108 in the image pickup unit 1 generates a reset pulse φRS and a horizontal drive pulse φH and supplies them to the CCD 104, and an output signal read from the CCD 104 based on these pulses is a CDS provided in the image pickup unit 1. After the signal processing in the circuit 105, it is given to the color separation circuit 113 of the control and signal processing unit 2 through the buffer 107 and the cable 3, and the video signal processing necessary for the monitor or the like is performed. As a result, it is possible to reduce signal deterioration caused by transmitting a signal necessary for the operation of the CCD 104 such as a reset pulse and a horizontal drive pulse and an output signal of the CCD 104 including a clock component via the cable.
Japanese Patent No. 2947663

  Recently, there has been a growing demand for higher definition of images in electronic endoscope systems, and it is necessary to increase the number of pixels in a CCD. The drive frequency and the output signal are increased in speed by increasing the number of pixels, but there is a limit to the increase in speed due to signal deterioration in the cable. Therefore, high definition is achieved without increasing the driving frequency by reading signals in parallel using a CCD having a plurality of channel outputs. However, simply applying this method to the conventional imaging device shown in FIGS. 10 and 11, if the CCD has a multi-channel output, the number of channels for transmitting the output signal is required. The number of cables increases and the cable diameter increases. For this reason, in the electronic endoscope system, the burden on the subject increases when the distal end insertion portion is inserted into the body. In addition, in the conventional imaging apparatus shown in FIG. 11, since the timing pulse generation circuit for generating the CCD reset pulse and the horizontal drive pulse is provided in the imaging unit, it is difficult to reduce the size of the imaging unit.

  As described above, the conventional imaging apparatus shown in FIGS. 10 and 11 transmits a signal without increasing the number of cables by the number of channels of the solid-state imaging device even when a solid-state imaging device having a plurality of channel outputs is used. This point of view is not considered.

  The present invention has been made paying attention to the above viewpoint, and even when a solid-state imaging device having a plurality of channel outputs is used in the imaging unit at the distal end of the scope of the electronic endoscope system, the number of cables is the number of channels of the solid-state imaging device. It is an object of the present invention to provide an electronic endoscope system including an imaging device that can transmit a signal without increasing the size and prevent the cable diameter from becoming thick.

In order to solve the above-described problem, an invention according to claim 1 is an electronic endoscope system including an imaging device that is separated from an imaging unit and a control and signal processing unit and transmits a signal via a cable. The control and signal processing comprising: a solid-state imaging device having a plurality of channel outputs in the imaging unit; and switching means for switching a plurality of channel outputs from the solid-state imaging device during a predetermined period and outputting them to a cable via a buffer. Provided with analog signal processing means for performing A / D conversion processing , wherein the imaging section has an input terminal connected to an output terminal of the solid-state imaging device, an output terminal connected to an input terminal of the switching means, A plurality of correlated double sampling means for sampling a plurality of channel output signals of the solid-state imaging device and outputting a video signal component, and a cable from the control and signal processing section; Via further comprising a pulse generating means for generating a pulse signal in which the driving of the correlated double sampling means based on the pulse signal transmitted to the solid-state imaging device, and is characterized in that is.

Examples of the imaging apparatus in the electronic endoscope system corresponding to the first aspect of the invention are Example 1 and Example 2. In an electronic endoscope system including an imaging apparatus configured as described above, a plurality of channel outputs from a solid-state imaging device are input to a switching unit, and the switching unit sequentially switches over a predetermined period of time via a buffer. Therefore, it is possible to transmit signals from the imaging unit to the control and signal processing unit with a smaller number of cables than a multi-channel output, so even when using a solid-state imaging device having a multi-channel output, the number of cables can be reduced. Signals can be transmitted without increasing the number of channels of the image sensor, and signal transmission and signal processing with reduced deterioration of the video signal can be achieved without increasing the number of cables. Therefore, it is possible to increase the definition of the image without doing so. In addition, the correlated double sampling means samples a plurality of channel output signals of the solid-state imaging device to output video signal components, and the output signals of the correlated double sampling means are sequentially switched during a predetermined period by the switching means and buffered. Therefore, signal degradation caused by transmitting the output signal of the solid-state imaging device including the clock component via the cable can be reduced. Further, the pulse signal for driving the correlated double sampling means can be generated from the pulse signal for driving the solid-state imaging device by the pulse generation means. Therefore, even when a solid-state imaging device having a plurality of channel outputs is used, a signal can be transmitted by connecting the imaging unit and the control and signal processing unit with fewer cables than the number of channels of the solid-state imaging device. Even if multiple sampling means are provided in the imaging unit, there is no need to give drive pulses from the control and signal processing unit via the cable, so signal transmission and signal processing with reduced deterioration of the video signal on the cable without increasing the number of cables. Is possible.

According to a second aspect of the present invention, there is provided an electronic endoscope system including an imaging device that is separated from an imaging unit and a control and signal processing unit and transmits a signal via a cable, and the imaging unit includes a plurality of channels. A solid-state imaging device having an output; and a switching unit that switches a plurality of channel outputs from the solid-state imaging device during a predetermined period and outputs them to a cable via a buffer. The control and signal processing unit includes an A / D converter. Analog signal processing means for performing processing, and the imaging section generates a pulse signal for driving the switching means based on a pulse signal transmitted from the control and signal processing section to the solid-state imaging device via a cable It further has a switching pulse generating means .

Examples of the imaging device in the electronic endoscope system corresponding to the invention according to claim 2 are Example 1 and Example 2. In the electronic endoscope system using the imaging apparatus configured as described above, the multi-channel output from the solid-state imaging device is input to the switching unit, and the switching unit sequentially switches the cable through a buffer during a predetermined period. Therefore, it is possible to transmit signals from the imaging unit to the control and signal processing unit with a smaller number of cables than a multi-channel output, so even when using a solid-state imaging device having a multi-channel output, the number of cables can be reduced. Signals can be transmitted without increasing the number of channels of the image sensor, and signal transmission and signal processing with reduced deterioration of the video signal can be achieved without increasing the number of cables. Therefore, it is possible to increase the definition of the image without doing so. Further, the pulse signal for driving the switching means can be generated from the pulse signal for driving the solid-state imaging device by the switching pulse generating means. Therefore, even when a solid-state imaging device having a plurality of channel outputs is used, a signal can be transmitted by connecting the imaging unit and the control and signal processing unit with a smaller number of cables than the number of channels of the solid-state imaging device. Even if it is installed in the imaging unit, it is not necessary to give drive pulses from the control and signal processing unit via the cable, so signal transmission and signal processing with reduced deterioration of the video signal on the cable are possible without increasing the number of cables It becomes.

  According to the present invention, even when a solid-state imaging device having a plurality of channel outputs is used, a signal is transmitted by connecting the imaging unit and the control and signal processing unit with fewer cables than the number of output channels of the solid-state imaging device. In addition, signal transmission and signal processing with reduced deterioration of the video signal on the cable can be performed without increasing the number of cables, so that it is possible to increase the image definition without increasing the cable diameter. An electronic endoscope system equipped with a simple imaging device can be realized.

  Next, the best mode for carrying out the invention will be described.

  First, an embodiment of an imaging device in an electronic endoscope system according to the present invention will be described. FIG. 1 is a block diagram illustrating a configuration of a first embodiment of an imaging apparatus in an electronic endoscope system according to the present invention. The imaging unit 1 has a CCD 4 that is a solid-state imaging device having a two-channel output, and each input terminal is connected to each two-channel output terminal of the CCD 4. The first and second CDS circuits 5a and 5b to be output, and switching means for switching the outputs from the first and second CDS circuits 5a and 5b to the cable 3 via the buffer 7 during a predetermined period. 6 and pulse generation means 8 for generating pulses for driving the CDS circuits 5a and 5b from a pulse φRS for resetting the output portion of the CCD 4 transmitted from the control and signal processing section 2 to the CCD 4 via the cable 3, and the CCD 4 Pulse φRS for resetting the output section of the CCD 4 and the horizontal drive of the CCD 4 which is also transmitted from the control and signal processing section 2 to the CCD 4 via the cable 3 A switching pulse generating means 9 for generating a pulse for driving the switching means 6 from the moving pulse φH is provided.

  Further, the control and signal processing unit 2 includes an analog signal processing means 10 for processing a video signal transmitted from the switching means 6 via the buffer 7 and the cable 3, and a pulse for driving the CCD 4 (reset pulse φRS, CCD driving means 11 for generating horizontal driving pulse φH and vertical driving pulse φV), analog signal processing means 10 and timing signal generating means 12 for the operation of CCD driving means 11 are provided. The signal processing unit 2 is separated from the signal processing unit 2 and is connected by a cable 3 for signal transmission.

  Here, a configuration example of the pulse generation means 8 is shown in FIG. In the figure, 13a and 13b are delay circuits, and 14a and 14b are buffers. Further, two configuration examples of the first and second CDS circuits 5a and 5b are shown in FIGS. In the figure, 15 is a coupling capacitor, 16, 17 and 18 are sample hold circuits, 19 is a differential amplifier, 20 and 21 are switches, 22 is a buffer, and 23 is a hold capacitor.

  Next, the operation of the first embodiment of the imaging apparatus configured as described above will be described. FIG. 5 shows a timing chart of output waveforms and drive pulses in the first embodiment. CCD output 1 and CCD output 2 are 2-channel output of CCD 4, φRS is a pulse for resetting the output part of CCD 4, φH is a horizontal drive pulse for CCD 4, SHP is a first pulse for each CDS circuit 5a, 5b, SHD Is the second pulse for each CDS circuit 5a, 5b, CDS1 output is the output of the first CDS circuit 5a, CDS2 output is the output of the second CDS circuit 5b, SWP is the switching pulse of the switching means 6, VOUT is It is a waveform of an output given from the buffer 7 to the cable 3.

  In response to the drive pulse supplied from the CCD drive circuit 11, a 2-channel output CCD output 1 and a CCD output 2 corresponding to the input video light signal are output from the CCD 4. In the first and second CDS circuits 5a and 5b, the levels of the feedthrough period and signal period of the two-channel output CCD output 1 and CCD output 2 are set to the timing of the first pulse SHP and the second pulse SHD. The signal is sampled and held, the reset noise and 1 / f noise included in the CCD output signal are removed, and the signal CDS1 output and CDS2 output corresponding to the level difference between the feedthrough period and the signal period are output. As shown in FIG. 2, the first pulse SHP and the second pulse SHD are created by delaying the reset pulse φRS by the delay circuits 13a and 13b by the pulse generation means 8. The delay times DL1 and DL2 from the reset pulse φRS of the first pulse SHP and the second pulse SHD are set so as to match the timing of the feedthrough period and the signal period of the CCD output 1 and the CCD output 2. Next, the CDS1 output and the CDS2 output can be sequentially switched and output to the buffer 7 as shown in FIG. 5 by the switching means 6 that performs switching with the switching pulse SWP generated from the horizontal drive pulse φH.

  Therefore, even when a CCD 4 having a two-channel output is used, a signal can be transmitted by connecting the imaging unit 1 and the control and signal processing unit 2 with a smaller number of cables than the number of channels of the CCD 4. Even if the second CDS circuits 5a and 5b and the switching means 6 are provided in the image pickup unit 1, it is not necessary to supply drive pulses for this purpose via the cable from the control and signal processing unit 2, so the number of cables is increased. In addition, signal transmission and signal processing with reduced deterioration of the video signal on the cable can be performed.

  Next, based on the block diagram of FIG. 6, the structure of Example 2 of the imaging device in the electronic endoscope system according to the present invention will be described. The imaging unit 1 includes a CCD 4 that is a solid-state imaging device having a 4-channel output, and an input terminal connected to each output terminal of the CCD 4, and outputs a video signal component by sampling the 4-channel output signal of the CCD 4. A fourth CDS circuit 5a, 5b, 5c, 5d and a switching means 6 for switching the outputs from the CDS circuits 5a, 5b, 5c, 5d to a cable 3 via a buffer 7 during a predetermined period. Pulse generation for generating pulses SHP and SHD for driving the respective CDS circuits 5a, 5b, 5c and 5d from a pulse φRS for resetting the output portion of the CCD 4 transmitted from the control and signal processing unit 2 to the CCD 4 via the cable 3 Means 8 and a pulse φRS for resetting the output part of the CCD 4, and also transmitted from the control and signal processing part 2 to the CCD 4 via the cable 3 A switching pulse generating means 9 for generating a switching pulse SWP for driving the switching means 6 from the horizontal drive pulse φH of the CCD 4 is provided.

  The control and signal processing unit 2 includes an analog signal processing means 10 for processing a video signal transmitted from the switching means 6 via the buffer 7 and the cable 3, and a CCD drive for generating a pulse for driving the CCD 4. And a timing signal generating means 12 for the operation of the means 11, the analog signal processing means 10 and the CCD driving means 11, and the imaging unit 1 and the control and signal processing unit 2 are separated from each other, and a cable for transmitting signals 3 to connect.

  Next, the operation of Embodiment 2 of the imaging apparatus configured as described above will be described. FIG. 7 shows a timing chart of output waveforms and drive pulses in the second embodiment. CCD output 1, CCD output 2, CCD output 3, CCD output 4 are the 4-channel output of CCD 4, φRS is a pulse for resetting the output portion of CCD 4, φH is a horizontal drive pulse for CCD 4, SHP is the first to fourth CDS First pulse for circuits 5a, 5b, 5c, 5d, SHD is a second pulse for each CDS circuit 5a, 5b, 5c, 5d, CDS1 output is the output of first CDS circuit 5a, CDS2 output Is the output of the second CDS circuit 5b, the output of CDS3 is the output of the third CDS circuit 5c, the output of CDS4 is the output of the fourth CDS circuit 5d, SWP1 and SWP2 are the switching pulses of the switching means 6, and VOUT is from the buffer 7 It is the waveform of the output given to the cable 3.

  The operation until the correlated double sampling processing is performed by the CDS circuits 5a, 5b, 5c, and 5d for each output of the 4-channel output of the CCD 4 is the same as in the first embodiment. Next, the switching means 6 switches each CDS output according to the setting shown in FIG. 8 with the switching pulses SWP1 and SWP2 generated from the horizontal drive pulse φH, so that each of the CDS1 output, CDS2 output, CDS3 output, and CDS4 output is changed. The output can be sequentially switched as shown in FIG.

  Therefore, even when a CCD 4 having a 4-channel output is used, a signal can be transmitted by connecting the imaging unit 1 and the control and signal processing unit 2 with a smaller number of cables than the number of channels of the CCD 4. Even if the fourth CDS circuit 5a, 5b, 5c, 5d and the switching means 6 are provided in the imaging unit 1, it is not necessary to provide a driving pulse for this purpose from the control and signal processing unit 2 via the cable. Thus, signal transmission and signal processing with reduced deterioration of the video signal through the cable can be performed without increasing the signal.

  Next, a configuration example of the entire electronic endoscope system including the imaging device according to the present invention will be described. FIG. 9 is a block diagram showing a configuration example of an electronic endoscope system according to the present invention. An electronic endoscope system according to this configuration example includes a light source device 31, a video processor 32 including a digital signal processing circuit, an imaging device 33, and an imaging unit (internal view) of illumination light from the light source device 31. And a light guide 34 for guiding it to the mirror tip. The imaging device 33 includes the imaging device according to the first or second embodiment (the imaging device according to the first embodiment in the illustrated example).

  In the electronic endoscope system configured as described above, even when the imaging apparatus uses a solid-state imaging device having a plurality of channel outputs, signal transmission with reduced deterioration of the video signal in the cable without increasing the number of cables, Since signal processing is possible, it is possible to increase the definition of an image without increasing the cable diameter.

It is a block diagram which shows the structure of Example 1 of the imaging device in the electronic endoscope system which concerns on this invention. It is a block block diagram which shows the structure of the pulse production | generation means shown in FIG. FIG. 2 is a block configuration diagram illustrating a configuration example of a CDS in Embodiment 1 of the imaging apparatus illustrated in FIG. 1. FIG. 6 is a block configuration diagram illustrating another configuration example of the CDS in the first embodiment of the imaging apparatus illustrated in FIG. 1. 3 is a timing chart for explaining an operation of the imaging apparatus illustrated in FIG. 1 according to the first embodiment. It is a block diagram which shows the structure of Example 2 of the imaging device in the electronic endoscope system which concerns on this invention. 7 is a timing chart for explaining an operation of the image pickup apparatus illustrated in FIG. 6 according to the second embodiment. It is a figure which shows the relationship between the output of switching pulse SWP1, SWP2 from the switching pulse production | generation means in Example 2 of the imaging device shown in FIG. 6, and the operation | movement aspect of a switching means. It is a block diagram which shows the structural example of the whole electronic endoscope system which concerns on this invention. It is a block diagram which shows the structural example of the imaging device of the structure by which the conventional imaging part and a control and signal processing part are connected via a cable. It is a block diagram which similarly shows the other structural example of the conventional imaging device.

1 Imaging unit 2 Control and signal processing unit 3 Cable 4 CCD
5a First CDS circuit 5b Second CDS circuit 5c Third CDS circuit 5d Fourth CDS circuit 6 Switching means 7 Buffer 8 Pulse generating means 9 Switching pulse generating means
10 Analog signal processing means
11 CCD drive means
12 Timing signal generation means
13a, 13b Delay circuit
14a, 14b buffer
15 Coupling capacity
16, 17, 18 sample hold circuit
19 Differential amplifier
20, 21 switch
22 buffers
23 Hold capacity
31 Light source device
32 video processor
33 Imaging device
34 Light Guide

Claims (2)

An electronic endoscope system including an imaging device that is separated from an imaging unit and a control and signal processing unit and transmits a signal via a cable,
A solid-state imaging device having a plurality of channel outputs in the imaging unit; and switching means for switching a plurality of channel outputs from the solid-state imaging device during a predetermined period and outputting them to a cable via a buffer,
The control and signal processing unit includes analog signal processing means for performing A / D conversion processing ,
The imaging unit has an input terminal connected to the output terminal of the solid-state imaging device, an output terminal connected to the input terminal of the switching means,
A plurality of correlated double sampling means for sampling a plurality of channel output signals of the solid-state imaging device and outputting a video signal component;
Further comprising pulse generation means for generating a pulse signal for driving the correlated double sampling means based on a pulse signal transmitted from the control and signal processing unit to the solid-state imaging device via a cable;
An electronic endoscope system provided with an imaging device. An electronic endoscope system including an imaging device that is separated from an imaging unit and a control and signal processing unit and transmits a signal via a cable,
A solid-state imaging device having a plurality of channel outputs in the imaging unit; and switching means for switching a plurality of channel outputs from the solid-state imaging device during a predetermined period and outputting them to a cable via a buffer,
The control and signal processing unit includes analog signal processing means for performing A / D conversion processing,
The imaging unit further includes a switching pulse generation unit that generates a pulse signal that drives the switching unit based on a pulse signal transmitted from the control and signal processing unit to the solid-state imaging device via a cable,
An electronic endoscope system provided with an imaging device.

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