JP2006263009A - Electronic endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic endoscope capable of highly efficiently and reliably transmitting and receiving signals by electric waves. <P>SOLUTION: This electronic endoscope 2 comprises a CCD 16 capturing an observation object image in the body cavity, an AFE (Analog Front End) 33 converting image signals obtained by the CCD 16 into digital image signals, a modulation part 34 performing a digital orthogonal modulation to the image signals to modulate them into RF signals, an electronic endoscope 10 having a transmission part 35 transmitting the RF signals as electric waves, a receiving part 63 receiving the electric waves, a demodulation part 64 performing digital orthogonal detection to the RF signals expressed by the electric waves to demodulate them into the original image signals, a synchronous separation part 65 performing various types of signal processings to the demodulated image signals to generate an endoscopic image, a video signal processing part 66, an image processing part 67, and a processor device 11 having a monitor 19 displaying the endoscopic image. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic endoscope apparatus that includes an electronic endoscope and a processor device, and exchanges signals by radio waves between them.

  Conventionally, medical diagnosis using an electronic endoscope has been actively performed in the medical field. An imaging element such as a CCD is built in the distal end of the insertion portion to be inserted into the body cavity of the electronic endoscope, and the image signal acquired by the CCD is subjected to signal processing by the processor device, thereby being monitored. With this, an image inside the body cavity (endoscopic image) can be observed.

  Usually, an electronic endoscope and a processor device are connected by a signal cable, but a modulation unit that modulates a signal and a transmission unit that transmits a signal by radio waves are used as an electronic endoscope and a reception unit that receives radio waves. , And a demodulator that demodulates radio waves into the original signals, each of which is provided with a processor unit so that signals can be exchanged by radio waves, and the signal cable is removed to improve the operability of the electronic endoscope. An endoscope apparatus has also been devised (see Patent Documents 1 and 2).

As described above, the wireless electronic endoscope apparatus is free from the restriction of operation by the signal cable when the electronic endoscope is used, and the operability is improved. Moreover, in a conventional electronic endoscope apparatus using a signal cable, it is essential to maintain a dielectric breakdown voltage of about 4 kV between the patient circuit and the secondary circuit. In a wireless electronic endoscope apparatus, Since there is no electrical connection by a signal cable between the endoscope and the processor device, a configuration for maintaining a high withstand voltage as described above becomes unnecessary.
JP 60-48011 A JP 2001-46334 A

  By the way, recent electronic endoscopes are equipped with a high-pixel CCD for the purpose of obtaining a higher-definition endoscope image. For this reason, in the field of the wireless electronic endoscope apparatus as described above, it is important how efficiently and reliably the signal output from the high pixel CCD can be transmitted to the processor apparatus. It is a difficult issue. In addition, since there is a restriction on the frequency band that can be used for wireless transmission of medical devices (1.2 GHz or 2.4 GHz), it is necessary to transmit and receive signals using a method corresponding to this frequency band.

  However, since the techniques described in Patent Documents 1 and 2 use an analog modulation method for signal modulation / demodulation, the amount of signal data that can be handled per unit time is small, and the technique is suitable for a high-pixel CCD. Is hard to say. In addition, since it is easily affected by noise, the C / N ratio (Carrier to Noise Ratio) is low, and there is a problem of lack of reliability.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic endoscope apparatus that can transmit and receive signals by radio waves more efficiently and with high reliability.

  In order to achieve the above object, the present invention provides an image sensor that captures an image of an object to be observed in a body cavity, a signal converter that converts an image signal acquired by the image sensor into a digital image signal, and a digital orthogonal to the image signal. An electronic endoscope having a modulation unit that modulates and modulates an RF signal, and a transmission unit that transmits the RF signal as a radio wave, a reception unit that receives the radio wave, and performs digital quadrature detection on the RF signal represented by the radio wave A processor having a demodulator that demodulates the original image signal, a signal processor that performs various signal processing on the demodulated image signal to generate an endoscope image, and an image display that displays the endoscope image; It is characterized by comprising.

  The modulation unit and the demodulation unit preferably perform the quadrature modulation and the quadrature detection using a multi-level phase modulation method.

  According to the electronic endoscope apparatus of the present invention, an image sensor that captures an image of an object to be observed in a body cavity, a signal converter that converts an image signal acquired by the image sensor into a digital image signal, and a digital orthogonal to the image signal An electronic endoscope having a modulation unit that modulates and modulates an RF signal, and a transmission unit that transmits the RF signal as a radio wave, a reception unit that receives the radio wave, and performs digital quadrature detection on the RF signal represented by the radio wave A processor having a demodulator that demodulates the original image signal, a signal processor that performs various signal processing on the demodulated image signal to generate an endoscope image, and an image display that displays the endoscope image; Therefore, it is possible to transmit and receive signals by radio waves more efficiently and with high reliability.

  In FIG. 1, an electronic endoscope apparatus 2 to which the present invention is applied includes an electronic endoscope 10 and a processor apparatus 11. The electronic endoscope apparatus 2 is a so-called wireless electronic endoscope apparatus that exchanges signals between the electronic endoscope 10 and the processor device 11 using radio waves 12.

  The electronic endoscope 10 includes an insertion portion 13 that is inserted into a body cavity, and an operation portion 14 that is connected to a proximal end portion of the insertion portion 13. The distal end portion 13a connected to the distal end of the insertion portion 13 is provided with an objective lens 15 for capturing image light of the body image to be observed in the body cavity, and a CCD 16 as an image sensor for capturing the body image to be observed in the body cavity. (For example, a pixel size: 1280 × 960, a frame rate: 30 frames / second), and an irradiation lens 17 and an LED light source (LED) 18 for body cavity illumination (both see FIG. 2) are incorporated. The image inside the body cavity acquired by the CCD 16 is displayed as an endoscopic image on the monitor 19 connected to the processor device 11.

  A bending portion 20 that connects a plurality of bending pieces is provided behind the distal end portion 13a. The bending portion 20 is bent in the vertical and horizontal directions when the angle knob 14a provided in the operation portion 14 is operated and the wire inserted in the insertion portion 13 is pushed and pulled, and the distal end portion 13a. Is directed in a desired direction within the body cavity.

  A cartridge 23 containing a water storage tank 21 in which water is stored and an air cylinder 22 in which air is stored is detachably attached below the operation unit 14. The water and air stored in the water storage tank 21 and the air cylinder 22 are linked to the operation of the water supply / air supply button 14b of the operation unit 14, and the water supply pipe and the air supply provided in the electronic endoscope 10 are operated. It is jetted toward the objective lens 15 through a pipe from a cleaning nozzle (not shown) formed at the tip 13a. Thereby, it is possible to remove dirt attached to the surface of the objective lens 15 and to supply air into the body cavity. Here, the cartridge 23 is attached at a position where the base of the operator's hand abuts when the electronic endoscope 10 is used, and also plays a role of stabilizing the operability of the electronic endoscope 10. Reference numeral 24 denotes a forceps port through which the treatment tool is inserted.

  In FIG. 2, the CPU 30 comprehensively controls the overall operation of the electronic endoscope 10. Connected to the CPU 30 is a ROM 31 in which various programs and data for controlling the operation of the electronic endoscope 10 are stored. The CPU 30 reads necessary programs and data from the ROM 31 and controls the operation of the electronic endoscope 10.

  A driving unit 32 is connected to the LED 18. The drive unit 32 drives the LED 18 on / off under the control of the CPU 30. The light emitted from the LED 18 is irradiated to the object to be observed in the body cavity via the irradiation lens 17. In addition, it is good also as a structure which arrange | positions LED18 inside the operation part 14 instead of the front-end | tip part 13a, and guides it to the front-end | tip part 13a with a light guide.

  The CCD 16 focuses the image light of the observed object image in the body cavity incident from the objective lens 15 on the imaging surface, and outputs an imaging signal corresponding to this from each pixel. The AFE 33 performs correlated double sampling, amplification, and A / D conversion on the imaging signal input from the CCD 16 to convert the imaging signal into a digital image signal (10 bits, see FIG. 3).

  The modulation unit 34 performs digital quadrature modulation on the digital image signal output from the AFE 33, as will be described in detail later. The transmission unit 35 transmits an image signal (hereinafter referred to as an RF signal) subjected to digital quadrature modulation by the modulation unit 34 to the processor device 11 through the antenna 36 as a radio wave 12.

  A battery 38 is connected to the connector 37. The power of the battery 38 is supplied to each part of the electronic endoscope 10 from a power supply unit 39 controlled by the CPU 30. Although not shown in FIG. 1, a battery storage chamber for storing the battery 38 is provided at the rear of the operation unit 14, and the connector 37 is disposed therein.

  In FIG. 3, the modulation unit 34 includes a parallel / serial conversion circuit (P / S) 40, a 256 QAM (Quadrature Amplitude Modulation) modulation circuit (256 QAM MOD) 41, and a serial / parallel conversion circuit (S / P) 42. , An inverse Fourier transform circuit (IFFT) 43, a digital quadrature modulation circuit 44, a D / A converter 45, an up-converter mixer 46, a band-pass filter (BPF) 47, and the like.

  The P / S 40 converts the 10-bit digital image signal input from the AFE 32 from parallel data to serial data. The 256QAM MOD 41 performs symbol mapping of the image signal serially converted by the P / S 40 into the in-phase component I and the quadrature component Q in accordance with the 256QAM modulation method.

  The S / P 42 converts one symbol mapped by 256QAM MOD 41 into N parallel data. The IFFT 43 performs inverse Fourier transform on the data converted in parallel by the S / P 42 and converts the data into a sum of N subcarriers. As a result, IQ baseband OFDM (Orthogonal Frequency Division Multiplexing) signals (hereinafter simply referred to as baseband signals) based on symbols mapped by 256QAM MOD41 are generated.

  The digital quadrature modulation circuit 44 digitally converts the baseband signal output from the IFFT 43 using a multilevel PSK (Phase Shift Keying) system, for example, a binary PSK (BPSK) system or a quaternary PSK (QPSK) system. Based on a frequency control signal input from an oscillator 49 via a PLL (Phase Locked Loop) circuit 48, an IF signal having an intermediate frequency IF (Intermediate Frequency) is output.

  The D / A 45 performs D / A conversion on the IF signal output from the digital quadrature modulation circuit 44. The up-converter mixer 46 generates an RF signal from the IF signal D / A converted by the D / A 45 and the frequency control signal input from the oscillator 49 via the PLL circuit 48. The BPF 47 performs band limitation on the RF signal generated by the upconverter mixer 46 to remove unnecessary portions, and outputs an RF signal having a desired frequency band (1.2 GHz or 2.4 GHz).

  The transmission unit 35 includes a power amplifier (PA) 50 and an RF switch (RF-SW) 51. The PA 50 amplifies the RF signal output from the BPF 47 to a power level that can be received by the processor device 11. The RF-SW 51 is turned on / off in accordance with the channel burst timing of the TDMA (Time Division Multiple Access) method employed in the electronic endoscope apparatus 2. The RF signal amplified by the PA 50 is fed to the antenna 36 by the circulator (not shown) via the RF-SW 51 and transmitted as the radio wave 12 from the antenna 36.

  In FIG. 4, the CPU 60 controls the overall operation of the processor device 11. Connected to the CPU 60 is a ROM 61 in which various programs and data for controlling the operation of the processor device 11 are stored. The CPU 60 reads necessary programs and data from the ROM 61 and controls the operation of the processor device 11.

  The antenna 62 receives the radio wave 12 from the electronic endoscope 10. The radio wave 12 received by the antenna 62 is supplied to the receiving unit 63 by a circulator (not shown). The receiving unit 63 amplifies the radio wave 12, that is, the RF signal. As will be described later in detail, the demodulator 64 performs digital quadrature detection on the RF signal and demodulates the RF signal into an image signal before being modulated by the electronic endoscope 10.

  Under the control of the CPU 60, the synchronization separation unit 65 separates the synchronization signal from the image signal demodulated by the demodulation unit 64 by amplitude separation, and then separates the horizontal synchronization signal and the vertical synchronization signal by frequency separation. The video signal processing unit 66 generates a digital video signal from the image signal. The image processing unit 67 performs various image processing such as mask generation and character information addition on the video signal generated by the video signal processing unit 66. The buffer 68 temporarily stores a video signal that is subjected to various image processing by the image processing unit 67 and displayed as an endoscopic image on the monitor 19.

  In FIG. 5, the receiving unit 63 includes an RF switch (RF-SW) 70 and a low noise amplifier (LNA) 71. The RF-SW 70 is turned on / off in accordance with the TDMA channel burst timing employed in the electronic endoscope apparatus 2 in the same manner as the RF-SW 51 described above. The LNA 71 amplifies the RF signal input via the RF-SW 70.

  The demodulator 64 includes a down-converter mixer 72, a bandpass filter (BPF) 73, an A / D converter (A / D) 74, a digital quadrature detection circuit 75, a Fourier transform circuit (FFT) 76, a parallel / serial conversion circuit ( P / S) 77, 256QAM demodulation circuit (256QAM DEMOD) 78, serial / parallel conversion circuit (S / P) 79, and the like.

  The down-converter mixer 72 generates an IF signal from the RF signal amplified by the LNA 71 and the frequency control signal input from the oscillator 81 via the PLL circuit 80. The BPF 73 performs band limitation on the IF signal generated by the down converter mixer 72 to remove unnecessary portions. The A / D 74 performs A / D conversion on the IF signal whose band is limited by the BPF 73.

  Similarly to the digital quadrature modulation circuit 44, the digital quadrature detection circuit 75 performs digital quadrature detection on the IF signal A / D converted by the A / D 74 using, for example, the BPSK method, the QPSK method, etc. The baseband signal is output based on the frequency control signal input from the oscillator 81 through the control circuit.

  The FFT 76 performs a Fourier transform on the baseband signal output from the digital quadrature detection circuit 75 and outputs parallel data that is the source of the baseband signal. The P / S 77 converts the parallel data output from the FFT 76 into serial data, and outputs data symbol-mapped into the in-phase component I and the quadrature component Q. The 256QAM DEMOD 78 demodulates the data serially converted by the P / S 77 in accordance with the 256QAM modulation method. The S / P 79 converts the data demodulated by the 256QAM DEMOD 78 into parallel data. Thereby, the image signal before being modulated by the electronic endoscope 10 is demodulated.

When the inside of the body cavity is observed with the electronic endoscope apparatus 2 configured as described above, the insertion unit 13 is inserted into the body cavity, and the LED light source 18 is turned on to illuminate the inside of the body cavity. An endoscopic image is observed on the monitor 19.

  At this time, the image light of the observed body image in the body cavity incident from the objective lens 15 is imaged on the imaging surface of the CCD 16, and an imaging signal is output from the CCD 16. The imaging signal output from the CCD 16 is subjected to correlated double sampling, amplification, and A / D conversion by the AFE 33, and is converted into a digital image signal.

  The digital image signal output from the AFE 33 is subjected to digital quadrature modulation by the modulation unit 34. In the modulation unit 34, the digital image signal input from the AFE 32 is converted from parallel data to serial data by the P / S 40. Next, the image signal serially converted by the P / S 40 is symbol-mapped into an in-phase component I and a quadrature component Q by 256QAM MOD41.

  In S / P42, one symbol mapped by 256QAM MOD41 is converted into N parallel data. The data converted in parallel by S / P 42 is subjected to inverse Fourier transform in IFFT 43 and converted into a sum of N subcarriers, thereby generating a baseband signal.

  In the digital quadrature modulation circuit 44, the baseband signal output from the IFFT 43 is subjected to digital quadrature modulation by the multi-level PSK method, and based on the frequency control signal input from the oscillator 49 via the PLL circuit 48, the IF A signal is output.

  The IF signal output from the digital quadrature modulation circuit 44 is D / A converted by the D / A 45 and input to the up-converter mixer 46. The upconverter mixer 46 generates an RF signal from the IF signal D / A converted by the D / A 45 and the frequency control signal input from the oscillator 49 via the PLL circuit 48.

  The RF signal generated by the up-converter mixer 46 is band-limited by the BPF 47 and becomes an RF signal having a desired frequency band. The RF signal is amplified by the PA 50 of the transmission unit 35, supplied to the antenna 36 by the circulator via the RF-SW 51, and transmitted as the radio wave 12 from the antenna 36.

  On the other hand, in the processor device 11, when the radio wave 12 transmitted from the antenna 36 of the electronic endoscope 10 is received by the antenna 62, the radio wave 12 is supplied to the receiving unit 63 by the circulator. In the receiving unit 63, the RF signal input via the RF-SW 70 is amplified by the LNA 71.

  The RF signal amplified by the LNA 71 is input to the down converter mixer 72 of the demodulation unit 64. In the down converter mixer 72, an IF signal is generated from the RF signal amplified by the LNA 71 and the frequency control signal input from the oscillator 81 via the PLL circuit 80. The IF signal generated by the downconverter mixer 72 is band-limited by the BPF 73 and A / D converted by the A / D 74.

  In the digital quadrature detection circuit 75, the digital quadrature detection is performed on the IF signal A / D converted by the A / D 74 by the multilevel PSK method, and the frequency control signal input from the oscillator 81 through the PLL circuit 80 is converted into a frequency control signal. Based on this, a baseband signal is output.

  The baseband signal output from the digital quadrature detection circuit 75 is subjected to Fourier transform by the FFT 76 to become parallel data that is the source of the baseband signal. Next, the parallel data is converted into serial data in P / S 77 and becomes data that is symbol-mapped into the in-phase component I and the quadrature component Q. Then, the data is demodulated by the 256QAM DEMOD 78 in accordance with the 256QAM modulation method, and finally the data demodulated by the 256QAM DEMOD 78 is converted into parallel data by the S / P 79, so that the data before being modulated by the electronic endoscope 10 is obtained. The image signal is demodulated.

  The image signal demodulated by the demodulation unit 64 is subjected to synchronization separation by the synchronization separation unit 65 under the control of the CPU 60 and output as a digital video signal by the video signal processing unit 66. The video signal output from the video signal processing unit 66 is subjected to various types of image processing by the image processing unit 67, temporarily stored in the buffer 68, and displayed on the monitor 19 as an endoscopic image. As described above, signals are transmitted and received by the radio wave 12 between the electronic endoscope 10 and the processor device 11.

  As described above in detail, the electronic endoscope apparatus 2 includes the CCD 16 that captures an image of an object to be observed in a body cavity, the AFE 33 that converts an imaging signal acquired by the CCD 16 into a digital image signal, and a digital orthogonal to the image signal. The electronic endoscope 10 having the modulation unit 34 that modulates and modulates the RF signal, and the transmission unit 35 that transmits the RF signal as a radio wave, the reception unit 63 that receives the radio wave, and the digital RF signal represented by the radio wave A demodulator 64 that performs quadrature detection and demodulates the original image signal, a sync separator 65 that performs various signal processing on the demodulated image signal to generate an endoscopic image, a video signal processor 66, and an image processor 67 And the processor device 11 having the monitor 19 for displaying an endoscopic image, signals can be transmitted and received by radio waves more efficiently and with high reliability.

  Note that the configurations of the modulation unit 34, the transmission unit 35, the reception unit 63, and the demodulation unit 64 described in the above embodiment are merely examples, and the present invention is not particularly limited thereto.

It is the schematic which shows the structure of an electronic endoscope apparatus. It is a block diagram which shows the internal structure of an electronic endoscope. It is a block diagram which shows the internal structure of a modulation part and a transmission part. It is a block diagram which shows the internal structure of a processor apparatus. It is a block diagram which shows the internal structure of a receiving part and a demodulation part.

Explanation of symbols

2 Electronic endoscope apparatus 10 Electronic endoscope 11 Processor apparatus 12 Radio wave 16 CCD
19 Monitor 30 CPU
33 AFE
34 Modulator 35 Transmitter 41 256QAM Modulator (256QAM MOD)
44 Digital quadrature modulation circuit 60 CPU
63 Receiver 64 Demodulator 75 Digital Quadrature Detector 78 256QAM Demodulator (256QAM DEMOD)

Claims (2)

An image sensor for taking an image of a body to be observed in a body cavity
A signal converter that converts an image signal acquired by the image sensor into a digital image signal;
A modulation unit that performs digital quadrature modulation on an image signal to modulate an RF signal;
And an electronic endoscope having a transmission unit for transmitting RF signals as radio waves,
A receiver for receiving radio waves,
A demodulator that performs digital quadrature detection on an RF signal represented by radio waves and demodulates the original image signal;
A signal processor that performs various signal processing on the demodulated image signal to generate an endoscopic image;
An electronic endoscope apparatus comprising: a processor device having an image display unit for displaying an endoscope image. The electronic endoscope apparatus according to claim 1, wherein the modulation unit and the demodulation unit perform the quadrature modulation and the quadrature detection using a multilevel phase modulation method.

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