JP2005312713A - Electronic endoscope and electronic endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make brightness of images displayed on a TV monitor constant automatically in cases of changing an electronic endoscope connected to a light source device for electronic endoscopes. <P>SOLUTION: The light source for endoscopes is connectable to a plurality of endoscopes, and is connected to one of the plurality of endoscopes. Each endoscope includes a CCD 20, an image signal processing IC 22, a CPU 23, and an EEPROM 24 or the like. The CCD 20 captures a subject image, converts the subject image into image signals, and outputs the image signals to the TV monitor through image signal processing IC 22. The EEPROM 24 has a luminance coefficient corresponding to each electronic endoscope. The CPU 23 acquires a correction luminance value by multiplying a luminance value of the image signal by the luminance coefficient. The CPU 23 adjusts the luminance value of the image signals from the correction luminance value, and adjusts the brightness of the images output to the monitor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic endoscope system having a plurality of electronic endoscopes and a light source device connectable to the plurality of electronic endoscopes.

  An electronic endoscope (electronic scope) has a solid-state image sensor at its tip, and a subject image captured by the solid-state image sensor is converted into an image signal, and this image signal is predetermined in the electronic endoscope. After being subjected to the signal processing, it is input to the processor. In the processor, the image signal is further subjected to predetermined image processing and the like, sent to a TV monitor, and displayed as a video.

Conventionally, in order to make the brightness of an image displayed on a TV monitor constant, as described in Patent Document 1, for example, by adjusting an electronic shutter speed in a solid-state imaging device having an electronic shutter function or adjusting an aperture of a light source device It is known to adjust the amount of illumination light and set the output value (luminance value) of the image signal to a reference value (a constant value).
JP-A-7-39514

  By the way, there are various types of electronic endoscopes, for example, for bronchial, lower gastrointestinal tract, duodenum, upper gastrointestinal tract, etc., and the processor is connected to such multiple types of electronic endoscopes. Is possible.

  However, depending on the type of electronic endoscope, the lens, color filter, viewing angle, observation depth, etc. differ, and the appearance of the image displayed on the TV monitor depends on the electronic endoscope connected to the light source device. May be different. That is, when the output value (luminance value) of the image signal output to the TV monitor is set to the reference value (a constant value), the apparent brightness of the video is not always the same.

  Even when the type of electronic endoscope is the same (that is, the lenses and the like of the electronic endoscope are the same) and the output value (luminance value) of the image signal is set to a reference value (a constant value) Since each person feels the brightness, the apparent brightness may be different depending on the user (doctor).

  Therefore, when connecting a plurality of electronic endoscopes to the processor, it is necessary to manually change the reference value of the luminance value in the processor in order to make such apparent brightness the same. However, every time the type of electronic endoscope connected to the processor is changed, manually changing the reference value of the luminance value is complicated.

  Therefore, the present invention has been made in view of such a problem, and even if the connected electronic endoscope is changed, the electronic endoscope and the electronic device that do not need to manually change the reference value. An object is to provide an endoscope system.

  An electronic endoscope system according to the present invention includes a plurality of electronic endoscopes each having a solid-state imaging device and generating an image signal from a subject image captured by the solid-state imaging device, and a plurality of electronic endoscopes A light source device for an electronic endoscope to which an electronic endoscope included in the plurality of electronic endoscopes is connected, and an image signal generated by the connected electronic endoscope is monitored Each electronic endoscope has a unique correction value, and the correction value is applied to the luminance value of the image signal by calculation of addition / subtraction / multiplication / division. The brightness value of the image signal output to the monitor is adjusted based on the corrected brightness value.

  When the output means sequentially outputs at least the first and second image signals obtained by converting the subject image in time series to the monitor, each electronic endoscope uses a correction value as a luminance value of the first image signal. Is operated by at least one of addition / subtraction / multiplication / division calculation to obtain a corrected luminance value, and the luminance value of the second image signal is adjusted based on the corrected luminance value. Preferably, the solid-state imaging device of the electronic endoscope has an electronic shutter function, and each electronic endoscope adjusts the brightness value of the second image signal by adjusting the shutter speed of the solid-state imaging device.

  Each electronic endoscope preferably adjusts the luminance value so that the corrected luminance value matches a predetermined reference value. The unique correction value is preferably stored in a memory provided in each electronic endoscope.

  The unique correction value is preferably calculated by dividing a predetermined value of each electronic endoscope by a predetermined constant, and the predetermined value is stored in a memory provided in the electronic endoscope. It is preferable. Further, it is preferable that the specific correction value is different for each electronic endoscope.

  Each electronic endoscope can be connected to a plurality of light source devices, and each electronic endoscope has a plurality of unique correction values. It is preferable to change according to the light source device connected to the mirror.

  When the luminance value of the image signal is a luminance value obtained from the luminance value of each pixel of the solid-state imaging device by one method selected from at least two different methods, the correction value depends on the selected method Are preferably different.

  The brightness value of the image signal is the highest brightness value among the average brightness value of each pixel of the solid-state image sensor, the average brightness value of the pixels near the center of the solid-state image sensor, and the brightness value of each pixel of the solid-state image sensor. When the value is selected from among the values, the correction value is preferably different depending on the selected luminance value.

  A second electronic endoscope system according to the present invention includes a plurality of electronic endoscopes each having a solid-state imaging device and generating an image signal from a subject image captured by the solid-state imaging device, and a plurality of electronic A light source device for an electronic endoscope that can be connected to an endoscope and to which one electronic endoscope included in the plurality of electronic endoscopes is connected, and is generated by the connected electronic endoscope Output means for outputting the image signal to the monitor, and each electronic endoscope has a unique correction value, and the correction value is corrected by applying the unique correction value to the predetermined reference value by calculation of addition / subtraction / multiplication / division. A reference value is obtained, and the luminance value of the image signal output to the monitor is adjusted so that the luminance value of the image signal matches the correction reference value.

  An electronic endoscope according to the present invention includes a solid-state image sensor, generates an image signal from a subject image captured by the solid-state image sensor, and can be connected to at least one light source device for an electronic endoscope. An electronic endoscope that has a unique correction value, obtains a corrected luminance value by applying the correction value to the luminance value of the image signal by calculation of addition, subtraction, multiplication and division, and based on the corrected luminance value, a light source The brightness value of the image signal output to the apparatus is adjusted.

  A second electronic endoscope according to the present invention includes a solid-state image sensor, generates an image signal from a subject image captured by the solid-state image sensor, and at least one light source device for an electronic endoscope. A connectable electronic endoscope having a specific correction value, and applying a specific correction value to a predetermined reference value by addition / subtraction / multiplication / division calculation to obtain a correction reference value, and the luminance value of the image signal However, the luminance value of the image signal output to the light source device is adjusted so as to match the correction reference value.

  As described above, according to the present invention, even when the electronic endoscope connected to the light source device is changed, the apparent brightness of the image output to the monitor can be made constant.

  Embodiments according to the present invention will be described below in detail with reference to FIGS.

  FIG. 1 is a schematic diagram of an electronic endoscope system to which an embodiment of the present invention is applied. The electronic endoscope system includes two or more electronic endoscopes (schematically showing the first and second electronic endoscopes 10 and 90 in the present embodiment) and a processor (light source device for electronic endoscope). ) 14 and a TV monitor 15. The first electronic endoscope 10 has an insertion portion 11 for insertion into a body cavity, and an operation portion 12 for a user to grip and operate the first electronic endoscope 10. A connecting tube 17 is connected to the operation unit 12, and a connecting unit 13 is provided at the tip of the connecting tube 17. The first electronic endoscope 10 is connected to the processor 14 via the connection unit 13. Since the second electronic endoscope 90 has the same configuration as the first electronic endoscope 10, the description thereof is omitted.

  Among the plurality of electronic endoscopes, one selected electronic endoscope (for example, the first electronic endoscope 10 in FIG. 1) is connected to the processor 14. The processor 14 processes the image signal sent from the first electronic endoscope 10 and then outputs the image signal to the TV monitor 15 and has a light source (not shown). It also serves as a light source device. A keyboard 16 and a panel switch 18 are further connected to the processor 14. The panel switch 18 is provided with, for example, a brightness setting switch. When the brightness setting switch is operated, a reference luminance value (aer) to be described later is changed, so that the brightness of the image displayed on the TV monitor 15 is changed.

  In the present embodiment, the first and second electronic endoscopes 10 and 90 can also be connected to a plurality of types of processors, that is, light source devices via the connection unit 13 (not shown). There are a wide variety of processors connected to the electronic endoscope 10, and the light source provided in the processor is, for example, a xenon lamp, a halogen lamp, or the like.

  FIG. 2 shows an electrical configuration of the first electronic endoscope 10 in the present embodiment. Since the electrical configuration of the second electronic endoscope 90 is the same as that of the first electronic endoscope 10, the description thereof will be omitted, and hereinafter, the same members will be denoted by the same reference numerals. To do. A solid-state imaging device (CCD) 20 provided at the distal end of the insertion unit 11 (see FIG. 1) captures a subject image using light sent from the light source to the distal end of the insertion unit 11. The captured subject image is sequentially converted into first, second, third,..., N,... Image signals for each field (for example, every 1/60 seconds). The solid-state image sensor 20 has an electronic shutter function.

  The image signal converted by the solid-state imaging device 20 is input to the video signal processing IC 22 via an AGC (Auto Gain Controller) 21. The video signal processing IC 22 performs various signal processing on the image signal. The image signals subjected to the signal processing are sequentially output to the TV monitor 15 (see FIG. 1) via the processor 14 and displayed on the TV monitor 15 as an image.

  The video signal processing IC 22 transmits and receives data by serial communication with the CPU 23 and is controlled by the CPU 23. The CPU 23 is a so-called one-chip microcomputer, and includes a ROM, a RAM, an SCI (Serial Communication Interface), an I / O port, a timer, and the like. The CPU 23 transmits / receives data to / from the processor 14 by serial communication. The CPU 23 is connected to an EEPROM (nonvolatile memory) 24 for storing various setting values.

  The electrical drive of the solid-state imaging device 20, for example, the drive of the electronic shutter is controlled by the CCD drive circuit 25. A timing chart relating to the control of the solid-state imaging device 20 is shown in FIG. A vertical synchronizing signal VD is input from the video signal processing IC 22 to the CCD driving circuit 25 every 1/60 seconds, and a pulse A is also input. The pulse A is a signal that is inverted from OFF to ON while corresponding to the charge accumulation time (shutter speed) calculated by the video signal processing IC 22 in one field, and is inverted to OFF at the end of one field. Signal.

In the CCD drive circuit 25, a pulse B having a pulse P1 and a pulse P2 is generated. The pulse P1 is generated in synchronization with the vertical synchronization signal VD, and the pulse P2 is generated when the pulse A is inverted from OFF to ON. In the solid-state imaging device 20, charges corresponding to the subject image are accumulated, charges accumulated between the pulses P1 and P2 are discharged as unnecessary charges, and charges accumulated between the pulses P2 and P1 are image signals. As output. As described above, the _first , _second ,..., _N ,... Sequentially accumulated for each field based on the shutter speed (s ₁ , s ₂ ,..., Sn,...). The accumulated charges become the first, second,..., Nth,.

A method for determining the shutter speed (charge accumulation time) will be described by taking the (n + 1) th image signal as an example. As described above, the nth accumulated charge becomes the nth image signal and is input to the video signal processing IC 22. In the video signal processing IC 22, the luminance value (aey _n ) of the input nth image signal is calculated. The luminance value (aey _n ) is multiplied by a luminance coefficient P (unique correction value) and converted to a corrected luminance value (paey _n ). The corrected luminance value (paey _n ) is compared with the reference luminance value (aer), and the shutter speed s _{n + 1} when generating the (n + 1) th image signal is determined by the equation (1). Note that the luminance value (aey _n ) is an average value of luminance values of each pixel of the fixed imaging element 20 in the n-th image signal (hereinafter referred to as an average luminance value), and a luminance value of pixels near the center of the solid-state imaging element 20. Or the highest luminance value (hereinafter referred to as the peak luminance value) among the luminance values of the respective pixels of the solid-state imaging device 20. Which luminance value is selected is selected by the user in the panel switch 18 described above.

s _{n + 1} = s _n × (aer / paey _n ) (1)
However, pay _n = P × aey _n
Note that payn _n = corrected luminance value in the _n -th image signal
shutter speed when s _n = generated the image signals of the n

The brightness value is set as a numerical value of 8 bits (0 to 255). On the other hand, the reference luminance value is a value with which the corrected luminance value should be matched, and is set to 128, which is the center value of an 8-bit numerical value, for example. If the corrected brightness value is the same as the reference brightness value, the shutter speed s _{n + 1} need not be adjusted as shown in the equation (1), so the shutter speed s _{n + 1} is the nth image signal. Remains the same as the shutter speed s _n when generating. However, for example, when the corrected luminance value becomes smaller than the reference luminance value (128), aer / pay _n in equation (1) becomes larger than 1 and the shutter speed becomes longer. On the other hand, when the corrected luminance value is larger than the reference luminance value, the shutter speed is shortened. That is, the output value of each image signal is adjusted so that the corrected luminance value matches the reference luminance value.

The first, second,..., Nth,... Image signals whose output values are adjusted by the solid-state imaging device 20 are sequentially output to the monitor. Here, if each image signal is adjusted so that, for example, the luminance value (aey _n ) of the image signal captured by the solid-state imaging device 20 matches the reference luminance value (aer), the image signal is inherently a TV monitor. The apparent brightness (brightness) of the output video should be appropriate. That is, the shutter speed should be adjusted by the equation (1 ′).
s _{n + 1} = s _n × (aer / aey _n ) (1 ′)

  However, a plurality of electronic endoscopes are connected to the processor 14. If the types of the electronic endoscopes are different, for example, lenses used, color filters, and the like are different depending on the type. Therefore, when the electronic endoscope connected to the processor 14 is changed, the apparent brightness of the video displayed on the TV monitor 15 is changed every time the electronic endoscope is changed, and the luminance value is matched with the reference luminance value. Even so, the video displayed on the TV monitor feels bright or dark. Furthermore, a plurality of types of light source devices (processors) are similarly connected to the first electronic endoscope 10. The light emitted from the light source device varies greatly, for example, in color temperature depending on the type. Therefore, when the light source device connected to the electronic endoscope is changed, the apparent brightness of the video displayed on the TV monitor changes, and the video displayed on the TV monitor always looks the same brightness. Not necessarily.

  That is, every time the combination of the electronic endoscope and the light source device (processor) is changed, the video displayed on the TV monitor feels brighter or darker. In addition, there are various ways of feeling the brightness of each doctor who is a user, and even if the combination is the same, the doctor may determine that the apparent brightness is not the same.

Therefore, in the present embodiment, each of the electronic endoscopes 10 and 90 has a unique luminance coefficient P (correction value), and the luminance coefficient P is multiplied by each luminance value (aey _n ) to obtain a corrected luminance value ( payey _n ). Then, the shutter speed is adjusted so that the corrected luminance value matches the reference luminance value.

  Here, the luminance coefficient P is determined according to the apparent brightness. In a combination of a specific processor and a specific electronic endoscope, for example, when the apparent brightness displayed on the TV monitor is bright even though the output value of the image signal is the same as the reference luminance value, the image signal In order to suppress the output value, the luminance coefficient P is set to 1 or more. On the other hand, when the apparent brightness is dark, the luminance coefficient P is set to 1 or less in order to increase the output value of the image signal. Thereby, in this embodiment, the apparent brightness resulting from the difference in the combination in which the electronic endoscope and the processor (light source device) are connected can be appropriately maintained, and the user can adjust the brightness of the panel switch 18. It is possible to observe an image with appropriate brightness without operating the height setting switch.

  The method for setting the luminance coefficient P will be described in detail with reference to FIGS. FIG. 4 is a diagram showing a table stored in the EEPROM 24 in the first electronic endoscope 10. FIG. 5 is a diagram showing a table stored in the EEPROM 24 in the second electronic endoscope 90.

  When the first or second electronic endoscope 10 or 90 is connected to the processor 14, the processor 14 sends information for identifying the processor, that is, a serial number to the CPU 23. On the other hand, as shown in FIGS. 4 and 5, the EEPROM 24 stores a value to be set for the luminance variable (aec) corresponding to each serial number, together with the serial number of the processor. In this embodiment, as shown in FIGS. 4 and 5, the value for the brightness variable (aec) varies depending on whether the brightness value is selected from the average brightness value, the peak brightness value, or the center-weighted brightness value.

  The serial number sent from the processor 14 is compared with the serial number stored in the EEPROM 24, and the processor 14 connected to the first and second electronic endoscopes 10 and 90 is discriminated and discriminated. The brightness variable corresponding to the processor is read from the EEPROM 24. That is, when different processors are connected to the same electronic endoscope, the value of the brightness variable (aec) is set according to the connected processors.

  Furthermore, in the present embodiment, the value of the brightness variable (aec) stored in the second electronic endoscope 90 is the brightness variable stored in the first electronic endoscope 10 corresponding to the same serial number. Different from the value of (aec). That is, as shown in FIGS. 4 and 5, even if the serial number is the same as p20975 (that is, the processor is the same), the luminance variable (aec) stored in the first electronic endoscope 10 The value (for example, 128 in the average luminance value mode) is different from the value of the luminance variable (aec) stored in the second electronic endoscope 90 (for example, 120 in the average luminance value mode). That is, in this embodiment, if the electronic endoscope connected to the same processor is changed, the luminance variable (aec) is changed. Therefore, when different electronic endoscopes are connected to the same processor, the value of the luminance variable (aec) is set according to the connected electronic endoscope.

  The luminance variable is set to 65 to 255 according to the characteristics of the light source device and the electronic endoscope. The EEPROM 24 stores 128, which is a constant for dividing the luminance variable and is the center value of the bit. Here, the luminance variable is divided by the constant 128 to become the luminance coefficient P. That is, P = aec / 128. Therefore, the first and second electronic endoscopes have a substantially inherent luminance coefficient P (inherent correction value), and the luminance coefficient P is substantially stored in the EEPROM 24.

  For example, when the apparent brightness of the image displayed on the TV monitor is too bright even though the luminance value of the image signal matches the reference luminance value (for example, 128), the combination of the electronic endoscope and the processor In, the luminance variable is set to be larger than 128. On the other hand, when the apparent brightness of the image displayed on the TV monitor is too dark although the luminance value of the image signal matches the reference luminance value, in the combination of the electronic endoscope and the processor, The luminance variable is set smaller than 128.

  Therefore, for example, when the apparent brightness of the image projected on the TV monitor is too bright even though the brightness value is set to the reference brightness value (128), the brightness coefficient P becomes 1 or more, thereby correcting Since the magnitude of the luminance value is larger than the luminance value of the original image signal, the output value of the image signal is suppressed, and the brightness of the image displayed on the TV monitor is also suppressed. On the other hand, when the apparent brightness is too dark, the luminance coefficient P is set to 1 or less.

  FIG. 6 shows a program executed in the CPU 23 (see FIG. 2) of the first electronic endoscope 10. In this program, an initial setting process (step S200), an electronic endoscope switch process (step S300), a first communication process (step S400), a second communication process (step S500), and other processes (step S600). Then, automatic light control processing (step S700) is executed. When the automatic light control process ends, the program returns to step S300.

  In the initial setting process, settings of each register of the CPU 23 and the video signal processing IC 22 and other various variables are set. In the internal mirror switch processing, processing related to each switch provided in the electronic endoscope 10 is performed. That is, in step S300, when each switch is pressed, information related to these switches is sent to the processor 14 (see FIG. 1) via the CPU 23.

  In the first communication process, data related to processes other than the process performed in step S300 is transmitted and received between the processor 14 and the CPU 23. In the second communication process, various control data are transmitted and received between the video signal processing IC 22 and the CPU 23. Here, control data for mainly controlling the video signal processing IC 22 by the CPU 23 is sent to the video signal processing IC 22. In step S600, various other processes are performed, and in step S700, automatic light control is performed to keep the luminance value of the image signal constant.

The initial setting process will be further described in detail with reference to FIG. When the initial setting process is started, the register of the CPU 23 is first set in step S202. Next, in step S204, registers of other peripheral circuits such as the video signal processing IC 22 are set. In step S206, each variable is set to an initial value. In step S208, the CPU 23 requests the processor 14 to transmit a serial number. In step S209, the processor 14 is requested to transmit to the processor 14 which mode is set as the reference luminance value and the luminance calculation mode. That is, it is requested to transmit whether the luminance value (aey _n ) is the above-described average luminance value, peak luminance value, or center-weighted luminance value. In step S210, the serial number, reference luminance value, and luminance calculation mode are sent from the processor 14 to the CPU 23 in response to the request, and the CPU 23 receives the data. Here, the reference luminance value is a reference value for the brightness level (brightness level) set by the processor 14.

  In step S212, it is determined whether or not the serial number identical to the serial number transmitted from the processor 14 is stored in the EEPROM 24. If it is determined in step S212 that the same serial number is stored, the process proceeds to step S214. In step S214, the brightness variable is set according to the table shown in FIG. 4 according to the serial number and the set brightness calculation mode. The value of is read. Therefore, for example, when the serial number is q20087 and the luminance calculation mode is the average luminance value mode, the luminance variable is set to 154 (see FIG. 4). When the brightness variable is set, the initial setting process ends.

  On the other hand, when the same serial number as the serial number is not stored in the EEPROM 24, in step S220, the serial number of the processor connected to the electronic endoscope 10 is stored in the EEPROM 24 and the luminance corresponding to the serial number is stored. The value for the variable is temporarily set to 128, which is the center value of the 8-bit numerical value. In step S222, the CPU 23 requests the processor 14 to set a value for the brightness variable. When the request is completed, the initial setting process ends. When the processor 14 is requested to set a value for the brightness variable, the brightness variable setting process shown in FIG. 8 is started.

  In the brightness variable setting process, first, as shown in FIG. 8, the processor 14 displays on the TV monitor 15 that the request for setting the brightness variable (aec) has been transmitted from the electronic endoscope 10 in step S252. The value for the brightness variable is displayed on the TV monitor in step S254, and the user is informed that there is a request for setting the value for the brightness variable and the value for the brightness variable. Since the value for the luminance variable is initially set to 128, for example, aec = 128 is displayed on the TV monitor. In the brightness variable setting process, values for brightness variables in the average brightness value mode, the peak brightness value mode, and the center-weighted brightness value mode are set in order. Accordingly, in step S254, it is also displayed that the currently set value for the brightness variable is a value in the average brightness value mode.

  The user sets a value for the brightness variable while viewing the display on the TV monitor 15. Therefore, in step S256, it is determined whether or not the upper key of the keyboard 16 has been pressed. If it is determined that the upper key has been pressed, 1 is added to the value for the luminance variable (aec) in step S260, and the value is Is transmitted to the electronic endoscope 10. The added value for the brightness variable is displayed on the TV monitor 15 in step S254.

  If it is determined in step S256 that the up key is not pressed, the process proceeds to step S258. In step S258, it is determined whether or not the down key is pressed. If it is determined that the down key is pressed, step S262 is performed. 1 is subtracted from the value of aec and the value is transmitted to the electronic endoscope 10. In step S254, the reduced value of aec is displayed on the TV monitor.

  If it is determined in step S258 that the down key is not pressed, the process proceeds to step S264. In step S264, it is determined whether or not the enter key of the keyboard 16 is pressed. If it is determined that the enter key has not been pressed, the process returns to step S254. On the other hand, if it is determined that the enter key has been pressed, in step S266, the value changed by the up / down key (the value displayed on the TV monitor) is determined as the value of the brightness variable (aec) in the average brightness value mode. The Since the determined value is a value stored in the EEPROM 24, a command for instructing storage in the EEPROM 24 is transmitted from the processor to the CPU 23. In step S270, the value for the luminance variable in the peak luminance value mode is set in the same manner as in steps S254 to S266. Similarly, in step S280, the value for the luminance variable in the center-weighted luminance value mode is set. Note that the brightness variable setting process is set when a new type of light source device (processor) or electronic endoscope is delivered to the user, and is therefore normally set by a service person. Since the service person usually fully understands the characteristics of each light source device (processor), the value of the brightness variable can be easily set.

  As described above, the value of the brightness variable is stored in the electronic endoscope 10 for each processor (for each serial number), whereby the value of the brightness variable is changed when the light source device is changed. .

  FIG. 9 shows details of the first communication process (step S400). In the first communication process, first, in step S402, it is determined whether or not data is transmitted from the processor 14 to the CPU 23. Here, when data is not sent from the processor 14, the first communication process is ended. When data is transmitted from the processor 14, it is determined in step S404 whether or not the transmitted data is AE data. Here, AE data refers to data used for automatic light control, and specifically includes the reference luminance value (aer) and the luminance variable (aec) described above.

  That is, in steps S408 and S410, which will be described later, when the brightness setting switch of the panel switch 18 is operated as described above, information on the reference luminance value is transmitted from the processor 14, so that the CPU 23 performs processing on the information. Done. On the other hand, in step S412 and subsequent steps, when the value for the luminance variable is set in steps S260, S262, and S266 described above, the processor 14 transmits information about the value for the luminance variable. Is done.

  Data sent from the processor 14 is composed of 2 bytes, and each byte is composed of 8 bits. The first byte of the transmitted data is data for determining the type of the data. In the second byte, a numerical value related to the data is written. Here, the reference brightness value data is determined as a3h in the first byte, and the brightness variable data is determined as afh in the first byte. Therefore, if the first byte is afh or a3h data, the transmitted data is determined to be AE data, and the process proceeds to step S408. If it is determined that the data is not AE data, since the transmitted data is data other than data related to automatic light control in step S406, processing corresponding to the data is performed, and the first communication processing ends. .

  In step S408, it is determined whether or not the first byte is a3h. If it is a3h, in step S410, the reference luminance value (aer) is set to the value of the second byte of the received data, and the first byte The image processing ends.

  If it is determined in step S408 that the first byte is not a3h, the process proceeds to step S412. In step S412, it is determined whether the first byte is afh. If it is not afh, the first communication process ends. If the first byte is afh, the process proceeds to step S414. If it is determined in step S414 that the value for the brightness variable set in the brightness variable setting mode is the value for the brightness variable in the average brightness value mode, the process proceeds to step S416. In step S416, the value corresponding to the serial number of the processor 14 and the value corresponding to the average luminance value mode is stored as the value data of the luminance variable in the term corresponding to the average luminance value mode, and the first communication process is completed. To do. If it is determined in step S418 that the luminance calculation mode is the peak luminance value mode, in step S420, the value corresponding to the peak luminance value mode is stored as data of the value of the luminance variable in the same manner as in step S416. The same applies to step S422 and step S424.

  FIG. 10 shows details of the automatic light control processing (step S700). When the automatic dimming process is started, it is determined in step S702 whether one field has been completed or not. If it is determined in step S702 that one field has not been completed, the specific automatic dimming process is not performed. This process ends. That is, automatic light control (shutter adjustment) is performed for each field in this embodiment. If it is determined that one field has elapsed, automatic dimming is performed in steps S704 to S710.

In the automatic light control process, in step S704, the luminance value (aey _n ) of the nth image signal is first input from the video signal processing IC 22 to the CPU 23. In step S706, the corrected luminance value (paey _n ) of the image signal is calculated. Here, the corrected luminance value is calculated by multiplying the luminance value of the image signal by the luminance coefficient P. In step S708, based on the corrected luminance value (paey _n ) and the shutter speed (s _n ) of the n-th image signal, the shutter speed (s _{n + 1} ) of the (n + 1) -th image signal according to equation ( ₁ ). Is calculated.

In step S710, the shutter speed (s _{n + 1} ) is sent to the video signal processing IC 22 and stored in the corresponding register of the video signal processing IC 22. The video signal processing IC 22 sends a pulse A and a pulse B to the CCD drive circuit 25 based on the stored shutter speed (s _{n + 1} ), and the CCD drive circuit 25 based on the shutter speed (s _{n + 1} ). The shutter of the solid-state imaging device 20 when the (n + 1) th image signal is generated is controlled.

  In the present embodiment, a program similar to the above-described program is also executed in the CPU 23 (see FIG. 2) of the second electronic endoscope 90. Therefore, even when the second electronic endoscope 90 is connected to the processor 14, the value for the luminance variable is changed for each serial number in the same manner. Therefore, in the second electronic endoscope 90 as well, When the connected light source device is changed, the value for the luminance variable is changed. In addition, in each of the first and second electronic endoscopes 10 and 90, even if the serial numbers are the same value, different values for the luminance variable can be set. In, when the connected electronic endoscope is changed, the luminance variable can be changed.

In the present embodiment, as described above, the luminance value aey _n is multiplied by the luminance coefficient P to calculate the corrected luminance value payn _n , and the shutter speed s _{n + 1} is calculated. P may be removed to obtain a corrected reference luminance value (paer), and the shutter speed s _{n + 1} may be calculated by the following equation (2). Even in this case, the luminance coefficient P = aec (luminance variable) / 128.
s _{n + 1} = s _n × (paer / aey _n ) (2)
However, paer = aer / P

Further, in the present embodiment is multiplied luminance coefficient P to the luminance value AEy _n, the correction luminance value Paey _n is calculated, the luminance constant P (specific correction value) in luminance value AEy _n is acceleration, the corrected luminance The value payn _n may be calculated. In this case, the luminance variable (aec) = the luminance constant P, and the shutter speed s _{n + 1} is calculated by the following equation (3). In this case, the range of the luminance variable (aec) = P is set to −65 to +85 in this embodiment.
s _{n + 1} = s _n × (aer / paey _n ) (3)
However, pay _n = aey _n + aec

Incidentally, when the luminance value AEy _n luminance constant P (aec) is added to the corrected luminance value Paey _n is calculated, if the bright brightness of the apparent appearing on the TV monitor, in order to suppress the output value of the image signal In addition, the luminance coefficient P is set to 0 or more. On the other hand, when the apparent brightness is dark, the luminance constant P is set to 0 or less in order to increase the output value of the image signal.

Further, even when the corrected reference luminance value (paer) is obtained as described above, the luminance constant P is added to or subtracted from the reference luminance value as shown in the following equation (4), and the corrected reference luminance value (paer) is calculated. And the shutter speed s _{n + 1} may be calculated from the corrected reference luminance value paer. In this case, the luminance variable (aec) = luminance constant P, and the range of the luminance variable (aec) = P is set to −65 to +85 in this embodiment.
s _{n + 1} = s _n × (paer / aey _n ) (4)
However, paer = aer + ace

  In the case of the expression (4), when the apparent brightness reflected on the TV monitor is bright, the luminance constant P is set to 0 or less in order to suppress the output value of the image signal. On the other hand, when the apparent brightness is dark, the luminance constant P is set to 0 or more in order to increase the output value of the image signal.

Furthermore, as shown in equation (5) instead of equation (1), it is Jose luminance coefficient P to the luminance value AEy _n, the corrected luminance value Paey _n may be calculated.
s _{n + 1} = s _n × (aer / paey _n ) (5)
However, pay _n = aey _n / P

Further, as shown in Expression (6) instead of Expression (2), the reference luminance value may be multiplied by the luminance coefficient P to calculate the corrected reference luminance value paer.
s _{n + 1} = s _n × (paer / aey _n ) (6)
However, paer = P × aer

As described above, in the present embodiment, the correction value (brightness constant or luminance coefficient) is applied to the luminance value aey _n by any one of the addition and subtraction multiplications, and the corrected luminance value payn _n is calculated. corrected luminance value Paey _n is the luminance value AEy _n, s or more correction values may be calculated to act by the operation of subtraction NoJo. That is, for example, the corrected luminance value may be calculated by Expression (7).
payn _n = a × (aey _n + b) −c (7)
However, a, b, and c are correction values.

Further, the correction reference luminance value paer _n described above may be similarly calculated by the equation (8).
paer _n = a × (aer _n + b) −c (6)
However, a, b, and c are correction values.

  That is, in the claims, “acting the correction value on the luminance value of the image signal by addition / subtraction / multiplication / division calculation” does not use all the addition / subtraction / multiplication / division calculations, but the correction value by at least one addition / subtraction / multiplication / division calculation. Is applied to the luminance value. There may be a plurality of correction values.

1 schematically shows an electronic endoscope apparatus according to an embodiment of the present invention. 1 shows an electrical configuration of an electronic endoscope according to an embodiment of the present invention. 2 is a timing chart regarding control of a solid-state imaging device of an electronic endoscope. The table memorize | stored in the memory of the 1st electronic endoscope is shown. The table memorize | stored in the memory of the 2nd electronic endoscope is shown. The whole program which CPU which was provided in the electronic endoscope performs is shown. An initial setting process among the programs executed by the CPU will be described in detail. The program of the brightness | luminance variable setting process performed with a processor is shown. The first communication process in the program executed by the CPU will be described in detail. An automatic light control process among the programs executed by the CPU will be described in detail.

Explanation of symbols

10 first electronic endoscope 14 processor (light source device for electronic endoscope)
15 TV monitor 20 Solid-state image sensor (CCD)
24 EEPROM (memory)
90 Second electronic endoscope

Claims (14)

A plurality of electronic endoscopes each having a solid-state image sensor and generating an image signal from a subject image captured by the solid-state image sensor;
A light source device for an electronic endoscope that can be connected to the plurality of electronic endoscopes and to which one electronic endoscope included in the plurality of electronic endoscopes is connected;
Output means for outputting the image signal generated by the connected electronic endoscope to a monitor;
Each of the electronic endoscopes has a unique correction value, and the correction value is applied to the luminance value of the image signal by calculation of addition / subtraction / multiplication / division. Based on the correction luminance value An electronic endoscope system characterized by adjusting a luminance value of an image signal output to the monitor. The output means sequentially outputs at least first and second image signals obtained by converting the subject image in time series to the monitor,
Each of the connected electronic endoscopes obtains a corrected luminance value by applying the correction value to the luminance value of the first image signal by at least one of addition, subtraction, multiplication, and division. 2. The electronic endoscope system according to claim 1, wherein a luminance value of the second image signal is adjusted based on the first image signal.   The solid-state imaging device of the electronic endoscope has an electronic shutter function, and each electronic endoscope adjusts the brightness value of the second image signal by adjusting the shutter speed of the solid-state imaging device. The electronic endoscope system according to claim 2.   2. The electronic endoscope system according to claim 1, wherein each of the electronic endoscopes adjusts the luminance value so that the corrected luminance value matches a predetermined reference value.   The electronic endoscope system according to claim 1, wherein the unique correction value is stored in a memory provided in each electronic endoscope.   The electronic endoscope system according to claim 1, wherein the unique correction value is calculated by dividing a predetermined constant by a predetermined value of each electronic endoscope.   The electronic endoscope system according to claim 6, wherein the predetermined value is stored in a memory provided in the electronic endoscope.   The electronic endoscope system according to claim 1, wherein the unique correction value is different for each electronic endoscope.   Each of the electronic endoscopes can be connected to a plurality of light source devices, and each of the electronic endoscopes has a plurality of unique correction values, and the unique correction values that act on the luminance values are 2. The electronic endoscope system according to claim 1, wherein the electronic endoscope system is changed according to a light source device connected to each electronic endoscope.   The luminance value of the image signal is a luminance value obtained from the luminance value of each pixel of the solid-state imaging device by one method selected from at least two different methods, and the correction value is selected. The electronic endoscope system according to claim 1, wherein the electronic endoscope system differs depending on the method.   The luminance value of the image signal is an average value of luminance values of pixels of the solid-state image sensor, an average value of luminance values of pixels near the center of the solid-state image sensor, and a luminance value of pixels of the solid-state image sensor. 2. The electronic endoscope system according to claim 1, wherein the correction value is any one selected from among the highest luminance values, and the correction value differs according to the selected luminance value. A plurality of electronic endoscopes each having a solid-state image sensor and generating an image signal from a subject image captured by the solid-state image sensor;
A light source device for an electronic endoscope that can be connected to the plurality of electronic endoscopes and to which one electronic endoscope included in the plurality of electronic endoscopes is connected;
Output means for outputting the image signal generated by the connected electronic endoscope to a monitor;
Each of the electronic endoscopes has a unique correction value, and the correction value is obtained by applying the unique correction value to a predetermined reference value by calculation of addition / subtraction / multiplication / division, and the luminance value of the image signal is An electronic endoscope system, wherein a luminance value of an image signal output to the monitor is adjusted so as to coincide with the correction reference value. An electronic endoscope having a solid-state imaging device, generating an image signal from a subject image captured by the solid-state imaging device, and connectable to at least one light source device for an electronic endoscope,
A correction brightness value is obtained by applying the correction value to the brightness value of the image signal by calculation of addition / subtraction / multiplication / division, and is output to the light source device based on the correction brightness value. An electronic endoscope characterized by adjusting a luminance value of the image signal. An electronic endoscope having a solid-state imaging device, generating an image signal from a subject image captured by the solid-state imaging device, and connectable to at least one light source device for an electronic endoscope,
A correction reference value is obtained by operating the specific correction value on a predetermined reference value by calculation of addition / subtraction / multiplication / division, and the luminance value of the image signal matches the correction reference value. As described above, the electronic endoscope is characterized in that the luminance value of the image signal output to the light source device is adjusted.

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