JP2011010880A - Electronic endoscope system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic endoscope system capable of transmitting the large capacity of image signals without changing a transmission route.SOLUTION: The electronic endoscope system includes: an electronic endoscope provided with an imaging element corresponding to first resolution; an image processor which executes prescribed image processing to image data generated by the electronic endoscope and generates digital data; a transmission means which corresponds to second resolution lower than the first resolution and transmits the digital data; and a receiver which demodulates the digital data and outputs them to a monitor as observation images. The image processor includes: a determination means which determines whether or not the observation images are to be sent and displayed frame by frame; and an image division means which divides the digital data on the basis of a prescribed rule when it is determined that the observation images are to be sent and displayed frame by frame. The receiver demodulates the digital data on the basis of the prescribed rule.

Description

  The present invention relates to an electronic endoscope system that outputs an endoscopic observation image and displays it on a monitor.

  In the conventional electronic endoscope system, as shown in Patent Document 1, analog RGB, composite sync signal, composite video signal, S video signal, and digital video signal are employed as output signal formats. The image is transmitted in an SD (Standard Definition) format (effective pixel number: 720 × 480) and displayed on the monitor. In these electronic endoscope systems, there are cases in which a digital video signal of a frame-by-frame image is transmitted to a remote monitor using an electronic endoscope whose image processing frame rate is slower than a predetermined standard.

JP-A-8-214290

  In recent years, observation images taken with an electronic endoscope at the time of surgery are transmitted in real time to another room, hospital, laboratory, etc., and a remote doctor provides remote guidance and remote support to the practitioner while checking the observation images It is desired that an electronic endoscope can be used also in telemedicine.

  However, in the conventional configuration as described above, an image picked up using an image pickup device (such as a CCD image sensor or a CMOS image sensor) having a resolution equal to or higher than the SD format is displayed on a remote monitor. In this case, there may be a case where all image information cannot be transmitted and displayed to a peripheral device compatible with the SD format. If such a case occurs, it may be inconvenient for telemedicine, such as it becomes difficult for doctors in the remote area to confirm and judge from what viewpoint the image displayed on the monitor should be confirmed and judged. . In addition, a system corresponding to the HD (High Definition) format (effective pixel number: 1920 × 1080) can be constructed in order to realize transmission and display of larger-capacity image information. May be bulky.

  The present invention has been made in view of the above. An object of the present invention is to provide an electronic endoscope system capable of transmitting image information having an information amount equal to or greater than a predetermined format over a long distance using a transmission system corresponding to the predetermined format without reducing the information amount. Is to provide.

  An electronic endoscope system according to the present invention generates digital data by performing predetermined image processing on an electronic endoscope having an image sensor corresponding to a first resolution and image data generated by the electronic endoscope. Corresponding to a second resolution lower than the first resolution, transmitting means for transmitting digital data output from the image processing apparatus, and digital data input via the transmitting means A receiving device that demodulates and outputs the image as an observation image to a monitor, and the image processing device includes: When it is determined by the determination means that the observation image is frame-by-frame displayed, the digital data is divided into the maximum number of divided data equal to the number of frames in one frame based on a predetermined rule. And an image dividing means, the receiving device, based on a predetermined rule, and demodulates the digital data from the divided data. For this reason, in an existing SD format compatible system, image data of the SD format or higher can be transmitted to a remote location without reducing the amount of information.

  Preferably, the predetermined rule is to create a group of p × q (p and q are natural numbers; p × q ≧ 2) pixels that do not exceed the number of frames in one frame, and assign an address to each pixel in the group. The image processing apparatus has a plurality of storage areas, and the number of pixels that can be stored in each area is large. The first storage means having the same number as the number of pixels of the second resolution, the first image signal storage means for storing the image signal of the observation image in the first storage means by address, and the first storage means Image signal writing means for sequentially writing stored image signals into a plurality of consecutive frames of digital data, and the receiving device has at least the same number of storage areas as the first storage means, and stores in each area The number of possible pixels is at least a second Second storage means having the same number of pixels as the resolution is included. For this reason, even if a phenomenon occurs in which information of any frame in the thinned image data is lost, when the image signal is demodulated and the observation image is synthesized, the image is lost by the amount of the missing information. Although it is difficult to see, the entire observation image can be displayed on the monitor.

  More preferably, the image processing device includes an identification signal generating unit that generates an identification signal indicating a correspondence relationship between the pixel of the image sensor and the image signal stored in the first storage unit and the address, and the identification signal is converted into digital data. An identification signal writing means for writing, and the receiving device stores a second image signal storage means for storing the image signals written in the plurality of frames in the second storage means by address based on the identification signal; Image signal combining means for combining the image signals stored in the second storage means to restore the observation image based on the identification signal. An identification signal is written in the blanking period of the digital data. Furthermore, the image processing apparatus is configured so that a plurality of types of electronic endoscopes can be connected. The first resolution conforms to the HD standard, and the second resolution conforms to the SD standard.

  According to the present invention, in an electronic endoscope system that transmits a frame-by-frame image using an electronic endoscope whose image processing frame rate is slower than a predetermined standard, the amount of image information is not lost. Since it can transmit to a remote place, transmission efficiency can be raised. In addition, transmission can be performed using a transmission system corresponding to a predetermined format, and long-distance transmission can also be realized. Furthermore, image information can be directly input to a peripheral device corresponding to a predetermined format at a remote location. And since it is not necessary to thin out image information with a down converter etc., more image information can be transmitted than the system provided with a down converter etc.

1 is a block diagram illustrating an outline of an entire electronic endoscope system according to an embodiment of the present invention. It is a block diagram which shows the structure of the electronic endoscope system which is one Embodiment of this invention. It is a figure which shows the outline of the image process in the electronic endoscope system which is one Embodiment of this invention. It is a figure which shows the outline of the image process in the electronic endoscope system which is one Embodiment of this invention. (A) And (b) is a schematic diagram which shows an analog video signal and a digital video signal. It is a figure which shows the outline of multiplexing of an image signal. It is a figure which shows the outline of the data transmission in the electronic endoscope system which is one Embodiment of this invention.

  Hereinafter, an electronic endoscope system according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same number is attached | subjected, when showing the same member over several figures.

  FIG. 1 is a block diagram showing an outline of the entire electronic endoscope system according to an embodiment of the present invention. In the present embodiment, because of the performance of the image sensor, the image processing frame rate is 5 fps (frames per second). Is connected to a video processor 2. The digital video signal output as digital data from the video processor 2 is transferred to the remote receiving device 3 by the NTSC (National Television System Committee) method. In the case of the NTSC rate, 30 images are transferred per second. However, in the case of frame advance display in this embodiment, only 5 frames can be transferred per second, and 6 identical images are transferred per frame. The electrically erasable read-only memory (EEPROM) 10 of the electronic endoscope 1 stores property information unique to the image sensor 6 such as the number of pixels and the frame rate. When the electronic endoscope 1 is connected to the video processor 2, the property information stored in the EEPROM 10 is read by the peripheral drive 14 and then sent to the system control unit 15. Of the property information in the EEPROM 10, information such as the number of pixels and the frame rate necessary for demodulating and outputting the digital video signal transmitted from the video processor 2 is sent to the receiving device 3.

  The light generated by the light source unit 17 of the video processor 2 is propagated to the distal end of the insertion unit of the electronic endoscope 1 by the light guide 7 and irradiated as an illumination light onto the observation target in the patient's body cavity. Although not shown, the light source unit 17 is a light source such as a halogen lamp, a xenon lamp, or a white LED, a condensing lens that condenses light from the light source, and white light from the light source is red (R) or green (G ), A color filter for sequentially separating light into blue (B) light, and the speed and phase of the color filter so that the color filter rotates in synchronization with a timing pulse or a vertical synchronization signal when writing an image signal to the frame memory. A color filter rotation control circuit for controlling the light amount, a light amount diaphragm for adjusting the light amount of the illumination light, a circuit for controlling the light amount diaphragm, and the like, and generates illumination light by a frame sequential method. The imaging surface of the imaging device 6 is disposed at a position where an image of the observation object is formed by an objective optical system (not shown) provided at the distal end of the insertion portion in the insertion portion of the electronic endoscope 1. Further, by operating various operation buttons 8 provided in the operation unit of the endoscope, an operation signal is sent to the system control unit 15 of the video processor 2 to record a still image or a moving image, supply air, and supply water. Various processes such as these are performed.

  The imaging signal photoelectrically converted by the imaging element 6 is sent to the preprocessing unit 11 by the drive circuit 9. The preprocessing unit 11 extracts an image signal by performing preprocessing such as amplification, sample hold processing, A / D conversion, and noise removal on the imaging signal. The extracted image signal is sent to the host process unit 13 via the timing circuit 12. The host process unit 13 not only outputs an analog video signal to display an image on a television monitor (not shown) installed in the treatment room, for example, but also displays an image on a remote television monitor 4. Output a digital video signal for display. In addition, when displaying an image in a remote place, the output digital video signal is received by the receiving device 3. The receiving device 3 extracts an image signal, a character signal, and an audio signal from the digital video signal. The receiving device 3 converts the image signal into a digital video signal, an RGB video signal, a composite video signal, an S video signal, etc., displays an image on various monitors, displays character information, and reproduces sound. To go. In addition, the VTR 5 can be connected to the receiving device 3 to record images, text information, voice, and the like.

  The system control unit 15 determines whether or not the effective pixel number of the image sensor 6 is 720 × 480 or more based on the information about the effective pixel number and the frame rate of the image sensor 6 obtained from the EEPROM 10 of the electronic endoscope 1. Is determined to be frame advance, and the control of the image sensor 6 and the video processor 2 is switched. Further, the system control unit 15 is based on the information stored in the EEPROM 10 of the electronic endoscope 1, the operation of the buttons 8 and the panel switch 18, and the input from the keyboard 19, the preprocessing unit 11, the timing circuit 12, and the host The operation of the process unit 13 is controlled. For example, the system control unit 15 controls the operation of the timing circuit 12 based on the frame rate information. When it is determined that the size of the observation image captured by the image sensor 6 is within 720 × 480 or when it is determined that the image display is not frame advance, the system control unit 15 performs signal processing according to conventional image processing. The operation of each unit in the image processing apparatus is controlled so as to be output.

  Information indicating the current operation status of the electronic endoscope and the processing status of the observation image is displayed on the display unit (not shown) of the video processor 2 in accordance with the setting in the panel switch 18. In addition to the endoscope observation image, various character information such as the current time, patient name, practitioner's findings and comments are displayed on the TV monitor 4 and the remote TV monitor 4 installed in the operation room. It is displayed automatically or in accordance with an input from the keyboard 19.

  FIG. 2 is a block diagram specifically showing the above-described configuration in one embodiment of the present invention. An imaging signal output from the imaging device 6 is amplified by an amplifier (AMP) 20 of the preprocessing unit 11, and then an image signal is extracted by a sample hold circuit 21 and converted into a digital signal by an analog / digital conversion circuit 22. It is sent to the timing circuit 12. The timing circuit 12 is sequentially controlled by the system control unit 15 in synchronization with the timing at which the accumulated charge is sent from the image sensor 6, and sequentially outputs image signals of red (R), green (G), and blue (B). Are stored in the corresponding frame memory R23a, frame memory G23b, and frame memory B23c, respectively. The three-color image signals are simultaneously read from the frame memories 23a, 23b, and 23c and sent to the digital / analog conversion circuits 24a, 24b, and 24c and the digital signal processing circuit 25. The image signals sent to the digital / analog conversion circuits 24a, 24b, and 24c for the R, G, and B frame memories are converted into analog signals and then output as RGB video signals as they are, or RGB encoders (see FIG. Or output as a composite video signal or an S video signal via a monitor (not shown).

  The digital signal processing circuit 25 is provided with a plurality of image memories 30. Note that the image memory 30 may be provided outside the digital signal processing circuit 25. The number of pixels of image data that can be stored in one image memory is at most one frame, that is, it does not exceed 720 × 480. Therefore, the image sent to the digital signal processing circuit 25 is thinned out and stored in the image memory 30 so as to fit in the size of 720 × 480. Here, FIG. 3 shows an outline of processing when thinning out images. When the number of effective pixels of the image sensor is 1440 × 960, as shown in the figure, a square pixel area having a group of four pixels to which addresses 1 to 4 are assigned is arranged vertically and horizontally to display the entire effective pixels of the image sensor. Divide the cover image. Then, the image signal of the pixel corresponding to the address 1 is thinned out from the image and stored in one image memory of the plurality of image memories 30. Similarly, the pixels corresponding to the addresses 2 to 4 are also thinned out and stored in the image memory for each address.

  FIG. 4 shows an outline of another thinning process. In this case, the effective number of pixels of the image sensor is 1800 × 960. As shown in the figure, a rectangular pixel region having a group of 6 pixels to which addresses 1 to 6 are assigned is arranged to cover the entire effective pixels of the image sensor and the image is divided. As in FIG. 3, the image signal of the pixel corresponding to the address 1 is thinned out from the image and stored in one image memory. At this time, the number of pixels corresponding to address 1 is 600 × 480, but does not exceed 720 × 480, so that it can be stored in one image memory. Therefore, the number of pixels to be thinned out is not necessarily limited to 720 × 480, and can be thinned out with an arbitrary number of pixels as long as it does not exceed 720 × 480. The pixels corresponding to the addresses 2 to 6 are also thinned out and stored in the image memory for each address.

  The digital signal processing circuit 25 generates an identification signal indicating which pixel the image signal written during the effective image period corresponds to and which address is assigned to which pixel. After these processes, image signals are sequentially sent to the matrix circuit 26 from the image memory corresponding to the address 1. The identification signal is sent to the multiplexer 27 through the matrix circuit 26.

  Note that how to assign addresses and thin out an image is not limited to the above method, and various methods are possible depending on the number of effective pixels of the image sensor and the number of image memories. As shown in FIGS. 3 and 4, when the image signal is thinned out, some trouble occurs when the digital video signal is transmitted or when the image signal is demodulated in the receiving apparatus, and any frame of the thinned image data is lost. Even when information is missing, when the image signal is demodulated and the observation image is synthesized, the entire observation image can be displayed on the monitor, although the image is difficult to see by the amount of lack of information. If the image shown in FIG. 3 is thinned out, the effective pixels are divided into 720 × 480 pixel areas in the upper left, upper right, lower left, and lower right, and addresses 1, 2, 3, and 4 are assigned and stored in the image memory. In this case, if any frame information is missing, a 720 × 480 area where no image is displayed on the monitor is generated. Therefore, when assigning addresses to pixels, it is preferable to assign the same addresses so that they are uniformly distributed throughout the thinning target image. In other words, if the effective pixel number of the image sensor is m × n (m and n are natural numbers), a pixel region is created in which p × q pixels (p and q are natural numbers; p × q ≧ 2) are grouped. Then, an address is assigned to each pixel in the pixel area, the pixel areas are arranged to cover m × n effective pixels, and an image signal is thinned out for each address and stored in the image memory. Note that the value of p × q does not exceed the number of frames in one frame. This is because when the number of image memories to be used exceeds the number of frames in one frame, there is no frame to which the image signal stored in the image memory is written. The number of image memories to be used and the values of p and q are determined based on the frame rate and the number of effective pixels acquired from the EEPROM 10 by the system control unit 15.

  The video processor 2 is connected to a plurality of types of electronic endoscopes having different effective pixel numbers of the image sensor, and image data is thinned out as described above according to the effective pixel number. The image memory for storing the images divided by the digital signal processing circuit 25 is provided in a number that does not fall below the number of frames in at least one frame. Further, since the transmission system supports transmission of image data having a pixel number size of 720 × 480 or less, the number of pixels of the image signal stored in each image memory is set to 720 × 480 or less. Although details of processing in the receiving device 3 will be described later, an image memory that stores an image signal demodulated from a digital video signal in the receiving device 3 is an image memory that stores an image divided by the digital signal processing circuit 25. Provide at least the same size and at least the same number.

  In the matrix circuit 26, the R, G, B digital signals are, for example, the luminance signal Y, the color difference signal Cr ((r) such that the ratio of the sampling frequency of the luminance signal Y and the color difference signals Cr, Cb is 4: 2: 2. = R−Y) and Cb (= B−Y). Here, the sampling frequency is 13.5 MHz for Y, 6.75 MHz for Cr and Cb, and the clock frequency is 27 MHz, which is twice the sampling frequency of Y. Sampling is performed in the order of Cb, Y, Cr. In addition, the number of samples in the effective image period of each scanning line of each signal is 720 samples for Y, 360 samples for Cr and Cb, and 1440 samples in total.

  The luminance signal Y and the color difference signals Cr and Cb output from the matrix circuit 26 are sent to the multiplexer 27 and multiplexed together with the identification signal. At this time, the synchronization word output from the synchronization word generation circuit 29 is added before and after the effective image period. The identification signal is assigned to the blanking period of the digital video signal. The blanking period is a synchronization word that specifies an effective image period corresponding to one line of an image, that is, a synchronization word indicating the end of a certain effective image period and the start of the next effective image period in the digital video signal. It means a period that intervenes with the synchronization word indicating, and originally has no information. Therefore, even if a signal as described above is assigned to the blanking period of the digital video signal, the signal assigned to the effective image period has no effect.

  FIG. 6 is a diagram illustrating signal multiplexing in the effective image period. The luminance signals Y1, Y2, Y3, Y4... And the color difference signals Cr1, Cr2, Cr3... And Cb1, Cb2, Cb3. 27, multiplexing is performed in the order of Cb1, Y1, Cr1, Y2, Cb2, Y3, Cr2, Y4, Cb3. By this multiplexing processing, one parallel digital signal is generated.

  The multiplexed signal is sent to the digital output circuit 28 as a parallel digital video signal, converted into a serial digital video signal by the digital output circuit 28, and then sent from the least significant bit (LSB) to a remote location. It is transmitted by a transmission system compatible with the SD format. Each of the digital luminance signal Y and the color difference signals Cb and Cr is composed of a 10-bit bit string, and is transmitted through the 10 signal lines (buses) in the host process unit 13. Since the digital output circuit 28 outputs the digital video signal to the outside bit by bit, the bit data read from the LSB of the bit string and the right shift operation toward the most significant bit (MSB) are alternately executed. As a result, the digital video signal is serially transmitted to the receiving device 3. Note that the digital video signal may be compressed and output in accordance with the IEEE 1394 standard.

  FIGS. 5A and 5B are diagrams illustrating the relationship between the effective image period, the blanking period, and the synchronization word in the analog video signal and the digital video signal. FIG. 5A shows an analog video signal, and FIG. 5B shows a digital video signal corresponding to the analog video signal. Through the above processing, an analog image signal as shown in FIG. 5A is converted into a digital image signal as shown in FIG. In the digital image signal, the synchronization word output from the synchronization word generation circuit 29 is added before and after the effective image period for one scanning line. The receiving device 3 detects this synchronization word and extracts a signal sandwiched between the synchronization words as an image signal.

  FIG. 7 is a schematic diagram illustrating a transmission state of a digital video signal output from the video processor when the image display is frame advance. For convenience, one frame between the frames 104 and 106 and one frame between the frames 204 and 206 are omitted. First, consider the frames 101-106. As shown in the figure, when the frame rate of the image sensor is 5 fps and a frame-advanced digital video signal is transmitted, the top of six consecutive frames 101 to 106 transmitted during the display time of one frame. The image signal stored in the image memory corresponding to the address 1 is written in the frame 101 of FIG. 1, and the image signal stored in the image memory corresponding to the addresses 2, 3, and 4 is written in the frames 102, 103, and 104, respectively. Has been written. If there is no image signal to be written in the effective image period, the effective image period is an empty area as in the frame 106, and a synchronization word is added before and after the empty effective image period for transmission. The timing for switching from the frame 106 to the frame 201 of the next frame is determined by the system control unit 15 based on the frame rate of the image sensor 6. When switching to the next frame, the thinned new image signals are sequentially written from the first frame 201 in the same manner as the frames 101 to 106 for the frames 201 to 206. These processes are performed in the same manner for frames that are sequentially generated after the frame 301.

  Next, processing in the receiving device 3 at the remote site will be described with reference to FIG. 2 again. The video decoder circuit 31 and the timing circuit 32 of the reception device 3 perform signal processing based on property information regarding the image sensor 6 sent from the video processor 2. The transmitted serial digital video signal is reconverted into a parallel digital video signal by the video decoder circuit 31. The video decoder circuit 31 detects a blanking period and a synchronization word in the video signal based on the synchronization signal output from the timing circuit 32, and separates the image signal and the like from the video signal. The separated image signal is demodulated and then stored in the image memory 33 corresponding to each address 1 to 4. When all the image signals for one frame are stored in the image memory 33, the image signals in each image memory are sent to the synthesis circuit 34, and are synthesized into an image of the original 1440 × 960 format based on the identification signal. . The synthesized image is sent to the digital encoder 35, converted into an analog component signal such as an RGB video signal, composite video signal, or S video signal and output.

  The above is the description regarding the electronic endoscope system of the present invention. In implementing the present invention, the number and frequency of the digital video signal and the frame rate of the image sensor are not limited to the above-described values, and can be changed as appropriate according to the mode of the system to which the present invention is applied. . Further, it is possible to determine whether or not to perform frame advance display in consideration of the frame rate of a video device such as a monitor in addition to the frame rate of the image sensor. In the above description, it is assumed that an image is captured by the frame sequential method, but a simultaneous imaging method may be employed. In other words, the white light of the light source is collected as it is on the light guide and transmitted to irradiate the object to be observed, and the complementary color signal is separated by an on-chip complementary color filter on the image sensor, and this complementary color signal is converted into the RGB primary color. It is possible to obtain color difference signals RY and BY by converting the primary color signal into a signal and using a color difference matrix. In the above description, a plurality of image memories are provided to store image signals. However, one image memory corresponding to the total capacity of the plurality of image memories is provided, and a plurality of memory areas are provided in the image memory. An image signal may be stored. Therefore, a plurality of image memories can be used as image storage areas, and a plurality of memory areas in one image memory can be used as image storage areas.

DESCRIPTION OF SYMBOLS 1 Electronic endoscope 2 Video processor 3 Receiver 6 Image pick-up element 15 System control part 25 Digital signal processing circuit 30,33 Image memory 27 Multiplexer 28 Digital output circuit 31 Video decoder circuit 34 Synthesis | combination circuit

Claims (6)

An electronic endoscope having an image sensor corresponding to the first resolution;
An image processing device that performs predetermined image processing on image data generated by the electronic endoscope to generate digital data;
A transmission unit corresponding to a second resolution lower than the first resolution and transmitting the digital data output from the image processing device;
A receiving device that demodulates the digital data input via the transmission means and outputs it to a monitor as an observation image;
The image processing apparatus includes:
A determination unit that determines whether or not the observation image is frame-by-frame displayed with a frame rate of the image sensor smaller than a predetermined value;
An image dividing unit that divides the digital data into the same number of divided data as the number of frames in one frame based on a predetermined rule when the determination unit determines that the observation image is displayed by frame advance. Have
The electronic endoscope system, wherein the receiving device demodulates the digital data from the divided data based on the predetermined rule. The predetermined rule is:
A group of pixels of p × q (p and q are natural numbers; p × q ≧ 2) that does not exceed the number of frames in one frame is created, an address is assigned to each pixel in the group, and the groups are arranged. Dividing the observation image by dividing the entire effective pixel of the image sensor;
The image processing apparatus includes:
First storage means having a plurality of storage areas, wherein the number of pixels that can be stored in each area is at most equal to the number of pixels of the second resolution;
First image signal storage means for storing the image signal of the observation image in the first storage means for each address;
Image signal writing means for sequentially writing image signals stored in the first storage means into a plurality of consecutive frames of the digital data;
The receiving device is:
Second storage means having at least the same number of storage areas as that of the first storage means, and having at least the same number of pixels as that of the second resolution.
The electronic endoscope system according to claim 1. The image processing apparatus includes:
Identification signal generating means for generating an identification signal indicating a correspondence relationship between the pixel of the image sensor and the image signal stored in the first storage means and the address;
Identification signal writing means for writing the identification signal to the digital data,
The receiving device is:
Second image signal storage means for storing the image signals written in the plurality of frames in the second storage means by the address based on the identification signal;
Image signal combining means for recovering the observation image by combining the image signals stored in the second storage means based on the identification signal,
The electronic endoscope system according to claim 2. The identification signal is written in the blanking period of the digital data;
The electronic endoscope system according to claim 3. The image processing apparatus is configured to connect a plurality of types of electronic endoscopes.
The electronic endoscope system according to any one of claims 1 to 4, wherein the electronic endoscope system is characterized in that: The first resolution conforms to the HD (High Definition) standard,
The second resolution conforms to the SD (Standard Definition) standard.
The electronic endoscope system according to any one of claims 1 to 5, wherein

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