Endoscope system and interface adapter

Abstract

The invention provides an interface adapter and an endoscope system including the same, wherein the interface adapter can reduce the construction cost of a system capable of displaying an image based on an imaging signal obtained by an observer on a general-purpose portable information terminal. An interface adapter (4) is provided with: a first communication interface (41) for communicating with an observer (1) including an imaging sensor (23) and a light source device (5); a second communication interface (43) for communicating with a portable information terminal (7); and a processor (a signal processing unit (42) and a system control unit (44)) that performs processing in which imaging is performed by the imaging sensor (23) in a state in which the amount of illumination light of the observer (1) is controlled to be constant. A control unit (23) for controlling the imaging sensitivity and exposure time by the imaging sensor (23) in accordance with the brightness of the imaging target site determined on the basis of the imaging signal obtained by imaging; and converting the imaging signal into image data that can be displayed by the portable information terminal (7), and transmitting the image data to the portable information terminal (7).

Description

Technical Field

[0001] The present invention relates to an endoscope system and an interface adapter. Background Art

[0002] In recent years, disposable endoscopes, which can be used hygienically and safely with a single use, have attracted attention. Patent Document 1 describes an endoscope that transmits image signals from an endoscope camera to a control unit, and then transmits the image signals from the control unit to a video display via a wire. Patent Document 2 describes a laparoscope system in which the laparoscope communicates with an adapter (dongle), which transmits image data to a television display.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2012-511357

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2020-18876 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] An object of the present invention is to construct a system capable of displaying an image based on an imaging signal obtained by a viewer on a general-purpose portable information terminal at low cost.

[0009] Means for solving technical problems

[0010] An interface adapter according to one embodiment of the present invention comprises: a first communication interface for communicating with an observer, the observer including an imaging sensor and a light source device for generating illumination light for imaging by the imaging sensor; a second communication interface for communicating with a portable information terminal; and a processor for performing the following processing: performing imaging by the imaging sensor while controlling the light intensity of the illumination light to be constant; converting an imaging image signal obtained by the imaging sensor into image data displayable by the portable information terminal and transmitting the image data to the portable information terminal; deriving brightness of the image data based on the imaging image signal; and controlling imaging sensitivity of the imaging sensor and exposure time of the imaging sensor based on the brightness.

[0011] Effects of the Invention

[0012] According to the present invention, a system capable of displaying an image based on an imaging signal obtained by a viewer on a general-purpose portable information terminal can be constructed at low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing an example of an endoscope system 100 as one embodiment of the present invention.

[0014] Figure 2 This is a diagram showing an example of the interface adapter 4 (part 1).

[0015] Figure 3 This is a diagram showing an example of the interface adapter 4 (part 2).

[0016] Figure 4 FIG. 1 is a diagram showing an example of a state of the interface adapter 4 and the portable information terminal 7 before being housed in the frame 8 (Part 1).

[0017] Figure 5 This is a diagram (part 2) showing an example of a state of the interface adapter 4 and the portable information terminal 7 before being housed in the frame 8 .

[0018] Figure 6 This is a diagram (part 1) showing an example of a state where the interface adapter 4 and the portable information terminal 7 are attached to the rear case 82 .

[0019] Figure 7 This is a diagram (part 2) showing an example of a state where the interface adapter 4 and the portable information terminal 7 are attached to the rear case 82 .

[0020] Figure 8 1 is a diagram showing an example of a state in which the front cover 81 is attached to the rear case 82 .

[0021] Figure 9 This is a diagram (part 2) showing an example of a state in which the front cover 81 is attached to the rear case 82.

[0022] Figure 10 1 is a diagram showing an example of the internal structure of the scope 1 and the interface adapter 4 .

[0023] Figure 11 It is a diagram showing an example of the hardware configuration of the portable information terminal 7 .

[0024] Figure 12 This is a flowchart for explaining a detailed example of the photometry processing and exposure control performed by the system control unit 44 .

[0025] Figure 13 Schematic diagram illustrating the relationship between the exposure change amount ΔEV [Log], the exposure time SS, and the amplification factor DG.

[0026] Figure 14 is a schematic diagram for explaining gamma correction processing.

[0027] Figure 151 is a schematic diagram showing an example of an image displayed on the display unit 7 a when the scope 1 is a bronchial endoscope.

[0028] Figure 16 53 is a diagram showing a display example of image data subjected to gamma correction so as to obtain the output gradation characteristics shown by the solid line in Graph 53 .

[0029] Figure 17 is a diagram showing an example of a gain correction table. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0031] <Endoscope System 100 as One Embodiment of the Present Invention>

[0032] Figure 1 FIG. 1 is a diagram showing an example of an endoscope system 100 as an embodiment of the present invention. The endoscope system 100 includes: a scope 1; an interface adapter 4 connected to the scope 1; and a frame 8 for accommodating a portable information terminal 7 connected to the interface adapter 4. Figure 1 In the embodiment, the interface adapter 4 is located on the back side of the portable information terminal 7 and is covered by the frame 8, so that it is invisible. The endoscope system 100 may further include a portable information terminal 7.

[0033] The scope 1 is an endoscope and includes an insertion section 10, a tubular member extending in one direction and inserted into a subject; and an operating section 11, disposed at the base of the insertion section 10 and used to perform various operations of the scope 1. The operating section 11 may include, for example, an angle knob that bends the insertion section 10 by rotation. Furthermore, the operating section 11 may include operating components for switching observation modes of the scope 1, recording images, manipulating forceps, supplying air and water, and performing suction operations.

[0034] The scope 1 is connected to the interface adapter 4 via a communication cable 13. Furthermore, the scope 1 is detachable from the interface adapter 4 via the communication cable 13 and is capable of single-use (i.e., disposable) use. For example, the communication cable 13 may be detachable from the interface adapter 4, and the scope 1 may be detachable from the communication cable 13.

[0035] In addition, although Figure 1 Although omitted in the figure, various channels such as forceps holes for inserting forceps for collecting biological tissues such as cells or polyps, air and water supply channels, and suction channels may be provided inside the operation portion 11 and the insertion portion 10.

[0036] The insertion portion 10 consists of a flexible soft portion 10A, a curved portion 10B provided at the distal end of the soft portion 10A, and a rigid distal end portion 10C provided at the distal end of the curved portion 10B. The curved portion 10B is configured to be freely bendable by operating an operating portion 11 (e.g., an angle knob). The curved portion 10B can be bent in any direction and at any angle depending on the part of the subject being examined, thereby allowing the distal end portion 10C to be oriented in a desired direction.

[0037] The interface adapter 4 connects the scope 1 and the portable information terminal 7. Specifically, the interface adapter 4 is communicably connected to the scope 1 via, for example, a communication cable 13. Furthermore, the interface adapter 4 is communicably connected to the portable information terminal 7 by wire or wirelessly.

[0038] The interface adapter 4 receives an imaging signal from the scope 1 obtained by the imaging sensor of the scope 1 and converts the received imaging signal into image data displayable by the portable information terminal 7. The interface adapter 4 then transmits the converted image data to the portable information terminal.

[0039] The portable information terminal 7 is a general-purpose portable information terminal such as a tablet or smartphone. The portable information terminal 7 includes a display unit 7a capable of displaying images based on image data. The portable information terminal 7 receives images captured by the scope 1 from the subject's body, etc., from the interface adapter 4, and displays the received images on the display unit 7a. The display unit 7a includes a display surface with two-dimensionally arranged display pixels. The display surface displays images based on the image data by drawing pixel data constituting the image data onto each pixel on the display surface. Furthermore, the portable information terminal 7 also serves as a user interface for controlling the interface adapter 4.

[0040] <Interface Adapter 4>

[0041] Figure 2 and Figure 3 It is a diagram showing an example of the interface adapter 4. Figure 2 、 Figure 3 4 are views of the interface adapter 4 from different directions. Figure 2 、 Figure 3 As shown, the interface adapter 4 is substantially in the shape of a rectangular parallelepiped and has a video input terminal 4a and a video output terminal 4b.

[0042] The video input terminal 4a and the video output terminal 4b can each be a terminal of various communication standards capable of transmitting video signals, such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface), or DVI (Digital Visual Interface). HDMI is a registered trademark.

[0043] The video input terminal 4a is a terminal for communicably connecting to the viewer 1. For example, the video input terminal 4a is an HDMI terminal, and the viewer 1 is also provided with an HDMI terminal. The communication cable 13 is an HDMI cable, and the video input terminal 4a and the HDMI terminal of the viewer 1 are connected via the communication cable 13.

[0044] However, the connection between the interface adapter 4 and the viewer 1 is not limited to an HDMI-based connection. A wired connection other than HDMI, such as USB or DVI, or a wireless connection using Bluetooth or near-field communication, etc. (Bluetooth is a registered trademark). Furthermore, the connection between the interface adapter 4 and the viewer 1 may be established via a conversion adapter that converts communication standards.

[0045] The video output terminal 4b is a terminal for communicably connecting to the portable information terminal 7. For example, the video output terminal 4b is a USB terminal, and the portable information terminal 7 is also provided with a USB terminal. Then, the video output terminal 4b and the USB terminal of the portable information terminal 7 are connected via a USB cable.

[0046] However, the connection between the interface adapter 4 and the portable information terminal 7 is not limited to a USB-based connection. It may also be a wired connection other than USB, such as HDMI or DVI, or a wireless connection based on Bluetooth or near-field wireless communication. Furthermore, the connection between the interface adapter 4 and the portable information terminal 7 may be established via a conversion adapter that converts communication standards.

[0047] Furthermore, the interface adapter 4 includes a circuit for controlling the scope 1 or converting an image signal from the scope 1 into image data that can be displayed on the portable information terminal 7. The internal structure of the interface adapter 4 will be described later (for example, see Figure 10 ).

[0048] <State of the Interface Adapter 4 and the Portable Information Terminal 7 Before Being Accommodated in the Frame 8>

[0049] Figure 4 and Figure 5This is a diagram showing an example of a state before the interface adapter 4 and the portable information terminal 7 are housed in the frame 8 . Figure 4 、 Figure 5 1 and 2 are views showing the interface adapter 4, the portable information terminal 7 and the frame 8 from different directions. Figure 4 、 Figure 5 As shown, the frame 8 includes a front cover 81 and a rear shell 82 .

[0050] The front cover 81 protects the front surface of the portable information terminal 7. The front cover 81 has an opening 81a for exposing the display unit 7a from the front cover 81, so that the display unit 7a (touch panel) of the portable information terminal 7 can be displayed or the display unit 7a can be touched.

[0051] The rear case 82 protects the back of the portable information terminal 7. A cable insertion hole (not shown) is provided in the rear case 82 to allow the communication cable 13 to be connected from outside the frame 8 to the image input terminal 4a of the interface adapter 4 housed in the frame 8. A cable insertion hole cover 82a is provided on the rear case 82 to seal the cable insertion hole. Furthermore, a marking visibility hole 82b is provided in the rear case 82 to allow markings such as the reference mark on the interface adapter 4 within the frame to be visible from outside the frame 8.

[0052] The interface adapter 4 is housed in the frame 8 together with the portable information terminal 7, whereby the interface adapter 4 is fixed to the frame 8. Figure 4 、 Figure 5 In the example of FIG, the interface adapter 4 is fixed to the frame 8 via the portable information terminal 7 by being attached to the back surface of the portable information terminal 7 fixed by the frame 8 .

[0053] The interface adapter 4 is attached to the portable information terminal 7 by, for example, screwing using screw holes provided on the back of the portable information terminal 7. Alternatively, the interface adapter 4 may be attached to the portable information terminal 7 via a metal plate or the like formed according to the shape of the back of the interface adapter 4.

[0054] Furthermore, the interface adapter 4 is not limited to being fixed to the frame 8 via the portable information terminal 7 , and the interface adapter 4 may be directly attached to the frame 8 . For example, the interface adapter 4 may be attached to the rear case 82 of the frame 8 .

[0055] Furthermore, a bracket 82c may be provided outside the rear case 82. The bracket 82c is provided on the rear case 82 via a hinge, for example, and by partially pulling the bracket 82c out of the rear case 82, the frame 8 can be erected on a horizontal surface such as a table top.

[0056] Furthermore, in addition to or in place of the bracket 82c, the rear housing 82 may be provided with screw holes that can be used when mounting the frame 8 on a wall mount, arm, bracket, or the like. These screw holes can be screw holes that comply with the VESA (Video Electronics Standards Association) standard, for example.

[0057] exist Figure 4 、 Figure 5 In the state, the image output terminal 4b of the interface adapter 4 is connected to the portable information terminal 7 via a communication cable (for example, a USB cable).

[0058] <State where the interface adapter 4 and the portable information terminal 7 are mounted on the rear housing 82>

[0059] Figure 6 and Figure 7 This is a diagram showing an example of a state in which the interface adapter 4 and the portable information terminal 7 are attached to the rear case 82 . Figure 6 、 Figure 7 These are views showing the interface adapter 4 , the portable information terminal 7 , and the frame 8 as viewed from different directions.

[0060] like Figure 4 、 Figure 5 As shown, when the interface adapter 4 is mounted on the back of the portable information terminal 7, Figure 6 、 Figure 7 As shown, the portable information terminal 7 and the interface adapter 4 are mounted inside the rear case 82. This allows the interface adapter 4's housing, including reference marks and other markings, to be exposed through the marking viewing hole 82b. Furthermore, by removing the cable insertion hole cover 82a, the video input terminal 4a of the interface adapter 4 is exposed through the cable insertion hole of the rear case 82.

[0061] <State where the front cover 81 is mounted on the rear housing 82>

[0062] Figure 8 and Figure 9 This is a diagram showing an example of a state in which the front cover 81 is attached to the rear case 82 . Figure 8 、 Figure 9 These are views showing the frame 8 and the like as viewed from different directions.

[0063] like Figure 6 、 Figure 7 As shown, when the portable information terminal 7 and the interface adapter 4 are mounted on the rear housing 82, Figure 8 、 Figure 9 As shown, the front cover 81 is attached to the rear case 82 . As a result, the portable information terminal 7 and the interface adapter 4 are accommodated in the frame 8 .

[0064] Framework 8 Figure 8 、 Figure 9 In the illustrated state, the device has a waterproof structure to prevent the intrusion of water, dust, etc. from the outside. For example, a sealant is provided between the front cover 81 and the rear case 82 to fill the gap between the front cover 81 and the rear case 82. Furthermore, the frame of the opening 81a of the front cover 81 is sealed so as to closely fit the display unit 7a of the portable information terminal 7, and the opening 81a is blocked by the display unit 7a.

[0065] Furthermore, the frame portion of the mark-visible hole 82 b of the rear case 82 is sealed so as to be in close contact with the frame of the interface adapter 4 , and the mark-visible hole 82 b is blocked by the frame of the interface adapter 4 .

[0066] Furthermore, the frame portion of the cable insertion hole of the rear shell 82 is sealed so as to closely fit the frame of the interface adapter 4. When the cable insertion hole cover 82a is removed from the rear shell 82, the cable insertion hole of the rear shell 82 is blocked by the frame of the interface adapter 4. Furthermore, when the cable insertion hole cover 82a is removed from the rear shell 82, the periphery of the cable insertion hole of the rear shell 82 is sealed so that the communication cable 13 inserted through the cable insertion hole of the rear shell 82 blocks the cable insertion hole of the rear shell 82.

[0067] That is, the frame 8 has a waterproof structure to prevent water, dust, etc. from intruding into the interior of the frame 8 by virtue of the interface adapter 4 and portable information terminal 7 accommodated therein. Thus, even when the portable information terminal 7, the interface adapter 4, and the frame 8 are used outdoors, water, dust, etc. can be prevented from intruding into the interior of the frame 8, thereby protecting the interface adapter 4 and the portable information terminal 7.

[0068] As described above, the endoscope system 100 has a configuration in which the interface adapter 4 that converts an imaging signal obtained by the imaging sensor 23 of the scope 1 into image data displayable by the portable information terminal 7 is fixed to the frame 8 that accommodates the portable information terminal 7 .

[0069] Thus, the interface adapter 4 converts the imaging signal obtained by the imaging sensor 23 of the scope 1 into image data, so the portable information terminal 7 can be a general-purpose portable information terminal such as a tablet terminal. This makes it easier to purchase, replace, or update the portable information terminal 7.

[0070] Furthermore, the interface adapter 4 is fixed to the frame 8 that accommodates the portable information terminal 7, so that the portable information terminal 7 and the interface adapter 4 are integrated via the frame 8. Therefore, it is easy to operate the scope 1 while observing an image based on an imaging signal obtained by the imaging sensor 23 of the scope 1 through the portable information terminal 7.

[0071] For example, a user of the endoscope system 100 (e.g., a doctor) can operate the scope 1 while observing an image, regardless of the position of the interface adapter 4 between the scope 1 and the portable information terminal 7. Furthermore, when the user operates the scope 1 while observing an image, accidents such as the interface adapter 4 between the scope 1 and the portable information terminal 7 falling and pulling the scope 1 can be prevented.

[0072] Furthermore, by providing the interface adapter 4 between the scope 1 and the portable information terminal 7, it is unnecessary to provide the scope 1 with an image processing circuit (e.g., the signal processing unit 42) for converting the imaging signal obtained by the imaging sensor 23 of the scope 1 into image data. This reduces the manufacturing cost of the scope 1 and facilitates the handling of the scope 1 during single use.

[0073] <Internal Structure of Observer 1 and Interface Adapter 4>

[0074] Figure 10 1 is a diagram showing an example of the internal structure of the observer 1 and the interface adapter 4. Figure 10 As shown, the distal end portion 10C of the scope 1 is provided with an imaging optical system including an objective lens 21 and a lens group 22, an imaging sensor 23 for capturing an image of a subject via the imaging optical system, a memory 25 such as a RAM (Random Access Memory), a communication interface (I / F) 26, an imaging drive unit 27, a light source device 5, and an illumination lens 50.

[0075] A CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor can be used as the imaging sensor 23. The imaging sensor 23 can perform imaging using a rolling shutter method or a global shutter method.

[0076] The imaging sensor 23 has a light-receiving surface with a plurality of pixels arranged two-dimensionally. The optical image formed on this light-receiving surface by the imaging optical system is converted into an electrical signal (imaging signal) at each pixel. The imaging sensor 23 then converts the converted imaging signal from an analog signal into a digital signal with a predetermined number of bits and outputs the converted imaging signal to the memory 25. For example, the imaging sensor 23 may be an imaging sensor equipped with a primary color or complementary color filter. The collection of imaging signals output from each pixel on the light-receiving surface of the imaging sensor 23 is referred to as an imaging image signal.

[0077] The memory 25 temporarily stores the digital imaging signal output from the imaging sensor 23. The communication interface (I / F) 26 is connected to the first communication interface (I / F) 41 of the interface adapter 4. The communication interface 26 transmits the imaging signal stored in the memory 25 to the interface adapter 4 via the signal line in the communication cable 13.

[0078] The imaging drive unit 27 is connected to the system control unit 44 of the interface adapter 4 via the communication interface 26 . The imaging drive unit 27 drives the imaging sensor 23 and the memory 25 based on a command received from the system control unit 44 via the communication interface 26 .

[0079] The light source device 5 can emit ordinary light, such as white light, as illumination light, having a luminescence spectrum suitable for human recognition by doctors and other patients. Furthermore, the light source device 5 can emit special light, which has a luminescence spectrum different from ordinary light and suitable for computer-based image analysis, such as IEE (Image-Enhanced Endoscopy). For example, a semiconductor light source can be used as the light source of the light source device 5.

[0080] The light source device 5 is connected to the system control unit 44 of the interface adapter 4 via the communication interface 26. The light source device 5 emits illumination light in accordance with a command from the system control unit 44 received through the communication interface 26.

[0081] The illumination lens 50 directs the illumination light emitted from the light source device 5 toward the imaging target (e.g., within the subject) via the imaging sensor 23 and the imaging optical system. An aperture may be included between the illumination lens 50 and the light source device 5 or within the imaging optical system. However, from the perspective of reducing the manufacturing cost of the scope 1, it is preferable not to include an aperture. The lack of an aperture in the scope 1 simplifies exposure control of the scope 1, thereby also reducing the manufacturing cost of the interface adapter 4.

[0082] The interface adapter 4 includes a first communication interface 41 connected to the communication interface 26 of the scope 1 via a communication cable 13 , a signal processing unit 42 , a second communication interface (I / F) 43 , and a system control unit 44 .

[0083] The first communication interface 41 is used to communicate with the observer 1, for example, Figure 2 、 Figure 3 The video input terminal 4 a shown in FIG. 1 receives an imaging signal transmitted from the communication interface 26 of the scope 1 via the communication cable 13 and transmits the imaging signal to the signal processing unit 42 .

[0084] The signal processing unit 42 includes a built-in memory such as RAM for temporarily recording the digital imaging signals received from the first communication interface 41. The signal processing unit 42 processes the image signals (i.e., the image signals) recorded in the memory (amplification of each imaging signal, demosaicing, white balancing, gamma correction, and other image processing) to generate image data in a format that can be displayed by the portable information terminal 7, which serves as a general-purpose terminal. To enable setting white balance processing for each imaging sensor, the white balance gain can be written to a memory mounted on the viewer 1 during manufacturing and then read from this memory for use during white balance processing. To reduce manufacturing costs, a fixed white balance gain can be used for white balance processing.

[0085] The second communication interface 43 is used to communicate with the portable information terminal 7, for example Figure 3 The video output terminal 4 b shown in FIG. 1 transmits the image data generated by the signal processing unit 42 to the portable information terminal 7 .

[0086] The system control unit 44 controls the various components of the interface adapter 4 and sends commands to the scope 1 to centrally control the entire endoscope system 100. For example, the system control unit 44 is an example of a control unit for the imaging sensor 23, controlling the imaging by the imaging sensor 23 via the imaging drive unit 27. Furthermore, the system control unit 44 is an example of a control unit for the light source device 5, controlling the irradiation of illumination light by the light source device 5. In this embodiment, the system control unit 44 controls the imaging sensor 23 to perform imaging while maintaining a constant light intensity of illumination light emitted from the light source device 5.

[0087] The system control unit 44 also performs the following processes: photometry processing to derive a photometric value representing the brightness of image data (hereinafter referred to as brightness Y) from the captured image signal obtained by the imaging sensor 23; and exposure control to control the imaging sensitivity of the imaging sensor 23 (specifically, the amplification factor of the imaging signal in the aforementioned amplification process) and the exposure time of the imaging sensor 23 based on the brightness Y obtained in the photometry processing. For example, the system control unit 44 performs the following processes: deriving brightness YA of the captured image signal from the captured image signal before amplification processing by the base signal processing unit 42, amplifying this brightness YA at the amplification factor used in the amplification process to derive brightness Y, and controlling the imaging sensitivity of the imaging sensor 23 and the exposure time of the imaging sensor 23 so that this brightness Y approaches a brightness suitable for recognition by a human such as a doctor (hereinafter referred to as target brightness Yt).

[0088] The signal processing unit 42 and the system control unit 44 each include various processors, RAM, and ROM (Read Only Memory) that execute programs to perform processing. These processors include general-purpose processors such as CPUs (Central Processing Units) that execute programs to perform various processes, and processors with circuit structures that can be modified after manufacturing, such as FPGAs (Field Programmable Gate Arrays), which are programmable logic devices (PLDs) and ASICs (Application Specific Integrated Circuits), which are processors with circuit structures specifically designed to perform specific processes, i.e., dedicated circuits. More specifically, these various processors are circuits formed by combining circuit elements such as semiconductor devices.

[0089] The signal processing unit 42 and the system control unit 44 may be composed of a single processor of various types, or a combination of two or more processors of the same or different types (e.g., a combination of multiple FPGAs or a combination of a CPU and an FPGA). From the perspective of reducing the cost or miniaturization of the interface adapter 4, it is preferred that the signal processing unit 42 and the system control unit 44 be composed solely of an FPGA.

[0090] <Hardware Structure of Portable Information Terminal 7>

[0091] Figure 11 FIG. 7 is a diagram showing an example of the hardware configuration of the portable information terminal 7. The portable information terminal 7 can be configured as follows: Figure 11 The information terminal 110 shown is implemented as a general-purpose information terminal 110. The information terminal 110 includes a processor 111, a memory 112, a communication interface 113, and a user interface 114. The processor 111, the memory 112, the communication interface 113, and the user interface 114 are connected via a bus 119, for example.

[0092] Processor 111 is a circuit that performs signal processing, such as a CPU (Central Processing Unit) that manages the overall control of information terminal 110. Processor 111 can also be implemented as another digital circuit, such as an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor). Furthermore, processor 111 can be implemented by combining multiple digital circuits.

[0093] The memory 112 includes, for example, a main memory and an auxiliary memory. The main memory is, for example, a RAM. The main memory is used as a work area for the processor 111.

[0094] The auxiliary memory is a non-volatile memory such as a magnetic disk, an optical disk, or a flash memory. Various programs for operating the information terminal 110 are stored in the auxiliary memory. The programs stored in the auxiliary memory are loaded into the main memory and executed by the processor 111.

[0095] Furthermore, the auxiliary memory may include a portable memory that can be removed from the information terminal 110. Examples of the portable memory include a USB flash drive, a memory card such as an SD (Secure Digital) memory card, and the like.

[0096] Communication interface 113 is a communication interface for communicating with the outside of information terminal 110 (e.g., interface adapter 4). For example, communication interface 113 is a wired communication interface having a terminal that can be connected to image output terminal 4b of interface adapter 4 via a communication cable. Alternatively, communication interface 113 can be a wireless communication interface that enables wireless communication with interface adapter 4. Communication interface 113 is controlled by processor 111.

[0097] The user interface 114 includes, for example, an input device for receiving user input and an output device for outputting information to the user. For example, the input and output devices are implemented by the display unit 7a, which is configured as a touch panel. Furthermore, the user interface 114 may include keys or a remote control as input devices. Furthermore, the user interface 114 may include a speaker or a vibrator as output devices. The user interface 114 is controlled by the processor 111.

[0098] For example, the touch panel included in the user interface 114 displays image data received from the interface adapter 4 via the communication interface 113. This allows an image based on an imaging signal obtained by the imaging sensor 23 of the scope 1 to be displayed to a user such as a doctor.

[0099] Furthermore, the touch panel included in the user interface 114 receives instructions for image capture by the imaging sensor 23 of the scope 1 or for irradiation of illumination light by the light source device 5 of the scope 1, in response to user operations. A control signal representing the user operation received by the user interface 114 is transmitted to the system control unit 44 of the interface adapter 4 via the communication interface 113. The system control unit 44 controls image capture by the imaging sensor 23 of the scope 1 or irradiation of illumination light by the light source device 5 of the scope 1, based on the received control signal.

[0100] (Detailed example of light metering processing and exposure control)

[0101] Figure 12 This is a flowchart for explaining a detailed example of the photometric processing and exposure control performed by the system control unit 44. Below, assuming that the system control unit 44 is composed only of an FPGA, a detailed example of the photometric processing and exposure control will be explained. Furthermore, below, the values ​​obtained by converting the multiple exposure times that can be set by the image sensor 23 into information in a logarithmic space using a logarithmic conversion lookup table (hereinafter referred to as the first LUT) are recorded as exposure time SS, and the values ​​obtained by converting the multiple amplification factors (digital gains) that can be set and used in the amplification processing performed by the signal processing unit 42 into information in a logarithmic space using the first LUT are recorded as amplification factors DG. The first LUT is generated, for example, according to the formula y = Log (x) × a. In this formula, a is a specified coefficient, x is the value before conversion, and y is the value after conversion.

[0102] When the system control unit 44 acquires the captured image signal before amplification processing by the signal processing unit 42 (step S1), it performs a photometric calculation on the captured image signal using a predetermined photometric method to derive the brightness YA. The brightness Y is then derived by multiplying the brightness YA by the currently set amplification factor during the amplification process (step S2). The photometric method is not particularly limited, but in the case of endoscopes, for example, a method that varies the weighting between the central and peripheral portions of the captured image signal to obtain a photometric value is preferably used. In this case, the following equation (1) is calculated to derive the image feature quantity required for deriving the photometric value.

[0103] Image feature

[0104] ={α×central brightness value+(100-α)×peripheral brightness value}÷100……(1)

[0105] α in equation (1) is a coefficient for changing the weighting of the central portion and the peripheral portion, and may be a fixed value determined by the system or a variable value selected from a plurality of values ​​according to the imaging mode or user preference.

[0106] The division equation shown in equation (1) can be replaced by an equation not including division by using a bit shift operation as shown in the following equation (2): β is a coefficient corresponding to α.

[0107] Image feature

[0108] ={β×central brightness value+(256-β)×peripheral brightness value}>>8……(2)

[0109] If α in equation (1) is 20, for example, β in equation (2) becomes 51.

[0110] If α in equation (1) is 40, for example, β in equation (2) becomes 102.

[0111] If α in equation (1) is 60, for example, β in equation (2) becomes 154.

[0112] If α in equation (1) is 80, for example, β in equation (2) becomes 205.

[0113] The system control unit 44 can derive the image feature quantity using either equation (1) or equation (2). However, when the system control unit 44 is composed solely of an FPGA, it is preferable to derive the image feature quantity using the calculation shown in equation (2) in step S2, and to use this image feature quantity to derive the brightness Y (photometric value). The calculation shown in equation (2) does not include division and is performed only by addition and multiplication. Therefore, the circuit scale of the FPGA can be reduced or the calculation speed of the FPGA can be increased.

[0114] After deriving the brightness Y in step S2 , the system control unit 44 derives the exposure change ΔEV required to bring the image data to the target brightness Yt based on the brightness Y (step S3 ). The exposure change ΔEV can be derived by, for example, calculating the following equation (3).

[0115] Exposure change ΔEV = target brightness Yt ÷ brightness Y (3)

[0116] Regarding equation (3), by converting the target luminance Yt and luminance Y into information in a logarithmic space, they can be replaced with an arithmetic expression that does not include division, as shown in the following equation (4). [Log] represents information in a logarithmic space.

[0117] Exposure change ΔEV[Log]

[0118] = target brightness Yt[Log] - brightness Y[Log]……(4)

[0119] The target luminance Yt[Log] is a value obtained by converting the target luminance Yt into information in a logarithmic space using the first LUT. The luminance Y[Log] is a value obtained by converting the luminance Y into information in a logarithmic space using the first LUT.

[0120] The calculation shown in formula (4) does not include division and is performed only by subtraction. In other words, the calculation shown in formula (4) is performed only by subtraction. Therefore, when the system control unit 44 is composed only of FPGA, the circuit scale of the FPGA can be reduced or the calculation speed based on the FPGA can be improved.

[0121] Assuming that the system control unit 44 is comprised solely of an FPGA, in step S3 , the system control unit 44 converts the luminance Y to luminance Y[Log] using the first LUT, converts the target luminance Yt to target luminance Yt[Log], and subtracts the luminance Y[Log] from the target luminance Yt[Log] to derive the exposure variation ΔEV[Log]. A larger value for the exposure variation ΔEV[Log] indicates that the image data is darker relative to the target luminance Yt.

[0122] Next, the system control unit 44 selects one exposure time from the plurality of exposure times SS according to the magnitude of the exposure change ΔEV[Log] (step S4 ). For example, the system control unit 44 divides the exposure change ΔEV[Log] greater than zero into a plurality of ranges according to its magnitude.

[0123] Figure 13 Schematic diagram illustrating the relationship between the exposure change amount ΔEV [Log], the exposure time SS, and the amplification factor DG. Figure 13 Each graph shows that the value increases as the vertical axis moves upward. Figure 13 An example of a case where six exposure times SS can be set is shown in . In addition, in order to make the observation image composed of continuously acquired image data appear natural, as an example, the upper limit of the exposure time SS is preferably set to (1 / 38) second and the lower limit is preferably set to (1 / 800) second.

[0124] exist Figure 13 In the example shown in FIG, ranges RG1, RG2, RG3, RG4, RG5, RG6, and RG7 are set in ascending order of exposure change ΔEV[Log]. In step S4, if the exposure change ΔEV[Log] falls within ranges RG1 and RG2, the system control unit 44 selects the minimum value (lower limit) among the six exposure times SS. If the exposure change ΔEV[Log] falls within range RG3, the system control unit 44 selects the second minimum value among the six exposure times SS. If the exposure change ΔEV[Log] falls within range RG4, the system control unit 44 selects the third minimum value among the six exposure times SS. If the exposure change ΔEV[Log] falls within range RG5, the system control unit 44 selects the fourth minimum value among the six exposure times SS. If the exposure change ΔEV[Log] falls within range RG6, the system control unit 44 selects the fifth minimum value among the six exposure times SS. When the exposure change amount ΔEV[Log] falls within the range RG7 , the system control unit 44 selects the maximum value (the upper limit value of the exposure time SS) among the six exposure times SS.

[0125] Figure 13The range RG1 shown indicates that the exposure cannot be further reduced and that the generated image data has a brightness above the target brightness Yt. When the exposure change ΔEV[Log] falls within range RG1, the exposure time SS is set to the lower limit, and the amplification factor DG is set to the reference value (e.g., 1x).

[0126] After selecting the exposure time SS in step S4 , the system control unit 44 derives the amplification factor DG by calculating the following equation (5) (step S5 ).

[0127] Amplification DG = exposure change ΔEV[Log] - exposure time SS……(5)

[0128] Furthermore, if the numerical values ​​of the equation (5) are converted from information in a logarithmic space to information in a real number space, the following equation (6) can be obtained.

[0129] Magnification DG [real number]

[0130] =Exposure change ΔEV [real number] ÷Exposure time SS [real number]……(6)

[0131] In this method, the amount of illumination light is constant, and the exposure value is determined by multiplying the amplification factor by the exposure time. Therefore, the above equation (6) holds true. Then, if the values ​​in equation (6) are converted to information in logarithmic space, equation (5) holds true. Therefore, the amplification factor DG can be calculated by calculating equation (5). In this way, in step S5, only the subtraction of the division and subtraction operations is performed. This reduces the circuit scale of the system control unit 44 and increases the speed of deriving the amplification factor DG.

[0132] exist Figure 13 In the example shown in FIG. 1 , when the exposure change ΔEV[Log] is within the ranges RG2 to RG7, the system control unit 44 determines the amplification factor DG to a larger value as the exposure change ΔEV[Log] increases. Furthermore, within the ranges RG2 to RG6, the amplification factor DG varies within a range from a reference value to a predetermined value less than the upper limit of the amplification factor DG. Furthermore, within the ranges RG2 to RG6, the closer the range is to the range RG1, the greater the fluctuation range of the amplification factor DG (the difference between the reference value and the predetermined value). Meanwhile, within the range RG7, the amplification factor DG varies between the reference value and the upper limit.

[0133] After deriving the amplification factor DG in step S5, the system control unit 44 converts the exposure time SS selected in step S4 into a setting value for the imaging sensor 23 using a lookup table, and sets the setting value in a register of the imaging sensor 23 (step SS). As a result, in the next imaging frame, the exposure time of the imaging sensor 23 becomes a value corresponding to the exposure time SS selected in step S4.

[0134] Then, the system control unit 44 uses a lookup table to convert the amplification factor DG derived in step S5 into a setting value for the signal processing unit 42, and sets the setting value in a register of the signal processing unit 42 (step S7). As a result, in the next imaging frame, the amplification factor of the imaging signal during the amplification process becomes a value equivalent to the amplification factor DG derived in step S5.

[0135] like Figure 13 As shown, the exposure time of the imaging sensor 23 is discretely changed according to the brightness Y of the image data, and the amplification factor during the amplification process is continuously changed according to the brightness Y of the image data. By discretely changing the exposure time, the cost of the imaging sensor 23 or its control cost can be reduced. Furthermore, by being able to continuously change the amplification factor, the brightness of the image data can be finely adjusted, thereby improving the quality of the image displayed on the portable information terminal 7.

[0136] And, in Figure 13 In the example shown, as the exposure change ΔEV[Log] moves from range RG2 to range RG6, the maximum value of the amplification factor DG decreases. For example, when the exposure change ΔEV[Log] is within range RG6, the image data is dark, and increasing the amplification factor may make noise more noticeable. Therefore, in this case, reducing the amplitude of the amplification factor change can improve the signal-to-noise ratio. When the exposure change ΔEV[Log] is within range RG7, since the exposure time SS has reached its upper limit, increasing the exposure is not possible except by increasing the amplification factor DG. Therefore, by varying the amplification factor DG between the base value and the upper limit, the image data can be brought closer to the target brightness even in very dark imaging environments.

[0137] In addition, Figure 13 In the example shown, the amplification factor DG varies in each of the ranges RG2 to RG6 depending on the exposure change ΔEV [Log], but this is not limiting. For example, the amplification factor DG can be maintained at a reference value (equivalent to 1x) in each of the ranges RG2 to RG6. With this configuration, the signal-to-noise ratio can be improved across a wide range from ranges RG1 to RG6.

[0138] (Preferred method for image processing)

[0139] The signal processing unit 42 preferably generates image data by performing the above-mentioned gamma correction processing in a manner such that when a pixel value below the first threshold value TH1 is input to the display unit 7a, the output value of the display unit 7a is greater than the pixel value, and when a pixel value exceeding the first threshold value TH1 is input to the display unit 7a, the output value of the display unit 7a is consistent with the pixel value.

[0140] Figure 14 This is a schematic diagram for explaining gamma correction processing. Chart 51 is a chart showing the gamma characteristics of the display unit 7a (e.g., Y = 2.2). The dashed straight line in Chart 51 represents an ideal characteristic in which input and output are in direct proportion. Typically, when performing gamma correction, the gamma characteristics of Chart 51 are considered, and when the pixel value of the corrected image data is input to the display unit 7a, gamma correction is performed on the pre-corrected image data using correction data C1 shown in Chart 52 so that the pixel value and the output value (display brightness value) of the pixel value are consistent.

[0141] In this embodiment, gamma correction is performed on the image data before correction using, for example, correction data C2 shown in Graph 52. Graph 53 is a graph showing the relationship between the pixel values ​​(input values) of the image data obtained by gamma correction according to correction data C2 and the output values ​​of the display unit 7a when the pixel values ​​are input to the display unit 7a.

[0142] As shown in Chart 53, the output grayscale characteristics of the gamma-corrected image data generally coincide with the ideal characteristic straight line within the range where pixel values ​​exceed the first threshold value TH1, but deviate upward from the ideal characteristic straight line within the range where pixel values ​​are below the first threshold value TH1. In other words, when a pixel value below the first threshold value TH1 in the gamma-corrected image data is input to the display unit 7a, the output value of the display unit 7a is greater than that pixel value, and when a pixel value exceeding the first threshold value TH1 is input to the display unit 7a, the output value of the display unit 7a coincides with that pixel value.

[0143] In Figure 53, the range of the pixel values ​​of the gamma-corrected image data from the minimum value (=0) to the second threshold value TH2 which is smaller than the first threshold value TH1 is set as the first range R1, and the range from the third threshold value TH3 between the first threshold value TH1 and the second threshold value TH2 to the second threshold value TH2 is set as the second range R2, and these thresholds and ranges are shown.

[0144] In the gamma-corrected image data, the difference between the output value of the display unit 7a when pixel values ​​in the second range R2 are input to the display unit 7a and the pixel value is greater than the difference between the output value of the display unit 7a when pixel values ​​in the first range R1 are input to the display unit 7a and the pixel value. That is, in the gamma-corrected image data, in areas with very small and very dark pixel values ​​(areas with pixel values ​​in the first range R1) and areas with slightly small and slightly dark pixel values ​​(areas with pixel values ​​in the second range R2), the slightly dark areas appear relatively bright.

[0145] Figure 15 1 is a schematic diagram showing an example of an image displayed on the display unit 7a when the scope 1 is a bronchial endoscope. Figure 15 shows an example of an ideal output grayscale characteristic of image data after gamma correction. Display image 70 shows a thick tube 73, a thin tube 71, and a branch tube 72 inside thin tube 71. While the brightness of thin tube 71 is brighter than that of branch tube 72, the difference between the two brightnesses is minimal.

[0146] Figure 16 This is a diagram showing an example of displaying image data that has been gamma-corrected so as to have the output gradation characteristics shown by the solid line in Graph 53. Of the capillary tube 71 and the branch tube 72, the relatively bright capillary tube 71 is displayed brighter. Figure 15 In comparison, the state of the branch tube 72 observed in the capillary tube 71 is easier to visually recognize.

[0147] In addition, the signal processing unit 42 does not need to use the correction data C2 in the graph 52 in order to generate image data having the output grayscale characteristics shown by the solid line in the graph 53. For example, the signal processing unit 42 may perform gamma correction using the correction data C1 and further perform the correction according to the following. Figure 17 The gain correction table shown in FIG54 is used to apply a gain greater than 1 to small pixel values, thereby obtaining the output grayscale characteristics shown in FIG53. More preferably, it can be set as follows: gamma correction is performed using the correction data C1, and the pixel value is further converted into a brightness value, and the pixel value is converted into a brightness value according to FIG54. Figure 17 The gain correction table shown applies a gain greater than 1 to a luminance value less than a specified value, thereby obtaining the output grayscale characteristics shown in Figure 53.

[0148] In the above description, the imaging sensitivity based on the imaging sensor 23 is changed by changing the amplification factor used in the amplification processing performed by the signal processing unit 42. However, for example, the imaging sensitivity can also be changed by changing the amplification factor of the amplifier that amplifies the analog signal included in the imaging sensor 23.

[0149] As described above, the following matters are described in this specification: In addition, although the corresponding components in the above embodiment are shown in parentheses, the present invention is not limited to these. (1)

[0151] An interface adapter comprising:

[0152] a first communication interface (first communication interface 41) for communicating with an observer (observer 1) including an imaging sensor (imaging sensor 23) and a light source device (light source device 5) for generating illumination light for imaging by the imaging sensor;

[0153] a second communication interface (second communication interface 43) for communicating with a portable information terminal; and

[0154] Processor (system control unit 44 and signal processing unit 42),

[0155] The above processor performs the following processing:

[0156] performing imaging with the imaging sensor while controlling the light amount of the illumination light to be constant;

[0157] converting a camera image signal obtained by the camera sensor into image data displayable by a portable information terminal, and transmitting the image data to the portable information terminal;

[0158] deriving the brightness of the image data according to the camera image signal; and

[0159] The imaging sensitivity of the imaging sensor and the exposure time of the imaging sensor are controlled according to the brightness.

[0160] According to (1), exposure control is performed by adjusting two parameters, imaging sensitivity and exposure time, while the amount of illumination light is constant. Since the number of adjustment targets for exposure control is reduced to two, a processor does not require advanced capabilities. As a result, a system can be implemented at low cost that can display and confirm images captured by the observer via a general-purpose portable information terminal connected via a second communication interface. Furthermore, the interface adapter can be made compact and lightweight. (2)

[0162] The interface adapter according to (1), wherein

[0163] The above-mentioned processor performs the following processing: when the above-mentioned exposure time is controlled to the upper limit value (when the exposure change ΔEV[Log] is within the range R7), the variation range of the above-mentioned camera sensitivity is increased compared with the case where the above-mentioned exposure time is controlled to be less than the above-mentioned upper limit value (when the exposure change ΔEV[Log] is within the range RG2 to the range RG6).

[0164] According to (2), the fluctuation range of the imaging sensitivity becomes smaller before the exposure time reaches the upper limit, thereby improving the signal-to-noise ratio of the imaging signal. On the other hand, after the exposure time reaches the upper limit, the fluctuation range of the imaging sensitivity can be increased, thereby making dark objects appear brighter. (3)

[0166] The interface adapter according to (2), wherein

[0167] The processor performs processing to discretely change the exposure time and continuously change the imaging sensitivity.

[0168] According to (3), since a high-capacity imaging sensor (an imaging sensor capable of finely controlling the exposure time) is not required, the manufacturing cost of the observer can be reduced, or the manufacturing cost of the interface adapter can be reduced by simplifying the control content of the observer, thereby reducing the construction cost of the system. (4)

[0170] The interface adapter according to (2), wherein

[0171] The processor performs the following processing: the exposure time is set to a different value for each of the multiple ranges of brightness (the exposure change ΔEV[Log] in each range of brightness from RG2 to R67), and while the exposure time is controlled to be less than the upper limit value, the imaging sensitivity is changed between a reference value (amplification factor DG = 1 times) and a value lower than the upper limit value of the imaging sensitivity according to the brightness.

[0172] According to (4), since a high-performance imaging sensor (an imaging sensor capable of finely controlling the exposure time) is not required, the manufacturing cost of the viewer can be reduced. Alternatively, by simplifying the control content of the viewer, the manufacturing cost of the interface adapter can be reduced, thereby reducing the system construction cost. Furthermore, even when an arbitrary exposure time is set, by changing the imaging sensitivity, the exposure can be finely adjusted according to the subject, thereby improving the quality of the image data. (5)

[0174] The interface adapter according to any one of (1) to (4), wherein

[0175] The processor performs amplification processing for amplifying the digital image signal output from the image sensor.

[0176] The imaging sensitivity is the amplification ratio set in the amplification process.

[0177] According to (5), the brightness of the image data can be controlled by amplifying the digital signal. Therefore, exposure control can be performed with higher precision compared to the case where the amplification factor when amplifying the analog signal is controlled within the imaging sensor. Furthermore, since an imaging sensor with high analog signal amplification performance is not required, the manufacturing cost of the viewer can be reduced. (6)

[0179] The interface adapter according to any one of (1) to (5), wherein

[0180] The above processor is a programmable logic device.

[0181] According to (6), the cost of the interface adapter can be reduced, thereby reducing the construction cost of the system. (7)

[0183] The interface adapter according to (6), wherein

[0184] The processor performs only the subtraction of division and subtraction as a calculation process required to determine a combination of the imaging sensitivity and the exposure time for bringing the brightness (brightness Y) close to the target brightness (target brightness Yt).

[0185] According to (7), since there is no need to perform division to determine the imaging sensitivity and exposure time, the circuit scale of the processor can be reduced or the calculation time can be shortened. As a result, the manufacturing cost of the interface adapter can be reduced. (8)

[0187] The interface adapter according to (7), wherein

[0188] The values ​​obtained by performing logarithmic conversion on each of the plurality of exposure times that can be set for the imaging sensor are set as logarithmic values ​​of the exposure time (exposure time SS).

[0189] The above processor performs the following processing:

[0190] The logarithmic conversion value of the luminance (luminance Y [Log]) is subtracted from the logarithmic conversion value of the target luminance (target luminance Yt [Log]) to derive a first subtraction value (exposure change amount ΔEV [Log]);

[0191] selecting one from the plurality of exposure time logarithmic values ​​according to the magnitude of the first subtraction value;

[0192] deriving a second subtraction value (amplification ratio DG[Log]) by subtracting the selected logarithmic value of the exposure time from the first subtraction value; and

[0193] The selected logarithmic value of the exposure time is converted into the set value of the exposure time using a conversion table (lookup table), and the second subtraction value is converted into the set value of the imaging sensitivity using a conversion table (lookup table).

[0194] According to (8), since there is no need to perform division processing to determine the imaging sensitivity and exposure time, the circuit scale of the processor can be reduced or the calculation time can be shortened. (9)

[0196] The interface adapter according to any one of (6) to (8), wherein

[0197] The processor performs operations required for the brightness determination by bit shift operations.

[0198] According to (9), since there is no need to perform division processing for determining brightness, the circuit scale of the processor can be reduced or the calculation time can be shortened. (10)

[0200] The interface adapter according to any one of (1) to (9), wherein

[0201] The above processor performs the following processing:

[0202] performing a gamma correction process based on the gamma characteristics of the display unit (display unit 7a) of the portable information terminal as a process for converting the captured image signal into the image data; and

[0203] In the above-mentioned gamma correction processing, the above-mentioned image data is generated in the following state, that is, when a pixel value below the first threshold value (first threshold value TH1) is input into the above-mentioned display unit, the output value of the above-mentioned display unit is greater than the pixel value, and when a pixel value exceeding the above-mentioned first threshold value is input into the above-mentioned display unit, the output value of the above-mentioned display unit is consistent with the pixel value.

[0204] According to (10), when a specific portion of an image captured by an imaging sensor is dark, the dark portion can be brightened regardless of the grayscale characteristics of the display device. Therefore, inspection using an observer can be performed efficiently and accurately. (11)

[0206] The interface adapter according to (10), wherein

[0207] A range of pixel values ​​of the image data from a minimum value to a second threshold value (second threshold value TH2) smaller than the first threshold value is defined as a first range (first range R1), and a range from a third threshold value (third threshold value TH3) between the first and second threshold values ​​to the second threshold value is defined as a second range (second range R2).

[0208] The above-mentioned processor generates the following image data in the above-mentioned gamma correction processing, that is, the difference between the output value of the above-mentioned display unit when the pixel value of the above-mentioned second range is input to the above-mentioned display unit and the pixel value is greater than the difference between the output value of the above-mentioned display unit when the pixel value of the above-mentioned first range is input to the above-mentioned display unit and the pixel value.

[0209] According to (11), when image data contains a dark area and multiple areas with slight differences in brightness, the brighter area among the multiple areas is displayed brighter, making it easier to visually identify the boundaries between the multiple areas. For example, when using a bronchial scope, if the anterior bronchus branches into two, the two branching sites can be clearly identified. (12)

[0211] The interface adapter according to any one of (1) to (11), which is fixed to a frame (frame 8) capable of accommodating the portable information terminal. (13)

[0213] An endoscope system (endoscope system 100) comprising:

[0214] The interface adapter according to any one of (1) to (11);

[0215] a frame (frame 8) capable of accommodating the portable information terminal; and

[0216] The above observer,

[0217] The interface adapter is fixed to the frame.

[0218] While various embodiments have been described above, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art will readily appreciate that various variations or modifications are possible within the scope of the technical proposal, and that these variations or modifications are also within the technical scope of the present invention. Furthermore, the various constituent elements of the aforementioned embodiments may be arbitrarily combined without departing from the spirit of the invention.

[0219] In addition, this application is based on the Japanese patent application (Japanese patent application 2023-025924) applied on February 22, 2023, and the content is cited in this application as a reference.

[0220] Explanation of symbols

[0221] 1-Observer, 4-Interface Adapter, 4a-Image Input Terminal, 4b-Image Output Terminal, 5-Light Source Device, 7-Portable Information Terminal, 7a-Display Unit, 8-Frame, 10-Insertion Unit, 10A-Flexible Unit, 10B-Bending Unit, 10C-Tip Unit, 11-Operation Unit, 13-Communication Cable, 22-Lens Group, 23-Image Sensor, 25, 112-Memory, 26, 113-Communication Interface, 41-First Communication Interface, 27-Image Drive Unit, 42-Signal Processing Unit, 43-Second Communication Interface, 44-system control unit, 50-illumination lens, 81-front cover, 81a-opening, 82-rear shell, 82a-cable insertion hole cover, 82b-marking visible hole, 82c-bracket, 100-endoscope system, 110-information terminal, 111-processor, 114-user interface, 119-bus, RG1~RG7-range, 51, 52, 53-chart, C1, C2-calibration data, R1-first range, R2-second range, 70-displayed image, 71-thin tube, 72-branch tube, 73-thick tube.

Claims

1. An interface adapter comprising: a first communication interface for communicating with an observer including an imaging sensor and a light source device for generating illumination light for imaging by the imaging sensor; a second communication interface for communicating with a portable information terminal; and processor, The processor performs the following processing: performing imaging by the imaging sensor while controlling the light amount of the illumination light to be constant; converting a captured image signal obtained by the image sensor into image data displayable by the portable information terminal, and transmitting the image data to the portable information terminal; deriving the brightness of the image data according to the camera image signal; and The imaging sensitivity of the imaging sensor and the exposure time of the imaging sensor are controlled according to the brightness.

2. The interface adapter according to claim 1, wherein: The processor performs processing to increase a fluctuation range of the imaging sensitivity when the exposure time is controlled to an upper limit value, compared to a case where the exposure time is controlled to be less than the upper limit value.

3. The interface adapter according to claim 2, wherein: The processor performs processing to discretely change the exposure time and continuously change the imaging sensitivity.

4. The interface adapter according to claim 2, wherein: The processor performs the following processing: setting the exposure time to a different value for each of the multiple brightness ranges, and when the exposure time is set to be less than the upper limit value, changing the camera sensitivity between a baseline value and a value lower than the upper limit value of the camera sensitivity according to the brightness.

5. The interface adapter according to any one of claims 1 to 4, wherein: The processor performs amplification processing for amplifying the digital captured image signal output from the imaging sensor. The imaging sensitivity is an amplification ratio set in the amplification process.

6. The interface adapter according to any one of claims 1 to 4, wherein: The processor is a programmable logic device.

7. The interface adapter according to claim 6, wherein: The processor performs only the subtraction of division and subtraction as arithmetic processing required to determine a combination of the imaging sensitivity and the exposure time for bringing the brightness close to a target brightness.

8. The interface adapter according to claim 7, wherein: A value obtained by performing logarithmic conversion on each of a plurality of exposure times that can be set by the imaging sensor is set as a logarithmic value of the exposure time, The processor performs the following processing: deriving a first subtraction value by subtracting the logarithmic conversion value of the luminance from the logarithmic conversion value of the target luminance; selecting one from a plurality of exposure time logarithm values ​​according to the magnitude of the first subtraction value; deriving a second subtraction value by subtracting the selected logarithmic value of the exposure time from the first subtraction value; and The selected logarithmic value of the exposure time is converted into a set value of the exposure time using a conversion table, and the second subtraction value is converted into a set value of the imaging sensitivity using a conversion table.

9. The interface adapter according to claim 6, wherein: The processor performs operations required for determining the brightness through bit shift operations.

10. The interface adapter according to any one of claims 1 to 4, wherein: The processor performs the following processing: performing, as a process for converting the captured image signal into the image data, a gamma correction process based on a gamma characteristic of a display unit of the portable information terminal; and In the gamma correction processing, the image data is generated in the following state, that is, when a pixel value below the first threshold is input to the display unit, the output value of the display unit is greater than the pixel value, and when a pixel value exceeding the first threshold is input to the display unit, the output value of the display unit is consistent with the pixel value.

11. The interface adapter according to claim 10, wherein: A range from a minimum value to a second threshold value smaller than the first threshold value among the pixel values ​​of the image data is set as a first range, and a range from a third threshold value between the first threshold value and the second threshold value to the second threshold value is set as a second range, During the gamma correction processing, the processor generates the image data described below, namely, the difference between the output value of the display unit when the pixel value of the second range is input to the display unit and the pixel value is greater than the difference between the output value of the display unit when the pixel value of the first range is input to the display unit and the pixel value.

12. The interface adapter according to any one of claims 1 to 4, which is fixed to a frame capable of accommodating the portable information terminal.

13. An endoscope system comprising: The interface adapter according to any one of claims 1 to 4; a frame capable of accommodating the portable information terminal; and The observer, The interface adapter is fixed to the frame.

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