Medical image processing device and medical observation system

Abstract

To obtain a captured image suitable for observation.SOLUTION: A medical image processing device comprises an image processing unit for performing image processing for a captured image of a subject image. The image processing unit comprises: a memory 9231 for storing the captured image; and a noise processing unit 9232 capable of writing the captured image into the memory 9231 and reading the captured image from the memory 9231, and for executing noise reduction processing for reducing noise of the captured image of a current frame on the basis of the captured image of the input current frame and the captured image of a past frame read from the memory 9231. The noise processing unit 9232 executes reading stop processing for stopping the reading of the past frame from the memory 9231 at predetermined timing, and writing the captured image of the current frame into the memory 9231 without executing the noise reduction processing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a medical image processing device and a medical observation system. [Background technology]

[0002] BACKGROUND ART Conventionally, in the medical field, a medical observation system for observing the inside of a subject (inside a living body) has been known (see, for example, Patent Document 1). The medical observation system described in Patent Document 1 includes a noise processing unit that executes noise reduction processing to reduce noise in an input captured image of a current frame. Specifically, the noise processing unit executes noise reduction processing to reduce noise in an input captured image of a current frame based on the input captured image of the current frame and a captured image of a previous frame read from a memory. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-312832 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology described in Patent Document 1, if data of an indefinite value is stored in the memory, for example, when the power is turned on, the noise processing unit executes noise reduction processing between the input captured image of the current frame and the indefinite data stored in the memory. In such a case, since appropriate data is not stored in the memory as a captured image of a past frame, executing noise reduction processing results in inappropriate processing, making it impossible to reduce noise and obtaining an image suitable for observation.

[0005] The present disclosure has been made in view of the above, and has an object to provide a medical image processing device and a medical observation system that are capable of obtaining captured images suitable for observation. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the medical image processing device according to the present disclosure includes an image processing unit that performs image processing on an image of a subject, the image processing unit including a memory that stores the image, and a noise processing unit that is capable of writing the image to the memory and reading the image from the memory, and that performs noise reduction processing to reduce noise in the image of the current frame based on the image of the current frame that has been input and the image of the previous frame that has been read from the memory, and the noise processing unit performs read stop processing at a predetermined timing to stop reading of the previous frame from the memory and write the image of the current frame to the memory without performing the noise reduction processing.

[0007] A medical observation system according to the present disclosure includes a medical observation device that captures an image of a subject to generate a captured image, and a medical image processing device having an image processing unit that performs image processing on the captured image, wherein the image processing unit is equipped with a memory that stores the captured image, and a noise processing unit that is capable of writing the captured image to the memory and reading the captured image from the memory, and that performs noise reduction processing to reduce noise in the captured image of the current frame based on the captured image of the input current frame and the captured image of the previous frame read from the memory, and the noise processing unit performs read stop processing at a predetermined timing to stop reading of the previous frame from the memory and write the captured image of the current frame to the memory without performing the noise reduction processing. [Effects of the Invention]

[0008] According to the medical image processing device and medical observation system of the present disclosure, captured images suitable for observation can be obtained. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a medical observation system according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of the camera head and the control device. [Figure 3] FIG. 3 is a block diagram showing the function of executing noise reduction processing in the post-processing section. [Figure 4] FIG. 4 is a diagram illustrating the execution timing of the read stop process. [Figure 5] FIG. 5 is a diagram illustrating the execution timing of the read stop process. [Figure 6] FIG. 6 is a diagram illustrating the execution timing of the read stop process. [Figure 7] FIG. 7 is a diagram showing a modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, modes for carrying out the present disclosure (hereinafter, referred to as embodiments) will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. Furthermore, in the drawings, the same parts are denoted by the same reference numerals.

[0011] [General configuration of medical observation system] FIG. 1 is a diagram showing a medical observation system 1 according to an embodiment. The medical observation system 1 is used in the medical field to observe the inside of a subject (inside a living organism). As shown in Fig. 1, the medical observation system 1 includes an insertion section 2, a light source device 3, a light guide 4, a camera head 5, a first transmission cable 6, a display device 7, a second transmission cable 8, a control device 9, and a third transmission cable 10.

[0012] In this embodiment, the insertion section 2 is configured as a rigid endoscope. That is, the insertion section 2 has an elongated shape that is entirely rigid or has some flexible and other rigid parts, and is inserted into a living body. The insertion section 2 includes an optical system (not shown) that is configured using one or more lenses and focuses an image of a subject.

[0013] The light source device 3 is connected to one end of a light guide 4, and under the control of a control device 9, supplies illumination light of an amount specified by the control device 9 to the one end of the light guide 4. Note that in this embodiment, the light source device 3 is configured as a separate entity from the control device 9, but this is not limiting, and the light source device 3 may be configured to be provided within the control device 9. One end of the light guide 4 is detachably connected to the light source device 3, and the other end is detachably connected to the insertion portion 2. The light guide 4 transmits light supplied from the light source device 3 from one end to the other end and supplies it to the insertion portion 2. The light supplied to the insertion portion 2 is emitted from the tip of the insertion portion 2 and irradiated into the living body. The light irradiated into the living body and reflected within the living body (subject image) is collected by an optical system within the insertion portion 2.

[0014] The camera head 5 corresponds to the medical observation device according to the present disclosure. The camera head 5 is detachably connected to the eyepiece 21 of the insertion section 2. Under the control of the control device 9, the camera head 5 captures an image of a subject focused by the insertion section 2 and generates an image signal (hereinafter referred to as a captured image). The detailed configuration of the camera head 5 will be explained later in the section "Configuration of the Camera Head."

[0015] One end of the first transmission cable 6 is detachably connected to the control device 9 via a connector CN1 (FIG. 1), and the other end is detachably connected to the camera head 5 via a connector CN2 (FIG. 1). The first transmission cable 6 transmits captured images and the like output from the camera head 5 to the control device 9, and also transmits control signals, synchronization signals, clocks, power, and the like output from the control device 9 to the camera head 5. The captured images and the like may be transmitted as optical signals or electrical signals from the camera head 5 to the control device 9 via the first transmission cable 6. The same applies to the transmission of control signals, synchronization signals, and clocks from the control device 9 to the camera head 5 via the first transmission cable 6.

[0016] The display device 7 is configured with a display using liquid crystal or organic EL (Electro Luminescence) or the like, and displays an image based on a video signal from the control device 9 under the control of the control device 9. One end of the second transmission cable 8 is detachably connected to the display device 7, and the other end is detachably connected to the control device 9. The second transmission cable 8 transmits the video signal processed by the control device 9 to the display device 7.

[0017] The control device 9 corresponds to the medical image processing device according to the present disclosure. The control device 9 is configured with a CPU (Central Processing Unit), an FPGA (Field-Programmable Gate Array), etc., and controls the overall operations of the light source device 3, the camera head 5, and the display device 7. The detailed configuration of the control device 9 will be explained later in the section "Configuration of the Control Device." One end of the third transmission cable 10 is detachably connected to the light source device 3, and the other end is detachably connected to the control device 9. The third transmission cable 10 transmits a control signal from the control device 9 to the light source device 3.

[0018] [Camera head configuration] FIG. 2 is a block diagram showing the configuration of the camera head 5 and the control device 9. As shown in FIG. Next, the configuration of the camera head 5 will be described with reference to FIG. As shown in FIG. 2, the camera head 5 includes a lens unit 51, an imaging unit 52, a storage unit 53, and a communication unit . The lens unit 51 is configured using one or more lenses, takes in a subject image condensed by the insertion portion 2, and forms the image on the imaging surface of the imaging section 52 (imaging element 521).

[0019] The imaging unit 52 captures images of the inside of a living body under the control of the control device 9. The imaging unit 52 includes an imaging element 521 and a signal processing unit 522, as shown in FIG. The image pickup element 521 is composed of a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) that receives the subject image formed by the lens unit 51 and converts it into an electrical signal (analog signal). The signal processing unit 522 performs signal processing on the captured image generated by the image sensor 522 as an analog signal and outputs the captured image as a digital signal.

[0020] The storage unit 53 stores a camera head ID (Identifier) ​​for uniquely identifying the type of camera head 5. The camera head ID corresponds to the identification information according to the present disclosure.

[0021] The communication unit 54 is an interface that communicates with the control device 9 via the first transmission cable 6. The communication unit 54 transmits the captured image (digital signal) output from the imaging unit 52 and the camera head ID stored in the storage unit 53 to the control device 9, and also receives control signals and the like from the control device 9.

[0022] [Configuration of the control device] Next, the configuration of the control device 9 will be described with reference to FIG. As shown in FIG. 2, the control device 9 includes a communication unit 91, an image processing unit 92, a display control unit 93, a control unit 94, an input unit 95, an output unit 96, and a storage unit 97. The communication unit 91 is an interface that communicates with the camera head 5 (communication unit 53) via the first transmission cable 6. The communication unit 91 receives the captured image (digital signal) and the camera head ID output from the communication unit 53, and transmits control signals and the like from the control unit 94.

[0023] Under the control of the control unit 94, the image processing unit 92 executes image processing on the captured image (digital signal) output from the camera head 5 and received by the communication unit 91. Specifically, examples of the image processing include optical black subtraction processing, demosaic processing, white balance adjustment processing, noise reduction processing, color correction processing, color enhancement processing, and edge enhancement processing.

[0024] As shown in FIG. 2, the image processing unit 92 includes a synchronization generating unit 921, a pre-processing unit 922, and a post-processing unit 923. The synchronization generating unit 921 is a part that generates a synchronization signal under the control of the control unit 94. The pre-processing unit 922 performs some of the image processing described above, excluding noise reduction processing, on the captured image (digital signal) received by the communication unit 91 based on the synchronization signal generated by the synchronization generating unit 921. Based on the synchronization signal generated by the synchronization generation unit 921, the post-processing unit 923 performs image processing, such as noise reduction processing, which is not performed by the pre-processing unit 922 among the above-mentioned image processing, on the captured image (digital signal) after image processing has been performed by the pre-processing unit 922. The function of the post-processing unit 923 to perform noise reduction processing will be described later in the section "Function of the post-processing unit to perform noise reduction processing."

[0025] The display control unit 93 generates a video signal for displaying the captured image after image processing has been performed by the image processing unit 92. Then, the display control unit 93 outputs the video signal to the display device 7. As a result, the captured image is displayed on the display device 7.

[0026] The control unit 94 is realized by a controller such as a CPU or an MPU (Micro Processing Unit) executing various programs stored in the storage unit 97, and controls the operations of the light source device 3, the camera head 5, and the display device 7, as well as the operation of the entire control device 9. The control unit 94 is not limited to a CPU or an MPU, and may be configured using an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA. The control unit 94 has the functions of the processing control unit 941 (see FIG. 3) according to the present disclosure. This function will be described later in the section "Execution Timing of the Readout Stop Process."

[0027] The input unit 95 is configured using operation devices such as a mouse, a keyboard, and a touch panel, and receives user operations from a user such as a doctor. The input unit 95 then outputs an operation signal to the control unit 94 in response to the user operation. The output unit 96 is configured using a speaker, a printer, etc., and outputs various information. The storage unit 97 stores programs executed by the control unit 94, information necessary for the processing of the control unit 94, and the like.

[0028] [Function to perform noise reduction processing in post-processing section] Next, the function of the post-processing unit 923 for performing noise reduction processing will be described. FIG. 3 is a block diagram showing the function of the post-processing unit 923 for performing noise reduction processing. As shown in FIG. 3, the post-processing unit 923 includes a memory 9231 and a noise processing unit 9232 as a function of performing noise reduction processing.

[0029] The memory 9231 is a frame memory that stores one frame of a captured image. As shown in FIG. 3, the noise processing unit 9232 includes a memory access control unit 9233 and a noise reduction processing unit 9234 (hereinafter referred to as the NR processing unit 9234). The memory access control unit 9233 writes the captured image to the memory 9231 and reads the captured image from the memory 9231 based on the synchronization signal generated by the synchronization generation unit 921 .

[0030] The NR processing unit 9234 executes known noise reduction processing that blends, at a predetermined blend ratio, the captured image of the current frame input from the pre-processing unit 922 and the captured image of the previous frame read from the memory 9231. For example, the NR processing unit 9234 calculates the correlation between the captured image of the current frame and the captured image of the previous frame, and if it determines that the correlation is low (for example, when the subject moves a lot), it reduces the blend ratio of the captured image of the previous frame. On the other hand, if it determines that the correlation is high, it increases the blend ratio of the captured image of the previous frame.

[0031] In addition, at a predetermined timing, the noise processing unit 9232 stops reading out the captured image of the past frame from the memory 9231 and performs a read stop process in which the captured image of the current frame input from the pre-processing unit 922 is written into the memory 9231 without performing the above-mentioned noise reduction process. The noise processing section 9232 described above may be configured by hardware, by software, or by a combination of hardware and software.

[0032] [Execution timing of read stop process] Next, the execution timing of the readout stop process by the noise processor 9232 will be described. 4 to 6 are diagrams for explaining the execution timing of the read stop process. First, the process control unit 941 determines whether or not the captured image to be input to the noise processing unit 9232 is a stable image. For example, when a link is established between the camera head 5 (communication unit 54) and the control device 9 (communication unit 91), the process control unit 941 determines that the captured image to be input to the noise processing unit 9232 will be a stable image. On the other hand, when a link is not established between the camera head 5 (communication unit 54) and the control device 9 (communication unit 91), the process control unit 941 determines that the captured image to be input to the noise processing unit 9232 will not be a stable image. Furthermore, for example, when the processing control unit 941 detects a camera head ID via the communication unit 91, it determines that the captured image to be input to the noise processing unit 9232 will be a stable image. On the other hand, when the processing control unit 941 does not detect a camera head ID via the communication unit 91, it determines that the captured image to be input to the noise processing unit 9232 will not be a stable image.

[0033] If the processing control unit 941 determines that the captured image to be input to the noise processing unit 9232 will not be a stable image, it prohibits the input of the captured image to the noise processing unit 9232, as shown in FIG. Specifically, the process control unit 941 turns off the function of the pre-processing unit 922. This stops the output of the captured image from the pre-processing unit 922 to the noise processing unit 9232. In Fig. 4, the state in which the output of the captured image from the pre-processing unit 922 to the noise processing unit 9232 has been stopped is represented by an "x" mark.

[0034] On the other hand, the processing control unit 941 turns on the function of the pre-processing unit 922 at the timing when it determines that the captured image to be input to the noise processing unit 9232 will be a stable image. As a result, the pre-processing unit 922 starts outputting the captured image to the noise processing unit 9232, as shown in Fig. 5. Note that Fig. 5 represents a state in which output of the captured image from the pre-processing unit 922 to the noise processing unit 9232 has started by deleting the "x" mark shown in Fig. 4.

[0035] Furthermore, the process control unit 941 causes the noise processing unit 9232 to execute a readout stop process at the timing when it is determined that the captured image to be input to the noise processing unit 9232 has become a stable image. 5, the noise processing unit 9232 stops reading out the captured image of the previous frame from the memory 9231, does not execute the noise reduction process described above, and writes the normal image A, which is the captured image of the current frame input from the pre-processing unit 922, into the memory 9231 based on the synchronization signal generated by the synchronization generating unit 921. As a result, even if an undefined value is stored in the memory 9231, the undefined value is overwritten by the normal image A. Note that in FIG. 5, the state in which reading out the captured image of the previous frame from the memory 9231 has been stopped is represented by an "x" mark.

[0036] Then, under the control of the process control unit 941, the noise processing unit 9232 executes the readout stop process and then starts the noise reduction process. 6, the noise processing unit 9232 reads out a normal image A, which is a captured image of a previous frame, from the memory 9231 based on the synchronization signal generated by the synchronization generation unit 921, and performs noise reduction processing based on the normal image A and a normal image B, which is a captured image of a current frame input from the pre-processing unit 922. Furthermore, based on the synchronization signal generated by the synchronization generation unit 921, the noise processing unit 9232 reads out the normal image A from the memory 9231 and writes in normal images A+B, which are captured images after the noise reduction processing has been performed.

[0037] According to the present embodiment described above, the following effects are achieved. In the control device 9 according to this embodiment, the noise processing section 9232 executes a readout stop process at a predetermined timing. Therefore, even if an undefined value is stored in the memory 9231, the undefined value is replaced with the captured image of the current frame (normal image A shown in Figure 5) by writing the captured image into the memory 9231.

[0038] However, when noise reduction processing is performed between the input captured image of the current frame and the data of the indefinite value stored in the memory 9231, the following problem may occur. That is, the noise processing unit 9232 may determine that there is a high correlation between the captured image of the current frame and the data of the indefinite value. In this case, the noise processing unit 9232 increases the blend ratio of the captured image of the past frame by regarding the data of the indefinite value as an appropriate captured image of the past frame, so that it is not possible to reduce noise in the captured image of the current frame and it is not possible to obtain an image suitable for observation.

[0039] In contrast to this, in this embodiment, the noise processing unit 9232 performs noise reduction processing between the captured image of the input current frame (normal image B shown in Figure 5) and the captured image of the previous frame (normal image A shown in Figure 5) that is not data of an indefinite value stored in the memory 9231. Therefore, the control device 9 according to this embodiment can execute noise reduction processing using an appropriate captured image of a previous frame, thereby obtaining an image suitable for observation.

[0040] Incidentally, when the captured image input to the noise processing section 9232 is an unstable image, even if the noise processing section 9232 executes a read stop process, data of an indefinite value is simply rewritten with the unstable captured image in the memory 9231. In other words, when noise reduction process is executed between the input captured image of the current frame and the unstable captured image stored in the memory 9231, the same problem as that described above when indefinite data is stored in the memory 9231 may occur.

[0041] On the other hand, the timing for executing the readout stop process is the timing when the captured image input to the noise processing section 9232 becomes a stable image. Therefore, when the noise processing unit 9232 executes the readout stop processing, the data of the indefinite value is rewritten to the captured image, which is a stable image, in the memory 9231. In other words, the above-mentioned problem can be effectively solved.

[0042] (Other embodiments) Although the embodiments for carrying out the present disclosure have been described above, the present disclosure should not be limited to only the above-described embodiments. 7 is a diagram showing a modified example of the embodiment, specifically, FIG. 7 is a diagram corresponding to FIG. In the above-described embodiment, when the processing control unit 941 determines that the captured image to be input to the noise processing unit 9232 will not be a stable image, the processing control unit 941 prohibits the input of the captured image to the noise processing unit 9232 as shown in Fig. 4, but this is not limiting. For example, when the processing control unit 941 determines that the captured image to be input to the noise processing unit 9232 will not be a stable image, the processing control unit 941 may execute control according to this modified example shown in Fig. 7. Specifically, when the process control unit 941 determines that the captured image to be input to the noise processing unit 9232 will not be a stable image, it controls the synchronization generation unit 921 to prohibit the synchronization generation unit 921 from outputting a synchronization signal to the noise processing unit 9232. As a result, the noise processing unit 9232 does not write the captured image to the memory 9231 or read the captured image from the memory 9231, as shown in Fig. 7. Note that in Fig. 7, the state in which the synchronization generation unit 921 prohibits the output of a synchronization signal to the noise processing unit 9232 and the state in which the captured image is not written to the memory 9231 or read from the memory 9231 are represented by an "x" mark.

[0043] In the above-described embodiment, the function of the processing control unit 941 may be provided in the noise processing unit 9232 . In the above-described embodiment, the noise processing unit 9232 performs so-called temporal noise reduction processing, which reduces noise in a captured image of a current frame based on the captured image of the current frame and captured images of previous frames. However, this is not limiting. For example, the noise processing unit 9232 may also be configured to perform so-called spatial noise reduction processing, which reduces noise in a captured image based only on the captured image of the current frame.

[0044] In the above-described embodiment, the medical image processing device according to the present disclosure is mounted on a medical observation system 1 in which the insertion section 2 is configured as a rigid endoscope, but this is not limiting. For example, the medical image processing device according to the present disclosure may be mounted on a medical observation system in which the insertion section 2 is configured as a flexible endoscope. Furthermore, the medical image processing device according to the present disclosure may be mounted on a medical observation system such as a surgical microscope (see, for example, Japanese Patent Application Laid-Open No. 2016-42981) that magnifies and observes a predetermined field of view inside or on the surface of a living body.

[0045] The following configurations also fall within the technical scope of the present disclosure. (1) A medical image processing device comprising: an image processing unit that performs image processing on a captured image of a subject; a memory that stores the captured image; and a noise processing unit that is capable of writing the captured image to the memory and reading the captured image from the memory, and that performs noise reduction processing to reduce noise in the captured image of the current frame based on the captured image of the input current frame and the captured image of the previous frame read from the memory, and the noise processing unit performs read stop processing at a predetermined timing to stop reading of the previous frame from the memory and write the captured image of the current frame to the memory without performing the noise reduction processing. (2) The medical image processing device according to (1), wherein the predetermined timing is a timing when the captured image input to the noise processing unit becomes a stable image. (3) A medical image processing device as described in (2) further comprising a processing control unit that determines whether the captured image input to the noise processing unit will be a stable image, executes the readout stop processing at the timing when it is determined that the captured image will be a stable image, and starts execution of the noise reduction processing after executing the readout stop processing. (4) The medical image processing device described in (3) above, wherein the processing control unit determines that the captured image to be input to the noise processing unit will be a stable image when a link-up is established between the medical observation device that captures an image of a subject and generates the captured image and the medical image processing device. (5) The medical image processing device according to (3), wherein the medical observation device that captures an image of a subject and generates the captured image is connected to the medical image processing device, and the processing control unit determines that the captured image to be input to the noise processing unit will be a stable image when it detects identification information that is output from the medical observation device and uniquely identifies the medical observation device. (6) A medical image processing device described in any one of (3) to (5), wherein the processing control unit prohibits input of the captured image to the noise processing unit when it determines that the captured image to be input to the noise processing unit will not be a stable image. (7) A medical image processing device described in any one of (3) to (5), wherein the processing control unit, when determining that the captured image input to the noise processing unit will not be a stable image, does not cause the noise processing unit to perform both writing of the captured image to the memory and reading of the captured image from the memory. (8) A medical observation system comprising: a medical observation device that captures an image of a subject to generate a captured image; and a medical image processing device having an image processing unit that performs image processing on the captured image, wherein the image processing unit is equipped with a memory that stores the captured image, and a noise processing unit that is capable of writing the captured image to the memory and reading the captured image from the memory, and that performs noise reduction processing to reduce noise in the captured image of the current frame based on the captured image of the input current frame and the captured image of the previous frame read from the memory, and wherein the noise processing unit performs read stop processing at a predetermined timing to stop reading of the previous frame from the memory and write the captured image of the current frame to the memory without performing the noise reduction processing. [Explanation of symbols]

[0046] 1 Medical observation system 2 Insertion section 3 Light source device 4 Light Guide 5 Camera Head 6. First Transmission Cable 7 Display device 8 Second Transmission Cable 9 Control Device 10 Third Transmission Cable 51 Lens unit 52 Imaging unit 53 Storage section 54 Communications Department 91 Communications Department 92 Image processing section 93 Display control unit 94 Control Unit 95 Input section 96 Output section 97 Memory section 521 Image sensor 522 Signal Processing Unit 921 Synchronization Generation Unit 922 Pretreatment section 923 Post-processing section 9231 memory 9232 Noise Processing Unit 9233 Memory access control unit 9234 Noise reduction processing section CN1, CN2 connectors

Claims

1. an image processing unit that performs image processing on a captured image of a subject; The image processing unit a memory for storing the captured image; a noise processing unit that is capable of writing the captured image to the memory and reading the captured image from the memory, and that executes noise reduction processing to reduce noise in the captured image of the current frame based on the captured image of the input current frame and the captured image of the previous frame read from the memory, The noise processing unit a medical image processing apparatus that executes a read stop process at a predetermined timing, in which the readout of the past frame from the memory is stopped, the noise reduction process is not executed, and the captured image of the current frame is written to the memory;

2. The predetermined timing is The medical image processing apparatus according to claim 1 , wherein the captured image input to the noise processing section is input at a timing when the captured image becomes stable.

3. 3. The medical image processing device according to claim 2, further comprising a processing control unit that determines whether the captured image input to the noise processing unit will be a stable image, executes the readout stop processing at the timing when it is determined that the captured image will be a stable image, and starts execution of the noise reduction processing after executing the readout stop processing.

4. The processing control unit 4. The medical image processing device according to claim 3, wherein when a link-up is established between a medical observation device that captures an image of a subject and generates the captured image, it is determined that the captured image to be input to the noise processing unit will be a stable image.

5. The processing control unit 4. The medical image processing device according to claim 3, wherein the medical image processing device is connected to a medical observation device that captures an image of a subject and generates the captured image, and the medical image processing device determines that the captured image to be input to the noise processing unit will be a stable image when it detects identification information that is output from the medical observation device and uniquely identifies the medical observation device.

6. The processing control unit 4. The medical image processing apparatus according to claim 3, wherein when it is determined that the captured image to be input to the noise processing section will not be a stable image, input of the captured image to the noise processing section is prohibited.

7. The processing control unit 4. The medical image processing device according to claim 3, wherein when it is determined that the captured image input to the noise processing unit is not a stable image, the noise processing unit is not caused to write the captured image to the memory and read the captured image from the memory.

8. a medical observation device that captures an image of a subject and generates a captured image; a medical image processing device having an image processing unit that performs image processing on the captured image, The image processing unit a memory for storing the captured image; a noise processing unit that is capable of writing the captured image to the memory and reading the captured image from the memory, and that executes noise reduction processing to reduce noise in the captured image of the current frame based on the captured image of the input current frame and the captured image of the previous frame read from the memory, The noise processing unit a medical observation system that executes a read stop process at a predetermined timing, in which the readout of the past frame from the memory is stopped, the noise reduction process is not executed, and the captured image of the current frame is written to the memory;

Images