JP2006192058A - Image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent flickering of a pseudo color image using autofluorescence.
An endoscope processor (20) includes a reference light source (22), an excitation light source (23), a first signal processing circuit (35a), _a histogram calculation circuit (37), and a pseudo color calculation circuit (38). By connecting the endoscope processor 20 to the endoscope 50, to connect the imaging element 53 to the first signal processing circuit 35 _a. The image sensor 53 generates an image signal. The first signal processing circuit 35 _a histogram calculation circuit 37 sends the pseudo-color operation circuit 38 an image signal as image data. The pseudo color arithmetic circuit creates pseudo color image data whose hue gradually changes based on the reference light image data and the fluorescence image data.
[Selection] Figure 1

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 pixel By performing signal processing for extracting the image and displaying a pseudo color image in which the pixels are colored, it is possible to identify the lesioned part.

  However, the pseudo color image flickers around the boundary between the colored pixels and the non-colored pixels. In addition, when a plurality of colors are used, flickering occurs near the boundary between the first color pixel and the second color pixel.

Further, in the pseudo color image, since the colored pixels are filled with a single color, the operability is poor. That is, in order to display the mapping of the colored pixels, 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 according to the present invention includes an image signal acquisition unit that acquires an image signal generated by imaging a subject irradiated with a reference light or an excitation light that emits fluorescence when irradiated on a biological tissue, and irradiates the reference light. The fluorescence of each region constituting the autofluorescence image corresponding to the fluorescence image signal generated when irradiating the reference light luminance and the excitation light generated when irradiating the excitation light with the reference light luminance corresponding to the reference light image corresponding to the reference light image signal generated when Relative luminance calculating means for determining luminance and calculating relative luminance that is the other magnitude of either reference light luminance or fluorescent luminance in the same region, and a region in which the first hue changes according to the relative luminance. And image processing means for creating pseudo color image data corresponding to the pseudo color image. With such a configuration, a pseudo color image in which the color gradually changes is created, thereby preventing the occurrence of flicker near the boundary of the colored pixels.

  The positions in the pseudo color image of each of the areas constituting the pseudo color image are preferably the same positions as the areas corresponding to the reference light luminance or the fluorescence luminance used for calculating the relative luminance corresponding to the area.

  A reference light luminance is provided that includes a normalizing unit that normalizes the luminance of the other image with reference to either the reference light image or the autofluorescent image, and the image processing unit normalizes either the reference light luminance or the fluorescent luminance. Alternatively, it is preferable to calculate the relative luminance by replacing the normalized fluorescence luminance. By performing normalization, substantially the same relative luminance can be obtained even when the amount of reference light is changed by the diaphragm.

  Normalization is either the reference light image or the autofluorescence image, and is the ratio of the maximum brightness in the brightness of the area constituting the other image to the maximum brightness in the brightness of the area constituting the normalization image. This is preferably performed by obtaining a luminance ratio and multiplying the luminance of each region constituting the image to be normalized by the maximum luminance ratio.

  Alternatively, a distribution creating means for creating a frequency distribution with respect to the luminance of the regions constituting the reference light image and the autofluorescence image is provided, and normalization is performed using either the reference light image or the autofluorescence image. The luminance of each area constituting the image to be normalized by calculating the average luminance ratio, which is the ratio of the average luminance in the frequency distribution of the luminance of the area constituting the other image to the average luminance in the luminance frequency distribution of the area constituting the image Is preferably performed by multiplying the above average luminance ratio.

  The image processing means performs a signal process for changing the first hue of the region corresponding to the relative luminance in the reference light image or the autofluorescence image on the reference light image signal or the fluorescence image signal according to the relative luminance, and the pseudo color image It is preferable to create data.

  Preferably, the image processing means changes the second hue of the area constituting the pseudo color image according to the relative luminance.

  Switching means for switching light for irradiating the subject to either reference light or excitation light, and irradiating the subject with the image signal generated while the light irradiating the subject is switched to the reference light as the reference light image signal It is preferable to comprise a recognition means for recognizing an image signal generated while the light to be switched to the excitation light as a fluorescent image signal.

  It is preferable to display either one or both of the reference light image and the autofluorescence image together with the pseudo color image on the monitor that displays the pseudo color image. Since the reference light image or autofluorescence image is displayed together with the pseudo color image, it is not necessary to switch the image displayed on the monitor in order to see the image of the lesioned part.

  An image processing program according to the present invention includes an image signal acquisition unit that acquires an image signal generated by imaging a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a living tissue, and irradiates the reference light. The fluorescence of each region constituting the autofluorescence image corresponding to the fluorescence image signal generated when irradiating the reference light luminance and the excitation light generated when irradiating the excitation light with the reference light luminance corresponding to the reference light image corresponding to the reference light image signal generated when Relative luminance calculating means for determining luminance and calculating relative luminance that is the other magnitude of either reference light luminance or fluorescent luminance in the same region, and a region in which the first hue changes according to the relative luminance. The computer is caused to function as image processing means for creating pseudo color image data corresponding to a pseudo color image.

  The endoscope system of the present invention is generated when an electronic endoscope having an image sensor that images a subject irradiated with excitation light that emits fluorescence when irradiated with reference light or biological tissue, and when the reference light is irradiated. The reference light luminance for each region constituting the reference light image corresponding to the reference light image signal and the fluorescence luminance for each region constituting the autofluorescent image corresponding to the fluorescent image signal generated when the excitation light is irradiated are the same. A pseudo-color image composed of a relative luminance calculation means for obtaining a relative luminance that is the other magnitude of either the reference light luminance or the fluorescent luminance in the region, and a region in which the first hue changes according to the relative luminance. The image processing means for generating the corresponding pseudo color image data and a monitor for displaying the pseudo color image 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 site 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 image signal. The 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 image signal on which the predetermined processing has been performed is sent to the monitor 60, and an image corresponding to the 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 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 reference light is shielded by the shutter 27 when the excitation light source 23 is caused to emit light. 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 frame of the 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 histogram calculation circuit 37, a pseudo color calculation circuit 38, and first and second memories 39 _a and 39 _b .

Imaging device 53 is electrically connected to the first signal processing circuit 35 _a. 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. Then, predetermined signal processing such as white balance processing and γ correction is performed in the first signal processing circuit 35 _a, and is converted into image data which is digital data.

The first signal processing circuit 35 _a is connected to the timing controller 40. From the timing controller 40 to the first signal processing circuit 35 _a, fluorescent timing signal synchronized with the light emission timing signal to the reference timing signal synchronized with the shutter timing signal, and the excitation light source to emit light for passing reference light alternately Sent to.

In the first signal processing circuit 35 _a, image signals between the reference timing signal is sent is recognized as the reference light image signal obtained by imaging when irradiated with the reference light. On the other hand, the image signal while the fluorescence timing signal is sent is recognized as a fluorescence image signal captured when the excitation light is irradiated.

The first signal processing circuit 35 _a is connected to the first memory 39 _a and the second memory 39 _b . The reference light image data corresponding to the reference light image is stored in the first memory 39 _a. Fluorescence image data corresponding to the autofluorescence image is stored in the second memory 39 _b. The first and second memories 39 _a and 39 _b are connected to the timing controller 40, and receive the respective timing signals to store the reference light image data and the fluorescence image data.

The first signal processing circuit 35 _a is connected to the histogram calculation circuit 37. The reference light image data and the fluorescence image data are also output to the histogram calculation circuit 37. Based on the reference light image data or the fluorescence image data, in the histogram calculation circuit 37, the luminance histogram of the reference light image (see FIG. 3, symbol R) or the luminance histogram of the autofluorescent image (see FIG. 3, symbol F). ) Is created.

  The histogram calculation circuit 37 is connected to the pseudo color calculation circuit 38. In the pseudo color arithmetic circuit 38, pseudo color image data corresponding to the pseudo color image is created based on the reference light image data, the fluorescence image data, the brightness histogram of the reference light image, and the brightness histogram of the autofluorescence image. . In creating pseudo color image data, normalization processing, relative luminance calculation processing, and pseudo color image creation processing are performed.

In the normalization process, first, a maximum fluorescence brightness B _maxF that is the maximum value of the brightness distribution in the histogram F of the autofluorescence image and a maximum reference brightness B _maxR that is the maximum value of the brightness distribution in the histogram R of the reference light image are obtained. It is done.

Next, the brightness of each pixel (region) of the autofluorescence 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 image, the normalization is performed by dividing the maximum fluorescence intensity B _maxF.

  In the relative brightness calculation process, the relative brightness is a ratio of the brightness (fluorescence brightness) of the autofluorescence image that has been normalized to the brightness of the reference light image (reference light brightness), and is the reference light image and autofluorescence. It is calculated for each pixel at the same position in the entire image in the image.

  Next, a pseudo color image is created as pseudo color image data based on the relative luminance. The color of each pixel constituting the pseudo color image is determined by the relative luminance corresponding to the pixel position. Note that the position of each pixel constituting the pseudo color image is determined to be the same position as the position of the pixel corresponding to the reference light luminance or the fluorescence luminance used for calculating the corresponding relative luminance.

  The red hue (first hue) is enhanced as the relative luminance of the pixels constituting the pseudo color image decreases, while the green hue (second hue) is enhanced as the relative luminance increases. Accordingly, the pseudo color image data is created so that the color of each pixel gradually changes from red to orange, yellow, yellow-green, and green as the relative luminance changes from 0 to 100. Note that the degree of red and green hues to be emphasized according to the relative luminance is determined in advance and stored in a ROM (not shown).

The pseudo color arithmetic circuit 38 is connected to the second signal processing circuit 35 _b . Pseudo-color 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.

  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 pixel having a relatively low luminance of the autofluorescence image compared to the reference light image, that is, a pixel having a low relative luminance is a lesion. Therefore, in the pseudo color image, it is indicated that the pixel with the red hue emphasized has a higher possibility of being a lesion, and the pixel with the green hue emphasized has a higher possibility of being a healthy part. It shows that it becomes.

The second signal processing circuit 35 _b is also connected to the first memory 39 _a and the second memory 39 _b, and is stored in the reference light image data stored in the first memory 39 _a or the second memory 39 _b . The above-described fluorescent image data is also subjected to the above-described signal processing in the second signal processing circuit 35 _b to generate a reference light video signal and a fluorescent video signal, respectively.

The inputs to the input section (not shown), it is possible to switch the image displayed in the display area of the monitor 60 pseudo-color image P _C, the reference light image P _R, and either the autofluorescence image P _F. 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 and position to display 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 it outputs a shutter timing signal for driving the shutter 27 so as to insert the opening 27 _o 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 image signal generated by imaging to generate reference light image data that is digital data.

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

  In step S105, 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 emission state, and proceeds to step S106. In step S106, 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 S107.

In step S107, predetermined signal processing is performed on the fluorescent image signal generated by the imaging to generate fluorescent image data that is digital data. In the next step S108, stores the fluorescent image data in the second memory 39 _b, the process proceeds to step S109. In step S109, a histogram for the luminance of the pixels constituting the autofluorescence image is created based on the fluorescence image data.

In the next step S110, the luminance value of the autofluorescence image is normalized based on the luminance value of the reference light image. First, the maximum reference brightness B _maxR of the histogram R of the reference light image (see FIG. 3) and the maximum fluorescence brightness B _maxF of the histogram F of the autofluorescence image are _obtained . Then the brightness of each pixel constituting the autofluorescence 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 S111, a relative luminance, which is a ratio of the luminances of the respective pixels constituting the autofluorescent image that has been normalized with respect to the luminance of the respective pixels constituting the reference light image, is obtained. When the relative luminance is obtained, the process proceeds to step S112, and pseudo color image data corresponding to a pseudo color image in which the red hue is emphasized as the relative luminance decreases and the green hue is emphasized as the relative luminance increases is created.

In step S113, whether the display on the monitor 60, the reference light image P _R, and one of the autofluorescence image P _F, or there is a selection input for a plurality display mode for displaying the pseudo-color image P _C with both To check. If there is a selection input for a plurality of display modes, the process proceeds to step S114, where each image display position is assigned and image reduction processing is performed.

  If there is no selection input for the multiple display mode in step S113, or after the process of step S114, the process proceeds to step S115. In step S115, 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 S116, if there is an end input, the image processing by this program is ended. If there is no end input, the process returns to step S100, and the processes in steps S100 to S116 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. Thereby, a user's diagnostic property improves. Although the human eye is sensitive to brightness contrast, it is not sensitive to changes in saturation, so by changing the color step by step, a single color was colored, especially in conventional pseudo-color images. It is possible to suppress flickering that occurs near the boundary.

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 image is normalized so that the maximum fluorescence brightness matches the maximum reference brightness. The average value B _aveF of the brightness distribution in the histogram F ′ of the autofluorescence image is _used as the reference light. 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 image.

  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 this embodiment, the pseudo color image data is newly created based on the relative luminance. However, the pseudo color image data may be created by performing data processing on the reference light image data. . The pseudo-color image in the present embodiment is an image that displays in a different color from a site that is estimated as a lesioned part to a site that is estimated as a healthy part in the reference light image and the autofluorescence image, and an image that displays the subject image itself. is not.

  However, if the hue of each pixel in the reference light image is changed according to the relative luminance to enhance the red hue or the green hue, a pseudo color image that is a colored image of the captured subject image Can be created. With such a configuration, since the subject image is displayed, it is not necessary to switch the image for confirming the mapping of the part estimated as the lesioned part. A configuration in which hue enhancement processing is performed on fluorescence image data according to relative luminance may be employed.

  In the present embodiment, the pseudo color image is created by changing the hues of red and green according to the relative luminance. However, any color may be used, or a single color may be used. Even if it is the structure which changes a hue, and the structure which changes the hue of three or more colors, it has the effect of this invention.

  In the present embodiment, the relative luminance is a ratio of the luminance of the autofluorescent image to the luminance of the reference light image, but is the ratio of the luminance of the reference light image to the luminance of the autofluorescent image in the same pixel. May be. In such a configuration, the pseudo color image data is created so that a pseudo color image in which the red hue is enhanced as the relative luminance increases and the green hue is enhanced as the relative luminance decreases.

  In the present embodiment, the relative luminance is a ratio of the luminance of the autofluorescent image to the luminance of the reference light image. However, the luminance of the autofluorescent image with respect to the luminance of the reference light image in the same pixel is set. The relative brightness can be expressed as the difference between the brightness of the reference light image and the brightness of the autofluorescence image, or the brightness decrease rate obtained by dividing the difference between the brightness of the reference light image and the brightness of the autofluorescence image by the brightness of the reference light image. It can also be used to create pseudo color image data.

  In the present embodiment, the luminance of each pixel of the autofluorescence image is normalized, but the luminance of each pixel of the reference light image may be normalized. In the configuration in which the luminance of each pixel of the reference light image is normalized, the relative luminance is calculated as a ratio of the luminance of the autofluorescent image to the luminance of the normalized reference light image. Alternatively, the relative luminance is calculated as any variable indicating the magnitude of the luminance of the autofluorescence image with respect to the luminance of the normalized reference light image in the same image as described above. The normalization of the luminance of the reference light image may be normalized so that the maximum reference luminance matches the maximum fluorescence luminance, or may be normalized so that the average value of the luminance matches as described above.

  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 image and an autofluorescence 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 image and an autofluorescence 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 37 histogram operation circuit 38 pseudo color operation circuit 39 _a , 39 _b first and second memory 40 timing controller 41 image sensor drive circuit 50 endoscope 51 light guide 51 _a incident end 51 _b emission end 53 the imaging device 60 monitors P _C pseudocolor image P _R reference light image P _F autofluorescence image

Claims (11)

Image signal acquisition means for acquiring an image signal generated by imaging a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a biological tissue;
Reference light luminance for each region constituting the reference light image corresponding to the reference light image signal generated when the reference light is irradiated, and autofluorescence image corresponding to the fluorescence image signal generated when the excitation light is irradiated Relative luminance calculation means for obtaining a relative luminance that is the other magnitude of either the reference light luminance or the fluorescent luminance in the same region,
An image processing apparatus comprising: image processing means for generating pseudo color image data corresponding to a pseudo color image configured by a region in which the first hue changes according to the relative luminance.   The position in the pseudo color image of each area constituting the pseudo color image is the same position as the area corresponding to the reference light luminance or the fluorescence luminance used for the calculation of the relative luminance corresponding to the area. The image processing apparatus according to claim 1, wherein: Normalizing means for normalizing the brightness of the other image based on one of the reference light image or the autofluorescence image,
The image processing means replaces either the reference light luminance or the fluorescent luminance with the normalized reference light luminance or the normalized fluorescent luminance, and calculates the relative luminance. The image processing apparatus according to claim 1. The normalization is
The maximum which is the ratio of the maximum luminance in the luminance of the area constituting the other image to the maximum luminance in the luminance of the area constituting the image that is either the reference light image or the autofluorescence image and constitutes the normalization image Find the luminance ratio,
The image processing apparatus according to claim 3, wherein the image processing apparatus is performed by multiplying the luminance of each region constituting the image to be normalized by the maximum luminance ratio. A distribution creating means for creating a frequency distribution of the luminance of the region constituting the reference light image and the autofluorescence image;
The normalization is
In the frequency distribution of the luminance of the region constituting the other image with respect to the average luminance in the luminance frequency distribution of the region constituting the image to be normalized, which is either the previous reference light image or the autofluorescence image Find the average brightness ratio, which is the ratio of the average brightness,
The image processing apparatus according to claim 3, wherein the image processing apparatus is performed by multiplying the luminance of each region constituting the image to be normalized by the average luminance ratio. The image processing means
In accordance with the relative luminance, signal processing for changing the first hue of the region corresponding to the relative luminance in the reference light image or the autofluorescence image is performed on the reference light image signal or the fluorescence image signal. The image processing apparatus according to claim 1, wherein pseudo color image data is created.   The image processing apparatus according to claim 1, wherein the image processing unit changes a second hue of a region constituting the pseudo color image according to the relative luminance. Switching means for switching light irradiating the subject to either the reference light or the excitation light;
An image signal generated while light applied to the subject is switched to the reference light is used as the reference light image signal, and generated while the light applied to the subject is switched to the excitation light. The image processing apparatus according to claim 1, further comprising a recognition unit that recognizes an image signal as the fluorescent image signal.   The image processing apparatus according to claim 1, wherein one or both of the reference light image and the autofluorescence image are displayed together with the pseudo color image on a monitor that displays the pseudo color image. Image signal acquisition means for acquiring an image signal generated by imaging a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a biological tissue;
A reference light luminance for each region constituting a reference light image corresponding to a reference light image signal generated when the reference light is irradiated and an autofluorescence image corresponding to a fluorescent image signal generated when the excitation light is irradiated. A relative luminance calculation means for obtaining a fluorescence brightness for each of the areas to be configured, and for obtaining a relative brightness that is the other magnitude of either the reference light brightness or the fluorescence brightness in the same area;
An image processing program for causing a computer to function as image processing means for creating pseudo color image data corresponding to a pseudo color image configured by an area in which a first hue changes according to the relative luminance. An electronic endoscope having an imaging element for imaging a subject irradiated with reference light or excitation light that emits fluorescence when irradiated on a biological tissue;
A reference light luminance for each region constituting a reference light image corresponding to a reference light image signal generated when the reference light is irradiated and an autofluorescence image corresponding to a fluorescent image signal generated when the excitation light is irradiated. A relative luminance calculation means for obtaining a fluorescence brightness for each of the areas to be configured, and for obtaining a relative brightness that is the other magnitude of either the reference light brightness or the fluorescence brightness in the same area;
Image processing means for creating pseudo color image data corresponding to a pseudo color image constituted by a region in which the first hue changes according to the relative luminance;
An electronic endoscope system comprising: a monitor that displays the pseudo color image.

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