JP2002016931A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device capable of outputting an image signal of a visible region and an image signal of a near infrared region together and still reducing a volume and a mass of a head section. SOLUTION: This image pickup device comprises an isolation optical system for isolating an incident light into an infrared region and a visible region on the same optical axis, a CCD 6 for imaging the incident light of the infrared region, a CCD 7 for imaging the incident light of the visible region, a first signal processing unit 8 for conducting a predetermined infrared signal process for an infrared image signal obtained from the CCD 6 and outputting the infrared image signal after processing, and a second signal processing unit 9 inputting the image signal obtained from the CCD 7 and an output signal from the processing unit 8 to conduct a predetermined color signal process for the input signal and to output the signal after processing as a color image signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device for converting an optical image into an image signal, and more particularly to an imaging device suitable for an endoscope imaging device used during an endoscopic operation.

[0002]

2. Description of the Related Art In recent years, endoscopic surgery has rapidly become widespread in medical practice because the burden on patients is smaller than in conventional open surgery. Endoscopic surgery has a diameter of 1
The imaging is performed by attaching the imaging device to a rigid endoscope having a tubular shape of about 0 mm or less and monitoring an image obtained from the imaging device displayed on a display monitor.

[0003] The imaging device for an endoscope used here must be small and lightweight, and a separation unit composed of a camera head unit, a CCU (camera control unit) unit, and a camera cable for electrically connecting them. In many cases, it takes the form of a mold. Endoscopic surgery was initially performed in limited operations such as cholecystectomy, but many other operations have been performed due to the advantages that the patient's pain after the operation is much smaller than conventional laparotomy and the recovery is faster. Has been implemented. Accordingly, as a demand for an imaging device for an endoscope, imaging in an infrared region is required in addition to high image quality. This is, for example, by enabling the imaging of blood vessels existing in the mesentery, etc.,
It has the effect of avoiding the cutting of blood vessels when separating the mesentery from the small intestine or large intestine and improving the safety of surgery.

Imaging of blood vessels in a thin film such as the mesentery is performed in a region called near infrared in the infrared region, that is, 700 nm to 1000 n.
It becomes possible by imaging the m-th wavelength region. CCD (Charge), which is currently used most often as an image sensor
Coupled Device) area image sensor, (hereinafter "C
CD ”) has sensitivity in the near infrared region in addition to the visible light region. For this reason, in ordinary color imaging, in order to prevent the sensitivity in the near infrared region from affecting the color reproducibility and the like,
An infrared cut filter is provided between the imaging lens and the CCD to cut a region having a wavelength longer than near infrared. As an imaging device for an endoscope, a device that can output a color image with good color reproducibility in the visible light region and synthesize an image from the near-infrared region with a color image when necessary is desirable. Is disclosed in Japanese Patent Application Laid-Open No. 10-341446.

[0005]

However, in this imaging apparatus, incident light is divided into red, blue, green incident light and near-infrared incident light into four parts, and an image is taken using four image pickup elements. Because of the plate system, the imaging optical system becomes large-scale. As a result, there is a problem that both the volume and the mass of the camera head are too large to be used as an endoscope imaging device.

The present invention has been made in view of this point, and it is possible to output both an image signal in the visible region and an image signal in the near infrared region, and to reduce the volume and mass of the head portion. It is an object of the present invention to provide an imaging device capable of performing the following.

[0007]

According to a first aspect of the present invention, there is provided a separation optical system for separating incident light into an infrared region and a visible light region on the same optical axis. A first image sensor for imaging the incident light in the infrared region, a second image sensor for imaging the incident light in the visible light region, and a predetermined image signal for the infrared image signal obtained from the first image sensor And a first signal processing unit that outputs an infrared image signal after the processing, and an image signal obtained from the second image sensor and an output signal from the first signal processing unit are input. And a second signal processing unit that performs predetermined color signal processing on the input signal and outputs the processed signal as a color image signal. I do.

According to a second aspect of the present invention, in the image pickup apparatus of the first aspect, there is provided a changeover switch for turning on / off in response to an external control signal, and an output signal of the first signal processing unit is provided. , Is input to the second signal processing unit via the changeover switch.

According to a third aspect of the present invention, in the imaging device according to the first or second aspect, the first and second imaging elements are two-dimensional imaging elements in which the effective imaging area is equal in both horizontal and vertical dimensions. Wherein the first image sensor is an image sensor for black and white imaging, and the second image sensor is an image sensor for color imaging in which a color filter is formed on a pixel.

According to a fourth aspect of the present invention, there is provided a separation optical system for separating incident light into an infrared region, magenta and green in a visible light region on the same optical axis, and the incident light in the infrared region. A first imaging device for imaging, a second imaging device for imaging the magenta incident light, and a third imaging device for imaging the green incident light.
An image sensor, a first signal processing unit that performs predetermined signal processing on an infrared image signal obtained from the first image sensor, and outputs an infrared image signal after the processing, A second signal processing unit that performs predetermined signal processing on an image signal obtained from the image pickup device and outputs the processed image signal; an image signal obtained from the third image pickup device; Output signals from the first and second signal processing units are input,
An image pickup apparatus comprising: a third signal processing unit that performs predetermined color signal processing on the input signal and outputs the processed signal as a color image signal.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a configuration of an imaging apparatus according to a first embodiment of the present invention. The optical system of this device includes an imaging lens 1, an optical low-pass filter 2, prisms 3 and 5, and an optical filter 4. The prisms 3, 5 and the optical filter 4 convert incident light into an infrared region and a visible light region. A separation optical system for separation is configured. This separation optical system has a function of separating incident light into a near-infrared region and a visible light region on the same optical axis.

The optical filter 4 includes a prism 3 and a prism 5
Are formed at the interface of the substrate and selectively reflect near-infrared light and transmit visible light. Therefore, the incident light reflects near-infrared light on the optical filter 4 and travels along the path shown in FIG.
The light is incident on a CD 6 (first image sensor). On the other hand, the visible light transmitted through the optical filter 4 is incident on the CCD 7 (second imaging device) along the path shown in FIG.

As the CCD 7, a color imaging CCD in which a color filter is formed on each pixel by a photoresist process is used. Since near-infrared light is removed and light enters the CCD 7 in the same manner as a normal single-chip color imaging device, a color image with good color reproducibility can be captured and output. On the other hand, as the CCD 6, a black-and-white imaging CCD in which a color filter is not formed on a pixel is used. The CDDs 6 and 7 both have the same effective imaging dimensions and the same number of effective pixels in the horizontal and vertical directions.

The CCDs 6 and 7 include a drive signal generator 15.
The driving signal generator 15 includes a driving circuit 11 for supplying a driving signal to the CCD 6, a driving circuit 12 for supplying a driving signal to the CCD 7, a synchronizing signal generator 14 for generating a synchronizing signal, and a synchronizing signal generator 14. A timing signal is generated in accordance with the synchronization signal output from the signal generator 14, and the driving circuit 1
1 and 12 to supply the signals to a timing generator 13.

An image signal in the near-infrared light region imaged by the CCD 6 and converted into an electric signal is subjected to a first signal processing for performing predetermined signal processing.
Is input to the signal processing unit 8. The first signal processing unit 8
CDS (Correl) that performs correlated double sampling of input signals
ated Double Sampling) circuit 81 and an AGC which outputs a signal input from the CDS circuit 81 at a constant level.
(Automatic Gain Control) circuit 82 and an HPF (High P) for enhancing or extracting high-frequency signals in the horizontal and vertical directions.
ass Filter) 83. With the HPF 83, blood vessels can be emphasized in endoscopic surgery.

The signal output from the first signal processing unit 8 is input to a second signal processing unit 9 via a switch 10. The switch 10 is connected to a control signal SC
On / off control is performed according to TL. The image signal in the visible light region, which is imaged by the CCD 7 and converted into an electric signal,
The signal is input to a second signal processing unit 9 that performs predetermined color signal processing. The second signal processing unit 9 includes a CDS circuit 91 that performs correlated double sampling of an input signal, and an AG that outputs a signal input to the CDS circuit 91 at a constant level.
A C circuit 92; a color separation circuit 93 that separates an input signal into three primary color signals; a process matrix circuit 94 that performs signal processing such as gamma correction and knee processing and generates a luminance signal and a line-sequential color difference signal; It comprises a synchronization circuit 95 for generating two color difference signals from the color difference signals, and an encoder 96 for generating and outputting a composite color signal SC of the NTSC system or the PAL system. The encoder 96 outputs a luminance signal Y and a color signal (S video), an RGB component signal, or a luminance signal Y and a color difference signal Cb, if necessary.
It is configured to output a component signal composed of Cr.

The near-infrared image signal input to the signal processing unit 9 via the switch 10 is input to the encoder 96,
It is combined with a signal in the visible light region. When it is desired to enhance an image from the near infrared, a color component which hardly exists in the body, for example, green in the signal output from the encoder 96 according to the amplitude of the image signal from the near infrared is enhanced. It is effective.

For example, the operator of the endoscopic operation operates a remote switch such as a foot switch to normally turn off the switch 10 so that the switch 10 is difficult to find in the visible light region. An operation is performed to turn on the switch 10 when an image from near-infrared is required for blood vessel imaging or the like.

As described above, the imaging apparatus according to the present embodiment has a separation optical system for separating incident light into an infrared region and a visible light region on the same optical axis, and a second optical system for imaging the incident light in the infrared region. A CCD 6 as a first imaging device, a CCD 7 as a second imaging device for capturing incident light in a visible light region, and a CCD
A first signal processing unit 8 for performing a predetermined infrared signal process on the infrared image signal obtained from the CCD 6 and outputting the processed infrared image signal;
An output signal from the signal processing unit 8 is input, a predetermined color signal process is performed on the input signal, and a second signal processing unit 9 that outputs the processed signal as a color image signal Therefore, with the two-plate configuration, an image signal in the visible region and an image signal in the near-infrared region can both be output, and the size and weight of the optical system can be reduced. As a result, an imaging device suitable as an imaging device for an endoscope can be realized.

(Second Embodiment) FIG. 2 is a diagram showing a configuration of an imaging apparatus according to a second embodiment of the present invention. The optical system of this device includes an imaging lens 21, an optical low-pass filter 22, prisms 23, 24 and 25, an optical filter 2
6 and 27, and prisms 23, 24, 2
The optical filter 5 and the optical filters 26 and 27 constitute a separation optical system that separates incident light into an infrared region and magenta and green in a visible light region. This separation optical system, on the same optical axis,
It has a function of separating incident light into an infrared region and magenta and green in a visible light region.

An optical filter 26 is formed at the interface between the prisms 23 and 24 and selectively reflects near infrared light.
It has the property of transmitting visible light. The optical filter 27 is formed at the interface between the prisms 24 and 25 and has a characteristic of reflecting red and blue (magenta) in the visible light region and transmitting green. Accordingly, near-infrared light of the incident light is reflected by the optical filter 26, and the near-infrared light is incident on the CCD 28 (first image sensor) along the path shown in FIG. In addition, incident light in the visible light region passing through the optical filter 26 is
Red and blue are reflected by the CCD 2 along the path shown in FIG.
9 (second imaging element) and is imaged. The green incident light transmitted through the optical filter 27 is transmitted to the CCD 30 (third light source).
And an image is captured.

The CCDs 28 and 30 are monochrome CCDs in which no color filters are formed on the pixels.
For the CD 29, a red and blue imaging CCD in which red and blue color filters are alternately formed in a vertical stripe by one pixel in the horizontal direction by a photoresist process is used. In addition, CCD2
8, 29, and 30 have the same effective imaging dimensions and the same number of effective pixels in the horizontal and vertical directions.

The CCDs 28 to 30 include a drive signal generator 3
8 is connected, and the drive signal generation unit 38
A driving circuit 35 for supplying a driving signal to each of 8 to 30; a synchronizing signal generator 37 for generating a synchronizing signal;
And a timing generator 36 that generates a timing signal in accordance with the synchronization signal output from the controller 7 and supplies the timing signal to the drive circuit 35.

The image signal in the near-infrared light region captured by the CCD 28 and converted into an electric signal is input to a first signal processing unit 31 for performing predetermined signal processing. First signal processing unit 3
Reference numeral 1 denotes a CDS (Correlated Double Sampling) circuit 311 which has a configuration similar to that of the first signal processing unit 8 in the above-described first embodiment and performs correlated double sampling;
AGC (Automatic Gain Control) circuit 3 for outputting a signal input from the CDS circuit 311 at a constant level
12 and an HPF (High Pass Filter) 313 for enhancing or extracting high-frequency signals in the horizontal and vertical directions.

The signal output from the first signal processing unit 31 is input to a third signal processing unit 33 via a switch 34. The switch 34 is provided with a control signal S
On / off control is performed according to CTL. CCD29
R (red) signal which is imaged at and converted into an electric signal and B
The (blue) signal is input to a second signal processing unit 32 that performs predetermined signal processing. The second signal processing unit 32 performs a CDS circuit 321, an AGC circuit 322, an R / B separation circuit 323 that separates an R signal and a B signal, and performs γ correction, knee processing, and the like on the R and B signals. And a process circuit 324. The R signal and the B signal output from the process circuit 324 are input to the third signal processing unit 33.

The G signal imaged by the CCD 10 and converted into an electric signal is input to a third signal processing unit 33 which performs a predetermined color signal processing. The third signal processing unit 33 uses C
A DS circuit 331, an AGC circuit 332, a process circuit 333 that performs gamma correction, knee processing, and the like on the G signal, an R signal and a B signal input from the second signal processing unit 32, and an input from the process circuit 333. A matrix circuit 334 that generates a luminance signal Y and two color difference signals (RY) and (BY) from the G signal, and a luminance signal Y and color difference signals (RY) and (BY). , NTSC or P
And an encoder 335 that generates and outputs a composite color signal of the AL system. The encoder 335 may include a luminance signal Y and a color signal (S video), an RGB component signal, or a luminance signal Y and color difference signals Cb and Cr as necessary.
It is configured to output a component signal consisting of

The matrix circuit 334 includes a switch 34
, A near-infrared signal is input, and is synthesized with a color signal in the visible light region. When it is desired to enhance an image from the near infrared, similarly to the first embodiment, if the configuration is such that the G signal component which hardly exists in the body is enhanced according to the signal amplitude from the near infrared. It is effective.

The switch 34 is turned on / off similarly to the switch 10 in the first embodiment. That is, for example, an operator of an endoscopic operation operates a remote switch such as a foot switch to normally turn off the switch 34, and is used for imaging a blood vessel in the mesentery, which is difficult to find in imaging in the visible light region. Switch 34 when an image from infrared is required
Operate to turn on.

As described above, the image pickup apparatus according to the present embodiment includes, on the same optical axis, a separation optical system for separating incident light into an infrared region, magenta and green in a visible light region, and an incident light in an infrared region. A CCD 28 as a first imaging element for imaging light;
C as a second imaging element for imaging magenta incident light
A predetermined infrared signal process is performed on the infrared image signal obtained from the CD 29, the CCD 30 as a third image sensor that captures the green incident light, and the CCD 28, and the processed infrared image signal is output. A first signal processing unit 31 for outputting, a CCD
A second signal processing unit 3 that performs predetermined signal processing on the image signal obtained from the second image processing unit 29 and outputs the processed image signal
2, an image signal obtained from the CCD 30, and output signals from the first and second signal processing units 31 and 32,
The input signal is provided with a third signal processing unit 33 that performs predetermined color signal processing and outputs the processed signal as a color image signal. In addition, an image signal in the visible region and an image signal in the near-infrared region can both be output, and the size and weight of the optical system can be reduced. As a result, an imaging device suitable as an imaging device for an endoscope can be realized.

[0030]

As described above in detail, according to the imaging apparatus of the first aspect, incident light is separated into an infrared region and a visible light region on the same optical axis, and the incident light in the infrared region is separated. Is the first
Is converted into an infrared image signal by the image sensor of
The incident light in the visible light region is converted into an image signal by the second image sensor. A predetermined infrared signal process is performed on the infrared image signal, and a predetermined color signal process is performed on the processed infrared image signal and the image signal obtained from the second image sensor. Processing is performed, and the processed signal is output as a color image signal. Therefore, with the two-plate configuration, it is possible to output both the image signal in the visible region and the image signal in the near-infrared region, and it is possible to reduce the size and weight of the optical system. It is possible to realize a suitable imaging device.

According to the image pickup apparatus of the fourth aspect, on the same optical axis, the incident light is separated into magenta and green in the infrared region and the visible light region, and the incident light in the infrared region is separated into the first light. While being converted into an infrared image signal by the image sensor, magenta incident light and green incident light in the visible light region are converted into image signals by the second and third image sensors, respectively.
A predetermined infrared signal process is performed on the infrared image signal, and a predetermined signal process is performed on the image signal corresponding to magenta. Then, a predetermined color signal process is performed on the processed infrared image signal and magenta signal, and the image signal obtained from the third image sensor, and the processed signal is output as a color image signal. Is done. Therefore, with the three-plate configuration, it is possible to output both the image signal in the visible region and the image signal in the near-infrared region, and it is possible to reduce the size and weight of the optical system. A suitable imaging device can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an imaging device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of an imaging device according to a second embodiment of the present invention.

[Explanation of symbols]

 3, 5, 23, 24, 25 Prism (separation optical system) 4, 26, 27 Optical filter (separation optical system) 6, 28 CCD (first imaging device) 7, 29 CCD (second imaging device) 30 CCD (third imaging device) 8, 31 First signal processing unit 9, 32 Second signal processing unit 33 Third signal processing unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/225 H04N 5/225 C 5C065 5/335 5/335 Z 7/18 7/18 M N 9 / 04 9/04 CF term (reference) 2H054 BB01 BB07 4C061 BB01 BB08 CC06 HH54 LL02 MM05 PP11 WW04 5C022 AA09 AB13 AC01 AC42 AC54 AC55 5C024 AX01 AX06 BX02 CX38 CY15 CY18 CY50 DX01 EX18 H48X05 H05A CA04 CA05 CC02 CG08 EA01 ED04 EH01 FB03 FE09 FE12 FE23 FF02 HA12 5C065 AA04 AA06 BB15 BB48 CC01 DD02 DD18 DD19 EE01 EE05 EE06 EE14 FF07 GG05 GG10 GG12

Claims (4)

[Claims] 1. A separation optical system that separates incident light into an infrared region and a visible light region on the same optical axis, a first image sensor that captures the incident light in the infrared region, and the visible light. A second image sensor that captures the incident light of the area, a first signal processor that performs predetermined signal processing on an infrared image signal obtained from the first image sensor, and outputs an infrared image signal after the processing; A signal processing unit, an image signal obtained from the second image sensor, and an output signal from the first signal processing unit are input, and a predetermined color signal process is performed on the input signal. A second signal processing unit that outputs the processed signal as a color image signal. 2. A switch for turning on / off in response to an external control signal, wherein an output signal of the first signal processing unit is input to the second signal processing unit via the switch. The imaging device according to claim 1, wherein: 3. The first and second image sensors are two-dimensional image sensors in which an effective image area is equal in both horizontal and vertical dimensions, and the first image sensor is an image sensor for monochrome image capturing. 3. The image pickup apparatus according to claim 1, wherein the second image pickup element is a color image pickup element in which a color filter is formed on a pixel. 4. A separation optical system for separating incident light into an infrared region, magenta and green in a visible light region on the same optical axis, and a first image sensor for imaging the incident light in the infrared region. A second image sensor for imaging the magenta incident light, a third image sensor for imaging the green incident light, and a predetermined image signal for an infrared image signal obtained from the first image sensor. A first signal processing unit that performs signal processing and outputs an infrared image signal after the processing; and performs a predetermined signal processing on an image signal obtained from the second image sensor, and processes the image after the processing. Second signal output
A signal processing unit; an image signal obtained from the third image sensor;
And a third signal processing for inputting an output signal from the second signal processing unit, performing predetermined color signal processing on the input signal, and outputting the processed signal as a color image signal. And an imaging device.