JP2012110481A - Endoscope apparatus, focus control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope apparatus capable of performing suitable autofocus even for a subject of low contrast, and a focus control method, a program, etc.SOLUTION: The endoscope apparatus includes a first image acquiring part, a second image acquiring part, and a focus control part 150. The first image acquiring part acquires, as a first image, an image of the subject in a living body imaged by an imaging optical system and including a subject image having information in a wavelength band of white light. The second image acquiring part acquires, as a second image, an image including the subject image having information in a specific wavelength band corresponding to the first image. The focus control part 150 performs control of focusing on the subject image in the second image to make a focus adjustment of the imaging optical system. The first image acquiring part acquires the first image imaged by the focus-adjusted imaging optical system.

Description

  The present invention relates to an endoscope apparatus, a focus control method, a program, and the like.

  A contrast detection method is widely known as an autofocus method for automatically focusing on a subject. In this method, images are captured while changing the position of the lens, and an evaluation value is calculated based on the contrast of these images. Then, the position of the lens having the maximum evaluation value is determined, and it is determined that the position is the most focused position.

JP 2004-118141 A

  However, in the contrast detection method, in the case of a scene that originally does not have much contrast, there is a problem that a difference in contrast is small between the best focus position (focus position) and the other focus position. In this case, since the change in the evaluation value is small even if the lens position is changed, it is difficult to obtain a focused position and it is difficult to perform appropriate autofocus.

  For example, in an endoscope apparatus, the inside of a living body is mainly observed, but the inside of the living body often has low contrast. For this reason, there is a possibility that the autofocus cannot be appropriately performed on the inside of the living body by the contrast detection method.

  Japanese Patent Application Laid-Open No. 2004-133620 discloses a method of branching reflected light from a subject into visible light and infrared light, and controlling an in-focus position using an image acquired from the infrared light.

  However, since the spectral characteristics of a living body cannot be used with infrared light, an image with high contrast cannot be obtained. In addition, since the spectral sensitivity of the image sensor is generally small in a wavelength region other than visible light, only an image having a smaller contrast than visible light can be obtained with infrared light.

  According to some aspects of the present invention, it is possible to provide an endoscope apparatus, a focus control method, a program, and the like that can perform appropriate autofocus even with a low-contrast subject.

  One aspect of the present invention is a first image acquisition that acquires, as a first image, an image obtained by capturing an in-vivo subject with an imaging optical system, the image including a subject image having information in the wavelength band of white light. Corresponding to the first image, a second image acquisition unit that acquires an image including a subject image having information in a specific wavelength band as a second image, and a subject image in the second image. A focus control unit that performs focusing control and performs focus adjustment of the imaging optical system, wherein the first image acquisition unit captures the first image captured by the focus-adjusted imaging optical system. It relates to the endoscopic device to be acquired.

  According to one aspect of the present invention, a first image and a second image obtained by capturing an in-vivo subject are acquired. At this time, an image including a subject image having information in a specific wavelength band is acquired as the second image. Control to focus on the subject image in the second image is performed, and the first image is acquired. This makes it possible to perform appropriate autofocus even with a low-contrast in-vivo subject.

  According to another aspect of the present invention, there is provided a first image obtained by capturing an image of a subject in a living body using an imaging optical system, the image including a subject image having information in the wavelength band of white light as a first image. A second image acquisition unit that acquires, as a second image, an image including a subject image of a anatomy in which the anatomy of the subject image included in the first image is further emphasized; A focus control unit that performs control for focusing on a subject image in the image and performs focus adjustment of the imaging optical system, and the first image acquisition unit is configured by the imaging optical system with the focus adjusted. The present invention relates to an endoscope apparatus that acquires the captured first image.

  According to still another aspect of the present invention, an image obtained by capturing an in-vivo subject with an imaging optical system and including an image of the subject having information in the wavelength band of white light is acquired as the first image. In response to the first image, an image including a subject image having information in a specific wavelength band is acquired as a second image, and control is performed to focus on the subject image in the second image, The present invention relates to a focus control method for performing focus adjustment of the image pickup optical system and acquiring the first image picked up by the focus-adjusted image pickup optical system.

  According to still another aspect of the present invention, an image obtained by imaging an in-vivo subject using an imaging optical system and including an image of the subject having information in the wavelength band of white light is acquired as the first image. A first image acquisition unit, a second image acquisition unit for acquiring an image including a subject image having information in a specific wavelength band corresponding to the first image, and a second image acquisition unit; The computer is caused to function as a focus control unit that performs focus control on the subject image and adjusts the focus of the imaging optical system, and the first image acquisition unit captures images using the focus-adjusted imaging optical system. This relates to a program for acquiring the first image.

FIG. 1A to FIG. 1D are explanatory diagrams for an overview of the present embodiment. 1 is a first configuration example of an endoscope apparatus. The 1st detailed structural example of a rotary filter. An example of a Laplacian filter. 5A and 5B are explanatory diagrams of the autofocus process. FIG. 6A and FIG. 6B are explanatory diagrams of the autofocus process. The 2nd structural example of an endoscope apparatus. The 2nd detailed structural example of a rotary filter. Explanatory drawing about surface sequential. The 3rd structural example of an endoscope apparatus. The detailed structural example of a special light image acquisition part. Example of a histogram. An example of a gradation conversion curve. The 4th structural example of an endoscope apparatus. The 5th structural example of an endoscope apparatus. The 3rd detailed structural example of a rotation filter. The detailed structural example of a light source. The system block diagram which shows the structure of a computer system. The block diagram which shows the structure of the main-body part in a computer system. The example of a flowchart of software.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. First, an overview of autofocus processing performed by the present embodiment will be described. As described above, when the inside of a living body is observed with an endoscope, the inner wall of the digestive tract or the like is generally low in contrast, so that it is difficult to perform autofocus by the contrast detection method. For example, as shown in FIG. 1A, in an image using white light, a anatomy such as a blood vessel may not be so clear. In this case, as shown in FIG. 1B, the difference between the evaluation values at the time of focusing and at the time of defocusing is small, and the detection of the lens focus position df becomes inaccurate.

  Accordingly, in the present embodiment, as shown in FIGS. 1C and 1D, contrast detection type autofocus processing is performed using an image of special light. Special light is light in a wavelength band where absorption and reflection peculiar to a living body occur. Therefore, by using special light, it is possible to capture a high-contrast image in which the anatomy is emphasized, and the accuracy of autofocus can be improved using the image.

  For example, blood vessels have the property of absorbing light in specific bands of green and blue. Therefore, a high-contrast image in which blood vessels are emphasized can be obtained by observing with special light in that band. Further, since the lesioned part has a different structure from the peripheral part, a high-contrast image is obtained at the lesioned part.

2. First Embodiment Next, an endoscope apparatus that performs the autofocus process will be described. FIG. 2 shows a first configuration example of the endoscope apparatus of the present embodiment. The endoscope apparatus (imaging apparatus in a broad sense) includes an illumination unit 101, an imaging unit 102, an I / F unit 111 (I / F: Interface), and a control device 300.

  The illumination unit 101 irradiates the subject with illumination light. The illumination unit 101 includes a light source device 201 (light source unit), an exterior 205, a light guide fiber 206, and an illumination optical system 207. The light source device 201 generates illumination light. The light source device 201 includes a white light source 202, a rotary filter 203, and a condenser lens 204.

  The imaging unit 102 images the illuminated subject. The imaging unit 102 includes an exterior 205, a condenser lens 208 (objective lens), and an imaging element 209. The exterior 205 is an exterior of the scope unit in which the imaging unit 102, the light guide fiber 206, and the illumination optical system 207 are accommodated. The scope portion is formed to be elongate and bendable so as to be inserted into a body cavity, for example, and is detachable from the control device 300.

  The control device 300 controls each component of the endoscope device and performs image processing. The control device 300 includes an A / D conversion unit 103, a normal light image acquisition unit 104 (first image acquisition unit), a special light image acquisition unit 105 (second image acquisition unit), an evaluation value calculation unit 106, and a buffer 107 (storage). A focus position determination unit 108, an output unit 109, a control unit 110, and a determination unit 112. The control unit 110 includes, for example, a microcomputer and a CPU. The I / F unit 111 includes an interface for performing, for example, a power switch and variable setting.

  Operations and processing performed by the endoscope apparatus of the present embodiment will be described. The white light source 202 emits white light. As shown in FIG. 3, a white light transmission filter 210 and a narrow band transmission filter 211 (special light filter in a broad sense) are set in the rotary filter 203. The transmission band of the white light transmission filter 210 is, for example, 400 nm to 700 nm (nm: nanometer). The transmission bands of the narrow band transmission filter 211 are, for example, 390 nm to 445 nm (B2) and 530 nm to 550 nm (G2).

  White light emitted from the white light source 202 is alternately transmitted through the white light transmission filter 210 and the narrow band transmission filter 211 of the rotary filter 203. The white light transmitted through the white light transmission filter 210 and the special light transmitted through the narrow band transmission filter 211 alternately reach the condenser lens 204 and are condensed. The condensed white light or special light is irradiated to the subject from the illumination optical system 207 through the light guide fiber 206.

  The reflected light reflected from the subject is collected by the condenser lens 208. The condensed light reaches the image sensor 209 and is photoelectrically converted by the image sensor 209 to become an analog signal. The analog signal is sent to the A / D conversion unit 103. The image sensor 209 is a sensor in which, for example, light receiving elements that receive R, G, and B are arranged in a Bayer shape.

  The condenser lens 208 can move back and forth on the optical axis. Alternatively, the condensing lens 208 may have an AF lens, and the AF lens may move back and forth on the optical axis. When the lens moves in the direction along the optical axis, the distance to the subject to be focused is changed. Hereinafter, the position of the condensing lens 208 when the subject is in focus is referred to as an in-focus position.

  An image captured by irradiating special light is converted into a digital signal by the A / D conversion unit 103. The signal is sent to the special light image acquisition unit 105. The special light image acquisition unit 105 acquires a special light image based on the signal. At the same time, the position information of the condenser lens 208 is acquired. The position information is information representing the position of the condenser lens 208 when the special light image is captured.

  The evaluation value calculation unit 106 calculates an evaluation value based on the special light image. The evaluation value is a value that changes according to the in-focus position, and is a value for detecting the in-focus position where the subject is in focus. As an example of the evaluation value calculation method, a known edge extraction process is performed on the special light image. The evaluation value is higher as the extracted edge amount is larger. For example, an edge is extracted by applying the Laplacian filter shown in FIG. 4 to all the pixels of the special light image. Then, the sum of absolute values of the pixel values of all the pixels after applying the Laplacian filter is obtained, and the sum is used as the evaluation value.

  The buffer 107 holds (stores) the evaluation value and the position information of the condenser lens 208.

  As shown in FIG. 5A, it is assumed that the evaluation value ev1 is acquired at the lens position d1. The position of the lens is, for example, the distance from the condenser lens 208 to the image sensor 209. The control unit 110 moves the condenser lens 208 closer to the image sensor 209 side and moves it to the position d2. Thereafter, a special light image is acquired in the same manner, an evaluation value ev2 is calculated, and the position information d2 of the condenser lens is held.

  The in-focus position determining unit 108 compares the first evaluation value ev1 with the second evaluation value ev2. As shown in FIG. 5A, if the second evaluation value ev2 is larger, the condenser lens 208 is further moved closer to the image sensor 209 side. As shown in FIG. 5B, if the first evaluation value ev1 is larger, the condenser lens 208 is moved to a position farther from the image sensor 209 than the position d1 of the first sheet. That is, in order to search for a position where the evaluation value is maximized, the condenser lens 208 is moved in a direction in which the evaluation value may increase.

  Similarly, the special light image acquisition unit 105 acquires the special light image, the evaluation value calculation unit 106 calculates the evaluation value, and the buffer 107 holds the evaluation value and the position information of the condenser lens 208.

  As shown in FIGS. 6A and 6B, the in-focus position determination unit 108 approximates the three evaluation values with the quadratic function KC, and the position df at which the quadratic function KC is maximized. Ask for. It is estimated that the position df is the position of the condenser lens 208 in focus on the subject.

  In the above description, the evaluation value is obtained and approximated using three special light images. However, in this embodiment, the evaluation value may be obtained and approximated using three or more special light images. The approximation accuracy can be improved if the number of special light images is large. In the above description, approximation is performed using a quadratic function. However, in the present embodiment, approximation may be performed using a higher-order function than the quadratic function.

  When the position df that maximizes the evaluation value is obtained, the control unit 110 performs control to move the condenser lens 208 to the position df. The subject is irradiated with white light transmitted through the white light transmission filter 210 of the rotation filter 203, and the captured signal is converted into a digital signal by the A / D conversion unit 103. The signal is sent to the normal light image acquisition unit 104. The normal light image acquisition unit 104 acquires a normal light image from the signal. The output unit 109 outputs the acquired normal light image as a focused image to a monitor (not shown) or the like.

  In addition, although the case where edge extraction processing is performed by a Laplacian filter has been described above as an example, the present embodiment is not limited to this. For example, the edge extraction process may be performed using another edge extraction method such as a primary differential filter.

  Here, in the present embodiment, autofocus control can be performed in the magnification observation mode. Specifically, the determination unit 112 determines whether or not the magnification observation mode is set. In the magnification observation mode, the control unit 110 performs the above processing.

  As an example of the determination of the magnification observation mode, a sensor that acquires distance information (not shown) is held at the tip of the imaging unit, and the sensor measures the distance to the subject. When the distance is equal to or less than a predetermined threshold given in advance, the determination unit 112 determines that the magnification observation mode is set.

  In another example of the determination, the user instructs whether or not the magnification observation mode is set via the I / F unit 111. When the magnification observation mode is instructed, the determination unit 112 determines the magnification observation mode.

  Another example of the determination is to detect an object by performing predetermined edge extraction on the image acquired by the normal light image acquisition unit 104 or the special light image acquisition unit 105. The determination unit 112 determines the magnified observation mode when the detected object becomes larger after a predetermined time (for example, unit time).

  Another example of the determination is to perform a predetermined edge extraction process on the image acquired by the normal light image acquisition unit 104 or the special light image acquisition unit 105 to calculate the edge amount. When the edge amount decreases after a predetermined time (for example, unit time) and the total of pixel values (for example, luminance values) of the entire image (or part of the image) increases, the determination unit 112 determines that the magnification observation mode is set. Specifically, in normal observation, it is assumed that the subject is in the depth of field and is in focus. If you move the scope closer to the subject to zoom in on the subject, you will be out of focus and out of focus. Then, since the edge amount of the image is reduced, the autofocus process is started when the edge amount is reduced. That is, it is determined based on the edge amount that the image is out of focus. Further, even when an operation of moving away from the subject is performed, the depth of field is deviated. In this case, the image becomes dark. For this reason, it is determined based on the brightness of the image that the depth of field has been deviated in the direction approaching the subject.

  As described above, in contrast detection autofocus, when the inside of a living body is observed with an endoscope, the inner wall of the digestive tract is generally low in contrast, so it is difficult to detect the in-focus position. There is a problem of being.

  In this regard, the endoscope apparatus of the present embodiment includes a first image acquisition unit, a second image acquisition unit, and a focus control unit 150, as shown in FIG. The first image acquisition unit acquires an image including a subject image having information in a wavelength band of white light as a first image, which is an image obtained by capturing an in-vivo subject with an imaging optical system. The second image acquisition unit acquires an image including a subject image having information in a specific wavelength band as the second image corresponding to the first image. The focus control unit 150 performs focus adjustment of the imaging optical system by performing control (focusing) on a subject image in the second image. Then, the first image acquisition unit acquires a first image captured by the focus-adjusted imaging optical system.

  For example, in the present embodiment, the special light image acquisition unit 105 acquires a special light image, the evaluation value calculation unit 106 calculates an evaluation value based on the special light image, and the in-focus position determination unit 108 calculates the evaluation value. The in-focus position is obtained based on the value. The control unit 110 moves the condenser lens 208 to the in-focus position, and the normal light image acquisition unit 104 acquires a focused (focused) normal light image.

  Here, the first image acquisition unit corresponds to the normal light image acquisition unit 104. The second image acquisition unit corresponds to the special light image acquisition unit 105. The focus control unit 150 corresponds to the evaluation value calculation unit 106, the buffer 107, the focus position determination unit 108, and the control unit 110. The focus control unit 150 may not include the buffer 107. The imaging optical system corresponds to the condenser lens 208 and the imaging element 209. The first image corresponds to the normal light image. The second image corresponds to the special light image.

  According to the present embodiment, autofocus control is performed using a special light image in the endoscope apparatus, and a normal light image focused by the autofocus control can be acquired. Specifically, the special light image is easy to obtain an image with high contrast in the living body. Therefore, the accuracy of autofocus can be improved compared to the case where autofocus is performed with a normal light image. Thereby, the focused normal light image can be provided to the observer.

  In the present embodiment, the second image acquisition unit acquires the second image using a wavelength band in which the contrast of the subject in the living body is higher in the second image than in the first image as a specific wavelength band. The focus control unit 150 performs control to focus on the subject image in the second image based on the contrast of the second image.

  For example, in the present embodiment, an evaluation value representing contrast is obtained, and the in-focus position is detected based on the evaluation value. The contrast is a value that is larger in the case of focusing than in the case of being out of focus (out of focus), for example, the edge amount of the image as described above. As shown in FIGS. 1A to 1D, the difference (or ratio) in contrast between the in-focus state and the in-focus state is larger in the special light image than in the normal light image. The specific wavelength band is a wavelength band in which such a special light image is acquired for a subject in a living body.

  In this way, the contrast of the subject in the living body can be made higher in the special light image than in the normal light image. This makes it possible to perform contrast detection autofocus with high accuracy using the special light image.

  In the present embodiment, the second image acquisition unit acquires, as the second image, an image including the anatomical subject image in which the anatomy of the subject image included in the first image is further emphasized.

  In this way, autofocus control can be performed based on the second image in which the anatomy of the subject image is further emphasized. Thereby, the accuracy of autofocus can be improved in a low-contrast living body. That is, by enhancing the anatomy of the subject image, it is possible to increase the difference (or ratio) between the evaluation values when focused and when not focused.

  In the present embodiment, the specific wavelength band is a band narrower than the wavelength band of white light (for example, 380 nm to 650 nm) (NBI: Narrow Band Imaging). Specifically, the specific wavelength band is a wavelength band of a wavelength that is absorbed by hemoglobin in blood. More specifically, the specific wavelength band is 390 nanometers to 445 nanometers (second narrowband light), or 530 nanometers to 550 nanometers (first narrowband light).

  In this way, by irradiating the subject in the living body with the narrow band special light, it is possible to acquire a special light image in which the blood vessel structure or lesion of the living body is raised. As a result, a high-contrast image of blood vessels, lesions, etc. can be obtained, and accurate autofocus can be performed.

  More specifically, it becomes possible to image the structure of blood vessels located in the surface layer portion and deep portion of a living body, and the contrast can be improved by the structure of the blood vessels. In addition, by inputting the obtained signals to specific channels (G2 → R, B2 → G, B), lesions that are difficult to see with normal light such as squamous cell carcinoma can be displayed in brown, etc. The contrast of an image including a portion can be improved. Note that 390 nm to 445 nm or 530 nm to 550 nm are numbers obtained from the characteristic of being absorbed by hemoglobin and the characteristic of reaching the surface layer or the deep part of the living body, respectively. However, the wavelength band in this case is not limited to this. For example, the lower limit of the wavelength band is reduced by about 0 to 10% due to the variation factors such as the absorption by hemoglobin and the experimental results regarding the arrival of the living body on the surface layer or the deep part. It is also conceivable that the upper limit value increases by about 0 to 10%.

  Moreover, in this embodiment, as shown in FIG. 2, the determination part 112 which determines whether an observation state is an expansion observation state is included. When the determination unit 112 determines that the image is in the magnified observation state, the focus control unit 150 performs control to focus on the subject image in the second image, and performs focus adjustment of the imaging optical system. The first image acquisition unit acquires a first image picked up by the image pickup optical system whose focus has been adjusted.

  Here, the enlarged observation state is a state in which a lesion is observed at a high magnification, for example, facing the inner wall of the digestive tract. On the other hand, the normal observation state is an observation state in which a lesion is searched at a low magnification while moving in the digestive tract, for example.

  In this way, autofocus control can be performed in the magnified observation state. It is considered that when the observer is performing magnified observation, it is desirable to display the image large and observe it carefully. In the present embodiment, an image that is in focus at the time of magnified observation can be presented, which contributes to improving the ease of observation. In addition, the depth of field is reduced because the subject approaches the subject during magnification observation, and manual focus adjustment becomes difficult. In the present embodiment, focusing is possible by autofocus.

  In the present embodiment, the determination unit 112 acquires information regarding whether or not the scope unit of the endoscope apparatus is approaching the subject, and determines that the scope unit is approaching the subject based on the information. In this case, it is determined that the state is an enlarged observation state. Specifically, the determination unit 112 acquires the size of the edge shape of the subject as the information, and when determining that the size of the edge shape is larger than the size of the edge shape before a predetermined time, the enlarged observation state It is determined that

  For example, the size of the edge shape is the width of the shape, the area of the shape, or the magnification of the shape. The magnification of the shape is obtained by, for example, acquiring an edge image extracted from the current image and an edge image extracted from the image before a predetermined time, and matching the current edge image by converting the size of the edge image before the predetermined time It can be obtained by processing.

  In this way, when it is determined that the scope unit is approaching the subject, it can be determined that the state is an enlarged observation state. As a result, when the scope unit approaches the subject and the depth of field becomes narrow, autofocus can be performed.

  In the present embodiment, the determination unit 112 obtains an evaluation value for evaluating the in-focus state of the image from the first image or the second image, and the evaluation value is changed from the in-focus state to the out-of-focus state. When it is determined based on the above, it is determined that the state is an enlarged observation state.

  For example, in the present embodiment, the edge amount of the normal light image or the special light image is calculated, and when the edge amount has decreased after a predetermined time, it is determined that the state has changed to the out-of-focus state.

  In this way, it is possible to determine that the state is the magnified observation state when the depth of field is deviated by bringing the scope portion closer to the subject in order to perform the magnified observation. Thereby, even when the focus is out of focus when shifting from the normal observation state to the magnified observation state, it is possible to focus by autofocus.

  Moreover, in this embodiment, as shown in FIG. 2, a 1st image acquisition part acquires the 1st image based on the light irradiated from a light source part. The second image acquisition unit acquires a second image based on light emitted from the light source unit.

  Specifically, the light source unit includes a white light source 202. The first image acquisition unit acquires a first image based on white light emitted from the white light source 202. The second image acquisition unit acquires a second image based on white light emitted from the white light source 202.

  More specifically, as illustrated in FIG. 3, the light source unit emits light in a specific wavelength band by applying a filter 211 that transmits a specific wavelength band to white light. The second image acquisition unit acquires a second image having information on the specific wavelength band.

  In the present embodiment, the light source unit corresponds to the light source device 201. In the present embodiment, the subject is illuminated with the light emitted from the light source unit, and the illuminated subject is imaged by the imaging unit 102 to obtain the first image and the second image. In the present embodiment, the second image based on white light is not limited to an image obtained by illuminating with light of a specific wavelength band. For example, as will be described later with reference to FIG. 7, an image obtained by transmitting reflected light from a subject illuminated with white light through a filter 230 that transmits a specific wavelength band may be used.

  In this way, the normal light image and the special light image can be acquired using the white light source by switching the white light transmission filter and the special light filter. Since the white light source is a commonly used light source, the cost can be reduced.

3. Second Embodiment In the first embodiment, the normal light image and the special light image are acquired in a time division manner. However, in the present embodiment, the normal light image and the special light image may be acquired simultaneously by two image pickup devices. Good. An embodiment in this case will be described in detail.

  FIG. 7 shows a second configuration example of the endoscope apparatus. The endoscope apparatus includes an illumination unit 101, an imaging unit 402, an I / F unit 111, and a control device 300. In the following, the same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The illumination unit 101 includes a light source device 201, an exterior 205, a light guide fiber 206, and an illumination optical system 207. The light source device 201 generates RGB illumination light in a time-sharing manner. The light source device 201 includes a white light source 202, a rotary filter 203, and a condenser lens 204.

  The imaging unit 402 performs imaging with white light and imaging with special light at the same timing. The imaging unit 402 includes an exterior 205, a condensing lens 208, a splitter 228 that branches light, an imaging element 229 for normal light images (first imaging element), and a narrow-band transmission filter 230 that transmits only light in a specific band. The image sensor 231 (second image sensor) for special light images is included.

  The control device 300 includes a first A / D conversion unit 103a, a second A / D conversion unit 103b, a normal light image acquisition unit 104, a special light image acquisition unit 105, an evaluation value calculation unit 106, a buffer 107, an in-focus state. A position determination unit 108, an output unit 109, and a control unit 110 are included.

  Operations and processing performed by the endoscope apparatus of the present embodiment will be described. White light is emitted from the white light source 202. As shown in FIG. 8, a red light transmission filter 220, a green light transmission filter 221, and a blue light transmission filter 222 are set in the rotary filter 203. White light emitted from the white light source 202 passes through the rotary filter 203 and reaches the condenser lens 204 to be condensed. The condensed light is irradiated to the subject from the illumination optical system 207 through the light guide fiber 206.

  The reflected light reflected from the subject is collected by the condenser lens 208 and divided into two directions by the splitter 228. The light in one direction reaches the image sensor 229 and is photoelectrically converted by the image sensor 229. An analog signal obtained by photoelectric conversion is sent to the A / D conversion unit 103a. The light in the other direction reaches the narrowband transmission filter 230, and only a predetermined narrowband light is transmitted. The transmission bands of the narrowband transmission filter 230 are, for example, 390 nm to 445 nm (B2) and 530 nm to 550 nm (G2). The transmitted light reaches the image sensor 231 and is photoelectrically converted by the image sensor 231. An analog signal obtained by the photoelectric conversion is sent to the A / D conversion unit 103b.

  The A / D conversion unit 103 a converts the analog signal into a digital signal, and transmits the digital signal to the normal light image acquisition unit 104. The A / D conversion unit 103 b converts the analog signal into a digital signal and transmits the digital signal to the special light image acquisition unit 105.

  The condenser lens 208 can move back and forth on the optical axis.

  The normal light image acquisition unit 104 and the special light image acquisition unit 105 acquire a color image from the R image, the G image, and the B image that are captured in the frame sequence. Here, a signal obtained by the light transmitted through the red light transmission filter 220 of the rotary filter 203 is referred to as an R signal. A signal obtained by the light transmitted through the green light transmission filter 221 is referred to as a G signal. A signal obtained by the light transmitted through the blue light transmission filter 222 is referred to as a B signal. Since the rotary filter 203 is rotating, an R signal, a G signal, and a B signal are obtained in order. The normal light image acquisition unit 104 combines the R signal, the G signal, and the B signal to generate a color normal light image. The special light image acquisition unit 105 combines the R signal, the G signal, and the B signal to generate a color special light image.

  As in the first embodiment, autofocus processing is performed based on the special light image. That is, the evaluation value calculation unit 106 calculates an evaluation value from the special light image. The buffer 107 holds the evaluation value and the position information of the condenser lens 208. The control unit 110 performs control to change the position of the condenser lens 208, and the special light image acquisition unit 105 acquires the special light image. By repeating these operations, the in-focus position determination unit 108 determines a position where the evaluation value is maximized. In this way, the in-focus position is estimated.

  After obtaining the position where the evaluation value is maximized, the control unit 110 performs control to move the condenser lens 208 to that position.

  The A / D conversion unit 103 a converts an analog signal into a digital signal to acquire an R signal, a G signal, and a B signal, and transmits the acquired signal to the normal light image acquisition unit 104. The normal light image acquisition unit 104 combines the R signal, the G signal, and the B signal to generate a color normal light image. The output unit 109 outputs the acquired normal light image as a focused image to a monitor (not shown) or the like.

The frame sequential image generation method will be described with reference to FIG. As shown in A1 of FIG. 9, when the rotary filter 203 makes one rotation, an R _t1 signal, a G _t1 signal, and a B _t1 signal are sequentially acquired. As shown in A2, the R _t2 signal, the G _t2 signal, and the B _t2 signal are sequentially acquired in the next one rotation. As shown in A3, when the R _t1 signal, the G _t1 signal, and the B _t1 signal are acquired, a color image is generated based on these three signals. Thereafter, each time one signal is newly acquired, a color image is generated from the newly acquired signal and the previously acquired signal. For example, as shown in A4, when the R _t2 signal is acquired, a color image is generated from the R _t2 signal, the G _t1 signal, and the B _t1 signal.

  In the above description, the special light image is generated by combining the R signal, the G signal, and the B signal. However, the present embodiment is not limited to this. For example, a special light image may be generated from the G signal and the B signal, or a special light image may be generated from only the B signal.

  According to the present embodiment, as shown in FIGS. 7 and 8, the light source unit is a filter 220 that transmits the wavelength band of the first to Nth (N is an integer of 2 or more) monochromatic light constituting white light. ˜222 are applied to white light to emit first to Nth monochromatic lights. The first image acquisition unit acquires the first to Nth monochrome images having information on the wavelength bands of the first to Nth monochrome lights, and the first image based on the acquired first to Nth monochrome images. Is generated.

  In this embodiment, N = 3, the first monochromatic light is red light, the second monochromatic light is green light, and the third monochromatic light is blue light. The first to third monochrome images are an R image, a G image, and a B image. As shown in FIG. 9, the monochrome image pickup device 229 picks up an R image, a G image, and a B image in time division, and the normal light image acquisition unit 104 picks up the R image, G image, and B image picked up in that time division. A normal light image is generated from

  In this way, it is possible to perform image pickup by plane sequential. Further, since the white light source is a commonly used light source, the cost can be reduced. In addition, since a monochrome image pickup device is used in the frame order, the resolution is higher than that of a Bayer array image pickup device having the same number of pixels.

4). Third Embodiment In the first embodiment, a special light image is captured by irradiating a subject with special light. However, in the present embodiment, a special light image may be extracted from a normal light image. An embodiment in this case will be described in detail.

  FIG. 10 shows a third configuration example of the endoscope apparatus. The endoscope apparatus includes an illumination unit 101, an imaging unit 102, an I / F unit 111, and a control device 300. In the following description, the same components as those described in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The illumination unit 101 includes a light source device 201, an exterior 205, a light guide fiber 206, and an illumination optical system 207. The light source device 201 generates white illumination light. The light source device 201 includes a white light source 202 and a condenser lens 204.

  The imaging unit 102 images a subject illuminated with white light. The imaging unit 102 includes an exterior 205, a condenser lens 208, and an imaging element 209.

  The control device 300 includes an A / D conversion unit 103, a normal light image acquisition unit 104, a special light image acquisition unit 105, an evaluation value calculation unit 106, a buffer 107, a focus position determination unit 108, an output unit 109, and a control unit 110. Including. The special light image acquisition unit 105 acquires a special light image based on the normal light image acquired by the normal light image acquisition unit 104. FIG. 11 shows a detailed configuration example of the special light image acquisition unit 105. The special light image acquisition unit 105 includes a matrix data setting unit 401 and a signal extraction unit 403.

  Operations and processing performed by the endoscope apparatus of the present embodiment will be described.

  White light is emitted from the white light source 202, reaches the condenser lens 204, and is condensed. The condensed white light is irradiated to the subject from the illumination optical system 207 through the light guide fiber 206.

  The reflected light reflected from the subject is collected by the condenser lens 208 and reaches the image sensor 209. The reached light is photoelectrically converted by the image sensor 209 to become an analog signal, and the analog signal is sent to the A / D converter 103. The image sensor 209 is a sensor in which light receiving elements that receive R, G, and B are arranged in a Bayer shape.

  The condenser lens 208 can move back and forth on the optical axis.

  The signal converted into a digital signal by the A / D conversion unit 103 is sent to the normal light image acquisition unit 104. The normal light image acquisition unit 104 acquires the signal as a normal light image. Further, the normal light image acquisition unit 104 acquires the position information of the condenser lens 208 at the same time.

  The special light image acquisition unit 105 performs predetermined image processing to generate a special light image. Specifically, the matrix data setting unit 401 sets matrix data. The matrix data may be data set in advance or data set by the user. The signal extraction unit 403 extracts a signal based on the matrix data and the normal light image acquired by the normal light image acquisition unit 104. A detailed example of the predetermined image processing will be described later.

  As in the first embodiment, autofocus processing is performed based on the special light image. That is, the evaluation value calculation unit 106 calculates an evaluation value from the special light image. The buffer 107 holds the evaluation value and the position information of the condenser lens 208. The control unit 110 performs control to change the position of the condenser lens 208, and the special light image acquisition unit 105 acquires the special light image. By repeating these operations, the in-focus position determination unit 108 determines a position where the evaluation value is maximized. In this way, the in-focus position is estimated.

  After obtaining the position where the evaluation value is maximized, the control unit 110 performs control to move the condenser lens 208 to that position. The normal light image acquisition unit 104 acquires a normal light image. The output unit 109 outputs the acquired normal light image as a focused image to a monitor (not shown) or the like.

  Next, a first example of predetermined image processing performed by the special light image acquisition unit 105 will be described. The special light image acquisition unit 105 estimates the spectral reflectance of the subject in each pixel from the normal light image using a known spectral estimation technique, and obtains a narrow band (for example, 10 nm increments) spectral image. The special light image acquisition unit 105 calculates the product of the spectral reflectance of the subject, the spectral emissivity of the white light source, the spectral transmittance of the optical system, and the spectral sensitivity of the color filter, and acquires a special light image.

  More specifically, the normal light image acquisition unit 104 performs a known interpolation process on the input digital image signal, for example, and generates a color image having three channels of R, G, and B. This image is a color image when a subject is imaged using the image sensor 209 under a white light source. Next, the special light image acquisition unit 105 estimates the spectral reflectance of the subject in each pixel of the color image using the spectral estimation technique from the color image. For example, details of the spectral estimation technique are disclosed in JP-A-2000-115553, [0054] to [0065]. By performing such processing, the spectral reflectance characteristic O (λ) of the subject is acquired as spectral image information (for example, λ is 380 nm to 780 nm). O (λ) is acquired for each pixel, and is, for example, spectral reflectance characteristics in increments of 10 nm from 380 nm to 780 nm.

Here, the spectral reflectance characteristic at the position (x, y) on the image is described as O (λ) (x, y). Further, the spectral emissivity of the white light source in this embodiment is E (λ), and the spectral transmittance of the optical system is L (λ). In addition, the spectral sensitivities of the bands G2 and B2 of the narrowband transmission filter 211 in the first embodiment are assumed to be g2 (λ) and b2 (λ), respectively. Then, the signal value G2 (x, y) at the position (x, y) of the image G2 corresponding to the band G2 is calculated by the following equation (1). The signal value B2 (x, y) at the position (x, y) of the image B2 corresponding to the band B2 is calculated by the following equation (2).
G2 (x, y) = ∫E (λ) · O (λ) (x, y) · L (λ) · g2 (λ) dλ
(1)
B2 (x, y) = ∫E (λ) · O (λ) (x, y) · L (λ) · b2 (λ) dλ
(2)

  By performing such calculation for all positions (x, y) on the image, the G2 image and the B2 image can be acquired from the normal light image.

  Next, a color image having three channels of R, G, and B is generated from the G2 image and the B2 image. For example, a color image is generated by inputting a G2 image to the R channel of the color image and inputting a B2 image to the G channel and the B channel. Further, the generated color image is subjected to processing such as white balance and gradation conversion, and is output as a special light image.

A second example of the predetermined image processing will be described. The matrix data setting unit 401 sets the matrix of the first term on the right side of the following equation (3). The signal extraction unit 403 performs a conversion process represented by the following expression (3). Here, R _in , G _in , and B _in are RGB signal values of the normal light image. α, β, and γ are arbitrary positive numbers. For example, α = 1, β = 1.2, and γ = 0.9. The signal extraction unit 403 outputs R _out , G _out , and B _out as RGB signal values of the special light image.

  A third example of the predetermined image processing will be described. The special light image acquisition unit 105 obtains a gradation conversion curve for flattening the histogram based on the R signal of the normal light image. The special light image acquisition unit 105 creates a gain map from the gradation conversion curve, and converts the GB signal of the normal light image using the gain map.

  FIG. 12 shows an example of a histogram of R signal values of all pixels. In the R image, most of the pixels have signal values near the center. FIG. 13 shows an example of the gain map. As shown in FIG. 13, a tone conversion curve is generated so that pixel values are evenly distributed, and a gain map is generated. Then, the gain corresponding to the R signal value of the pixel is multiplied by the G signal value and the B signal value of the pixel. By flattening the histogram in this way, the contrast can be improved.

  Note that color conversion processing, green component enhancement processing, and blue component enhancement processing may be performed as the predetermined image processing. Alternatively, as predetermined image processing, processing may be performed in which a predetermined wavelength of light is specified via the I / F unit 111 and a color corresponding to the specified wavelength is emphasized.

  Here, although the color filter of the image sensor 209 is arranged in a Bayer shape in the above, the present invention is not limited to this, and the color filter may have a honeycomb structure or the like. In the above description, the image sensor 209 that receives primary colors RGB is used. However, the present embodiment is not limited to this. For example, an image sensor that receives complementary colors may be used.

  According to this embodiment, as shown in FIG. 10, the second image acquisition unit generates a second image based on the acquired first image.

  Specifically, as illustrated in FIG. 11, the second image acquisition unit includes a signal extraction unit 403 that extracts a signal in the wavelength band of white light from the acquired first image. The second image acquisition unit generates a second image including a signal in a specific wavelength band based on the extracted signal.

  More specifically, the second image acquisition unit includes a matrix data setting unit 401 that sets matrix data for calculating a signal in a specific wavelength band from a signal in the wavelength band of white light. The second image acquisition unit calculates a signal in a specific wavelength band from a signal in the wavelength band of white light using the set matrix data, and generates a second image.

  As a result, the special light image can be generated based on the normal light image, so that the system can be realized with only one light source that irradiates the normal light and one image sensor that images the normal light. . Therefore, a device such as a special light source is not required, and the equipment configuration can be simplified. Moreover, the insertion part of the scope type endoscope can be made small, and since the number of parts is reduced, an effect of reducing the cost can be expected.

5. Fourth Embodiment In the first embodiment, the special light is generated by the white light and the narrow band transmission filter. However, in the present embodiment, the special light may be generated by the special light source. An embodiment in this case will be described in detail.

  FIG. 14 shows a fourth configuration example of the endoscope apparatus. The endoscope apparatus includes an illumination unit 101, an imaging unit 102, an I / F unit 111, and a control device 300. In the following description, the same components as those described in the first to third embodiments are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The illumination unit 101 includes a light source device 201, an exterior 205, a light guide fiber 206, and an illumination optical system 207. The light source device 201 generates white light and special light in a time-sharing manner. The light source device 201 includes a white light source 202a, a special light source 202b, a switcher 202c, and a condenser lens 204.

  The imaging unit 102 performs time-sharing imaging with white light and imaging with special light. The imaging unit 102 includes an exterior 205, a condenser lens 208, and an imaging element 209.

  The control device 300 includes an A / D conversion unit 103, a normal light image acquisition unit 104, a special light image acquisition unit 105, an evaluation value calculation unit 106, a buffer 107, a focus position determination unit 108, an output unit 109, and a control unit 110. Including.

  Operations and processing performed by the endoscope apparatus of the present embodiment will be described. Special light is emitted from the special light source 202b. The wavelength bands of the special light are, for example, 390 nm to 445 nm (B2) and 530 nm to 550 nm (G2). Special light from the special light source 202b reaches the condenser lens 204 and is condensed. The condensed special light is irradiated to the subject from the illumination optical system 207 through the light guide fiber 206.

  The reflected light reflected from the subject is collected by the condenser lens 208. The condensed light reaches the image sensor 209 and is photoelectrically converted by the image sensor 209 to become an analog signal. The analog signal is sent to the A / D conversion unit 103. The image sensor 209 is a sensor in which, for example, light receiving elements that receive R, G, and B are arranged in a Bayer shape.

  The signal converted into a digital signal by the A / D conversion unit 103 is sent to the special light image acquisition unit 105. The special light image acquisition unit 105 acquires the signal as a special light image. The special light image acquisition unit 105 also acquires the position information of the condenser lens 208 at the same time.

  The condenser lens 208 can move back and forth on the optical axis.

  As in the first embodiment, autofocus processing is performed based on the special light image. That is, the evaluation value calculation unit 106 calculates an evaluation value from the special light image. The buffer 107 holds the evaluation value and the position information of the condenser lens 208. The control unit 110 performs control to change the position of the condenser lens 208, and the special light image acquisition unit 105 acquires the special light image. By repeating these operations, the in-focus position determination unit 108 determines a position where the evaluation value is maximized. In this way, the in-focus position is estimated.

  After obtaining the position where the evaluation value is maximized, the control unit 110 performs control to move the condenser lens 208 to that position. The controller 110 controls the switch 202c, and the switch 202c switches the light source to the white light source 202a based on the control.

  As in the case of the special light source, an analog signal is acquired by the image sensor 209, converted into a digital signal by the A / D conversion unit 103, and the signal is transmitted to the normal light image acquisition unit 104. The normal light image acquisition unit 104 performs processing such as interpolation to generate a color normal light image. The output unit 109 outputs the acquired normal light image as a focused image to a monitor (not shown) or the like.

  According to this embodiment, as shown in FIG. 14, the light source unit includes a white light source 202a and a special light source 202b that emits special light having information in a specific wavelength band. The first image acquisition unit acquires a first image based on white light emitted from the white light source 202a. The second image acquisition unit acquires a second image based on the special light emitted from the special light source 202b.

  In the present embodiment, the white light source and the special light source are not limited to a single light source, and may be a plurality of light sources. For example, as will be described later with reference to FIG. 17, the white light source may be composed of a red light source 202d, a green light source 202e, and a blue light source 202f. The special light source may include a green narrow band light source 202g and a blue narrow band light source 202h.

  In this way, the normal light image and the special light image can be acquired by switching between the white light source and the special light source. This makes it possible to acquire a high-contrast image because light is not cut by the filter. As a result, accurate autofocus can be performed, and an in-focus image can be provided to the observer.

6). Fifth Embodiment In the first embodiment, normal light and special light are irradiated in a time-sharing manner, but in this embodiment, red light, green light, blue light, first narrowband light, and second narrowband light are used. May be irradiated in a time-sharing manner. An embodiment in this case will be described in detail.

  FIG. 15 shows a fifth configuration example of the endoscope apparatus. The endoscope apparatus includes an illumination unit 101, an imaging unit 102, an I / F unit 111, and a control device 300. In the following description, the same components as those described in the first to fourth embodiments are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The illumination unit 101 includes a light source device 201, an exterior 205, a light guide fiber 206, and an illumination optical system 207. The light source device 201 generates red light, green light, blue light, first narrowband light, and second narrowband light. The light source device 201 includes a white light source 202, a rotary filter 203, and a condenser lens 204.

  The imaging unit 102 performs time-division imaging using red light, green light, blue light, first narrowband light, and second narrowband light. The imaging unit 102 includes an exterior 205, a condenser lens 208, and an imaging element 209.

  The control device 300 includes an A / D conversion unit 103, a normal light image acquisition unit 104, a special light image acquisition unit 105, an evaluation value calculation unit 106, a buffer 107, a focus position determination unit 108, an output unit 109, and a control unit 110. Including.

  Operations and processing performed by the endoscope apparatus of the present embodiment will be described. White light is emitted from the white light source 202. As shown in FIG. 16, the rotary filter 203 includes a red light transmission filter 220, a green light transmission filter 221, a blue light transmission filter 222, a green narrowband light transmission filter 223 (first narrowband light transmission filter), a blue narrow transmission filter. A band light transmission filter 224 (second narrow band light transmission filter) is set. The transmission band of the red light transmission filter 220 is, for example, 580 nm to 700 nm. The transmission band of the green light transmission filter 221 is, for example, 480 nm to 600 nm. The transmission band of the blue light transmission filter 222 is, for example, 400 nm to 500 nm. The transmission band of the green narrow-band light transmission filter 223 is, for example, 530 nm to 550 nm (G2). The transmission band of the blue narrow-band light transmission filter 224 is, for example, 390 nm to 445 nm (B2).

  White light emitted from the white light source 202 passes through the five filters of the rotary filter 203 in order. The transmitted light reaches the condenser lens 204 and is condensed. The condensed light is irradiated to the subject from the illumination optical system 207 through the light guide fiber 206.

  The reflected light reflected from the subject is collected by the condensing lens 208, reaches the monochrome image sensor 209, and is photoelectrically converted by the image sensor 209 to become an analog signal. The analog signal is sent to the A / D conversion unit 103. The analog signal is converted into a digital signal by the A / D conversion unit 103, and the digital signal is transmitted to the normal light image acquisition unit 104 or the special light image acquisition unit 105.

  The condenser lens 208 can move back and forth on the optical axis.

  Here, a signal obtained by the light transmitted through the red light transmission filter 220 of the rotary filter 203 is referred to as an R signal. A signal obtained by the light transmitted through the green light transmission filter 221 is referred to as a G signal. A signal obtained by the light transmitted through the blue light transmission filter 222 is referred to as a B signal. A signal obtained by the light transmitted through the green narrow band light transmission filter 223 is referred to as a G2 signal. A signal obtained by the light transmitted through the blue narrow band light transmission filter 224 is referred to as a B2 signal.

  The special light image acquisition unit 105 generates a special light image by combining the G2 signal and the B2 signal. The special light image acquisition unit 105 also acquires the position information of the condenser lens 208 at the same time.

  As in the first embodiment, autofocus processing is performed based on the special light image. That is, the evaluation value calculation unit 106 calculates an evaluation value from the special light image. The buffer 107 holds the evaluation value and the position information of the condenser lens 208. The control unit 110 performs control to change the position of the condenser lens 208, and the special light image acquisition unit 105 acquires the special light image. By repeating these operations, the in-focus position determination unit 108 determines a position where the evaluation value is maximized. In this way, the in-focus position is estimated.

  After obtaining the position where the evaluation value is maximized, the control unit 110 performs control to move the condenser lens 208 to that position. The R signal, G signal, and B signal at that position are acquired, and the normal light image acquisition unit 104 combines these signals to generate a normal light image. The output unit 109 outputs the acquired normal light image as a focused image to a monitor (not shown) or the like.

  In the present embodiment, a rotary filter 203 having three filters shown in FIG. 8 may be used instead of the rotary filter 203 having five filters shown in FIG. In this case, a special light image is generated using the G signal instead of the G2 signal and using the B signal instead of the B2 signal.

  In the present embodiment, the light source shown in FIG. 17 may be used instead of the white light source 202 and the rotary filter 203. The light source shown in FIG. 17 includes a switcher 202c, a red light source 202d, a green light source 202e, a blue light source 202f, a green narrow band light source 202g, and a blue narrow band light source 202h. The R signal described above corresponds to the signal obtained by irradiating the red light source 202d. Similarly, the G signal corresponds to the green light source 202e, the B signal corresponds to the blue light source 202f, and the G2 signal. Corresponds to the green narrowband light source 202g, and the B2 signal corresponds to the blue narrowband light source 202h.

  According to the present embodiment, as shown in FIGS. 15 and 16, the light source unit is a filter 223 that transmits the first to Mth (M is an integer of 2 or more) wavelength bands constituting a specific wavelength band. By applying 224 to white light, light in the first to Mth wavelength bands is emitted. The second image acquisition unit acquires the first to M-th constituent images having information on the first to M-th wavelength bands, and generates a second image based on the acquired first to M-th constituent images. .

  In this embodiment, N = 2, the light in the first wavelength band is green narrow band light, and the light in the second wavelength band is blue narrow band light. The first to second constituent images are a G2 image and a B2 image. As shown in FIG. 15, the monochrome imaging device 209 captures the G2 image and the B2 image in time division, and the special light image acquisition unit 105 generates the special light image from the G2 image and B2 image captured in the time division. To do.

  In this way, special light images can be picked up by plane sequential. Further, since the white light source is a commonly used light source, the cost can be reduced. In addition, since a monochrome image pickup device is used in the frame order, the resolution is higher than that of a Bayer array image pickup device having the same number of pixels.

7). Software In the present embodiment described above, each unit configuring the control device 300 is configured by hardware. However, the present invention is not limited to this. For example, the CPU may be configured to perform processing of each unit on the image acquired by the imaging unit, and may be realized as software by the CPU executing a program. Alternatively, a part of processing performed by each unit may be configured by software.

  When the imaging unit is a separate body and the processing performed by each unit of the control device 300 is realized as software, a known computer system such as a workstation or a personal computer can be used as the control device. A program (control program) for realizing processing performed by each unit of the control device 300 is prepared in advance, and this control program can be realized by the CPU of the computer system.

  FIG. 18 is a system configuration diagram showing the configuration of the computer system 600 in this modification, and FIG. 19 is a block diagram showing the configuration of the main body 610 in this computer system 600. As shown in FIG. 18, the computer system 600 includes a main body 610, a display 620 for displaying information such as an image on the display screen 621 according to an instruction from the main body 610, and various information on the computer system 600. A keyboard 630 for inputting and a mouse 640 for designating an arbitrary position on the display screen 621 of the display 620 are provided.

  Further, as shown in FIG. 19, a main body 610 in the computer system 600 includes a CPU 611, a RAM 612, a ROM 613, a hard disk drive (HDD) 614, a CD-ROM drive 615 that accepts a CD-ROM 660, and a USB memory. USB port 616 to which 670 is detachably connected, I / O interface 617 to which display 620, keyboard 630 and mouse 640 are connected, and a LAN interface for connection to a local area network or wide area network (LAN / WAN) N1 618.

  Further, the computer system 600 is connected to a modem 650 for connecting to a public line N3 such as the Internet, and is another computer system via a LAN interface 618 and a local area network or a wide area network N1. A personal computer (PC) 681, a server 682, a printer 683, and the like are connected.

  And this computer system 600 implement | achieves a control apparatus by reading the control program for implement | achieving the process sequence mentioned later with reference to the control program (for example, FIG. 20) recorded on the predetermined recording medium, and running it To do. Here, the predetermined recording medium is a “portable physical medium” including an MO disk, a DVD disk, a flexible disk (FD), a magneto-optical disk, an IC card, etc. in addition to the CD-ROM 660 and the USB memory 670, a computer A “fixed physical medium” such as HDD 614, RAM 612, and ROM 613 provided inside and outside the system 600, a public line N3 connected via the modem 650, and another computer system (PC) 681 or server 682 are connected. It includes any recording medium that records a control program readable by the computer system 600, such as a “communication medium” that stores a program in a short time when transmitting the program, such as a local area network or a wide area network N1.

  That is, the control program is recorded on a recording medium such as “portable physical medium”, “fixed physical medium”, and “communication medium” in a computer-readable manner, and the computer system 600 includes such a recording medium. The control device is realized by reading out and executing the control program from. Note that the control program is not limited to be executed by the computer system 600, and when the other computer system (PC) 681 or the server 682 executes the control program, or these cooperate with each other. The present invention can be similarly applied to the case where the above is executed.

  As an example of a case where a part of the processing performed by each unit is configured by software, a processing procedure when the processing of the control device 300 is realized by software for an image acquired by the imaging unit is illustrated in the flowchart of FIG. I will explain.

  As shown in FIG. 20, when this process is started, a normal light image is acquired (S1). In step S1, a special light image may be acquired. Next, based on the acquired image, it is determined whether or not it is in an enlarged observation state (S2). When it is determined that the state is not the magnified observation state (S2, NO), a normal light image is acquired (S1).

  On the other hand, if it is determined that the state is the magnified observation state (S2, YES), a special light image is acquired (S3). In step S3, the normal light image may also be acquired. Next, an evaluation value of the special light image is acquired (S4). Next, focus determination is performed based on the evaluation value (S5). If the in-focus position is not detected (S5, NO), control is performed to move the position of the condenser lens (S6), and a special light image is acquired (S3).

  On the other hand, when the in-focus position is detected (S5, YES), control is performed to move the condenser lens to the in-focus position (S7). Next, a normal light image is acquired (S8). In step S8, the special light image may be acquired together. Next, when the imaging is not finished (S9, NO), a special light image is acquired (S3). If the imaging is finished (S9, YES), the process is finished.

  Thus, for example, it is possible to acquire image data by capturing an image with a separate image capturing unit, and to process the image data in a software system using a computer system such as a PC.

  In the present embodiment, program codes for realizing each part (normal light image acquisition unit, special light image acquisition unit, evaluation value calculation unit, in-focus position determination unit, control unit, determination unit, etc.) of the present embodiment are recorded. It can also be applied to other computer program products.

  Here, the program code realizes a first image acquisition unit, a second image acquisition unit, and a focus control unit. The first image acquisition unit acquires an image including a subject image having information in a wavelength band of white light as a first image, which is an image obtained by capturing an in-vivo subject with an imaging optical system. The second image acquisition unit acquires an image including a subject image having information in a specific wavelength band as the second image corresponding to the first image. The focus control unit performs focus control on the subject image in the second image to adjust the focus of the imaging optical system. The first image acquisition unit acquires a first image picked up by the image pickup optical system whose focus has been adjusted.

  The computer program product includes, for example, an information storage medium (an optical disk medium such as a DVD, a hard disk medium, a memory medium, etc.) on which a program code is recorded, a computer on which the program code is recorded, and an Internet system (for example, a program code). , A system including a server and a client terminal), and the like. In this case, each component and each processing process of this embodiment are mounted by each module, and the program code constituted by these mounted modules is recorded in the computer program product.

  As mentioned above, although embodiment and its modification which applied this invention were described, this invention is not limited to each embodiment and its modification as it is, and in the range which does not deviate from the summary of invention in an implementation stage. The component can be modified and embodied. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments and modifications. For example, some constituent elements may be deleted from all the constituent elements described in each embodiment or modification. Furthermore, you may combine suitably the component demonstrated in different embodiment and modification. Thus, various modifications and applications are possible without departing from the spirit of the invention.

  In the specification or drawings, terms (endoscope device, normal light image, special light image, etc.) described at least once together with different terms (imaging device, first image, second image, etc.) having a broader meaning or the same meaning ) May be replaced by the different terms anywhere in the specification or drawings.

101 Illumination unit, 102 Imaging unit, 103, 103a, 103b A / D conversion unit,
104 normal light image acquisition unit, 105 special light image acquisition unit, 106 evaluation value calculation unit,
107 buffer, 108 in-focus position determination unit, 109 output unit, 110 control unit,
111 I / F unit, 112 determination unit, 150 focus control unit,
201 light source device, 202, 202a white light source, 202b special light source,
202c switcher, 202d red light source, 202e green light source,
202f Blue light source, 202g Green narrow band light source, 202h Blue narrow band light source,
203 Rotating filter, 204 Condensing lens, 205 Exterior,
206 light guide fiber, 207 illumination optical system, 208 condenser lens,
209 imaging device, 210 white light transmission filter, 211 narrow band transmission filter,
220 red light transmission filter, 221 green light transmission filter,
222 Blue light transmission filter, 223 Green narrow band light transmission filter,
224 Blue narrowband light transmission filter, 228 splitter,
229 first image sensor, 230 narrow-band transmission filter, 231 second image sensor,
300 control device, 331 special light image generation unit, 401 matrix data setting unit,
402 imaging unit, 403 signal extraction unit,
600 computer system, 610 main body,
611 CPU, 612 RAM, 613 ROM, 614 HDD,
615 CD-ROM drive, 616 USB port,
617 I / O interface, 618 LAN interface,
620 display, 621 display screen, 630 keyboard, 640 mouse,
650 modem, 660 CD-ROM, 670 USB memory, 681 PC,
682 server, 683 printer,
KC quadratic function, N1 wide area network, N3 public line,
d1 to d3 position, df focusing position, ev1, ev2 evaluation value

Claims (21)

A first image acquisition unit that acquires, as a first image, an image obtained by imaging an in-vivo subject using an imaging optical system, the image including a subject image having information in the wavelength band of white light;
A second image acquisition unit that acquires an image including a subject image having information in a specific wavelength band as a second image corresponding to the first image;
A focus control unit that performs control to focus on a subject image in the second image and performs focus adjustment of the imaging optical system;
Including
The first image acquisition unit includes:
An endoscope apparatus, wherein the first image captured by the imaging optical system with the focus adjusted is acquired. In claim 1,
The second image acquisition unit
The second image is acquired using a wavelength band in which the contrast of the subject in the living body is higher in the second image than in the first image as the specific wavelength band,
The focus control unit
An endoscope apparatus that performs the control to focus on a subject image in the second image based on a contrast of the second image. In claim 1,
The specific wavelength band is
An endoscope apparatus having a band narrower than the wavelength band of the white light. In claim 3,
The specific wavelength band is
An endoscope apparatus having a wavelength band of a wavelength absorbed by hemoglobin in blood. In claim 4,
The specific wavelength band is
An endoscope apparatus characterized by being in a range of 390 nanometers to 445 nanometers, or 530 nanometers to 550 nanometers. In claim 1,
The second image acquisition unit
An endoscope apparatus, wherein the second image is generated based on the acquired first image. In claim 6,
The second image acquisition unit
A signal extraction unit for extracting a signal in the wavelength band of the white light from the acquired first image;
The second image acquisition unit
An endoscope apparatus, wherein the second image including a signal in the specific wavelength band is generated based on the extracted signal. In claim 7,
The second image acquisition unit
A matrix data setting unit for setting matrix data for calculating a signal in the specific wavelength band from a signal in the wavelength band of the white light;
The second image acquisition unit
An endoscope apparatus, wherein the second image is generated by calculating a signal in the specific wavelength band from a signal in the wavelength band of the white light using the set matrix data. In claim 1,
Including a determination unit that determines whether the observation state is a magnified observation state,
When it is determined by the determination unit that the magnified observation state is present,
The focus control unit
Performing the control to focus on the subject image in the second image, adjusting the focus of the imaging optical system,
The first image acquisition unit includes:
An endoscope apparatus, wherein the first image captured by the imaging optical system with the focus adjusted is acquired. In claim 9,
The determination unit
When the information about whether or not the scope unit of the endoscopic device is approaching the subject is acquired, and when it is determined based on the information that the scope unit is approaching the subject, the magnified observation state It is determined that the endoscope apparatus is. In claim 10,
The determination unit
The size of the edge shape of the subject is acquired as the information, and when it is determined that the size of the edge shape is larger than the size of the edge shape before a predetermined time, it is determined that the state is the magnified observation state. An endoscope apparatus characterized by the above. In claim 9,
The determination unit
When the evaluation value for evaluating the in-focus state of the image is acquired from the first image or the second image and it is determined based on the evaluation value that the in-focus state is changed from the in-focus state, An endoscope apparatus characterized in that it is determined to be in a magnified observation state. In claim 1,
The first image acquisition unit includes:
Obtaining the first image based on the light emitted from the light source unit;
The second image acquisition unit
An endoscope apparatus, wherein the second image based on light emitted from the light source unit is acquired. In claim 13,
The light source unit is
A white light source,
The first image acquisition unit includes:
Obtaining the first image based on white light emitted from the white light source;
The second image acquisition unit
An endoscope apparatus that acquires the second image based on the white light emitted from the white light source. In claim 14,
The light source unit is
By applying a filter that transmits the wavelength band of the first to Nth (N is an integer of 2 or more) monochromatic light constituting the white light to the white light, the first to Nth monochromatic colors are applied. Emit light,
The first image acquisition unit includes:
Acquiring first to N-th monochromatic images having information on wavelength bands of the first to N-th monochromatic lights, and generating the first image based on the acquired first to N-th monochromatic images. An endoscope apparatus characterized by the above. In claim 14,
The light source unit is
By applying a filter that transmits the specific wavelength band to the white light, the light of the specific wavelength band is emitted,
The second image acquisition unit
An endoscope apparatus, wherein the second image having information on the specific wavelength band is acquired. In claim 16,
The light source unit is
By applying a filter that transmits the first to Mth (M is an integer of 2 or more) wavelength bands constituting the specific wavelength band to the white light, the first to Mth wavelength bands Emit light,
The second image acquisition unit
Acquiring the first to M-th component images having the information of the first to M-th wavelength bands, and generating the second image based on the acquired first to M-th component images. Endoscope device. In claim 13,
The light source unit is
A white light source,
A special light source that emits special light having information of the specific wavelength band;
The first image acquisition unit includes:
Obtaining the first image based on the white light emitted from the white light source;
The second image acquisition unit
An endoscope apparatus characterized by acquiring the second image based on the special light emitted from the special light source. A first image acquisition unit that acquires, as a first image, an image obtained by imaging an in-vivo subject using an imaging optical system, the image including a subject image having information in the wavelength band of white light;
A second image acquisition unit that acquires, as a second image, an image including a anatomical subject image in which the anatomy of the subject image included in the first image is further emphasized;
A focus control unit that performs control to focus on a subject image in the second image and performs focus adjustment of the imaging optical system;
Including
The first image acquisition unit includes:
An endoscope apparatus, wherein the first image captured by the imaging optical system with the focus adjusted is acquired. An image obtained by imaging an in-vivo subject with an imaging optical system and including an image of the subject having information in the wavelength band of white light is acquired as a first image;
Corresponding to the first image, an image including a subject image having information in a specific wavelength band is acquired as a second image,
Performing control to focus on the subject image in the second image, performing focus adjustment of the imaging optical system,
A focus control method characterized in that the first image captured by the focus-adjusted imaging optical system is acquired. A first image acquisition unit that acquires, as a first image, an image obtained by imaging an in-vivo subject using an imaging optical system, the image including a subject image having information in the wavelength band of white light;
A second image acquisition unit that acquires an image including a subject image having information in a specific wavelength band as a second image corresponding to the first image;
As a focus control unit that performs control for focusing on the subject image in the second image and performs focus adjustment of the imaging optical system,
Make the computer work,
The first image acquisition unit includes:
A program for acquiring the first image picked up by the image pickup optical system with the focus adjusted.

Images