JP2010068924A - Method and apparatus for image acquisition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate excellent display images even in the case of moving images. <P>SOLUTION: Illumination light L1 and auxiliary light L2 of a wavelength 805 nm are emitted onto an observation target 10 and obtained RGB image signals are outputted to an estimated spectroscopic data calculation unit 180 and an image processing unit 182. In the estimated spectroscopic data calculation unit 180, an estimated spectroscopic data value (q82) of 805 nm and an estimated spectroscopic data value (q61) of 700 nm are calculated for each pixel, using the RGB image signals and estimated spectroscopic matrix data. In a special superimposed image generation unit 187, [a light intensity ratio r]=[the data value (q82)]/[the data value (q61)] is calculated, a gain g is set on the basis of the light intensity ratio r, [signals m]=[ the data value (q82)]×g are generated, and special images based on quasi reflectivity information reflecting the reflectivity of the light of the wavelength band of the auxiliary light in each area of the observation target are generated using the signals m and a correspondence table T stored in a memory 190. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  Illumination light and auxiliary light are irradiated to the observed part to which a medicine that absorbs light of the auxiliary light wavelength is administered, and an image composed of the reflected light of the illumination light and the reflected light of the auxiliary light is captured at the observed part The present invention relates to an image acquisition method and apparatus.

  Conventionally, endoscope apparatuses for observing tissue in a body cavity are widely known, and a normal image is obtained by imaging a portion to be observed in a body cavity illuminated by white light, and this normal image is displayed on a monitor screen. Electronic endoscopes are widely used.

  In recent years, in the field of electronic endoscope devices using solid-state imaging devices, devices that perform spectral imaging combined with a narrow-band bandpass filter based on spectral reflectance in the digestive tract such as the gastric mucosa, that is, narrow An electronic endoscope apparatus with a built-in band filter (Narrow Band Imaging-NBl) has attracted attention. This device is provided with a band pass filter of a narrow (wavelength) band instead of a frame sequential type R (red), G (green), and B (blue) rotary filter, and through these narrow band band pass filters. Illumination light is sequentially output, and a spectral image is formed by performing the same processing as in the case of R, G, B (RGB) signals while changing the respective weights for the signals obtained with these illumination lights. It is. According to such a spectral image, in the digestive organs such as the stomach and the large intestine, a fine structure or the like that has not been obtained conventionally is extracted.

On the other hand, in Patent Document 1 and Patent Document 2, white light is irradiated in a simultaneous system in which a micro mosaic color filter is arranged on a solid-state imaging device, instead of the surface sequential type using the above-described narrowband bandpass filter. It has been proposed to form a spectral image by arithmetic processing based on an image signal obtained by imaging an observed part. This Patent Document 1 obtains estimated matrix data that takes into account the spectral characteristics of illumination light and the spectral characteristics of the entire imaging system, including the color sensitivity characteristics of the image sensor and the transmittance of the color filter, and is captured by the image sensor. A method is disclosed in which spectral data of the observed portion is obtained by calculating the RGB image signal and the estimated matrix data and not depending on the type of illumination light, the spectral characteristics unique to the imaging system, or the like.
JP 2003-93336 A JP 2007-202621 A

  In recent years, not only the observed part is illuminated with white light but also observed, a drug that absorbs light of a predetermined wavelength, for example, IGC (Indocyanine Green) is administered to the observed part, and the drug is applied to the observed part. An image acquisition device that emits auxiliary light, which is light having a wavelength that is absorbed by the light, picks up an image composed of reflected light of the auxiliary light in the observed portion, and generates a special image for observing the distribution of the drug in the observed portion Development is underway.

  Usually, in such an image acquisition device, it is sometimes necessary to acquire only a normal image by irradiating only the illumination light to the observed part and to acquire a special image by irradiating only the auxiliary light to the observed part. Do this by dividing.

  However, when a special image based on the reflected light of the auxiliary light and a normal image are acquired in a time-sharing manner, the number of frames per unit time of the special image based on the reflected light of the auxiliary light is reduced. When displaying as, there was a problem that a good display image could not be obtained.

  The present invention has been made in view of the above circumstances, and even when a special image based on reflected light of auxiliary light is acquired and displayed, an image acquisition capable of generating a good display image It is an object to provide a method and an image acquisition device.

The image acquisition method of the present invention irradiates the observation part simultaneously with illumination light and auxiliary light having a wavelength band different from that of the illumination light,
Taking an image composed of the reflected light of the illumination light and the reflected light of the auxiliary light in the observed portion,
For each pixel of the captured image signal, the estimated spectral data of the wavelength band of the auxiliary light is calculated using the image signal value and the preliminarily stored estimated spectral matrix of the wavelength band of the auxiliary light,
Based on the estimated spectral data of the wavelength band of the auxiliary light, quasi-reflectance information reflecting the reflectance of the observed portion in the wavelength band of the auxiliary light is obtained, and a special image is generated based on the quasi-reflectance information It is characterized by doing.

  It is preferable that the observed portion is administered with a medicine that absorbs light having the wavelength of the auxiliary light.

The image acquisition apparatus of the present invention includes a light irradiating unit that simultaneously irradiates an observation part with illumination light and auxiliary light having a wavelength band different from that of the illumination light, reflected light of the illumination light at the observation part, and the auxiliary light. Imaging means for imaging an image composed of the reflected light of
Storage means for storing at least an estimation matrix for calculating estimated spectral data of the wavelength band of the auxiliary light;
Estimated spectral data calculation means for calculating estimated spectral data of the wavelength band of the auxiliary light using an image signal value and the estimation matrix for each pixel of the image signal output from the imaging means;
For each pixel, based on estimated spectral data of the wavelength band of the auxiliary light, quasi-reflectance information reflecting the reflectance of the observed portion in the wavelength band of the auxiliary light is obtained, and based on the quasi-reflectance information And an image processing means for generating a special image.

  Here, “auxiliary light having a wavelength band different from that of illumination light” means that the wavelength range of the auxiliary light does not overlap with the wavelength band of the illumination light. The “estimation matrix for calculating the estimated spectral data of the wavelength band of the auxiliary light” is a matrix that takes into account the spectral characteristics of the auxiliary light and the spectral characteristics of the imaging means, and performs matrix calculation with the image signal. This is a matrix that can calculate estimated spectral data including estimated spectral reflectance information of the observed portion in the wavelength band of the auxiliary light.

  It is preferable that the observed portion is administered with a medicine that absorbs light having the wavelength of the auxiliary light.

The light irradiating means irradiates the observed part with reference light having a wavelength band different from that of the auxiliary light simultaneously with the irradiation of the auxiliary light,
If the imaging means captures an image including the reflected light of the reference light in the observed portion,
The image processing means calculates a reference light intensity that is an intensity of reflected light of the reference light from an image signal output from the imaging means, and divides the estimated spectral data of the wavelength band of the auxiliary light by the reference light intensity. By doing so, the reflectance information may be calculated.

  Here, the “reference light” may be light having a wavelength band different from that of illumination light, such as IR light, or may be light having a wavelength included in the wavelength band of illumination light. When the wavelength band of the reference light is included in the wavelength band of the illumination light, light in the entire illumination light or a part of the wavelength band of the illumination light can be used as the reference light.

  Further, for example, if the light in the red region in the illumination light is used as the reference light, the light intensity of the R image signal in the RGB image signal can be used as the “reference light intensity”. If light of a predetermined wavelength band in the illumination light is used as the reference light, the estimated spectral data of the wavelength band of the reference light is calculated using the image signal of the illumination light and the estimation matrix, and the estimation is performed. Spectral data can also be used as “reference light intensity”.

  The image processing means compares the semi-reflectance information with a predetermined reference value, and when the semi-reflectance information is larger than the reference value, increases the estimated spectral data of the wavelength band of the auxiliary light, The special image may be generated based on the estimated spectral data of the increased wavelength band of the auxiliary light.

  The image processing means compares the quasi-reflectance information with a predetermined reference value. If the quasi-reflectance information is smaller than the predetermined reference value, the estimated spectral data of the wavelength band of the auxiliary light is obtained. The special image may be generated based on the estimated spectral data of the increased wavelength band of the auxiliary light.

  Further, the image processing means compares the semi-reflectance information with a predetermined reference value, and sets a saturated value as an RGB image signal when the semi-reflectance information is smaller than the predetermined reference value. The special image may be generated.

  The image processing unit may generate a special superimposed image in which the special image is superimposed on an image generated based on an image signal output from the imaging unit.

  In the image acquisition method and the image acquisition apparatus according to the present invention, the illumination light and the auxiliary light having a wavelength band different from that of the illumination light are simultaneously applied to, for example, the observed part to which the medicine that absorbs the light having the wavelength of the auxiliary light is administered. The image of the reflected light of the illumination light and the reflected light of the auxiliary light is captured at the observed portion, and the image signal value and the auxiliary light stored in advance are stored for each pixel of the captured image signal. The estimated spectral data of the wavelength band of the auxiliary light is calculated using the estimated spectral matrix of the wavelength band, and the reflectance of the observed part in the wavelength band of the auxiliary light is calculated based on the estimated spectral data of the auxiliary light wavelength band. Since the semi-reflectance information to be reflected is obtained and a special image is generated based on the semi-reflectance information, it is possible to prevent a reduction in the number of frames per unit time of the special image based on the reflected light of the auxiliary light. Video Even when to display can be obtained a good display image. Further, since it is not necessary to switch between the emission of illumination light and the emission of auxiliary light, the structure of the light irradiation means can be simplified.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an endoscope apparatus that is an embodiment to which an image acquisition apparatus of the present invention is applied. The endoscope apparatus 100 provides illumination light L1 that is visible light and auxiliary light having a center wavelength of 805 nm to an observation part 10 to which ICG (Indocyanine Green), which is a drug having light absorption characteristics at a wavelength of 805 nm, is previously administered. A pseudo normal image and a special superimposed image on which a special image reflecting the reflectance information reflecting the reflectance of the observed portion 10 at 805 nm is superimposed are generated from the captured image signal by irradiating L2, respectively, Is displayed.

  As shown in the figure, the endoscope apparatus 100 is inserted into a body cavity of a subject, and a scope unit 110 for observing the observed portion 10, and a processor unit 170 to which the scope unit 110 is electrically detachably connected. The scope unit 110 is optically detachably connected, and includes a light source unit 150 that houses a xenon lamp 151 that emits illumination light L1 and auxiliary light L2. Note that the processor unit 170 and the light source unit 150 may be configured integrally or may be configured separately.

  An illumination lens 111 is provided at the tip of the scope unit 110. The lens 111 is opposed to one end of a light guide 112 through which the illumination light L1 and the auxiliary light L2 are guided. The light guide 112 extends to the outside of the scope unit 110, and an optical connector 113 is provided at the other end, and is detachably connected to an optical connector 153 of the light source unit 150 described later.

  In addition, an imaging lens 115 and a CCD (Charge Coupled Device) 117 that is a solid-state imaging device are provided coaxially in this order at the distal end portion of the scope unit 110. The imaging lens 115 forms an image of the observed portion 10 on the CCD 117. For example, a primary color filter 116 having RGB color filters is attached to the imaging surface of the CCD 117. The CCD 117 is connected to a CCD drive circuit 118 that forms a drive pulse based on a synchronization signal, and also CDS / AGC (correlated double sampling / automatic) that samples and amplifies an image (video) signal output from the CCD 117. Gain control) circuit 119 is connected. The CDS / AGC circuit 119 is connected to an A / D converter 120 that digitizes the analog output. Further, in the scope unit 110, a control unit 121 that controls various circuits provided therein and controls communication with the processor unit 170 is disposed. Further, near the base of the scope unit 110, a push-type switch 122 that is connected to the control unit 121 and switches the operation mode is provided. One end of a signal line 125 is connected to the A / D converter 120, and one end of a signal line 126 is connected to the control unit 121. The signal line 125 and the signal line 126 extend from the main body of the scope unit 110 to the outside, and a connector 127 is provided at the other end. This connector 127 is detachably connected to a connector 194 of a processor unit 170 described later.

  The light source unit 150 includes a xenon lamp 151, a drive circuit 152 that drives the xenon lamp 151, and an optical connector 153 that is detachably connected to the optical connector 113 provided at the tip of the light guide 112 of the scope unit 110. It has. A wavelength filter 155 and a condenser lens 158 are disposed between the xenon lamp 151 and the optical connector 153.

  FIG. 2 is a diagram showing a spectral spectrum of light emitted from the xenon lamp 151 and spectral spectra of the illumination light L1 and the auxiliary light L2. The dotted line indicates the spectrum of the light emitted from the xenon lamp 151, and the solid line indicates the spectrum of the illumination light L1 and the auxiliary light L2.

  The wavelength filter 155 transmits light having a wavelength of 400 nm to 700 nm and light having a wavelength of 805 nm. For this reason, when the light emitted from the xenon lamp 151 passes through the wavelength filter 155, it becomes illumination light L1 having a wavelength of 400 nm to 700 nm and auxiliary light L2 having a wavelength of 805 nm. The light source unit 150 is provided with a control unit 159 that controls the drive circuit 152.

  On the other hand, the processor unit 170 is provided with a processor unit 172 that performs various signal processing and control. The processor unit 172 includes a connector 195 detachably connected to the estimated spectral data calculation unit 180, the image processing unit 182, the display processing unit 184, the memory 190, the keyboard type input unit 192, and the connector 127 of the scope unit 110. It is connected. The processor unit 172 is connected to the control unit 121 of the scope unit 110 and the control unit 159 of the light source unit 150.

  In the estimated spectral data calculation means 180, the R, G, and B three-color image signals output from the A / D converter 120 of the scope unit 110 and the wavelength of auxiliary light stored in advance in the memory 190 for each pixel. The estimated spectral data of the wavelength band of the auxiliary light is calculated using the estimated spectral data of 805 nm that is the band, and is output to the image processing unit 182. Similarly, the 700 nm estimation is performed using the R, G, B three-color image signals output from the A / D converter 120 of the scope unit 110 and the 700 nm estimated spectral data stored in the memory 190 in advance. Spectral data is calculated and output to the image processing unit 182.

  The image processing unit 182 includes a pseudo normal image generation unit 186 that generates pseudo normal image data and a special superimposed image generation unit 187 that generates special superimposed image data. Details of operations in the pseudo normal image generation unit 186 and the special superimposed image generation unit 187 will be described later.

  The display processing unit 184 generates a display color image signal in which the pseudo normal image data and the special superimposed image data are displayed side by side, and outputs the generated color image signal to the monitor 11.

The memory 190 stores estimated matrix data for calculating estimated spectral data of the observed portion 10. The estimated matrix data is stored in advance in the memory 190 as a table. This estimated matrix data is the spectral characteristics of the entire imaging system including the spectral characteristics of the light irradiated to the observed portion 10, that is, the illumination light L1 and the auxiliary light L2, the color sensitivity characteristics of the imaging device, the transmittance of the color filter, and the like. The matrix data is calculated by calculating the RGB image signal captured by the CCD 117 and the estimated matrix data, and does not depend on the spectral characteristics of the illumination light and the auxiliary light, or the spectral characteristics specific to the imaging system. Spectral data of the observation unit 10 can be obtained. The details of the estimation matrix data are disclosed in Japanese Patent Laid-Open No. 2003-93336 or Japanese Patent Laid-Open No. 2007-202621. In this embodiment, an example of estimated matrix data stored in the memory 190 is as shown in Table 1 below.

  The matrix data in Table 1 is composed of, for example, 61 wavelength range parameters (coefficient sets) p1 to p61 obtained by dividing a wavelength range from 400 nm to 700 nm at 5 nm intervals, and a wavelength range parameter p82 corresponding to a wavelength of 805 nm. . In the present embodiment, the wavelength region parameters (coefficient sets) p62 to p81 are omitted because light having a wavelength of 705 nm to 800 nm is not irradiated on the observed portion 10.

For example, for the three-color image signals R, G, and B, using a 3 × 62 matrix including all parameters of the estimated matrix data stored in the memory 190, a matrix calculation represented by the following equation is performed. Estimated spectroscopic data (q1 to q61, q82) can be created.

  3 and 4 show an example of the estimated spectral data (q1 to q61, q82) as a spectral distribution. FIG. 3 shows estimated spectral data in a pixel corresponding to a region where ICG (Indocyanine Green) does not exist in the observed portion 10, that is, estimation when the auxiliary light L2 of 805 nm is not absorbed by ICG (Indocyanine Green). Spectral data is shown.

  On the other hand, FIG. 4 shows estimated spectral data in a pixel corresponding to a region where ICG (Indocyanine Green) exists, that is, estimated spectral data in the case where the auxiliary light L2 of 805 nm is absorbed by ICG (Indocyanine Green). ing. The horizontal axis represents the wavelength corresponding to each of the data values q1 to q61 and q82 of the estimated spectral data, and the vertical axis represents the intensity of each of the data values q1 to q61 and q82.

  As shown in FIG. 3, the 805 nm auxiliary light L2 is considerably reflected in the region where ICG (Indocyanine Green) does not exist, but in the region where ICG (Indocyanine Green) exists, the 805 nm auxiliary light L2 is ICG. Since it is absorbed by (Indocyanine Green), it is hardly reflected. That is, the estimated spectral data value (q82) at 805 nm is a value reflecting the reflectance of the auxiliary light L2 at 805 nm in the observed object 10, and at the same time, reflecting the presence or absence of absorption by ICG (Indocyanine Green). . In the present embodiment, a special image is generated based on the estimated spectral data value (q82) at 805 nm.

  Furthermore, the memory 190 stores in advance a correspondence table T between light intensity of 805 nm obtained by actual measurement and RGB signals.

  Hereinafter, the operation of the endoscope apparatus of the present embodiment having the above configuration will be described. Prior to use of the endoscope apparatus, the cleaned and sterilized scope unit 110 is attached to the processor unit 170 and the light source unit 150. The connector 127 provided at the tip of the signal line 125 and the signal line 126 of the scope unit 110 is connected to the connector 195 of the processor unit 170. The optical connector 113 provided at the tip of the light guide 112 is connected to the optical connector 153 of the light source unit 150.

  Thereafter, the scope unit 110 is inserted into the body cavity of the subject, for example, the esophagus and the like, and the image of the observed part 10 is acquired. While being performed, the subject is administered ICG (Indocyanine Green), for example, by intravenous injection. ICG (Indocyanine Green) is carried to the observed part 10 by the blood flow of the subject.

  When the user presses a predetermined key of the input unit 192 or the switch 122 of the scope unit 110, the xenon lamp 151 is turned on by the drive circuit 152 in the light source unit 150. The light emitted from the xenon lamp 151 is transmitted through the wavelength filter 155 and the wavelength band is limited to become illumination light L1 having a wavelength band of 400 nm to 700 nm and auxiliary light L2 having a wavelength of 805 nm. The light is condensed on the end face and enters the light guide 112. The illumination light L1 and the auxiliary light L2 that have propagated through the light guide 112 are emitted from the tip of the light guide 112 and are applied to the observed portion 10 through the lens 111.

  The CCD 117 driven by the CCD driving circuit 118 takes an image of the observed portion 10 and outputs an image pickup signal. The imaging signal is amplified by correlated double sampling and automatic gain control by the CDS / AGC circuit 119, and then A / D converted by the A / D converter 18, and is processed as an RGB image signal by the processor unit 172 of the processor unit 170. The estimated spectral data calculation means 180 and the image processing unit 182 are input.

In the estimated spectral data calculation means 180, the R, G, and B three-color image signals output from the A / D converter 120 of the scope unit 110 and the wavelength of auxiliary light stored in advance in the memory 190 for each pixel. The estimated spectral data value (q82) at 805 nm is calculated using the estimated spectral matrix data of 805 nm, which is the band, to calculate the estimated spectral data value (q82) at 805 nm. The data is output to the generation unit 187.

Similarly, using the R, G, B three-color image signals output from the A / D converter 120 of the scope unit 110 and the estimated spectral matrix data of 700 nm stored in the memory 190 in advance, The estimated spectral data value (q61) of 700 nm is calculated and output to the special superimposed image generation unit 187 of the image processing unit 182.

  In the pseudo normal image generation unit 186, for each pixel, first, the estimated spectral data value (q82) at 805 nm and the correspondence table T between the light intensity at 805 nm and the RGB signal stored in the memory 190 are used as an auxiliary. An RGB image signal resulting from the light L2 is calculated, and an auxiliary light image composed of these image signals is generated.

  On the other hand, an image composed of R, G, and B color image signals output from the A / D converter 120 of the scope unit 110 is obtained from a normal image composed of reflected light of the illumination light L1 and reflected light of the auxiliary light L2. The auxiliary light image can be regarded as an image made up of the reflected light of the auxiliary light L2.

  The pseudo normal image generation unit 186 subtracts the RGB image signal at 805 nm from the RGB image signal output from the A / D converter 120 of the scope unit 110 for each pixel, that is, subtracts the auxiliary light image from the mixed image. Thus, a pseudo normal image that can be regarded as a pseudo normal image is generated and output to the display processing unit 184.

  Next, a procedure for generating a special superimposed image in the special superimposed image generation unit 187 will be described with reference to a flowchart shown in FIG.

  In step S101, for each pixel, the light intensity ratio r is calculated by dividing the estimated spectral data value (q82) at 805 nm by the estimated spectral data value (q61) at 700 nm.

  The intensity of the auxiliary light L2 reflected by the observed portion 10, that is, the intensity of the reflected light of the auxiliary light L2, is substantially proportional to the illuminance of the auxiliary light L2, but the illuminance of the auxiliary light L2 decreases in inverse proportion to the square of the distance. To do. Therefore, there may be cases where strong reflected light is received from an area where ICG (indocyanine green) is located closer than an area where there is no ICG (indocyanine green) located far from the light source. It is not possible to know whether ICG (Indocyanine Green) exists in the area only by the information of the reflected light intensity of light. Therefore, the light to be observed is irradiated as a reference light with a wavelength band different from that of the auxiliary light, and the intensity of the reflected light (hereinafter referred to as the reference light intensity) reflected by the observed part that has been irradiated with the reference light is There is known a method of detecting and dividing the reflected light intensity of auxiliary light by the reference light intensity to obtain a light intensity ratio and generating an image based on the light intensity ratio. This light intensity ratio is less influenced by the difference in distance from the distal end of the scope unit 110 to each region of the observed portion 10 or by the variation in the irradiation intensity of the auxiliary light L2. The light intensity ratio is a value that reflects the reflectance of light in the wavelength band of the auxiliary light in each region of the observed portion, and corresponds to the quasi-reflectance information of the present invention.

  In the present embodiment, the estimated spectral data value (q82) at 805 nm is used as the reflected light intensity of the auxiliary light, and the estimated spectral data value (q61) at 700 nm is used as the reference light intensity. The wavelength 700 nm is a wavelength at which the absorbance due to oxyhemoglobin is minimized within the wavelength band of the illumination light L1, and is a wavelength that is not easily affected by the presence or absence of blood vessels in the observed portion. When the estimated spectral data value (q61) at 700 nm is 0, the light intensity ratio diverges. Therefore, when calculating the light intensity ratio, the estimated spectral data value (q61) at 700 nm is calculated in advance. It is preferable to confirm that is not 0 and then calculate the light intensity ratio.

  The reference light is preferably light having a wavelength in the red to infrared region that penetrates the tissue to the same extent as the auxiliary light L2. For example, the red component of the illumination light L1 may be used. For example, near infrared light having a desired wavelength in the range of 700 nm to 1000 nm (excluding the vicinity of 805 nm) may be used. When generating a pseudo normal image, the reference light component can be removed by the same processing as that of the auxiliary light L2.

  In step S102, in order to reduce the influence of noise when the signal intensity is small, the light intensity ratio r is compared with preset upper and lower limit values, and the light intensity ratio r greater than or equal to the upper limit value is set to the upper limit value. The light intensity ratio r below the lower limit is set to the lower limit. The light intensity ratio r above the upper limit and the light intensity ratio r below the lower limit may be set to 0 as invalid.

  In step S103, for each pixel, the light intensity ratio is compared with a reference value S stored in advance in the memory 190. If the light intensity ratio is smaller than the reference value S as shown in FIG. A small gain g is set, and when the light intensity ratio is 1 or more, a gain g greater than 1 is set.

  In step 104, for each pixel, the estimated spectral data value (q82) at 805 nm is multiplied by the gain g calculated in step 103 to generate an enhanced light intensity signal m = estimated spectral data value (q82) · g.

  In step 105, for each pixel, the enhanced light intensity signal m calculated in step 104 and the correspondence table T between the 805 nm light intensity and the RGB signal stored in the memory 190 are used. And corresponding RGB image signals are calculated. The image composed of the enhanced light intensity signal m and the corresponding RGB image signal is based on the quasi-reflectance information reflecting the reflectance of the light in the wavelength band of the auxiliary light in each region of the observed portion of the present invention. This corresponds to a special image to be created.

  In step 106, the RGB image signal corresponding to the enhanced light intensity signal m calculated in step 105 is added to the RGB image signal output from the A / D converter 120 of the scope unit 110 for each pixel. That is, a special superimposed image is generated by superimposing the special image composed of the RGB image signal created in step 105 on the mixed image composed of the RGB image signal output from the A / D converter 120 of the scope unit 110. And output to the display processing unit 184.

  The display processing unit 184 generates a display image in which the pseudo normal image and the special superimposed image are displayed side by side, and outputs the display image to the monitor 11 for display. In the special superimposed image, the region where the light intensity ratio r is large, that is, the region where ICG (indocyanine green) does not exist is displayed brightly because the light intensity is increased, and the region where ICG (indocyanine green) exists is relatively Therefore, the visibility of the area where ICG (Indocyanine Green) exists is improved.

    As apparent from the above description, since the pseudo normal image and the special superimposed image can be acquired simultaneously, for example, even when the pseudo normal image and the special superimposed image are displayed as a moving image, the number of frames per unit time is There is no reduction, and a good display image can be obtained. In addition, since it is not necessary to switch between the emission of the illumination light L1 and the emission of the auxiliary light L2, the structure of the light source unit 150 can be simplified.

  In this embodiment, in step S103, as shown in FIG. 6, when the light intensity ratio r is smaller than the reference value S, a gain smaller than 1 is set, and the light intensity ratio r is greater than or equal to the reference value S. In this case, a gain larger than 1 is set, but various methods can be used for setting the gain. For example, the gain may be set continuously as shown in FIG. 7A, or the gain may be set stepwise as shown in FIG. 7B.

  Alternatively, as shown in FIG. 5, step S201 may be performed instead of step S103. In step S201, as shown in FIG. 8, when the light intensity ratio r is smaller than the reference value S, a gain greater than 1 is set, and when the light intensity ratio r is greater than or equal to the reference value S, a gain smaller than 1 is set. Set. In step S201, the gain may be set continuously as shown in FIG. In such a case, a region where the light intensity ratio r is small, that is, a region where ICG (indocyanine green) exists is displayed brightly, and the visibility of the region where ICG (indocyanine green) exists is improved.

  Furthermore, as shown in FIG. 10, steps S202 to S204 may be performed instead of steps S103 to S105. In step S202, as shown in FIG. 11, when the light intensity ratio r is smaller than the reference value S, a positive offset value f larger than 1 is set, and when the light intensity ratio r is larger than the reference value S, it is negative. Is set to the offset value f. In step 203, the offset light value f calculated in step 202 is added to the estimated spectral data value (q82) at 805 nm for each pixel, and the enhanced light intensity signal m ′ = estimated spectral data value (q82) + offset value f. Is generated. In step 204, for each pixel, the enhanced light intensity signal m ′ calculated in step 203 and the correspondence table T between the 805 nm light intensity and the RGB signal stored in the memory 190 are used. An RGB image signal corresponding to m ′ is calculated to generate a special image. Also in this case, a region where the light intensity ratio r is small, that is, a region where ICG (indocyanine green) exists is displayed brightly, and the visibility of the region where ICG (indocyanine green) exists is improved.

  Also, as shown in FIG. 12, step 205 may be performed instead of steps 103-105. In step 205, when the light intensity ratio r is smaller than the reference value S, a saturated value is set as the RGB signal, and when the light intensity ratio r is greater than or equal to the reference value S, a zero value is set as the RGB signal. To generate a special image. In such a case, the area where ICG (Indocyanine Green) is present shines white, and a normal color image is displayed in the other areas. For example, when detecting the sentinel lymph node, the lymph node that the lymph flow from the tumor reaches first, the lymph node with ICG (Indocyanine Green) shines white, so it is easy to send sentinel lymph node. Can be detected.

  In the present embodiment, the illumination light L1 and auxiliary light L2 emitted from the light source unit 150 and propagated through the scope unit 110 are simultaneously irradiated onto the observed portion 10 and captured by the CCD 117 to generate an image. However, the form of the image acquisition device of the present invention is not limited to the above-described embodiment, and the observation target is irradiated simultaneously with the illumination light and the auxiliary light. However, any form may be used as long as an image is acquired. The auxiliary light source may be an LED. Further, for example, an endoscope apparatus, a colposcope, a capsule endoscope apparatus, or the like provided with a light source unit such as an LED at the tip of the scope unit 110, or a microscope or the like having an image acquisition function. Also good.

  Further, although the description has been given using the primary color type three-color filter as the mosaic filter of the CCD 117, the present invention is not limited to this, and a mosaic filter such as a four-color type or a complementary color type can also be used. In this case, the signal output from the CCD 117 may be converted into a primary color type signal by signal processing, or estimated matrix data matching the spectral characteristics of these mosaic filters may be stored in the memory in advance. Good.

The block diagram which shows the structure of the endoscope apparatus which concerns on one Embodiment of this invention. The figure which shows the spectrum of illumination light and auxiliary light Diagram showing estimated spectral data as spectral distribution Diagram showing estimated spectral data as spectral distribution Explanatory drawing of the procedure for generating special superimposed images Illustration of how to set the gain Illustration of how to set the gain Illustration of how to set the gain Illustration of how to set the gain Illustration of how to set the gain Explanatory drawing of the procedure for generating special superimposed images Illustration of offset setting method Explanatory drawing of the procedure for generating special superimposed images

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Monitored part 11 Monitor 100 Endoscope apparatus 110 Scope unit 111 Lens 112 Light guide 113 Optical connector 115 Imaging lens 116 Color filter 117 CCD
118 CCD Drive Circuit 121 Control Unit 122 Switch 125 Signal Line 126 Signal Line 127 Connector 150 Light Source Unit 151 Xenon Lamp 152 Drive Circuit 153 Optical Connector 155 Wavelength Filter 158 Condensing Lens 170 Processor Unit 172 Processor Unit 180 Estimated Spectral Data Calculation Unit 182 Image Processing unit 184 Display processing unit 186 Pseudo normal image generation unit 187 Special superimposed image generation unit 190 Memory 192 Input unit 195 Connector

Claims (9)

Irradiate illumination light and auxiliary light having a wavelength band different from that of the illumination light simultaneously onto the observed part
Taking an image composed of the reflected light of the illumination light and the reflected light of the auxiliary light in the observed portion,
For each pixel of the captured image signal, the estimated spectral data of the wavelength band of the auxiliary light is calculated using the image signal value and the preliminarily stored estimated spectral matrix of the wavelength band of the auxiliary light,
Based on the estimated spectral data of the wavelength band of the auxiliary light, quasi-reflectance information reflecting the reflectance of the observed portion in the wavelength band of the auxiliary light is obtained, and a special image is generated based on the quasi-reflectance information An image acquisition method characterized by:   The image acquiring method according to claim 1, wherein the observed part is administered with a medicine that absorbs light having the wavelength of the auxiliary light. An illumination light and a light irradiating means for simultaneously irradiating the observation part with auxiliary light having a wavelength band different from that of the illumination light, and an image composed of the reflected light of the illumination light and the reflected light of the auxiliary light in the observation part Imaging means for imaging;
Storage means for storing at least an estimation matrix for calculating estimated spectral data of the wavelength band of the auxiliary light;
Estimated spectral data calculation means for calculating estimated spectral data of the wavelength band of the auxiliary light using an image signal value and the estimation matrix for each pixel of the image signal output from the imaging means;
For each pixel, based on estimated spectral data of the wavelength band of the auxiliary light, quasi-reflectance information reflecting the reflectance of the observed portion in the wavelength band of the auxiliary light is obtained, and based on the quasi-reflectance information And an image processing means for generating a special image.   The image acquiring apparatus according to claim 3, wherein the observed part is administered with a medicine that absorbs light having a wavelength of the auxiliary light. The light irradiating means irradiates the observed part with reference light having a wavelength band different from that of the auxiliary light simultaneously with the irradiation of the auxiliary light,
The imaging means captures an image including reflected light of the reference light in the observed portion;
The image processing means calculates a reference light intensity that is an intensity of reflected light of the reference light from an image signal output from the imaging means, and divides the estimated spectral data of the wavelength band of the auxiliary light by the reference light intensity. The image acquisition apparatus according to claim 3, wherein the reflectance information is calculated by performing the operation.   The image processing means compares the semi-reflectance information with a predetermined reference value, and when the semi-reflectance information is larger than the reference value, increases the estimated spectral data of the wavelength band of the auxiliary light, 6. The image acquisition apparatus according to claim 3, wherein the special image is generated based on estimated spectral data of the increased wavelength band of the auxiliary light.   The image processing means compares the semi-reflectance information with a predetermined reference value, and when the semi-reflectance information is smaller than the predetermined reference value, increases the estimated spectral data of the wavelength band of the auxiliary light. 6. The image acquisition apparatus according to claim 3, wherein the special image is generated based on estimated spectral data of the increased wavelength band of the auxiliary light.   The image processing means compares the quasi-reflectance information with a predetermined reference value, and sets a value that saturates as an RGB image signal when the quasi-reflectance information is smaller than the predetermined reference value. The image acquisition apparatus according to claim 3, wherein the image acquisition apparatus generates an image.   The said image processing means produces | generates the special superimposition image which superimposed the said special image on the image produced | generated based on the image signal output from the said imaging means, Either of Claim 3 to 8 characterized by the above-mentioned. The image acquisition apparatus according to item 1.

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