JP4500207B2 - Biological observation device - Google Patents

Description

The present invention relates to a living body observation apparatus that uses a color image signal obtained by imaging a living body to generate a pseudo narrowband filter by signal processing and displays it as a spectral image on a monitor .

2. Description of the Related Art Conventionally, endoscope apparatuses that obtain an endoscopic image in a body cavity by irradiating illumination light have been widely used as living body observation apparatuses . In this type of endoscope apparatus, an electronic endoscope having an image pickup unit that guides illumination light from a light source device into a body cavity using a light guide or the like and picks up an image of a subject using the return light is used. An image signal from the imaging means is signal-processed to display an endoscopic image on an observation monitor and observe an observation site such as an affected area.

When normal biological tissue observation is performed in an endoscope apparatus, one method is to emit white light in the visible light region with a light source device, and use, for example, a rotation filter such as RGB to subject the surface sequential light to a subject. irradiated, that has gained a color image by image processing synchronized with the video processor return light by the frame sequential light. When performing normal biological tissue observation in an endoscope apparatus, as another method , a color chip is arranged in front of the imaging surface of the imaging means of the endoscope, and white light in the visible light region is emitted by the light source device. It emits the return light by the white light imaged by separating for each color component by the color chips, to obtain a color image by image processing by the video processor.

Biological organizations, since the absorption characteristics and scattering characteristics of light differ according to the wavelength of light irradiated, for example, Japanese in 2002-95635, JP-narrowband RGB discrete spectral characteristics illumination light in the visible light region A narrow-band optical endoscope apparatus that irradiates a living tissue with frame sequential light and obtains tissue information of a desired deep portion of the living tissue has been proposed.
Japanese Patent Laid-Open No. 2003-93336 discloses a narrowband optical endoscope that generates a discrete spectral image by performing signal processing on an image signal generated by illumination light in a visible light region and obtains tissue information of a desired deep part of a living tissue. A device has been proposed.
JP 2002-95635 A JP 2003-93336 A

However, for example, the device described in JP-A-2003-93336, to obtain a spectral image by signal processing, but does not require a filter for generating a narrowband RGB light, a spectral image obtained Since the image is simply output to the monitor, the image displayed on the monitor is not an image having a color tone suitable for observing tissue information in a desired deep part of the living tissue, and there is a possibility that the visibility is not good. .

Therefore, the present invention has been made in view of the above circumstances, adjusting tissue information of a desired deep part of a living tissue based on a spectral image obtained by signal processing to image information of a color tone suitable for observation, and and its object is to provide a biological observation apparatus capable of favorably with to Rukoto visibility by improving the quality of the signal displayed output.

A first living body observation apparatus according to the present invention includes an illumination unit that irradiates light to a living body that is a subject, and an imaging unit that photoelectrically converts light reflected from the living body based on the irradiation light and generates an imaging signal And a signal processing control unit that controls the operation of the illuminating unit and / or the imaging unit and outputs the imaging signal to a display device, and the signal processing control unit receives an optical wavelength from the imaging signal. A spectral signal generation unit that generates a spectral signal corresponding to a narrow-band image by signal processing, and a color that assigns a different color tone to each of a plurality of bands that form the spectral signal when the spectral signal is output to the display device An adjustment unit; an image quality adjustment unit that adjusts an image quality of a signal output to the display device; and a signal amplification unit that amplifies a signal level of the imaging signal and / or the spectral signal. The imaging signal The amplification control is changed depending on the spectral signal. The amplification control starts the amplification operation when the light amount control by the light amount control unit for controlling the light amount irradiated from the illumination unit cannot be performed. It is a follow-up speed when performing.
The second living body observation apparatus of the present invention includes an illumination unit that irradiates light to a living body that is a subject, and an imaging unit that photoelectrically converts light reflected from the living body based on the irradiation light and generates an imaging signal And a signal processing control unit that controls the operation of the illuminating unit and / or the imaging unit and outputs the imaging signal to a display device, and the signal processing control unit receives an optical wavelength from the imaging signal. A spectral signal generation unit that generates a spectral signal corresponding to a narrow-band image by signal processing, and a color that assigns a different color tone to each of a plurality of bands that form the spectral signal when the spectral signal is output to the display device An adjustment unit, and an image quality adjustment unit that improves the brightness and / or S / N ratio of the signal output to the display device, wherein the image quality adjustment unit is a luminance signal and / or a spectral signal of an imaging signal. Luminance signal weighting And performing calculation.
A third living body observation apparatus of the present invention includes an illuminating unit that irradiates light to a living body that is a subject, and an imaging unit that photoelectrically converts light reflected from the living body based on the irradiated light and generates an imaging signal And a signal processing control unit that controls the operation of the illuminating unit and / or the imaging unit and outputs the imaging signal to a display device, and the signal processing control unit receives an optical wavelength from the imaging signal. A spectral signal generation unit that generates a spectral signal corresponding to a narrow-band image by signal processing, and a color that assigns a different color tone to each of a plurality of bands that form the spectral signal when the spectral signal is output to the display device An adjustment unit, and an image quality adjustment unit that improves the brightness and / or S / N ratio of the signal output to the display device, and the image quality adjustment unit performs predetermined conversion from the imaging signal or the imaging signal Generated by And performing control for changing the spatial frequency characteristics for.

  ADVANTAGE OF THE INVENTION According to this invention, the tissue information of the desired deep part of the biological tissue based on the spectral image obtained by signal processing is adjusted to the image information of the color tone suitable for observation, and the image quality of the signal displayed and output is improved. There is an effect that can be.

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

FIGS. 1 to 26 relate to the first embodiment of the present invention, FIG. 1 is a conceptual diagram showing a signal flow when a spectral image signal is created from a color image signal, and FIG. 2 is a conceptual diagram showing an integral operation of the spectral image signal. 3 is an external view showing the external appearance of the electronic endoscope apparatus, FIG. 4 is a block diagram showing the configuration of the electronic endoscope apparatus of FIG. 3, and FIG. 5 is an external view showing the external appearance of the chopper of FIG. 6 is a diagram showing an arrangement of color filters arranged on the image pickup surface of the CCD shown in FIG. 3, FIG. 7 is a diagram showing spectral sensitivity characteristics of the color filter shown in FIG. 6, and FIG. 9 is a spectrum diagram showing a spectrum of a light source, and FIG. 10 is a spectrum diagram showing a reflection spectrum of a living body .
Figure 11 is a diagram showing a layer direction structure of the biological tissue to be observed by the electronic endoscope apparatus in FIG. 4, FIG. 12 is the arrival state to the layer direction of the illumination light of the living tissue from the electronic endoscope apparatus in FIG. 4 FIG. 13 is a diagram illustrating spectral characteristics of each band of white light, FIG. 14 is a first diagram illustrating each band image by white light in FIG. 13, and FIG. 15 is each band image by white light in FIG. FIG. 16 is a third diagram showing each band image by white light in FIG. 13, FIG. 17 is a diagram showing the spectral characteristics of the spectral image generated by the matrix operation unit in FIG. Is a first diagram showing each spectral image of FIG. 17, FIG. 19 is a second diagram showing each spectral image of FIG. 17, and FIG. 20 is a third diagram showing each spectral image of FIG .
Figure 21 is a block diagram showing the configuration of a color adjusting section of FIG. 4, FIG. 22 is a diagram explaining the operation of the color adjusting section of FIG. 21, FIG. 23 is a block diagram showing a configuration of a modification of the color adjusting section of Fig. 4 24 is a diagram showing the spectral characteristics of the first modification of the spectral image of FIG. 17, FIG. 25 is a diagram showing the spectral characteristics of the second modification of the spectral image of FIG. 17, and FIG. 26 is the spectral characteristics of FIG. It is a figure which shows the spectral characteristic of the 3rd modification of an image.
In an electronic endoscope apparatus as a living body observation apparatus according to an embodiment of the present invention, an imaging unit emits light from a light source for illumination to a living body that is a subject and is reflected from the living body based on the irradiated light. A solid-state image sensor receives light and performs photoelectric conversion to generate an image signal that is a color image signal, and a spectral image signal that is a spectral signal corresponding to an optical wavelength narrow band image is generated from the image signal by signal processing. It is supposed to be.

Hereinafter, before describing Example 1 according to the present invention, a matrix calculation method as a basis of the present invention will be described. Here, the matrix is a predetermined coefficient used when generating a spectral image signal from a color image signal acquired to generate a color image (hereinafter referred to as a normal image).
Further, following the description of this matrix, a correction method for obtaining a more accurate spectral image signal and a method for improving the S / N ratio for improving the S / N ratio of the generated spectral image signal will be described. The correction method and the S / N ratio improvement method may be used as necessary. In the following, vectors and matrices (matrix) are indicated by bold characters or “” (for example, the matrix A is expressed as “A bold character of A” or “A” ”), and the others are expressed without character modification.

(Matrix calculation method)
FIG. 1 shows a color image signal (here, R, G, and B for simplicity of explanation, but in a complementary color solid-state imaging device as in the embodiments described later, G, Cy, Mg, FIG. 4 is a conceptual diagram showing a signal flow when generating a spectral image signal corresponding to an image in a narrower optical wavelength band.
First, the electronic endoscope apparatus, numerical data the respective color sensitivity characteristics of R · G · B. Here, the color sensitivity characteristics of R, G, and B are output characteristics with respect to wavelengths obtained when a white object is imaged using a white light source.

  The color sensitivity characteristics of R, G, and B are shown on the right side of each image data as a simplified graph. Further, the color sensitivity characteristics of R, G, and B at this time are assumed to be n-dimensional column vectors “R”, “G”, and “B”, respectively.

Next, the electronic endoscope apparatus has a narrow band Pand pass filter F1, F2, F3 for spectral images to be extracted (the electronic endoscope apparatus knows the characteristics of a filter that can efficiently extract the structure as foresight information. The characteristics of this filter are those whose wavelength bands are approximately 590 nm to approximately 610 nm, approximately 530 nm to approximately 550 nm, and approximately 400 m to approximately 430 nm, respectively.

となるマトリックスの要素を求めればよい。 Here, “substantially” is a concept including about ± 10 nm in wavelength. The filter characteristics at this time are n-dimensional column vectors “F1”, “F2”, and “F3”, respectively. Based on the obtained numerical data, an optimum coefficient set that approximates the following relationship is obtained. That is,
[Equation 1]

What is necessary is just to obtain the elements of the matrix.

となる。従って、（１）式に示した命題は、以下の関係を満足するマトリックス「Ａ」を求めるに等しい。 The solution of the above optimization proposition is given mathematically as follows: If the matrix representing the color sensitivity characteristics of R, G and B is “C”, the matrix representing the spectral characteristics of the narrow-band Pandpass filter to be extracted is “F”, and the coefficient matrix to be obtained is “A”.
[Equation 2]

It becomes. Therefore, the proposition shown in the equation (1) is equivalent to obtaining a matrix “A” that satisfies the following relationship.

ここで、分光特性を表すスペクトルデータとしての点列数nとしては、n＞３であるので、（３）式は１次元連立方程式ではなく、線形最小二乗法の解として与えられる。即ち、（３）式から擬似逆行列を解けばよい。マトリックス「Ｃ」の転置行列を「^ｔＣ」とすれば、（３）式は
［数４］

となる。「^ｔＣＣ」はn×nの正方行列であるので、（４）式はマトリックス「Ａ」についての連立方程式と見ることができ、その解は、
［数５］

で与えられる。 [Equation 3]

Here, since the number of point sequences n as spectral data representing spectral characteristics is n> 3, equation (3) is not a one-dimensional simultaneous equation but is given as a solution of the linear least square method. That is, the pseudo inverse matrix may be solved from the equation (3). Assuming that the transposed matrix of the matrix “C” is “ ^t C”, the equation (3) is expressed as

It becomes. Since “ ^t CC” is an n × n square matrix, equation (4) can be viewed as a simultaneous equation for the matrix “A”, and its solution is
[Equation 5]

Given in.

For the matrix “A” obtained by the equation (5), the electronic endoscope apparatus performs the transformation of the left side of the equation (3) to obtain the characteristics of the narrow band Pandpass filters F1, F2, and F3 to be extracted. It can Rukoto to approximate. The above is the description of the matrix calculation method that is the basis of the present invention.

  Using the matrix calculated in this manner, a matrix calculation unit 436 described later generates a spectral image signal from the normal color image signal.

(Correction method)
Next, a correction method for obtaining a more accurate spectral image signal will be described.
In the above description of the matrix calculation method, the light beam received by a solid-state imaging device such as a CCD is exactly white light (all wavelength intensities are the same in the visible range), and is applied accurately. . That is, the approximation is optimal when the RGB outputs are the same.

  However, under an actual endoscope, the illuminating light beam (light beam from the light source) is not completely white light, and the reflection spectrum of the living body is not uniform. The RGB values are not the same because they have arrived.)

Therefore, in an actual process, in order to solve the proposition shown in the expression (3) more accurately, it is desirable to consider the spectral characteristics of illumination light and the reflection characteristics of a living body in addition to RGB color sensitivity characteristics.
Here, the color sensitivity characteristics are respectively R (λ), G (λ), and B (λ), an example of the spectral characteristic of the illumination light is S (λ), and an example of the reflection characteristic of the living body is H (λ). . Note that the spectral characteristics of the illumination light and the reflection characteristics of the living body do not necessarily have to be the characteristics of the inspection apparatus and the subject, and may be general characteristics acquired in advance, for example.

Using these coefficients, the correction coefficients kR, kG, and kB are
[Equation 6]
kR = (∫S (λ) × H (λ) × R (λ) dλ) ⁻¹
kG = (∫S (λ) × H (λ) × G (λ) dλ) ⁻¹
kB = (∫S (λ) × H (λ) × B (λ) dλ) ⁻¹ (6)
Given in. When the sensitivity correction matrix is “K”, it is given as follows.

従って、係数マトリックス「Ａ」については、（５）式に（７）式の補正を加えて、以下のようになる。 [Equation 7]

Accordingly, the coefficient matrix “A” is as follows after adding the correction of the equation (7) to the equation (5).

また、実際に最適化を行う場合、目標とするフィルタの分光感度特性（図１中のＦ1・Ｆ2・Ｆ3）が負のときは画像表示上では０となる（つまりフィルタの分光感度特性のうち正の感度を有する部分のみ使用される）ことを利用し、最適化された感度分布の一部が負になることも許容されることが付加される。電子内視鏡装置は、ブロードな分光感度特性から狭帯域な分光感度特性を生成するためには、図１に示すように目標とするＦ1・Ｆ2・Ｆ3の特性に、負の感度特性を付加することで、感度を有する帯域を近似した成分を生成することができる。 [Equation 8]

Also, when performing actual optimization, when the spectral sensitivity characteristic of the filter to the target (F1 · F2 · F3 in FIG. 1) is negative becomes 0 on the display image (i.e. of the spectral sensitivity characteristics of the filter It is added that it is also allowed that a part of the optimized sensitivity distribution becomes negative. In order to generate a narrow-band spectral sensitivity characteristic from a broad spectral sensitivity characteristic , the electronic endoscope device adds a negative sensitivity characteristic to the target characteristics of F1, F2, and F3 as shown in FIG. By doing so, it is possible to generate a component approximating a sensitive band.

(S / N ratio improvement method)
Next, a method for improving the S / N ratio and accuracy of the generated spectral image signal will be described. This method for improving the S / N ratio solves the following problems by adding to the processing method described above.
( I ) If any of the original signals (R, G, B) in the matrix calculation method described above is saturated, the characteristics of the filters F1 to F3 in the processing method are characteristics of a filter that can extract the structure efficiently (ideal (In the case of R, G, and B, when two signals are generated, it is necessary that neither of the two original signals is saturated. ) ).
( Ii ) Since a narrowband filter is generated from a wideband filter during conversion from a color image signal to a spectral image signal, sensitivity degradation occurs, and the component of the generated spectral image signal is also reduced. N ratio is not good.

As shown in FIG. 2, the method of improving the S / N ratio is that illumination light is irradiated several times (for example, n times, n times) in one field (one frame) of a normal image (general color image). (The irradiation intensity may be changed at each time. It is indicated by I0 to In in Fig. 2. This is realized only by controlling the illumination light. It is possible.)
Thereby, the electronic endoscope apparatus can reduce the irradiation intensity of one time, and can suppress that each of the RGB signals is saturated. Further, the image signal divided into several times is added for n sheets in the subsequent stage. Thereby, the electronic endoscope apparatus can increase the signal component and improve the S / N ratio. In FIG. 2, the integration units 438a to 438c function as image quality adjustment units that improve the S / N ratio.

  The above is the matrix calculation method that is the basis of the present invention, the correction method for obtaining an accurate spectral image signal that can be performed together with this, and the method for improving the S / N ratio of the generated spectral image signal. It is an explanation.

Here, a modified example of the above-described matrix calculation method will be described.
(Modification of matrix calculation method)
The color image signals are R, G, B, and the spectral image signals to be estimated are F1, F2, F3. Strictly speaking, the color image signals R, G, and B are also functions of the positions x and y on the image, and therefore should be described as, for example, R (x, y), but are omitted here.
The goal is to estimate a 3 × 3 matrix “A” that calculates F1, F2, F3 from R, G, B. If “A” is estimated, F1, F2, and F3 can be calculated from R, G, and B by the following equation (9).

ここで、以下のデータの表記を定義する。 [Equation 9]

Here, the following data notation is defined.

Spectral characteristics of subject: H (λ), “H” = (H (λ1), H (λ2),..., H (λn)) ^t
λ is a wavelength, and t represents transposition in matrix calculation. Similarly,
Spectral characteristics of illumination light: S (λ), “S” = (S (λ1), S (λ2),..., S (λn)) ^t
Spectral sensitivity characteristics of CCD: J (λ), “J” = (J (λ1), J (λ2),..., J (λn)) ^t
Spectral characteristics of filters for color separation: For primary colors
R (λ), “R” = (R (λ1), R (λ2),..., R (λn)) ^t
G (λ), “G” = (G (λ1), G (λ2),..., G (λn)) ^t
B (λ), “B” = (B (λ1), B (λ2),..., B (λn)) ^t
“R”, “G”, and “B” are combined into a matrix “C” as shown in the equation (10).

画像信号Ｒ，Ｇ，Ｂ、分光信号Ｆ1，Ｆ2，Ｆ3を行列で以下のように表記する。 [Equation 10]

The image signals R, G, B and the spectral signals F1, F2, F3 are expressed in matrix as follows.

画像信号「Ｐ」は次式で計算される。 [Equation 11]

The image signal “P” is calculated by the following equation.

いま、「Ｑ」を得るための色分解フィルタを「Ｆ」とすると、（１２）式同様に
［数１３］

ここで、重要な第１の仮定として、いま、被検体の分光反射率が基本的な３つの分光特性の線形和で表現できると仮定すると、「Ｈ」は以下のように表記できる。 [Equation 12]

Assuming that the color separation filter for obtaining “Q” is “F”, [Equation 13] as in equation (12).

Here, as an important first assumption, assuming that the spectral reflectance of the subject can be expressed by a linear sum of three basic spectral characteristics, “H” can be expressed as follows.

ここで、「Ｄ」は３つの基本スペクトルＤ1（λ）、Ｄ2（λ）、Ｄ3（λ）を列ベクトルに持つ行列で、「Ｗ」は「Ｈ」に対するＤ1（λ）、Ｄ2（λ）、Ｄ3（λ）の寄与をあらわす重み係数である。被検体の色調がそれほど大きく変動しない場合には、この近似が成立することが知られている。 [Formula 14]

Here, “D” is a matrix having three basic spectra D1 (λ), D2 (λ), and D3 (λ) as column vectors, and “W” is D1 (λ) and D2 (λ) for “H”. , D3 (λ) is a weighting coefficient representing the contribution. It is known that this approximation is established when the color tone of the subject does not vary so much.

  Substituting equation (14) into equation (12) yields:

ここで、３×３の行列「Ｍ」は、行列「ＣＳＪＤ」の計算結果を１つにまとめた行列を示す。 [Equation 15]

Here, the 3 × 3 matrix “M” indicates a matrix in which the calculation results of the matrix “CSJD” are combined.

  Similarly, the following equation is obtained by substituting the equation (14) into the equation (13).

同じく、「Ｍ’」は、行列「ＦＳＪＤ」の計算結果を１つにまとめた行列を示す。
結局、（１５）式と（１６）式から「Ｗ」を消去して、以下の式を得る。 [Equation 16]

Similarly, “M ′” indicates a matrix in which the calculation results of the matrix “FSJD” are combined into one.
Eventually, “W” is eliminated from the equations (15) and (16), and the following equation is obtained.

「Ｍ^−１」は行列「Ｍ」の逆行列を示す。結局、「Ｍ’Ｍ^−１」は３×３の行列となり、推定目標の行列「Ａ」となる。 [Equation 17]

“M ⁻¹ ” indicates an inverse matrix of the matrix “M”. Eventually, “M′M ⁻¹ ” becomes a 3 × 3 matrix, and becomes the estimation target matrix “A”.

色分解用のバンドパスが完全なバンドパスでなく、他の帯域にも感度を持つ場合も考慮して、この仮定が成立する場合、（１５）式、（１６）式における「Ｗ」を上記「Ｈ」と考えれば、結局（１７）式と同様な行列が推定できる。 Here, as an important second assumption, when color separation is performed using a bandpass filter, it is assumed that the spectral characteristic of the subject in the band can be approximated by one numerical value. That is,
[Equation 18]

In consideration of the case where the bandpass for color separation is not a complete bandpass and has sensitivity in other bands as well, when this assumption is satisfied, “W” in the expressions (15) and (16) is Considering “H”, a matrix similar to the equation (17) can be estimated after all.

Next, a specific configuration of the electronic endoscope apparatus according to the first embodiment of the present invention will be described with reference to FIG. The other embodiments described below have the same configuration .
3, the electronic endoscope apparatus 100 includes an endoscope 101, an endoscope apparatus main body 105, and a display monitor 106 as a display device. Further, the endoscope 101 includes an insertion portion 102 which is inserted into the body of the subject, the distal portion 103 provided at the distal end of the insertion portion 102 is provided on the opposite side of the distal end side of the insertion portion 102, the distal end It is composed mainly of the angle control member 104. for instructing the bending operation or the like of the parts 103.

The subject image acquired by the endoscope 101 is subjected to predetermined signal processing in the endoscope apparatus main body 105, and the processed image is displayed on the display monitor 106.

Next, the endoscope apparatus main body 105 will be described in detail with reference to FIG. FIG. 4 is a block diagram of the simultaneous electronic endoscope apparatus 100.
As shown in FIG. 4, the endoscope apparatus main body 105, a light source unit 41 as a main illumination unit, a control unit 42, and a main unit 43. The control unit 42 and the main body processing device 43 constitute a signal processing control unit that controls the operation of the CDD 21 as the light source unit 41 and / or the imaging unit and outputs an imaging signal to the display monitor 106 that is a display device. .
In this embodiment, the endoscope apparatus main body 105, which is a single unit, is described as having a light source unit 41 and a main body processing device 43 that performs image processing. However, the light source unit 41 and the main body processing are described. The apparatus 43 may be configured to be removable as a unit different from the endoscope apparatus main body 105 .

The light source unit 41 is connected to the control unit 42 and the endoscope 101, and emits white light (including a case where the light is not perfect white light) with a predetermined light amount based on a signal from the control unit 42. Further, the light source unit 41 has a lamp 15 as a white light source, a chopper 16 as a light quantity control unit for adjusting the light amount, and a chopper driving section 17 for driving the chopper 16.

  As shown in FIG. 5, the chopper 16 has a configuration in which a notch portion having a predetermined length in the circumferential direction is provided in a disk-like structure having a predetermined radius r and having a center at a point 17 a. The center point 17a is connected to a rotating shaft provided in the chopper driving unit 17. That is, the chopper 16 performs rotational movement around the center point 17a. In addition, a plurality of notches are provided for each predetermined radius. In this figure, the notch has a maximum length = 2πr × θ0 degrees / 360 degrees and a width = r0−ra between the radius r0 and the radius ra. Similarly, the maximum length = 2πra × 2θ1 degrees / 360 degrees between the radius ra and the radius rb, the width = ra−rb, and the maximum length = 2πrb × 2θ2 between the radius rb and the radius rc. Degree / 360 degrees and width = rb−rc (respective radii are r0> ra> rb> rc).

In addition, the length and width of the notch in the chopper 16 are examples, and are not limited to the present embodiment.
Further, the chopper 16 has a protrusion 160a extending in the radial direction substantially at the center of the notch. The control unit 42 switches the frame when the light is blocked by the projection 160a, thereby minimizing the interval between the light irradiated one frame before and after the frame, and blurring due to the movement of the subject. Minimize.
Further, the chopper driving unit 17 is configured to be movable in the direction with respect to the lamp 15 as indicated by an arrow in FIG.

That is, the control unit 42 can change the distance R between the rotation center 17a of the chopper 16 shown in FIG. 5 and the luminous flux from the lamp (shown by a dotted circle). For example, in the state shown in FIG. 5, since the distance R is quite small, the amount of illumination light is small. By increasing the distance R (the chopper driving unit 17 is moved away from the lamp 15), the cutout portion through which the light beam can pass becomes longer, so the irradiation time becomes longer, and the control unit 42 can increase the amount of illumination light. .

As described above, in the electronic endoscope apparatus, one of the signals and the spectral image newly generated is likely to be insufficient as S / N ratio, RGB signal necessary for generating the spectral image is If it is saturated, the correct calculation is not performed, so it is necessary to control the amount of illumination light. The light amount adjustment is performed by the chopper 16 and the chopper driving unit 17. The endoscope 101 connected to the light source unit 41 via the connector 11 includes an objective lens 19 and a solid-state imaging device 21 such as a CCD (hereinafter simply referred to as a CCD) at the distal end portion 103. The CCD 21 constitutes an imaging unit that photoelectrically converts light reflected from a living body, which is a subject, based on irradiation light from a light source unit 41 that constitutes an illumination unit, and generates an imaging signal. The CCD in this embodiment is a single plate type (CCD used for a simultaneous electronic endoscope) and is a primary color type. Incidentally, FIG. 6 shows the arrangement of color filters arranged on the imaging surface of the CDD. Further, FIG. 7 shows the RGB respective spectral sensitivity characteristics of the color filter in FIG.

Further, as shown in FIG. 4, the insertion portion 102 includes a light guide 14 for guiding the light emitted from the light source unit 41 to the distal end portion 103, and transmits the image of the subject obtained by the CCD to the main unit 43 and a signal line for, and a like forceps channel 28 for performing a treatment. A forceps port 29 for inserting forceps into the forceps channel 28 is provided in the vicinity of the operation unit 104. In addition, the main body processing device 43 is connected to the endoscope 101 via the connector 11, similarly to the light source unit 41. Main unit 43 includes a CCD drive circuit 431 for driving the CCD 21. The main body processing device 43 has a luminance signal processing system and a color signal processing system as signal circuit systems for obtaining a normal image.

The luminance signal processing system includes a contour correction unit 432 that is connected to the CCD 21 and performs contour correction, and a luminance signal processing unit 434 that generates a luminance signal from data corrected by the contour correction unit 432. The color signal processing system is connected to the CCD 21 and samples and holds signals obtained by the CCD 21 to generate RGB signals, and sample hold circuits (S / H circuits) 433a to 433c, and S / H circuits 433a to 433c. And a color signal processing unit 435 for generating a color signal.
Then, a normal image generating unit 437 that generates one normal image from the output of the luminance signal processing system and the output of the color signal processing system is provided, and the display monitor 106 via the switching unit 439 from the normal image generating unit 437. Y signal, RY signal, and BY signal are sent to.

On the other hand, as a signal circuit system for obtaining a spectral image, a matrix calculation unit 436 is provided which receives the outputs (RGB signals) of the S / H circuits 433a to 433c and performs a predetermined matrix calculation on the RGB signals . . Matrix calculation refers to a process of performing addition processing or the like between color image signals and multiplying the matrix obtained by the above-described matrix calculation method (or a modification thereof).

In this embodiment, a method using electronic circuit processing (processing by hardware using an electronic circuit) will be described as the matrix calculation method. However, as in the embodiments described later, numerical data processing (program A method using software processing using Moreover, when implementing, it is also possible to combine these methods .

Figure 8 shows the circuit diagram of the matrix computing section 436. The RGB signals are input to the amplifiers 32a to 32c through the resistor groups 31a to 31c, respectively. Each resistor group has a plurality of resistors to which RGB signals are respectively connected, and the resistance value of each resistor is a value corresponding to the matrix coefficient. In other words, the gain of the RGB signal is changed by each resistor, and the amplifiers add (or subtract). The outputs of the amplifiers 32a to 32c are the outputs of the matrix operation unit 436. That is, the matrix calculation unit 436 performs so-called weighted addition processing. Note that the resistance value of each resistor used here may be variable.

The outputs of the matrix operation unit 436 are connected to the integration units 438a to 438c, respectively, and after integration is performed, the color adjustment operation described later is performed on the spectral image signals ΣF1 to ΣF3 by the color adjustment unit 440. We, color channel Rch from the spectral image signals ΣF1 to ΣF3, Gch, Bch is Ru is generated. The generated color channels Rch, Gch, and Bch are sent to the display monitor 106 via the switching unit 439 . The configuration of the color adjustment unit 440 will be described later.

Note that the switching unit 439 switches between a normal image and a spectral image, and can also switch between spectral images. That operator ordinary image, the spectral channel image by Rch, to display the spectral channel image by Gch, from the spectral channel image according Bch to selectively display monitor 106 can Rukoto. Further, any two or more images may be displayed on the display monitor 106 at the same time. In particular, when the normal image and the spectral channel image can be displayed at the same time, it is possible to easily compare the normal image and the spectral channel image that are generally observed. It is easy to observe because the color degree is close to that of normal visual observation, and the characteristics of the spectral channel image can observe predetermined blood vessels that cannot be observed in the normal image.) It is very useful for diagnosis.

Next, the operation of the electronic endoscope apparatus 100 according to the present embodiment will be described in detail with reference to FIG.
In the following, the operation when observing a normal image will be described first, and the operation when observing a spectral image will be described later.

First, that describes the operation of the light source unit 41. Based on the control signal from the control unit 42, the chopper driving unit 17 is set to a predetermined position and rotates the chopper 16. The light beam from the lamp 15 passes through the notch portion of the chopper 16 and is a light guide 14 that is an optical fiber bundle provided in the connector 11 at the connection portion of the endoscope 101 and the light source portion 41 by a condenser lens. Condensed at the incident end of.
The condensed light flux passes through the light guide 14 and is irradiated into the body of the subject from the illumination optical system provided at the distal end portion 103. The irradiated light beam is reflected in the subject, and signals are collected for each color filter shown in FIG.

  The collected signals are input in parallel to the luminance signal processing system and the color signal processing system. The luminance signal-based contour correction unit 432 adds the signals collected for each color filter for each pixel and inputs them. After contour correction, the signals are input to the luminance signal processing unit 434. In the luminance signal processing unit 434, a luminance signal is generated and input to the normal image generating unit 437.

  On the other hand, signals collected by the CCD 21 are input to the S / H circuits 433a to 433c for each filter, and R, G, and B signals are respectively generated. Further, the R, G, and B signals are generated by a color signal processing unit 435, and the normal image generation unit 437 generates a Y signal, an RY signal, and a BY signal from the luminance signal and the color signal. Then, the normal image of the subject is displayed on the display monitor 106 via the switching unit 439.

Next, the operation when observing a spectral image will be described. In addition, what performs the same operation | movement as normal image observation is abbreviate | omitted here.
The operator, by operating the switch or the like provided in the endoscope apparatus operation unit 104 of which the keyboard or the endoscope 101 provided in the main body 105, an instruction for observing a spectral image from a normal image. At this time, the control unit 42 changes the control state of the light source unit 41 and the main body processing device 43.
Specifically, the amount of light emitted from the light source unit 41 is changed as necessary. As described above, since it is not desirable that the output from the CCD 21 is saturated, the amount of illumination light is made smaller when observing a spectral image than when observing a normal image. The control unit 42 can also control the amount of light so that the output signal from the CCD does not saturate, and can change the amount of illumination light within a range that does not saturate.

Further, as a control change to the main body processing device 43 by the control unit 42, the signal output from the switching unit 439 is switched from the output of the normal image generation unit 437 to the output of the color adjustment unit 440 . Further, the outputs of the S / H circuits 433a to 433c are amplified and added by the matrix calculation unit 436, and are output to the integration units 438a to 438c according to the respective bands, and are output to the color adjustment unit 440 after the integration processing. Ru is. Even when the amount of illumination light is reduced by the chopper 16, the signal intensity can be increased and the S / N ratio can be increased as shown in FIG. 2 by storing and integrating in the integrating units 438a to 438c. An improved spectral image can be obtained.

Hereinafter, specific matrix processing of the matrix calculation unit 436 in the present embodiment will be described. In this embodiment, from the spectral sensitivity characteristics of the RGB color filter indicated by the solid line in FIG. 7, the ideal narrow-band bandpass filters F1 to F3 (in this case, the respective transmission wavelength regions are indicated by F1). : 590 nm to 620 nm, F2: 520 nm to 560 nm, F3: 400 nm to 440 nm), when trying to create a bandpass filter (hereinafter referred to as a pseudo bandpass filter), the above equation (1) (5) Depending on what is shown in the equation, the following matrix is optimal.

更に、（６）式及び（７）式に示した内容により補正を行うと、以下の補正係数を得る。 [Equation 19]

Further, when correction is performed according to the contents shown in the equations (6) and (7), the following correction coefficients are obtained.

なお、（６）式に示す光源のスペクトルＳ（λ）は図９に示すものであり、（７）式に示す注目する生体の反射スペクトルＨ（λ）は図１０に示すものである、という先見情報を使用している。 [Equation 20]

Note that (6) spectrum S (lambda) of the light source shown in the expression are those shown in FIG. 9, (7) the reflection spectrum H of the biological of interest shown in the expression (lambda) is shown in FIGS. 10, referred to Use foresight information.

  Therefore, the processing performed by the matrix calculation unit 436 is mathematically equivalent to the following matrix calculation.

このマトリックス演算を行うことにより擬似フィルタ特性（図７にはフィルタ擬似Ｆ1乃至Ｆ3の特性として示されている）が得られる。即ち、上述のマトリックス処理は、カラー画像信号に、上述のようにして予め生成された擬似バンドパスフィルタ（即ちマトリックス）を用いて、分光画像信号を作成するものである。 [Equation 21]

By performing this matrix operation, pseudo filter characteristics (shown as characteristics of filter pseudo F1 to F3 in FIG. 7) are obtained. That is, the matrix processing described above creates a spectral image signal using a pseudo bandpass filter (that is, a matrix) generated in advance as described above for a color image signal.

An example of an endoscopic image generated using this pseudo filter characteristic is shown below.
As shown in FIG. 11, the body cavity tissue 45 often has an absorber distribution structure such as blood vessels that differ in the depth direction. A large number of capillaries 46 are mainly distributed near the surface of the mucous membrane, and a blood vessel 47 that is thicker than the capillaries is distributed in addition to the capillaries in the middle layer deeper than this layer, and a thicker blood vessel 48 is further distributed in the deep layer. become.

On the other hand, invasion depth in the depth direction of light relative to a body cavity tissue 45 is dependent on the wavelength of light, illumination light including a visible region, as shown in FIG. 12, blue (B) colors so In the case of light with a short wavelength, the light reaches the surface layer only due to the absorption and scattering characteristics in living tissue, and the light emitted from the surface is observed by absorption and scattering within the depth range. The In the case of green (G) light, which has a wavelength longer than that of blue (B) light, it reaches deeper than the range where blue (B) light deepens, absorbs and scatters within that range, and exits from the surface. Light is observed. Still further, red (R) light having a wavelength longer than that of green (G) light reaches a deeper range.

Since the RGB light during normal observation of the tissue 51 in the body cavity is overlapped with each other as shown in FIG.
(1) Band images having shallow layer and middle layer tissue information including a lot of tissue information in the shallow layer as shown in FIG.
(2) In addition, the image signal picked up by the CCD 21 with the G-band light is picked up with a shallow layer image including a lot of tissue information in the middle layer and a band image having the middle layer tissue information as shown in FIG.
(3) Further, a band image having middle layer and deep layer tissue information including a lot of tissue information in the deep layer as shown in FIG.
Then, the endoscope apparatus body 105 performs signal processing on these RGB imaging signals, so that it is possible to obtain an endoscopic image having a desired or natural color reproduction as an endoscopic image.

The matrix processing in the matrix calculation unit 436 is to create a spectral image signal by using the pseudo bandpass filter (matrix) generated in advance as described above for the color image signal. For example, spectral image signals F1 to F3 are obtained using pseudo bandpass filters F1 to F3 having discrete and narrow-band spectral characteristics capable of extracting desired deep tissue information as shown in FIG. As shown in FIG. 17, the pseudo bandpass filters F1 to F3 are not overlapped with each other.
(4) A band image having tissue information in a shallow layer as shown in FIG. 18 is captured in the spectral image signal F3 by the pseudo bandpass filter F3,
(5) A band image having tissue information in the middle layer as shown in FIG. 19 is captured in the spectral image signal F2 by the pseudo bandpass filter F2, and (6) the spectral image signal F1 by the pseudo bandpass filter F1 A band image having tissue information in the deep layer as shown in FIG. 20 is captured.

Next, for the spectral image signals F1 to F3 obtained in this way, the color adjustment unit 440, as an example of the simplest color conversion, uses the spectral image signal F1 as a color channel Rch and the spectral image signal F2 as a color. The spectral image signal F3 is allocated to the channel Gch to the color channel Bch, and is output to the display monitor 106 via the switching unit 439.
Color adjusting section 440, as shown in FIG. 21, a 3 × 3 matrix circuit 61, 3 × 3 3 sets of LUTs provided before and after the matrix circuit 61, 62b, 62c, 63a, 63 b, and 63c, LUTs, 62b, 62c, 63a, 63b, are constituted by the color conversion processing circuit 440a with a coefficient changing circuit 64 for changing the coefficient table data and 3 × 3 matrix circuit 61 63c, a.
Spectral image signal F1 to F3 inputted to the color conversion processing circuit 440a is, LUTs for each band data, 62b, by the 62c Rigyaku γ correction and nonlinear contrast conversion processing is performed.

Next, after color conversion is performed in the 3 × 3 matrix circuit 61, γ correction and appropriate gradation conversion processing are performed in the subsequent LUTs 63a, 63b, and 63c.
The table data of these LUTs 62a, 62b, 62c, 63a, 63b, 63c and the coefficients of the 3 × 3 matrix circuit 61 can be changed by the coefficient changing circuit 64.

Change by the coefficient changing circuit 64 is performed based on the control signal from the processing conversion switch provided in the operation portion or the like of the endoscope 101 (not shown).
Upon receiving these control signals, the coefficient changing circuit 64 calls appropriate data from the coefficient data stored in the color adjustment unit 440 in advance, and rewrites the current circuit coefficient with this data.

この式（２２）による処理は、分光チャンネル画像Ｒch、Ｇch、Ｂchに分光画像信号Ｆ1乃至Ｆ3を波長の短い順に割り当てる色変換である。 Next, specific color conversion processing contents will be described. An example of the color conversion formula is shown in Formula (22).
[Equation 22]

The processing according to the equation (22) is color conversion in which the spectral image signals F1 to F3 are assigned to the spectral channel images Rch, Gch, and Bch in order of decreasing wavelength.

When observed with color images of these color channels Rch, Gch, and Bch, for example, an image as shown in FIG. 22 is obtained. A thick blood vessel is in a deep position, the spectral image signal F3 is reflected, and the color is shown as a blue pattern. Since the spectral image signal F2 is strongly reflected in the vascular network near the middle layer, the color image is shown as a red pattern. Those existing in the vicinity of the mucosal surface in the vascular network are expressed as a yellowish pattern.
In particular, this pattern change near the mucosal surface is important for early differential detection and diagnosis of lesions. However, yellow patterns tend to have low contrast with the background mucosa and low visibility.

この式（２３）による処理は、分光画像信号Ｆ1をある一定の比率で分光画像信号Ｆ2に混合し生成されたデータを新たに分光Ｇチャンネル画像Ｇchとする変換例であり、血管網などの吸収散乱体が深さ位置で異なることをより明確化することが可能となる。 Therefore, in order to reproduce the pattern near the mucosal surface more clearly, the conversion shown in Expression (23) is effective.
[Equation 23]

The processing according to the equation (23) is a conversion example in which the spectral image signal F1 is mixed with the spectral image signal F2 at a certain ratio and the generated data is newly used as the spectral G channel image Gch. It becomes possible to further clarify that the scatterers are different in depth positions.

Accordingly, by adjusting the matrix coefficient through the coefficient changing circuit 64, the user can adjust the display effect. As an operation, the matrix coefficient is set to a default value from the through operation in the color conversion processing circuit 440a in conjunction with a mode change switch (not shown) provided in the operation unit of the endoscope 101.
The through operation here, the unit matrix is the 3 × 3 matrix circuit 61, referred LUTs, 62b, 62c, 63a, 63 b, the state 63c is equipped with a non-conversion tape b le. The default value means that the set values of ωG = 0.2 and ωB = 0.8 are given to the matrix coefficients ωG and ωB , for example.

Then, the user operates the operation unit or the like of the endoscope 101 and adjusts the coefficient so that ωG = 0.4, ωB = 0.6, and the like. A reverse γ correction table and a γ correction table are applied to the LUTs 62a, 62b, 62c, 63a, 63b, and 63c as necessary.

  Although the color conversion processing circuit 440a performs color conversion using a matrix computing unit including the 3 × 3 matrix circuit 61, the color conversion processing means may be configured by a numerical operation processor (CPU) or an LUT.

For example, in the above embodiment, the color conversion processing circuit 440a is shown with a configuration centered on the 3 × 3 matrix circuit 61. However, as shown in FIG. 23, the color conversion processing circuit 440a is replaced with a three-dimensional LUT 65 corresponding to each band. The same effect can be obtained by replacing with. In this case, the coefficient changing circuit 64 performs an operation of changing the contents of the table based on a control signal from a processing conversion switch (not shown) provided in the operation unit or the like of the endoscope 101.

  Note that the filter characteristics of the pseudo bandpass filters F1 to F3 are not limited to the visible light range. As a first modification of the pseudo bandpass filters F1 to F3, the filter characteristics are discrete spectrum as shown in FIG. It may be a narrow band of characteristics. The filter characteristic of the first modification is that normal observation is performed by setting F3 in the near ultraviolet region and F1 in the near infrared region in order to observe the irregularities on the surface of the living body and the absorber near the extreme deep layer. It is suitable for obtaining image information that cannot be obtained by.

As a second modification of the pseudo bandpass filters F1 to F3, two pseudo bandpass filters F3a and F3b whose filter characteristics are close in the short wavelength region are used instead of the pseudo bandpass filter F2 as shown in FIG. It is also good. This is suitable for visualizing a subtle difference in the scattering characteristic rather than the absorption characteristic by utilizing the fact that the wavelength band in the vicinity reaches only near the extreme surface layer of the living body. Medically, it is assumed to be used for identification diagnosis of diseases such as early cancer, which are accompanied by disorder of cell arrangement near the mucosal surface layer.
Furthermore, as a third modification of the pseudo bandpass filters F1 to F3, two pseudo-bandwidth narrowband filter characteristics of two discrete spectral characteristics from which desired layer structure information can be extracted as shown in FIG. the band-pass filter F2, F3 may be generated by the matrix computing section 436.

In the case of the pseudo bandpass filters F2 and F3 in FIG. 26, the color adjustment unit 440 performs spectral channel image Rch ← spectral image signal F2, spectral channel image Gch ← spectral spectrum in colorization of an image during narrowband spectral image observation. An RGB three-channel color image is generated as an image signal F3 and a spectral channel image Bch ← spectral image signal F3.
That is, for the spectral image signal F2 and the spectral image signal F3, the color adjustment unit 440 generates RGB three-channel color images (Rch, Gch, Bch) by the following equation (24).

例えば、ｈ11＝１、ｈ12＝０、ｈ21＝０、ｈ22＝１．２、ｈ31＝０、ｈ32＝０．８とする。
例えば分光画像Ｆ3は中心波長が主に４１５ｎｍに相当する画像、分光画像Ｆ2は中心波長が主に５４０ｎｍに相当する画像である。 [Equation 24]

For example, h11 = 1, h12 = 0, h21 = 0, h22 = 1.2, h31 = 0, h32 = 0.8.
For example, the spectral image F3 is an image whose central wavelength mainly corresponds to 415 nm, and the spectral image F2 is an image whose central wavelength mainly corresponds to 540 nm.

  Further, for example, the spectral image F3 is calculated as an image whose central wavelength mainly corresponds to 415 nm, the spectral image F2 is an image whose central wavelength mainly corresponds to 540 nm, and the spectral image F1 is an image whose central wavelength mainly corresponds to 600 nm. Even if the color adjustment unit 440 does not use the F1 image, the color image can be composed of the F2 and F3 images. In this case, a matrix operation of the following equation (24 ′) may be applied instead of the equation (24).

Rch = h11 × F1 + h12 × F2 + h13 × F3
Gch = h21 × F1 + h22 × F2 + h23 × F3
Bch = h31 × F1 + h32 × F2 + h33 × F3 (24 ′)
In the matrix calculation of the above equation (24 ′), the coefficients of h11, h13, h21, h22, h31, and h32 may be set to 0, and the other coefficients may be set to predetermined numerical values.

  As described above, according to the present embodiment, a pseudo narrowband filter is generated by using a color image signal for generating a normal electronic endoscopic image (normal image). A spectral image having tissue information of a desired deep portion such as a blood vessel pattern can be obtained without using an optical wavelength narrow-band bandpass filter, and the parameters of the color conversion processing circuit 440a of the color adjustment unit 440 are converted into spectral images. By setting it accordingly, it becomes possible to realize an expression method that makes use of the feature of depth-of-depth information when observing a narrow-band spectral image, and it is possible to effectively obtain tissue information of a desired deep part near the tissue surface of a living tissue. It can be visually recognized separately.

In particular, in the color adjustment unit 440,
(1) In the case of a two-band spectral image, for example, when an image corresponding to 415 nm is allocated to the color channels Gch and Bch, for example, an image corresponding to 540 nm is allocated to the color channel Rch,
Or
(2) In the case of a three-band spectral image, for example, an image corresponding to 415 nm is assigned to the color channel Bch, an image equivalent to 445 nm, for example, is assigned to the color channel Gch, and an image equivalent to 500 nm, for example, is assigned to the color channel Rch. The following image effects can be obtained.

・ The epithelium or mucous membrane of the outermost layer of living tissue is reproduced with low saturation color, and the outermost capillaries are reproduced with low brightness, that is, dark lines, so that high visibility of the outermost capillaries is obtained. It is done.
At the same time, since the blood vessel at a deeper position than the capillary is rotated and reproduced in the blue direction in the hue direction, it is easier to distinguish from the outermost capillary.
Further, according to the channel assignment method, residues and bile observed in a yellow tone under normal observation in a colonoscopy are observed in a red tone.

FIG. 27 is a block diagram showing another configuration example of the matrix calculation unit.
The configuration other than the matrix calculation unit 436 is the same as that in FIG. The configuration of the matrix calculation unit 436 shown in FIG. 27 is only different from the configuration of the matrix calculation unit 436 shown in FIG. Only different points will be described, and the same components will be denoted by the same reference numerals and description thereof will be omitted.
In Figure 8, the matrix operation by the electronic circuit, it is assumed that performed by so-called hardware processing, in FIG. 2 7, performed by the matrix calculation numerical data processing (processing by software using a program).

A matrix calculation unit 436 shown in FIG. 27 has an image memory 50 for storing RGB color image signals. The coefficient register 51 stores each value of the matrix “A ′” shown in the equation (21) as numerical data.
The coefficient register 51 and the image memory 50 are connected to the multipliers 53a to 53i, the multipliers 53a, 53d, and 53g are connected to the multiplier 54a, and the output of the multiplier 54a is connected to the integrating unit 438a in FIG. Is done. The multipliers 53b, 53e, and 53h are connected to the multiplier 54b, and the output thereof is connected to the integrating unit 438b. The multipliers 53c, 53f, and 53i are connected to the multiplier 54c, and the output thereof is connected to the integrating unit 438c.

  As an operation of this embodiment, the input RGB image data is once stored in the image memory 50. Next, each coefficient of the matrix “A ′” from the coefficient register 51 is multiplied with the RGB image data stored in the image memory 50 by a multiplier by an arithmetic program stored in a predetermined storage device (not shown). The

  FIG. 27 shows an example in which the R signal and each matrix coefficient are multiplied by multipliers 53a to 53c. Also, as shown in the figure, the G signal and each matrix coefficient are multiplied by multipliers 53d to 53f, and the B signal and each matrix coefficient are multiplied by multipliers 53g to 53i. The data multiplied by the matrix coefficients are respectively output from the multipliers 53a, 53d and 53g by the multiplier 54a, by the multipliers 53b, 53e and 53h by the multiplier 54b and by the multipliers 53c, 53f, The outputs of 53i are respectively multiplied by the multiplier 54c. The output of the multiplier 54a is sent to the integrating unit 438a. The outputs of the multiplier 54b and the multiplier 54c are sent to the integrating units 438b and 438c, respectively.

According to the configuration example of FIG. 27, a spectral image in which a blood vessel pattern is clearly displayed can be obtained as in the configuration example of FIG.
In the configuration example of FIG. 27, matrix processing is not performed by hardware as in the configuration example of FIG. 8, but is performed using software. For example, it is possible to respond quickly to changes in matrix coefficients, for example. it can.
In addition, matrix coefficients are stored not only as a result value, that is, as a matrix “A ′”, but also as S (λ), H (λ), R (λ), G (λ), and B (λ). When the matrix “A ′” is obtained and used by performing calculations as necessary, only one of the elements can be changed, and convenience is improved. For example, it is possible to change only the spectral characteristic S (λ) of the illumination light.

FIG. 28 is a block diagram illustrating a configuration of the electronic endoscope apparatus according to the second embodiment of the present invention.
Since the second embodiment is almost the same as the first embodiment, only differences from the first embodiment will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.
This example is the same as the actual Example 1, the light source unit 41 for controlling the illumination light amount is different. In this embodiment, the amount of light emitted from the light source unit 41 is controlled not by the chopper but by the current control of the lamp 15. Specifically, the lamp 15 shown in FIG. 28 is provided with a current control unit 18 as a light amount control unit.

In the operation of this embodiment, the control unit 42 controls the current flowing through the lamp 15 so that none of the RGB color image signals are saturated. Thereby, since the current used for light emission in the lamp 15 is controlled, the amount of light changes according to the magnitude of the current.
Since other operations are the same as those in the first embodiment, they are omitted here.

  According to the present embodiment, as in the first embodiment, a spectral image in which the blood vessel pattern is clearly displayed can be obtained. Further, the present embodiment has an advantage that the control method is simpler than the light amount control method using the chopper as in the first embodiment.

In biological observation apparatus shown in FIG. 4, when the spectral image acquisition, using the Chi Yoppa 16 of Figure 5 for light quantity control block light at a predetermined time interval, is controlled so as to reduce the amount of light. That is, it in the appropriate dynamic range R, G, so that all of the color separation signals B to reduce the amount of light from the light source to be captured.
In the third embodiment of the present invention, an example will be described in which a movable light shielding member such as a diaphragm spring and a shutter, and a light shielding filter such as a mesh turret and an ND filter are used as an alternative to the chopper 16 in the biological observation apparatus of FIG.

FIG. 29 shows an example of the diaphragm spring 66 . A diaphragm spring 66 rotates around a central axis 67 , and has a blocking portion 69 for blocking a light beam 68 condensed to a certain size at a tip portion and a diaphragm blade portion 71 having a notch 70 for controlling the amount of emitted light. The light is blocked at a predetermined time interval to control the amount of light.
The diaphragm spring 66 may be used as the shared and the diaphragm spring dimming controlling the emitted light quantity of the light source unit 41 may be another provided as a mechanism for separately blocked.

FIG. 30 shows an example of the shutter 66A . The shutter 66 A is has the same shape as the example of the diaphragm spring 66, and has a notch 70 is no structure of the diaphragm spring 66 to the shut-off unit 69. The operation of the shutter 66A controls the light quantity by controlling two operation states of full open and full close to block light at a predetermined time interval.
FIG. 31 shows an example of the mesh turret 73 . A mesh 75 having a large lattice interval or a mesh 76 having a smaller lattice interval is attached to the hole formed in the rotating plate 74 by welding or the like, and rotates around the rotation center shaft 77 . At this time, the length of the mesh, the roughness of the mesh, the position, etc. are changed, and the light is blocked at a predetermined time interval to control the light quantity.

32 and 33 relate to the fourth embodiment of the present invention, FIG. 32 is a block diagram showing the configuration of the electronic endoscope apparatus, and FIG. 33 is a diagram showing the charge accumulation time of the CCD of FIG.
Since the fourth embodiment is almost the same as the first embodiment, only differences from the first embodiment will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.
The present embodiment is mainly different from the first embodiment in the light source section 41 and the CCD 21. In the first embodiment, the color filter shown in FIG. 6 is provided in the CCD 21 and a color signal is generated by the color filter. In contrast, in the fourth embodiment, the illumination light is transmitted for a period of one frame. In addition, a so-called frame sequential method is used in which color signals are generated in the order of RGB.

  As shown in FIG. 32, the light source unit 41 in the present embodiment is provided with a diaphragm 25 that performs dimming on the front surface of the lamp 15, and emits R, G, B surface sequential light further on the front surface of the diaphragm 25. For this purpose, an RGB rotation filter 23 that rotates, for example, once in one frame is provided. The diaphragm 25 is connected to a diaphragm control unit 24 serving as a light amount control unit, and restricts a light beam to be transmitted among light beams emitted from the lamp 15 in accordance with a control signal from the diaphragm control unit 24. Dimming is possible by changing. The RGB rotation filter 23 is connected to the RGB rotation filter control unit 26 and rotates at a predetermined rotation speed.

  As the operation of the light source unit in the present embodiment, the light beam output from the lamp 15 is limited to a predetermined light amount by the diaphragm 25, and the light beam that has passed through the diaphragm 25 passes through the RGB rotation filter 23 for a predetermined time. The light is output from the light source unit as R, G, and B illumination light each time. Each illumination light is reflected within the subject and received by the CCD 21. Signals obtained by the CCD 21 are distributed by a switching unit (not shown) provided in the endoscope apparatus main body 105 according to the irradiation time, and input to the S / H circuits 433a to 433c, respectively. That is, when the illumination light is irradiated from the light source unit 41 through the R filter, the signal obtained by the CCD 21 is input to the S / H circuit 433a. Since other operations are the same as those in the first embodiment, they are omitted here.

According to the fourth embodiment, as in the first embodiment, a spectral image in which the blood vessel pattern is clearly displayed can be obtained. Also, in the fourth embodiment, unlike the first embodiment, it is possible to enjoy the advantages of the so-called frame sequential method. This merit includes, for example, a modification of FIG. 34 described later.
In the first embodiment described above, the illumination light amount (light amount from the light source unit) is controlled and adjusted in order to avoid saturation of the RGB color signals. On the other hand, in the fourth embodiment, a method of adjusting the electronic shutter of the CCD 21 is adopted. In the CCD 21, charges proportional to the intensity of light incident within a predetermined time are accumulated, and the amount of charges is used as a signal. The accumulation time corresponds to what is called an electronic shutter. By adjusting the electronic shutter with the CCD drive circuit 431, the amount of accumulated charge, that is, the signal amount can be adjusted. As shown in FIG. 33, a similar spectral image can be obtained by obtaining an RGB color image in a state where the charge accumulation time is sequentially changed for each frame. That is, in each of the above-described embodiments, the control of the amount of illumination light by the diaphragm 25 is used for obtaining a normal image, and when obtaining a spectral image, the electronic shutter is changed to change the R, G, B color signals. Saturation can be avoided.

  FIG. 34 is a diagram showing the charge accumulation time of a CCD which is another example of Embodiment 4 of the present invention. Similar to the example of FIG. 33, this example uses the frame sequential method and takes advantage of this frame sequential method. That is, the generation of spectral image data can be simplified by adding weights to the charge accumulation time by the electronic shutter control in the example of FIG. 33 for each of R, G, and B. In the example of FIG. 34, a CCD drive circuit 431 that can change the charge accumulation time of the CCD 21 for each of R, G, and B within one frame period is provided. Others are the same as the example of FIG.

As an operation of the example of FIG. 34, when each illumination light is irradiated through the RGB rotation filter 23, the charge accumulation time by the electronic shutter in the CCD 21 is changed. Here, tdr, tdg, and tdb are the charge accumulation times of the CCD 21 when the illumination light is R, G, and B (in this figure, since the B color image signal has no accumulation time, tdb is omitted. ). For example, the F3 pseudo filter image in the case of performing the matrix processing represented by the equation (21) is obtained from an RGB image obtained by a normal endoscope,
[Equation 25]
F3 = -0.050R-1.777G + 0.829B (25)
Therefore, the charge accumulation time by RGB electronic shutter control in FIG.
tdr: tdg: tdb = 0.050: 1.777: 0.829 (26)
It can be set to be. Further, the matrix calculation unit simply adds the signal obtained by inverting only the R and G components and the B component. Thereby, the same spectral image as Example 1 thru | or Example 3 can be obtained.

  According to Example 4 of FIGS. 33 and 34, a spectral image in which a blood vessel pattern is clearly displayed can be obtained. Further, in the example of FIG. 34, the frame sequential method is used to create the color signal, and the charge accumulation time can be made different for each color signal by using an electronic shutter. In this case, it is only necessary to perform addition and difference processing, and the processing can be simplified. That is, an operation equivalent to matrix calculation can be performed by electronic shutter control, and the processing can be simplified.

It goes without saying that the light amount control in the first to third embodiments and the electronic shutter (charge accumulation time) in the fourth embodiment (example in FIG. 33 or FIG. 34) can be performed at the same time. Further, as described above, the normal observation image may be controlled by controlling the amount of illumination light by a chopper or the like, and of course, when obtaining the spectral observation image, control by an electronic shutter may be performed.
Next, as Example 5 to Example 7, signal amplification means for amplifying the signal level of the biological signal of the normal image and / or the spectral signal of the spectral image and its amplification control will be described.

  4, 28, or 32 is applied to the configuration of the living body observation apparatus according to the fifth embodiment of the present invention. The AGC (auto gain control) in these configurations is an AGC circuit (signal amplifying means of each of the luminance signal processing unit 434 and the color signal processing processing unit 435 in FIG. 4, FIG. (Not shown). The AGC at the time of spectral image observation is performed by an AGC circuit (for example, the amplifiers 32a to 32c in FIG. 8 are variable amplifiers) which is a signal amplifying means in the matrix calculation unit 436 in FIG. 4, FIG. 28 or FIG. Is called.

  Then, the control of the amplification operation, that is, the control of the AGC is changed between the normal image observation and the spectral image observation. AGC control refers to the amplification level of the amplification function, the operation speed (follow-up speed) of the amplification function, or the operation / non-operation (also referred to as on / off) of the amplification function.

  Regarding the operation / non-operation (on / off) of the amplification function, the AGC is often not operated during normal image observation. This is because the amount of light is sufficient for observation with normal light. On the other hand, when observing a spectral image, the amount of light is insufficient, so that the AGC is operated.

  With regard to the operating speed (follow-up speed) of the amplification function, for example, as the camera and the subject scene move away, the amount of light gradually decreases and becomes darker. The dimming function works at first and tries to increase the amount of light when it gets dark, but the dimming operation cannot follow. The AGC operates when it cannot follow. The speed of the AGC operation is important, and if the follow-up speed is too fast, noise will be generated when it gets dark. An appropriate speed that is neither too fast nor too slow is important. During normal image observation, the AGC operation may be quite slow, but during spectroscopic image observation, it becomes dark immediately, so the AGC operation needs to follow the fast eye. As a result, the image quality of the signal to be displayed and output can be improved.

  4, 28, or 32 is applied to the configuration of the living body observation apparatus according to the sixth embodiment of the present invention. The AGC (auto gain control) in these configurations is an AGC circuit (signal amplifying means of each of the luminance signal processing unit 434 and the color signal processing processing unit 435 in FIG. 4, FIG. (Not shown). The AGC at the time of spectral image observation is performed by an AGC circuit (for example, the amplifiers 32a to 32c in FIG. 8 are variable amplifiers) which is a signal amplifying means in the matrix calculation unit 436 in FIG. 4, FIG. 28 or FIG. Is called.

  In the sixth embodiment, the AGC circuit as the signal amplifying means is controlled to operate in conjunction with the light amount control means such as the chopper 16, the lamp current control unit 18, or the aperture control unit 24.

  The interlock operation is controlled so that the AGC circuit, which is the signal amplifying means, functions only after the emitted light quantity becomes maximum in the light quantity control means, for example. That is, the light quantity control means is set to control the maximum light quantity (for example, the dimming blades are fully opened), and the AGC is controlled to function only when the screen is dark even when the light quantity becomes maximum. Thereby, the range of light quantity control can be widened.

  4, 28, or 32 is applied to the configuration of the living body observation apparatus according to the seventh embodiment of the present invention. The AGC (auto gain control) in these configurations is an AGC circuit (signal amplifying means of each of the luminance signal processing unit 434 and the color signal processing processing unit 435 in FIG. 4, FIG. (Not shown). The AGC at the time of spectral image observation is performed by an AGC circuit (for example, the amplifiers 32a to 32c in FIG. 8 are variable amplifiers) which is a signal amplifying means in the matrix calculation unit 436 in FIG. 4, FIG. 28 or FIG. Is called.

  When displaying a normal image and a spectral image at the same time (the spectral image is estimated from RGB and can be displayed simultaneously), the amount of light may be reduced in consideration of CCD saturation. For example, a normal image may have a reduced amount of light to suppress CCD saturation. In this case, the normal image is naturally dark. On the other hand, the spectral image is adjusted within an appropriate dynamic range so that details can be observed. Therefore, when displaying the normal image and the spectral image at the same time, if the image is left as it is, the normal image remains dark. Therefore, the brightness of the normal image is adjusted for simultaneous display and output. Amplification of the image output is performed by electrically increasing the gain with an AGC circuit which is a signal amplifying means. Thereby, the image quality in the simultaneous display can be improved.

  Next, image quality improvement will be described with reference to Examples 8 to 11.

FIG. 35 is applied to the configuration of the living body observation apparatus according to the eighth embodiment of the present invention. In the eighth embodiment, the brightness and S / N are improved by weighting and adding the broadband luminance signal to the luminance component of the spectral image.
35, the electronic endoscope apparatus 100 includes a scope 101, an endoscope apparatus main body 105, and a display monitor 106. The endoscope apparatus main body 105 mainly includes a light source section 41, a control section 42, and a main body processing apparatus 43. The main body processing device 43 is provided with a CCD drive circuit 431 for driving the CCD 21 and has a signal circuit system for obtaining a normal image and a signal circuit system for obtaining a spectral image.

The signal circuit system for obtaining a normal image is connected to the outputs of the S / H circuits 433a to 433c and the S / H circuits 433a to 433c, which sample the signals obtained by the CCD 21 and generate RGB signals, and provide color signals. A color signal processing unit 435 for generating the.
On the other hand, as a signal circuit system for obtaining a spectral image, a matrix calculation unit 436 is provided at the output of the S / H circuits 433a to 433c, and a predetermined matrix calculation is performed on the RGB signals.

  The output of the color signal processing unit 435 and the output of the matrix calculation unit 436 are supplied to the white balance processing (hereinafter referred to as WB) circuit 451, the γ correction circuit 452, and the color conversion circuit (1) 453 via the switching unit 450, Y signal, RY signal and BY signal are generated, and further emphasized luminance signal YEH, RY signal and BY signal, which will be described later, are generated and supplied to the color conversion circuit (2) 455. , R, G, B output to the display monitor 106.

  By the way, when performing spectral image observation (NBI observation) without providing an optical filter, a separate spectral image is generated separately from the normal observation image by the processing system inside the main body processing device (processor) 43. Matrix calculation unit 436 is required. However, if the normal observation image and the spectroscopic image are individually generated with such a configuration, it is necessary to have two systems for white balance processing (WB), γ correction, enhancement circuit, etc. It will increase.

  Further, if the electrical gain is increased to improve the brightness, the S / N in the spectral image deteriorates. Therefore, a plurality of images are captured and integrated to increase the signal component. A method for improving the ratio (for example, the integration units 438a to 438c in Japanese Patent Application Laid-Open No. 2003-93336 corresponds to this) has been proposed. In order to acquire a plurality of images, a CCD is used at a high frequency. It was technically difficult to drive.

Therefore, in order to solve the above problem, in the eighth embodiment of the present invention, the following configuration is added as shown in FIG.
That is,
(1) When generating the normal observation image and the spectral image, the following circuits a) to c) are used in common. a) WB circuit 451, b) gamma correction circuit 452, c) enhancement circuit 454.
(2) In order to improve brightness and S / N, a broadband luminance signal generation unit 444 is provided to generate a broadband luminance signal (YH) in which S / N is not deteriorated from the output signal of the CCD. Weighted addition with the luminance component Y is performed.

That is, the broadband luminance signal (YH) and the luminance signal (Y) in the spectral image (F1, F2, F3) generated by the color conversion unit (1) 453 are respectively weighted by the weighting circuits (445, 446). Weighting is performed, addition is performed by the adder 447, and contour correction is performed by the enhancement circuit 454 for the luminance signal after the addition. That is, the broadband luminance signal generation unit 444, the weighting circuits 445 and 446, and the addition unit 447 constitute an image quality adjustment unit. The luminance signal Y EH whose contour has been corrected is supplied to the color conversion unit (2) 455, and is then converted again to RGB by the color conversion unit (2) 455 and output to the display monitor 106.

The weighting coefficients in the weighting circuits (445, 446) can be switched according to the observation mode and the number of connected CCD pixels, and can be arbitrarily set within a range where there is no problem in contrast degradation of the spectral image. Possible, for example, if the weighting factor of the weighting circuit 445 is α and the weighting factor of the weighting circuit 446 is β, the following method can be considered.
A) When displaying a normal observation image: α = 0, β = 1
B) Spectral image display when CCD type A is connected: α = 0.5, β = 0.5
C) Spectral image display when CCD type B is connected: α = 1, β = 0
The effect of the configuration of the eighth embodiment is that brightness and S / N can be improved without acquiring a plurality of images, and the weighting coefficient can be optimized depending on the type of connected CCD. Since it is possible, optimization is possible within a range not affected by contrast degradation according to the number of pixels and spectral characteristics of each CCD.

36 or 37 is applied to the configuration of the living body observation apparatus according to the ninth embodiment of the present invention. The ninth embodiment is intended to improve S / N.
As shown in FIG. 2, the method of improving the S / N ratio is that illumination light is irradiated several times (for example, n times, n times) in one field (one frame) of a normal image (general color image). (I may be an integer greater than or equal to 2) (irradiation intensity may be changed each time. In FIG. 2, it is indicated by I0 to In. This is realized only by controlling illumination light. In this way, it is possible to reduce the intensity of one irradiation, and it is possible to suppress the saturation of any of the RGB signals. Further, the image signal divided into several times is added for n sheets in the subsequent stage. Thereby, a signal component can be enlarged and S / N ratio can be improved.

  As described above, when performing NBI observation without providing an optical filter, in order to improve brightness and S / N, a plurality of images (n) are obtained by performing imaging a plurality of times within one field period. In this configuration, the signal component can be increased and the S / N ratio can be improved by adding the plurality of images in the subsequent processing system.

However, there are the following problems in order to perform imaging a plurality of times within one field period as shown in the above configuration.
(1) Since the drive frequency increases as the number of CCD pixels increases, the main unit processor (processor) has a drive circuit, and the connection cable to the CCD is driven by a circuit with high drive capability. Technical difficulty is high.
(2) The higher the driving frequency, the higher the unnecessary radiated electromagnetic field component, and the more difficult it is to take EMC (electromagnetic wave noise) countermeasures.

In order to solve the above problem, the following configuration is added in the ninth embodiment of the present invention.
That is, for example, with respect to the configuration of FIG. 4, as shown in FIG. 36, the CCD drive circuit 431 is moved from the main body processing unit (processor) 43 to the scope 101 side, and the connection cable between the CCD drive circuit 431 and the CCD 21 is connected. The configuration is made as short as possible.
Thereby, since the cable length is shortened, the distortion of the drive waveform can be reduced. Unnecessary EMC radiation is reduced. Further, since the CCD drive circuit 431 is on the scope 101 side, the drive capability required for the drive circuit can be set low. That is, the drive capability may be low, which is advantageous in terms of cost.

For example, as shown in FIG. 37, the CCD drive circuit 431 is built in the main body processing device (processor) 43 as shown in FIG. 37, and the processor 43 outputs a drive pulse with a waveform close to a sine wave. The waveform is shaped by a waveform shaping circuit 450 provided near the CCD at the tip of the scope 101, and the CCD 21 is driven.
As a result, the CCD drive pulse from the processor 43 can be output with a waveform close to a sine wave, so that the EMC characteristics are good. That is, an unnecessary radiated electromagnetic field can be suppressed.

  4, 28, or 32 is applied to the configuration of the living body observation apparatus according to the tenth embodiment of the present invention. In these configurations, the noise suppression circuit is provided in the matrix calculation unit 436 required at the time of spectral image observation or in the input unit before the matrix calculation unit 436.

  During spectral image observation, the wavelength band is limited, so that the amount of illumination light may be smaller than that during normal image observation. In that case, the lack of brightness due to the small amount of illumination can be electrically corrected by amplifying the captured image. However, simply increasing the amplification factor by the AGC circuit makes noise in the dark image portion conspicuous. It becomes an image. Therefore, by passing the noise suppression circuit, the contrast in the bright area is reduced while the noise in the dark area is suppressed. The noise suppression circuit is described in FIG. 5 of Japanese Patent Application No. 2005-82544.

The noise suppression circuit 36 shown in FIG. 38 is a circuit applied to a biological observation apparatus as shown in FIG. 32 that handles frame-sequential R, G, and B image data. R, G, B image data is input.
In FIG. 38, the noise suppression circuit 36 performs filtering processing 81 for performing filtering processing using a plurality of spatial filters on image data captured by a CCD serving as an imaging unit, and brightness in a local region of the image data. The average pixel calculation unit 82 as a brightness calculation unit to be calculated and the output of the filter processing unit 81 are weighted according to the output of the filter processing unit 81 and / or the output of the average pixel calculation unit 82. A weighting unit 83 and an inverse filter processing unit 85 that performs inverse filter processing for generating image data subjected to noise suppression processing on the output of the weighting unit 83 are configured.

The p filter coefficients in the filter processing unit 81 are switched for each of R, G, and B input image data, and are read from the filter coefficient storage unit 84 and set to the filters A1 to Ap.
The average pixel value calculation unit 82 calculates an average value Pav with respect to pixel values of a small region (local region) of n × n pixels of the same input image data used in the spatial filter processing by the filter processing unit 81. The weighting coefficient W is read from the look-up table (LUT) 86 according to the average value Pav and the value of the filter processing result in the filter processing unit 81, and set to the weighting circuits W1, W2,.
With the circuit in FIG. 38, noise is suppressed while avoiding a decrease in contrast of the image data by changing the weighting of the noise suppression processing by the spatial filter according to the brightness of the local region of the image data.

  FIG. 4, FIG. 28 or FIG. 32 is applied to the living body observation apparatus of Example 11 of the present invention. In these configurations, a spatial frequency filter (LPF) (not shown) is provided in the matrix calculation unit 436, but this spatial frequency characteristic is controlled to be slightly changed when a spectral image is displayed. For example, control is performed to widen the band.

The control unit 42 changes the setting of the spatial frequency filter characteristic (LPF characteristic) provided in the matrix calculation unit 436 in the main body processing device (processor) 43. Specifically, the control unit 42 Control is performed to change the band characteristics of the LPF so as to widen the band. Such a control operation is described in FIG. 4 of Japanese Patent Application No. 2004-25 0 978.

Here, it is assumed that the biological observation apparatus is currently in the normal image observation mode.
In this state, the surgeon can perform an endoscopic examination by inserting the insertion portion 102 of the endoscope 101 into the body cavity of the patient. When the operator wants to observe in more detail the running state of the blood vessels on the surface of the tissue to be examined such as the affected part in the body cavity, the operator operates a mode changeover switch (not shown).
When the mode switch is operated, the control unit 42 changes the operation mode of the light source unit 41 and the main body processing device 43 to the setting state of the spectral image observation mode.
Specifically, the control unit 42 performs light amount control so as to increase the light amount for the light source unit 41, and the spatial frequency LPF band in the matrix calculation unit 436 for the main body processing device 43. The characteristic is changed so as to broaden the band, and change setting such as switching to the spectral image processing system including the matrix calculation unit 436 by controlling the switching unit 439 is performed.
By performing such a change setting, it is possible to display the running state of the capillary blood vessels in the vicinity of the surface layer of the biological tissue in the spectral image observation mode in an easy-to-identify state.
In addition, since the band characteristics of LPF signal passage are widened, near the surface layer equivalent to that obtained by the running state of capillaries and the G color signal imaged under the illumination light of the specific color G. It is possible to improve the resolution (resolution) of a nearby blood vessel running state and the like and obtain an image with good image quality that is easy to diagnose.
According to this embodiment that operates in this way, the existing simultaneous color imaging function is maintained in the normal image observation mode, and the coefficients and the like of each part in the main body processing device 43 are set even in the spectral image observation mode. By changing the processing characteristics such as changing, it is possible to sufficiently secure the observation function in the spectral image observation mode.

4, 28, or 32 is applied to the configuration of the living body observation apparatus according to the twelfth embodiment of the present invention. In those configurations, NBI display indicating that the spectral image is being observed is performed.
(1) When displaying on the display monitor 106 On the display monitor 106, there is no display during normal image observation, and NBI characters are displayed during spectral image observation. Alternatively, a mark such as ◯ may be displayed at any one of the four corners of the monitor instead of the character display.

(2) When displaying on the front panel of the endoscope apparatus main body 105: see FIG. 39, FIG. 40, and FIG. 41 An LED is simply provided on the operation panel. The LED is turned off during normal image observation and turned on during spectral image observation. . Specifically, as shown in FIG. 39, an LED lighting unit 91 is provided in the vicinity of the NBI character, and is turned off during normal image observation and turned on during spectral image observation.
As shown in FIG. 40, an LED is provided so that the NBI character itself 92 is turned on or the character peripheral portion 93 other than the NBI character is turned on, and is turned off during normal image observation and turned on during spectral image observation.
As shown in FIG. 41, an LED is provided so that the NBI character itself 94 is lit, or a character peripheral portion 95 other than the NBI character is lit, and the green light is turned off during normal image observation, white light is emitted during spectral image observation, etc. Lights with different colors.

(3) When displaying on the screen of the centralized controller The biological observation apparatus is assembled by a system composed of a plurality of devices, and displayed on the controller screen for centrally controlling them in the same manner as in FIG. 39, FIG. 40, and FIG. Alternatively, the spectral image observation mode changeover switch (that is, the NBI switch) itself displays black characters during normal image observation and reverse characters during spectral image observation.
(4) Other display locations include keyboards and foot switches.

42 and 43 relate to the living body observation apparatus according to the thirteenth embodiment of the present invention, FIG. 42 is a diagram showing the arrangement of color filters, and FIG. 43 is a diagram showing the spectral sensitivity characteristics of the color filters.
Since the living body observation apparatus according to the thirteenth embodiment is almost the same as the first embodiment, only differences from the first embodiment will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.
In the present embodiment, the color filter provided in the CCD 21 is mainly different from that in the first embodiment. In the first embodiment, an RGB primary color filter is used as shown in FIG. 6, whereas in the present embodiment, a complementary color filter is used.

As shown in FIG. 42, the complementary color filter array includes G, Mg, Ye, and Cy elements. The relationship between each element of the primary color filter and each element of the complementary color filter is Mg = R + B, Cy = G + B, Ye = R + G.
In this case, all the pixels of the CCD 21 are read out, and the image from each color filter is subjected to signal processing or image processing. Further, when the equations (1) to (8) and (19) to (21) for the primary color filter are modified in the case of a complementary color filter, the following equation (33) is obtained from the following equation (27): become that way. However, the characteristics of the target narrow-band bandpass filter are the same.

［数２８］

［数２９］
ｋG＝（∫Ｓ（λ）×Ｈ（λ）×Ｇ（λ）ｄλ）^−１
ｋMg＝（∫Ｓ（λ）×Ｈ（λ）×Ｍｇ（λ）ｄλ）^−１
ｋCy＝（∫Ｓ（λ）×Ｈ（λ）×Ｃｙ（λ）ｄλ）^−１
ｋYe＝（∫Ｓ（λ）×Ｈ（λ）×Ｙｅ（λ）ｄλ）^−１ …（２９）
［数３０］

［数３１］

［数３２］

［数３３］

また、図４３に、補色型カラーフィルタを用いた場合の分光感度特性、目標とするバンドパスフィルタ及び上記（２７）式乃至（３３）式により求められ擬似バンドパスフィルタの特性を示す。
なお、補色型フィルタを用いる場合には、図４で示されるＳ／Ｈ回路は、それぞれＲ・Ｇ・Ｂではなく、Ｇ・Ｍｇ・Ｃｙ・Ｙｅについて行われることは言うまでもない。 [Equation 27]

[Equation 28]

[Equation 29]
kG = (∫S (λ) × H (λ) × G (λ) dλ) ⁻¹
kmg = (∫S (λ) × H (λ) × Mg (λ) dλ) ⁻¹
kCy = (∫S (λ) × H (λ) × Cy (λ) dλ) ⁻¹
kYe = (∫S (λ) × H (λ) × Ye (λ) dλ) ⁻¹ (29)
[Equation 30]

[Equation 31]

[Formula 32]

[Equation 33]

FIG. 43 shows the spectral sensitivity characteristics when the complementary color filter is used, the target bandpass filter, and the characteristics of the pseudo bandpass filter obtained by the above equations (27) to (33).
When the complementary color filter is used, it goes without saying that the S / H circuit shown in FIG. 4 is performed for G, Mg, Cy, and Ye instead of R, G, and B, respectively.

  According to the present embodiment, as in the first embodiment, a spectral image in which the blood vessel pattern is clearly displayed can be obtained. Further, in this embodiment, it is possible to enjoy the advantages of using a complementary color filter.

The embodiments of the present invention have been described above. However, the present invention may be used by combining various embodiments described above, and modifications may be made without departing from the spirit of the present invention.
For example, for all the embodiments described above, a new pseudo band-pass filter can be created by the operator himself / herself at other timings in the clinic and applied to the clinic. That is, in the first embodiment, a design unit (not shown) capable of calculating and calculating matrix coefficients is provided in the control unit 42 in FIG.

  Thus, a pseudo bandpass filter suitable for obtaining a spectral image that the operator wants to know is newly designed by inputting conditions via the keyboard provided in the endoscope apparatus main body 105 shown in FIG. In addition, the calculated matrix coefficient (corresponding to each element of the matrix “A” in the expressions (19) and (31)) is corrected to each element of the matrix “K” in the expressions (20) and (32). 4), the final matrix coefficients (corresponding to the elements of the matrix “A ′” in the equations (21) and (33)) are set in the matrix calculation unit 436 in FIG. be able to.

  FIG. 44 shows a flow until application. This flow will be described in detail. First, the operator inputs information about a target bandpass filter (for example, a wavelength band) via a keyboard or the like. As a result, the matrix “A ′” is calculated together with the characteristics of the light source / color filter already stored in a predetermined storage device or the like, and as shown in FIG. 43, along with the characteristics of the target bandpass filter, The calculation result (pseudo bandpass filter) by the matrix “A ′” is displayed on the monitor as a spectrum diagram.

After confirming the calculation result, the operator performs setting when using the newly created matrix “A ′”, and generates an actual endoscopic image using this matrix “A ′”. Is done. In addition, the newly created matrix “A ′” is stored in a predetermined storage device and can be used again according to a predetermined operation by the operator.
As a result, the operator can generate a new band-pass filter based on his / her own experience etc. without being bound by the existing matrix “A ′”, and is particularly effective when used for research purposes. .
The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.

FIG. 3 is a conceptual diagram illustrating a signal flow when creating a spectral image signal from a color image signal according to Embodiment 1 of the present invention. The conceptual diagram which shows the integral calculation of the spectral image signal which concerns on Example 1 of this invention. 1 is an external view showing an external appearance of a living body observation apparatus according to Embodiment 1 of the present invention. The block diagram which shows the structure of the biological observation apparatus of FIG. The external view which shows the external appearance of the chopper of FIG. It shows the arrangement of the color filter arranged on the imaging surface of the CCD of FIG. The figure which shows the spectral sensitivity characteristic of the color filter of FIG. The block diagram which shows the structure of the matrix calculating part of FIG. The spectrum figure which shows the spectrum of the light source which concerns on Example 1 of this invention. The spectrum figure which shows the reflection spectrum of the biological body which concerns on Example 1 of this invention. FIG. 11 is a diagram showing a layer direction structure of a biological tissue observed by the biological observation apparatus of FIG. The figure explaining the arrival state to the layer direction of the biological tissue of the illumination light from the biological observation apparatus of FIG. The figure which shows the spectral characteristic of each band of white light. The 1st figure which shows each band image by the white light of FIG. The 2nd figure which shows each band image by the white light of FIG. The 3rd figure which shows each band image by the white light of FIG. The figure which shows the spectral characteristics of the spectral image produced | generated by the matrix calculating part of FIG. The 1st figure which shows each spectral image of FIG. The 2nd figure which shows each spectral image of FIG. The 3rd figure which shows each spectral image of FIG. The block diagram which shows the structure of the color adjustment part of FIG. The figure explaining the effect | action of the color adjustment part of FIG. The block diagram which shows the structure of the modification of the color adjustment part of FIG. The figure which shows the spectral characteristic of the 1st modification of the spectral image of FIG. The figure which shows the spectral characteristic of the 2nd modification of the spectral image of FIG. The figure which shows the spectral characteristic of the 3rd modification of the spectral image of FIG. The block diagram which shows the other structural example of the matrix calculating part which concerns on Example 1 of this invention. The block diagram which shows the structure of the biological observation apparatus which concerns on Example 2 of this invention. The figure which shows an example of the light quantity control means in the biological observation apparatus which concerns on Example 4 of this invention. The figure which shows the other example of a light quantity control means. The figure which shows another example of a light quantity control means. The block diagram which shows the structure of the biological observation apparatus which concerns on Example 4 of this invention. The figure which shows the electric charge accumulation time of CCD of FIG. FIG. 33 is a modification of FIG. 32 and shows the charge accumulation time of the CCD. The figure which shows an example of the image quality improvement in the biological observation apparatus which concerns on Example 8 of this invention. The figure which shows an example of the image quality improvement in the biological observation apparatus which concerns on Example 9 of this invention. The figure which shows the other example of the image quality improvement in the biological observation apparatus which concerns on Example 9 of this invention. The figure which shows an example of the image quality improvement in the biological observation apparatus which concerns on Example 10 of this invention. The figure which shows an example of the image quality improvement in the biological observation apparatus which concerns on Example 12 of this invention. The figure which shows the other example of the image quality improvement in the biological observation apparatus concerning Example 12 of this invention. The figure which shows another example of the image quality improvement in the biological observation apparatus which concerns on Example 12 of this invention. The figure which shows the arrangement | sequence of the color filter in the biological observation apparatus which concerns on Example 13 of this invention. The figure which shows the spectral sensitivity characteristic of the color filter of FIG. The flowchart in the case of the matrix calculation in the biological observation apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 ... Lamp 16 ... Chopper 18 ... Current control part 24 ... Aperture control part 41 ... Light source part 42 ... Control part 43 ... Main body processing apparatus (processor)
100: Electronic endoscope apparatus (biological observation apparatus)
101 ... endoscope 102 ... insertion portion 103 ... tip 104 ... the angle control member 105 ... endoscope apparatus main body 106 ... display monitor (Table 示装 location)
436 ... Matrix operation unit 440 ... Color adjustment unit 440a ... Color conversion processing circuit 444 ... Broadband luminance signal generation unit

Claims (3)

An illumination unit that irradiates light to a living body as a subject;
An imaging unit that photoelectrically converts light reflected from the living body based on the irradiation light and generates an imaging signal;
A signal processing control unit that controls the operation of the illumination unit and / or the imaging unit and outputs the imaging signal to a display device;
Comprising
The signal processing control unit
A spectral signal generation unit that generates a spectral signal corresponding to an optical wavelength narrowband image from the imaging signal by signal processing;
A color adjustment unit that assigns different color tones for each of a plurality of bands forming the spectral signal when the spectral signal is output to the display device;
An image quality adjustment unit for adjusting the image quality of a signal output to the display device;
A signal amplifying unit for amplifying the signal level of the imaging signal and / or spectral signal;
The signal amplifying unit changes the amplification control between the imaging signal and the spectral signal,
The biological observation apparatus, wherein the amplification control is a follow-up speed when the amplification function starts an amplification operation when the light amount control unit that controls the light amount irradiated from the illumination unit cannot be performed. . An illumination unit that irradiates light to a living body as a subject;
An imaging unit that photoelectrically converts light reflected from the living body based on the irradiation light and generates an imaging signal;
A signal processing control unit that controls the operation of the illumination unit and / or the imaging unit and outputs the imaging signal to a display device;
Comprising
The signal processing control unit
A spectral signal generation unit that generates a spectral signal corresponding to an optical wavelength narrowband image from the imaging signal by signal processing;
A color adjustment unit that assigns different color tones for each of a plurality of bands forming the spectral signal when the spectral signal is output to the display device;
An image quality adjusting unit for improving brightness and / or S / N ratio of a signal output to the display device;
Comprising
The living body observation apparatus, wherein the image quality adjustment unit performs weighted addition of a luminance signal of an imaging signal and / or a luminance signal of a spectral signal. An illumination unit that irradiates light to a living body as a subject;
An imaging unit that photoelectrically converts light reflected from the living body based on the irradiation light and generates an imaging signal;
A signal processing control unit that controls the operation of the illumination unit and / or the imaging unit and outputs the imaging signal to a display device;
Comprising
The signal processing control unit
A spectral signal generation unit that generates a spectral signal corresponding to an optical wavelength narrowband image from the imaging signal by signal processing;
A color adjustment unit that assigns different color tones for each of a plurality of bands forming the spectral signal when the spectral signal is output to the display device;
An image quality adjusting unit for improving brightness and / or S / N ratio of a signal output to the display device;
Comprising
The living body observation apparatus, wherein the image quality adjustment unit performs control to change a spatial frequency characteristic with respect to an imaging signal or a signal generated by predetermined conversion from the imaging signal.

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