JP4864325B2 - Image processing device - Google Patents

Description

  The present invention relates to an image processing apparatus in an electronic endoscope using autofluorescence.

  Autofluorescence that emits fluorescence by irradiating a living tissue with light (excitation light) having a specific wavelength such as ultraviolet rays is known. Further, it is known that the amount of fluorescent light is low in a lesion such as a cancer cell. An electronic endoscope system using this property is known (see Patent Document 1).

  That is, comparing the image when the reference light such as white light is irradiated with the image when the excitation light is irradiated, the image when the excitation light is irradiated is dark and the image when the reference light is irradiated is a bright region By performing signal processing for extracting the image and displaying a pseudo color image in which this region is colored, it is possible to identify the lesioned part.

  However, the pseudo color image flickers in the vicinity of the boundary between the colored region and the non-colored region. In addition, when a plurality of colors are used, flickering occurs near the boundary between the first color coloring area and the second color coloring area.

In addition, in the pseudo color image, the colored area is filled with a single color, so that the operability is poor. That is, in order to display the mapping of the colored region, it is necessary to switch to the image when the reference light is irradiated manually by the operator.
JP 2003-290130 A

  Accordingly, it is an object of the present invention to provide an image processing apparatus for an electronic endoscope that can prevent occurrence of flickering in a pseudo color image and reduce the complexity of an image switching operation by an operator.

  An image processing apparatus of the present invention includes an image signal acquisition unit that acquires an original image signal generated by imaging a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a living tissue, and an original image Based on filter means for removing noise components from the signal to generate filter image data, reference light filter image data generated when the reference light is irradiated, and autofluorescence filter image data generated when the excitation light is irradiated And image processing means for creating pseudo color image data. With such a configuration, noise components are removed from the generated image data, so that the boundary between the colored region and the non-colored region is stabilized and flickering is prevented.

  Switching means for switching light irradiating the subject to either reference light or excitation light, and an original image signal generated while the light irradiating the subject is switched to reference light as a reference light original image signal It is preferable to include an identification unit that identifies an original image signal generated while the light irradiated to the excitation light is switched to excitation light as an autofluorescence original image signal.

  The first colored region is detected based on the reference light filter image data and the autofluorescence filter image data, and the pseudo color image data is the first color in the reference light original image corresponding to the reference light original image signal generated when the reference light is irradiated. It is preferably created by performing image processing for emphasizing the first hue of one colored region on the reference light original image signal. With such a configuration, the first colored area is an image in which the first hue is emphasized without being displayed in a single color, the lesion area can be easily identified, and the mapping of the colored area can be confirmed by the pseudo color image. become.

  Normalizing the brightness of the autofluorescence filter image corresponding to the autofluorescence filter image data with reference to the reference light filter image corresponding to the reference light filter image data, and normalizing the autofluorescence with respect to the brightness of the pixels constituting the reference light filter image It is preferable to detect, as the first colored region, a pixel whose luminance ratio, which is a luminance ratio of pixels constituting the filter image, is lower than a predetermined first threshold value.

  Normalization obtains the maximum luminance ratio, which is the ratio of the maximum luminance in the luminance of the pixel constituting the reference light filter image to the maximum luminance in the luminance of the pixel constituting the auto fluorescent filter image, and each pixel constituting the auto fluorescent filter image Preferably, this is performed by multiplying the brightness of 1 by the maximum brightness ratio.

  A distribution creating means for creating a frequency distribution for the luminance of the pixels constituting the filter image corresponding to the filter image data is provided, and the normalization is a frequency of the luminance of the pixels constituting the auto fluorescent filter image corresponding to the auto fluorescent filter image data The average luminance ratio, which is the ratio of the average luminance in the frequency distribution of the luminance of the pixels constituting the reference light filter image corresponding to the reference light filter image data with respect to the average luminance in the distribution, is obtained, and the luminance of each pixel constituting the autofluorescent filter image Is preferably performed by multiplying by the average luminance ratio.

  Image processing in which the image processing means detects pixels of the fluorescent filter image whose luminance ratio is lower than a predetermined second threshold as a second colored region, and emphasizes the second hue of the second colored region in the reference light original image Is preferably performed on the reference light original image signal. With such a configuration, a region estimated to be a lesioned part and a region that may be a lesioned part can be painted in different colors, and diagnosis can be performed more easily.

  It is preferable that the filter means is any one of a median filter, a moving average filter, and a time axis average filter.

  On a monitor that displays a pseudo color image corresponding to the pseudo color image data, one or both of the reference light image corresponding to the reference light original image signal and the auto fluorescence image corresponding to the auto fluorescence original image signal are displayed in pseudo color. It is preferable to display it together with an image. Since the reference light image or the autofluorescence image is displayed together with the pseudo color image, it is not necessary to switch the displayed image in order to see the image of the lesion that is not colored.

  The image processing program of the present invention includes an image signal acquisition unit that acquires an original image signal generated by imaging a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a living tissue, and an original image Based on filter means for removing noise components from the signal to generate filter image data, reference light filter image data generated when the reference light is irradiated, and autofluorescence filter image data generated when the excitation light is irradiated The computer is caused to function as image processing means for creating pseudo color image data.

  An endoscope system according to the present invention includes an electronic endoscope having an imaging element that images a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a living tissue, and an original image signal generated by the imaging element Based on the filter that generates the filter image data by removing the noise component from the reference light, the reference light filter image data that is generated when the reference light is irradiated, and the autofluorescence filter image data that is generated when the excitation light is irradiated The image processing means for generating color image data and a monitor for displaying a pseudo color image corresponding to the pseudo color image data are provided.

  According to the present invention, it is possible to prevent flickering that occurs in the vicinity of a color-coded boundary that occurs in a pseudo color image created by a reference light image and an autofluorescence image. Further, it is not necessary to switch the image displayed for confirming the mapping of the region estimated to be a lesion.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram schematically showing an internal configuration of an endoscope system having an image processing apparatus to which an embodiment of the present invention is applied.

  The endoscope system 10 includes an endoscope processor 20, an endoscope 50, and a monitor 60. The processor 20 is connected to the endoscope 50 and the monitor 60. A light source system 21 that emits light for irradiating a subject is provided inside the processor 20. Light emitted from the light source system 21 is irradiated to a subject (not shown) via a light guide 51 provided in the endoscope 50.

  An image of a subject imaged by an imaging element 53 such as a CCD provided at the distal end of the insertion portion 52 of the endoscope 50 is sent to the processor 20 as an original image signal. The original image signal is subjected to predetermined processing in an image processing system 34 provided in the processor 20. The processor 20 can execute the functions of the image processing apparatus according to the present embodiment, and can generate pseudo color image data to be described later along with predetermined processing. The original image signal subjected to the predetermined processing is sent to the monitor 60, and an image corresponding to the original image signal is displayed on the monitor 60.

  The light source system 21 includes a reference light source 22 that emits reference light such as white light, an excitation light source 23 that emits light (excitation light) of a specific wavelength such as ultraviolet light, a condenser lens 24, a reference light source power circuit 25, and excitation. And a light source control circuit 26, a shutter 27, a diaphragm 28, and the like.

An aperture 28, a shutter 27, a dichroic mirror 29, and a condenser lens 24 are provided in the optical path for guiding the reference light emitted from the reference light source 22 to the incident end 51 _a of the light guide 51. Light of substantially parallel light flux emitted from the reference light source 22 passes through the dichroic mirror 29, is incident on the incident end 51 _a is condensed by the condenser lens 24.

The light amount adjustment of the reference light is executed by driving the diaphragm 28. The diaphragm 28 is driven by _a first motor 31 _a whose operation is controlled by a diaphragm driving circuit 30. Diaphragm driving circuit 30 is connected to the first signal processing circuit 35 _a. Based on the original image signal generated in the imaging device 53, in the first signal processing circuit 35 _a, the received light amount of an image captured is detected. The driving amount of the first motor 31 _a is obtained by the diaphragm driving circuit 30 according to the received light amount of the image.

The shutter 27 is, for example, a rotary shutter shown in FIG. 2, and is switched between passing and blocking of the reference light to the incident end 51 _a . When passing the reference light, the opening 27 _o is inserted into the optical path of the reference light. When the reference light is shielded, the light shielding portion 27 _s is inserted in the optical path of the reference light. The shutter 27 is driven by a second motor 31 _b whose operation is controlled by a shutter drive circuit 32.

The excitation light source 23 is fixed at a position where light of a substantially parallel light beam emitted from the excitation light source 23 is reflected by the dichroic mirror 29 and incident on the incident end 51 _a . For example, when the dichroic mirror 29 is fixed at an angle of 45 ° with respect to the optical path of the reference light source 22, the optical path of the excitation light source 23 is disposed at a position at an angle of 90 ° with respect to the optical path of the reference light source 22. Is done. Light emission and extinction of the excitation light source 23 are controlled by the excitation light source control circuit 26.

  The shutter drive circuit 32 and the excitation light source control circuit 26 are connected to the timing controller 40. A shutter timing signal for controlling the timing of passage and blocking of the reference light by the shutter 27 is output from the timing controller 40 to the shutter drive circuit 32. A light emission timing signal for controlling the timing of light emission and extinction of the excitation light source 23 is output from the timing controller 40 to the excitation light source control circuit 26.

The timing controller 40 outputs a shutter timing signal and a light emission timing signal so that the excitation light source 23 is turned off when the reference light is passed through the shutter 27 and the excitation light source 23 is caused to emit light when the reference light is blocked by the shutter 27. To do. In other words, the light to be irradiated on the subject is switched by the timing controller 40, the excitation light source control circuit 26, the shutter drive circuit 32, the second motor 31 _b , and the shutter 27 operating in cooperation.

  The timing controller 40 outputs a timing signal necessary for driving the image sensor 53 to the image sensor drive circuit 41. As will be described later, the timing controller 40 is connected to the image processing system 34. A predetermined timing signal is output to the image processing system 34.

  The power to the reference light source 22 is supplied from the reference light source power circuit 25. The reference light source power circuit 25 and the excitation light source control circuit 26 are connected to the system controller 33. By turning on the scope button 42 connected to the system controller 33, the reference light source power supply circuit 25 and the excitation light source control circuit 26 are activated.

As described above, the reference light or the excitation light is incident on the incident end 51 _a of the light guide 51. Light emitted from the emission end 51 _b of the light guide 51 is applied to the vicinity of the distal end of the insertion portion 52 through the light distribution lens 54. The image sensor 53 is controlled by the image sensor drive circuit 41 so as to capture at least one field of subject image while the reference light is continuously irradiated or while the excitation light is continuously irradiated. .

  The subject image is captured by the image sensor 53 via the objective lens 55 and the excitation light cut filter 56. The excitation light component is removed from the optical image of the subject by the excitation light cut filter 56. By removing the excitation light component, only the fluorescence component emitted from the biological tissue that is the subject when irradiated with the excitation light is imaged by the imaging element 53.

The image processing system 34 includes a first signal processing circuit 35 _a , a second signal processing circuit 35 _b , a filter processing circuit 36, a histogram calculation circuit 37, a pseudo color calculation circuit 38, and first and second memories 39 _a and 39 _b. Consists of.

Imaging device 53 is electrically connected to the first signal processing circuit 35 _a. Original image signal generated by the execution of the imaging operation of the image sensor 53 is acquired in the first signal processing circuit 35 _a. Thereafter, predetermined signal processing such as white balance processing and γ correction is performed and converted into original image data which is digital data.

The first signal processing circuit 35 _a is connected to the timing controller 40. Identifying timing signal is sent from the timing controller 40 to the first signal processing circuit 35 _a. The identification timing signal includes a reference timing signal synchronized with the shutter timing signal and a fluorescence timing signal synchronized with the light emission timing signal.

In the first signal processing circuit 35 _a, the original image signal between the reference timing signal is sent is recognized as a reference HikariHara image signals captured when irradiated with the reference light. On the other hand, the original image signal while the light emission timing signal is sent is recognized as an autofluorescence original image signal captured when the excitation light is irradiated.

The first signal processing circuit 35 _a, the first memory 39 _a and the second memory 39 _b are connected. Referring HikariHara image data corresponding to the reference HikariHara image is stored in the first memory 39 _a. Fluorogenic image data corresponding to autofluorescence original image is stored in the second memory 39 _b. First, second memory 39 _a, 39 _b is connected to the timing controller 40, receives the respective timing signals, reference HikariHara image data, and stores the autofluorescence original image data is executed.

The first signal processing circuit 35 _a is connected to the filter processing circuit 36. The reference light original image data and the autofluorescence original image data are also output to the filter processing circuit 36. In the filter processing circuit 36, noise components are removed from the original image data, and filter image data is formed. As the filter processing circuit 36, for example, a conventionally known filter circuit for removing noise components such as a median filter, a moving average filter, a time axis average filter, or the like is applied.

  The filter processing circuit 36 is connected to the histogram calculation circuit 37. Filter image data is sent to the histogram calculation circuit 37. Based on the filter image data, a histogram of luminance of the reference light filter image which is the reference light original image from which the noise component has been removed (see reference numeral R in FIG. 3) or the home from which the noise component has been removed. A brightness histogram (see reference numeral F in FIG. 3) of the autofluorescence filter image that is the fluorescence original image is created.

  The histogram calculation circuit 37 is connected to the pseudo color calculation circuit 38. In the pseudo color arithmetic circuit 38, an area estimated to be a lesion is identified based on the histogram F of the autofluorescence filter image and the histogram R of the reference light filter image. Further, in the pseudo color arithmetic circuit 38, the coloring process for the region estimated to be a lesion is performed on the reference light filter image data.

  A description will be given of identification of a region estimated to be a lesion and coloring processing. As described above, the fluorescence emitted from the living tissue that is the lesioned part is lower than that of the living tissue that is the healthy part. Therefore, it is possible to estimate that a region where the luminance of the fluorescent filter image is relatively low compared to the reference light filter image is a lesion.

First, a maximum fluorescence luminance B _maxF that is the maximum value of the luminance distribution in the histogram F of the auto-fluorescent filter image and a maximum reference luminance B _maxR that is the maximum value of the luminance distribution in the histogram R of the reference light filter image are obtained ( (See FIG. 3).

Next, each pixel of the autofluorescence filter image is normalized so that the maximum fluorescence brightness B _maxF matches the maximum reference brightness B _maxR . That is, by multiplying the maximum reference beam intensity B _maxR to the luminance of each pixel of the autofluorescence filter image, the normalization is performed by dividing the maximum fluorescence intensity B _maxF. Next, in each pixel, a discriminant value obtained by dividing the luminance of the normalized auto-fluorescent filter image by the luminance of the reference light filter image is obtained.

  It is determined whether or not it is a lesioned part by comparing the determination value with a first threshold value and a second threshold value stored in a ROM (not shown). It is determined that a pixel having a determination value lower than the first threshold is displaying an area that is likely to be a lesion. A pixel having a determination value equal to or higher than the first threshold and lower than the second threshold is determined to display an area having a relatively high possibility of being a lesion. Further, it is determined that a pixel having a determination value equal to or greater than the second threshold is displaying a region that is estimated to be a healthy part.

  Next, a coloring process of the reference light filter image is performed. The reference light filter image data is displayed in such a manner that a pixel whose discrimination value is lower than the first threshold is displayed in red as a lesion display pixel, and a pixel that is equal to or higher than the first threshold and lower than the second threshold is displayed in yellow as a caution display pixel. A coloring process is performed.

The pseudo color arithmetic circuit 38 is connected to the second signal processing circuit 35 _b . The pseudo color image data obtained by performing the coloring process on the reference light filter image data is output to the second signal processing circuit 35 _b . In the second signal processing circuit _35b , the pseudo color image data is converted into an analog signal, and predetermined signal processing such as clamping and blanking processing is performed to generate a pseudo color video signal.

The second signal processing circuit 35 _b is connected to the monitor 60. A pseudo color video signal is output from the second signal processing circuit 35 _b to the monitor 60, and a pseudo color image as shown in FIG. 4 is displayed on the entire display surface of the monitor 60. Lesion guess region A _S suspected of lesion is displayed in red. High note region A _C be a lesion is displayed in yellow. The area | region estimated as a healthy part other than that is displayed with the color of the state irradiated with the reference light.

The second signal processing circuit 35 _b is also connected to the first memory 39 _a and the second memory 39 _b . The reference light original image data stored in the first memory 39 _a or the second memory 39 _b stored autofluorescence original image data is also in the second signal processing circuit 35 _b, is performed signal processing described above, each reference beam a video signal, and the autofluorescence video signal is generated.

Images to be displayed in the display area of the monitor 60 by the input to the scope button 42 or an input unit (not shown) on the front panel of the processor 20 are the pseudo color image P _C , the reference light image P _R , and the autofluorescence image P _F. It is possible to switch to either of these. Or, as shown in FIGS. 5 and 6, the pseudo-color image P _C, the reference light image P _R, and any two of autofluorescence image P _F, or choose to display all at the same time is also possible.

On the monitor 60, when displaying a plurality of images, the second signal processing circuit 35 _b, allocation or area for displaying each image, image reduction process is performed. The timing controller 40 is connected to the second signal processing circuit 35 _b. The image switching process in the second signal processing circuit 35 _{b and} the above-described process for displaying a plurality of images are performed based on the timing signal output from the timing controller 40.

  Next, image processing executed in the image processing apparatus will be described with reference to the flowchart of FIG.

The image processing of this embodiment is started by switching to the setting for displaying the pseudo color image on the monitor 60. First, in step S100, and outputs a shutter timing signal for driving the shutter 27 so as to insert the opening 27 _a of the shutter 27 in the optical path of the reference light to the shutter driving circuit 32. The shutter 27 is driven by the output of the shutter timing signal, and the light that irradiates the subject is switched to the reference light.

  In the next step S101, the image sensor 53 is driven to capture the reference light image of the subject irradiated with the reference light, and the process proceeds to step S102. In step S102, predetermined signal processing is performed on the reference light original image signal generated by imaging to generate reference light original image data which is digital data.

In step S103, the reference HikariHara image data stored in the first memory 39 _a, the process proceeds to step S104. In step S104, the reference light filter image data is generated by performing filtering on the reference light original image data. In the next step S105, a histogram for the luminance of the pixels constituting the reference light filter image is created based on the reference light filter image data.

  In step S106, a light emission timing signal for emitting excitation light is output to the excitation light source control circuit 26. The excitation light source control circuit 26 switches the excitation light source 23 to the light emitting state, and proceeds to step S107. In step S107, the image sensor 53 is driven to capture an autofluorescence image of the subject irradiated with the excitation light, and the process proceeds to step S108. In step S108, the autofluorescence original image signal generated by the imaging is subjected to predetermined signal processing to generate autofluorescence original image data that is digital data.

In step S109, stores the autofluorescence original image data in the second memory 39 _b, the process proceeds to step S110. In step S110, the autofluorescence original image data is filtered to generate autofluorescence filter image data. In the next step S111, a histogram for the luminance of the pixels constituting the autofluorescence filter image is created based on the autofluorescence filter image data.

In the next step S112, the autofluorescence filter image is normalized based on the reference light filter image. First, the maximum reference brightness B _maxR of the histogram R based on the reference light filter image and the maximum fluorescence brightness B _maxF of the histogram based on the autofluorescence filter image are _obtained . Then the brightness of each pixel constituting the autofluorescence filtered image, multiplied by the maximum reference brightness B _maxR, by dividing the maximum fluorescence intensity B _maxF, the normalization is performed.

  In the next step S113, the discriminant value is obtained by dividing the luminance of each pixel constituting the normalized auto-fluorescent filter image by the luminance of each pixel constituting the reference light filter image. When the discriminant value is obtained, the process proceeds to step S114, and it is discriminated whether each pixel is the first or second colored region. A pixel having a determination value obtained in step S113 that is smaller than the first threshold is determined as a first colored region, and a pixel that is greater than or equal to the first threshold and smaller than the second threshold is determined as a second colored region.

  In step S115, pseudo color image data is obtained by performing image processing so that the pixel corresponding to the first colored region in the reference light filter image data is red and the pixel corresponding to the second colored region is yellow. Create

Proceeds to step S116, the display on the monitor 60, the reference light image P _R, and one of the autofluorescence image P _F, or whether there is a selection input for a plurality display mode for displaying the pseudo-color image P _C with both Confirm. If there is a selection input for a plurality of display modes, the process proceeds to step S117, where an area for displaying each image is assigned and image reduction processing is performed.

  If there is no selection input for the multiple display mode in step S116, or after the process of step S117, the process proceeds to step S118. In step S118, pseudo color image data or data for displaying a plurality of images is output to the monitor 60 as a video signal. In the next step S119, if there is an end input, the image processing by this program ends. If there is no end input, the process returns to step S100, and the processes in steps S100 to S119 are repeated until there is an end input.

  As described above, according to the endoscope system having the image processing apparatus of the present embodiment, a pseudo color image without flickering is displayed on the monitor 60, so that the diagnostic ability of the user is improved. Even noise that does not cause recognizable flicker in the reference light image or the fluorescence image is considered to have caused flicker near the boundary of the color coding of the pseudo color image. Therefore, by removing such noise, it is possible to obtain a pseudo color image in which the occurrence of flickering is suppressed.

Further, the pseudo-color image can be displayed either one or both of the reference light image P _R and autofluorescence image P _F on the monitor 60. Therefore, by keeping to display the plurality of images including the pseudo color image on the monitor 60, the switching input of the image for confirmation of the reference light image P _R is not required.

In the present embodiment, the autofluorescence filter image is normalized so that the maximum fluorescence luminance matches the maximum reference luminance. However, the average value B _aveF of the luminance distribution in the histogram F ′ of the autofluorescence filter image is _expressed as _follows : It is also possible to carry out so as to match the average value B _aveR of the luminance distribution in the histogram R ′ of the reference light filter image (see FIG. 8).

When the reference light original image causes halation, normalization cannot be performed with the maximum luminance as shown in FIG. On the other hand, according to the normalization that matches the average value, it is possible to normalize the auto-fluorescent filter image even when the reference light original image is halated.

  In the present embodiment, the coloring process is performed on the reference light filter image data. However, the coloring process may be performed on the reference light original image data.

  In the present embodiment, the first and second coloring regions are colored with different single colors. However, the first and second colors may be emphasized in hue. With the configuration that emphasizes the hues of the first and second colors, the mapping in the first and second colored areas is displayed, so that it is not necessary to switch the image to confirm the mapping of the lesion estimated area. .

  Further, the image processing apparatus to which the present embodiment is applied can be configured by causing a general-purpose image processing apparatus including a reference light source and an excitation light source to read a pseudo color image creation program.

1 is a block diagram schematically showing an internal configuration of an endoscope system having an image processing apparatus to which an embodiment of the present invention is applied. FIG. It is a top view of a shutter. It is a histogram which shows the luminance distribution of a reference light filter image and an autofluorescence filter image. It is a figure which shows the state by which the pseudo color image was displayed on the monitor. It is a figure which shows the state by which the pseudo color image and the reference light image were displayed on the monitor. It is a figure which shows the state by which the pseudo color image, the reference light image, and the autofluorescence image were displayed on the monitor. 5 is a flowchart for explaining an image processing operation by the image processing apparatus. It is another histogram which shows the luminance distribution of a reference light filter image and an autofluorescence filter image.

Explanation of symbols

10 endoscopic system 20 endoscope processor 21 light source system 22 the reference light source 23 for excitation light source 25 for reference light source power supply circuit 26 for excitation light source control circuit 27 a shutter 32 shutter driving circuit 34 the image processing system 35 _a, 35 _b first , Second signal processing circuit 36 filter processing circuit 37 histogram calculation circuit 38 pseudo color calculation circuit 39 _a , 39 _b first and second memory 40 timing controller 41 image sensor driving circuit 50 endoscope 51 light guide 51 _a incident end 51 _b exit end 53 imaging device 60 monitors A _C Note area A _S lesion guess region P _C pseudocolor image P _R reference light image P _F autofluorescence image

Claims (7)

Image signal acquisition means for acquiring an original image signal generated by imaging a subject irradiated with excitation light that emits fluorescence when irradiated with reference light and biological tissue;
A moving average filter that removes noise components from the original image signal to generate filter image data;
Imaging the reference light filter image data that is the filter image data based on the reference light original image signal that is the original image signal generated by imaging the subject irradiated with the reference light, and the subject irradiated with the excitation light Image processing means for creating pseudo color image data based on the auto-fluorescence filter image data that is the filter image data based on the fluorescence original image signal that is the original image signal generated by
Based on the reference light filter image corresponding to the reference light filter image data, the brightness of the auto fluorescent filter image corresponding to the auto fluorescent filter image data is normalized,
Pixels whose luminance ratio, which is the ratio of the luminance of the pixels constituting the normalized auto-fluorescent filter image to the luminance of the pixels constituting the reference light filter image, is lower than a predetermined first threshold value Detect as
The pseudo color image data is created by performing image processing for emphasizing the first hue of the first colored region on the reference light original image signal in the reference light original image corresponding to the reference light original image signal. An image processing apparatus characterized in that: Switching means for switching light irradiating the subject to either the reference light or the excitation light;
An original image signal generated while the light illuminating the subject is switched to the reference light is used as a reference light original image signal, and the light irradiating the subject is generated while the excitation light is switched to the excitation light. The image processing apparatus according to claim 1, further comprising: a recognition unit that recognizes an original image signal as an autofluorescence original image signal. The normalization is
Obtaining a maximum luminance ratio which is a ratio of the maximum luminance in the luminance of the pixels constituting the reference light filter image to the maximum luminance in the luminance of the pixels constituting the autofluorescent filter image;
The image processing apparatus according to claim 1, wherein the image processing device is performed by multiplying the luminance of each pixel constituting the auto-fluorescent filter image by the maximum luminance ratio. The image processing means
Detecting the pixel of the fluorescent filter image whose luminance ratio is lower than a predetermined second threshold as a second colored region;
The image processing apparatus according to claim 1, wherein image processing for enhancing a second hue of the second colored region in the reference light original image is performed on the reference light original image signal.   One or both of a reference light image corresponding to the reference light original image signal and an autofluorescence image corresponding to the autofluorescence original image signal on a monitor that displays a pseudo color image corresponding to the pseudo color image data The image processing apparatus according to claim 1, wherein the image processing apparatus displays the image together with the pseudo color image. Image signal acquisition means for acquiring an original image signal generated by imaging a subject irradiated with excitation light that emits fluorescence when irradiated with reference light and biological tissue;
A moving average filter that removes noise components from the original image signal to generate filter image data;
Imaging the reference light filter image data that is the filter image data based on the reference light original image signal that is the original image signal generated by imaging the subject irradiated with the reference light, and the subject irradiated with the excitation light Based on the autofluorescence filter image data that is the filter image data based on the fluorescence original image signal that is the original image signal that is generated by causing the computer to function as image processing means that creates pseudo color image data,
Based on the reference light filter image corresponding to the reference light filter image data, the brightness of the auto fluorescent filter image corresponding to the auto fluorescent filter image data is normalized,
Pixels whose luminance ratio, which is the ratio of the luminance of the pixels constituting the normalized auto-fluorescent filter image to the luminance of the pixels constituting the reference light filter image, is lower than a predetermined first threshold value Detect as
The pseudo color image data is created by performing image processing for emphasizing the first hue of the first colored region on the reference light original image signal in the reference light original image corresponding to the reference light original image signal. An image processing program characterized by being executed. An electronic endoscope having an imaging element that images a subject irradiated with excitation light that emits fluorescence when irradiated with reference light and biological tissue;
A moving average filter that removes noise components from the original image signal generated by the image sensor and generates filter image data;
Imaging the reference light filter image data that is the filter image data based on the reference light original image signal that is the original image signal generated by imaging the subject irradiated with the reference light, and the subject irradiated with the excitation light Image processing means for creating pseudo color image data based on the auto-fluorescent filter image data which is the filter image data based on the fluorescence original image signal which is the original image signal generated by
A monitor that displays a pseudo color image corresponding to the pseudo color image data,
Based on the reference light filter image corresponding to the reference light filter image data, the brightness of the auto fluorescent filter image corresponding to the auto fluorescent filter image data is normalized,
Pixels whose luminance ratio, which is the ratio of the luminance of the pixels constituting the normalized auto-fluorescent filter image to the luminance of the pixels constituting the reference light filter image, is lower than a predetermined first threshold value Detect as
The pseudo color image data is created by performing image processing for emphasizing the first hue of the first colored region on the reference light original image signal in the reference light original image corresponding to the reference light original image signal. An electronic endoscope system characterized by being made.

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