JP2010279457A - Electronic endoscope, electronic endoscopic system, and color adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic endoscope capable of performing the color adjustment suitable for the characteristics of a display device such as a monitor, and to provide an electronic endoscope system and a color adjusting method for them. <P>SOLUTION: This electronic endoscopic system includes a photographing means for photographing an observation target to form an image signal, a memory means for storing a predetermined image, an output means for outputting the predetermined image to the display device in order to display the same on the display means, a reference value setting means for setting a reference value on the basis of the image signal formed by photographing the predetermined image displayed on the display device by the photographing means, and a color adjusting means for performing color adjustment with respect to the image signal formed by the photographing means on the basis of the reference value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic endoscope, an electronic endoscope system, and an image color adjustment method in the electronic endoscope and the electronic endoscope system.

  In order to diagnose or treat a patient's body, an electronic endoscope having a solid-state image sensor such as a CCD at the tip, and an electronic endoscope that processes an image signal generated by the solid-state image sensor and outputs it to a monitor An electronic endoscope system including a mirror processor is widely known and put into practical use. In order to perform accurate diagnosis and treatment using such an electronic endoscope system, it is desired that the color of the subject be reproduced faithfully in an image obtained by the electronic endoscope.

  However, in general, the design of optical elements such as lenses and color filters (for example, viewing angle, observation depth, absorption spectrum, etc.) differs depending on the type of electronic endoscope. Therefore, even when the same processor is used, the appearance (brightness and color tone) of the image displayed on the monitor differs depending on the type of electronic endoscope to be connected. In addition, depending on the type of the light source lamp to be used, the color tone or the like of the obtained observation image varies depending on the difference in the emission spectrum.

  Japanese Patent Application Laid-Open No. 2004-228561 compensates for the difference in color tone of an observation image caused by the difference in the types of electronic endoscopes and processors (light source lamps) used as described above, and realizes high color reproducibility. One solution is disclosed. In the electronic endoscope system described in Patent Document 1, data relating to characteristics of the electronic endoscope and color adjustment data corresponding to each of a plurality of types of light source lamps are stored in advance in the storage means in the electronic endoscope. Has been. Based on these data, a color adjustment process suitable for the electronic endoscope and the light source lamp to be used is performed on the observation image.

JP 2002-369798 A

  Incidentally, the monitor used in the electronic endoscope system is not a dedicated one for the electronic endoscope system, but is a general-purpose product that is arbitrarily procured depending on the site where observation is performed. Even in a general-purpose monitor having a general image receiving function, color reproduction characteristics differ depending on the model and individual differences. For this reason, as in the electronic endoscope system described in Patent Document 1, even if the color adjustment is performed based on the color adjustment data in consideration of the variation caused by the difference between the types of the electronic endoscope and the processor, the monitor Due to the variation in color, color reproduction may not be performed properly in an actual observation image.

  Therefore, the present invention has been made in view of the above circumstances, and provides an electronic endoscope, an electronic endoscope system, and a color adjustment method in these that can perform color adjustment suitable for the characteristics of the monitor. With the goal.

  In order to solve the above-described problem, according to the present invention, a photographing unit that photographs an observation target and generates an image signal, a storage unit that stores a predetermined image, and a predetermined unit for displaying a predetermined image on a display device. Output means for outputting the image to the display device, reference value setting means for setting a reference value based on an image signal generated by photographing a predetermined image displayed on the display device by the photographing means, and reference There is provided an electronic endoscope system comprising: a color adjustment unit that performs color adjustment on an image signal generated by a photographing unit based on a value.

  With this configuration, it is possible to set a reference value according to the characteristics of a display device such as a monitor. As a result, even when the characteristics of the display device are different, color adjustment based on the reference value can be performed to compensate for variations in color reproduction, and an appropriate image can be provided.

  The predetermined image may be a color chart including a reference color component. The reference values may be R, G, and B gain values and R and B gain values for white balance adjustment.

  The storage means may store an ideal range related to color information. The reference value setting means sets the reference value by comparing color information in an image signal generated by photographing a predetermined image displayed on the display device by the photographing means and an ideal range. It may be configured to do so. With this configuration, the reference value can be set so that the color of the image displayed on the display device is included in the ideal range.

  In the electronic endoscope system, the output unit switches between an adjustment mode in which a predetermined image is output to the display device and a normal mode in which the output unit outputs an image signal generated by the imaging unit to the display device. The structure which further has a switching means may be sufficient.

  Further, according to the present invention, a photographing unit that photographs an observation target and generates an image signal, a storage unit that stores a predetermined image, and a predetermined image on the display device in order to display the predetermined image on the display device. Based on an image signal generated by photographing a predetermined image displayed on the display device by an output means that outputs, a reference value setting means that sets a reference value based on a reference value, There is provided an electronic endoscope comprising: a color adjustment unit that performs color adjustment on an image signal generated by an imaging unit.

  Further, according to the present invention, there is provided a color adjustment method in an electronic endoscope system, the step of displaying a predetermined image on a display device, the step of photographing the predetermined image displayed on the display device by a photographing means, A step of setting a reference value based on an image signal generated by shooting a predetermined image by the shooting unit; a step of performing color adjustment on the image signal generated by the shooting unit based on the reference value; Is provided.

  Therefore, according to the electronic endoscope, the electronic endoscope system, and the color adjustment method in these according to the present invention, color adjustment suitable for the characteristics of the monitor can be performed, and an appropriate observation image can be provided. Become.

It is a figure which shows schematic structure of the electronic endoscope system in embodiment of this invention. It is a schematic diagram which shows the structure of the front stage processing circuit of the electronic endoscope in embodiment of this invention. It is a flowchart which shows the flow of the gain value setting process in the adjustment mode of this invention. It is a flowchart which shows the flow of the R adjustment process in the gain value setting process of this invention. It is a flowchart which shows the flow of the WB adjustment process in the gain value setting process of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an electronic endoscope system 1 according to an embodiment of the present invention. As shown in FIG. 1, the electronic endoscope system 1 includes an electronic endoscope 10, a processor 20, and a monitor 30. In this embodiment, the electronic endoscope system 1 is a medical electronic endoscope system for performing observation and treatment in a patient's body.

  The electronic endoscope 10 is electrically and optically connected to an insertion portion 10a made of a long flexible tube inserted into a patient's body, an operation portion 10b grasped by an operator, and a processor 20. Part 10c. The insertion part 10a of the electronic endoscope 10 has a light guide 11 that propagates light supplied from the processor 20, and a light distribution lens 12 that diffuses and emits the light propagated by the light guide 11 into the body. An objective lens 13 for forming an image of the light reflected by the observation site on the light receiving surface of the image pickup device, and a CCD 14 as an image pickup device for generating an image signal based on the subject image formed on the light receiving surface. Yes.

  The operation unit 10 b of the electronic endoscope 10 is provided with an operation button group 19 including various operation buttons including a capture button 19 a for acquiring a still image by the CCD 14. In addition, the connection unit 10c of the electronic endoscope 10 includes a pre-processing circuit 15 that performs processing to be described later on the image signal generated by the CCD 14, and color adjustment to be described later along with characteristics of the electronic endoscope 10 (such as the number of pixels). The EEPROM 17 in which data related to the above are stored in advance, and the control unit 16 that performs overall control of the entire electronic endoscope 10 are provided.

  The processor 20 includes a front panel 21 on which various operation buttons including a mode switching button 21a, which will be described later, are arranged, a system controller 22 that performs overall control of the entire processor 20, and a lamp 23 that generates illumination light to be supplied to the electronic endoscope 10. , A lamp power supply 24 for supplying driving power to the lamp 23, a condenser lens 25 for converging the light emitted from the lamp 23 and coupling it to the light guide 11 of the electronic endoscope 10, and incidence of light coupled to the light guide 11 Received from a diaphragm 26 that adjusts the amount of light applied to the observation site by regulating the angle, a timing controller 28 that generates clock pulses for controlling the synchronization of each part in the electronic endoscope system 1, and the electronic endoscope 10 A post-processing circuit 29 that performs predetermined processing on the video signal is provided. The monitor 30 is an image receiving device that displays an image based on the video signal processed by the post-processing circuit 29.

  In-body cavity observation in the electronic endoscope system 1 is performed as follows. First, when a main power switch (not shown) provided on the front panel 21 is turned on by an operator, a drive current is supplied from the lamp power source 24 to the lamp 23 under the control of the system controller 22. Then, the lamp 23 is turned on in response to the drive current, and the light emitted from the lamp 23 passes through the condenser lens 25 and the diaphragm 26 to the incident end 11A of the light guide 11 provided in the electronic endoscope 10. Incident. The light incident on the incident end 11A of the light guide 11 passes through the light guide 11 and is emitted from the emitting end 11B to the observation site in the body. Then, the emitted light is reflected by the observation site and imaged on the light receiving surface of the CCD 14 via the objective lens 13.

  In this embodiment, a single-plate simultaneous type is applied as a color imaging method, and yellow (Ye), cyan (Cy), magenta (Mg), and green (G) color elements are checked on the light receiving surface of the CCD 14. Complementary color filters (not shown) arranged in a pattern are arranged corresponding to each pixel on the light receiving surface. Then, in the CCD 14, an image signal of a subject image corresponding to the intensity of light transmitted through the complementary color filter is generated by photoelectric conversion, and an image signal for one frame or one field is generated at a predetermined time interval by a color difference line sequential method. Read sequentially. In this embodiment, an interline transfer type CCD is used, and an image for one frame (one field) is provided every 1/30 seconds (1/60 seconds) corresponding to the NTSC vertical synchronization frequency. The signals are sequentially read and sent to the pre-processing circuit 15.

  In the pre-processing circuit 15, predetermined processing is performed on the color image signal generated by the CCD 14 to generate a video signal. FIG. 2 is a diagram illustrating the configuration of the pre-processing circuit 15. As shown in FIG. 2, the pre-processing circuit 15 includes a matrix circuit 152, a gain adjustment circuit 154, and a white balance adjustment circuit 156. The matrix circuit 152 uses a known method to detect R (color signal) composed of yellow (Ye), cyan (Cy), magenta (Mg), and green (G) components generated by the complementary color checkered color difference line sequential CCD 54 using a known method. , G, B primary color signals are generated. The R, G, and B primary color signals generated by the matrix circuit 152 are output to the gain adjustment circuit 154.

  The gain adjustment circuit 154 performs gain adjustment for each of R, G, and B colors. In the present embodiment, gain adjustment of each primary color signal is performed based on an R gain value rs, a G gain value gs, and a B gain value bs obtained by a method described later. Each of these gain values is stored in the EEPROM 17 as a reference value and is appropriately read out by the control unit 16.

  The R, G, and B color signals that have been gain-adjusted by the gain adjustment circuit 154 are output to the white balance adjustment circuit 156. The white balance adjustment circuit 156 performs further gain adjustment on the R and B color signals among the input R, G, and B signals. The white balance adjustment circuit 156 also uses an R gain value rws and a B gain value bws obtained by a method described later. These gain values are also stored in the EPROM 17 as reference values and are appropriately read out by the control unit 16.

  Further, in the pre-processing circuit 15, in addition to the processing in each circuit shown in FIG. 2, signal separation processing for separating luminance signals and color signals, gamma correction processing for performing gamma correction, or image contour enhancement Processing such as image contour enhancement processing is performed. Further, the pre-processing circuit 15 includes a CCD driver (not shown) for driving the CCD 14, and a drive signal is output from the CCD driver to the CCD 14. Then, the video signal generated by the above-described processes in the pre-processing circuit 15 is sent to the post-processing circuit 29 of the processor 10.

  In the post-processing circuit 29 of the processor 20, processing such as D / A conversion is performed on the video signal sent from the pre-processing circuit 15, and an NTSC composite signal and Y / C separation signal (so-called “so-called”) suitable for display on the monitor 30. S video signal) and RGB separated signals are generated. The video signal generated by the post-processing circuit 29 is output to the monitor 30, whereby the subject image is displayed on the monitor 30. An operator or a diagnostician can observe the state in the body cavity of the patient from the subject image displayed on the monitor 30.

  Subsequently, each gain value used in the pre-processing circuit 15 will be described. In the present embodiment, gain values rs, gs, bs, rws and bws suitable for the characteristics of the monitor 30 connected to the processor 20 are set by performing the following operations and stored in the EEPROM 17.

  First, in the electronic endoscope system 1, when the monitor 30 is connected for the first time, the operator operates the mode switching button 21a on the front panel 21 of the processor 20. The mode switching button 21a is used to switch between a normal mode for performing the above-mentioned in-body cavity observation by the electronic endoscope system 1 and an adjustment mode for setting a gain value according to the characteristics of the monitor 30. . When the mode switch button 21a is operated by the surgeon to switch to the adjustment mode, the system controller 22 performs a gain value setting process, which will be described later, on the control unit 16 of the electronic endoscope 10. Instructions are given.

  The control unit 16 of the electronic endoscope 10 receives an instruction from the system control 22 and starts gain value setting processing. FIG. 3 is a flowchart showing a flow of gain value setting processing executed by the control unit 16 of the electronic endoscope 10. As shown in FIG. 3, in this process, first, a video signal corresponding to the reference color chart of R (red) is transmitted to the processor 20 (S1). Here, in the EEPROM 17 of the electronic endoscope 10, data corresponding to R, G, B, and W (white) color charts as a reference are set and stored in advance. When the gain value setting process is started, a video signal corresponding to the R color chart is first read from the EEPROM 17 and transmitted to the processor 20.

  In the processor 20, predetermined processing is performed on the video signal corresponding to the R color chart received from the electronic endoscope 10 by the post-stage processing circuit 29 and output to the monitor 30. The monitor 30 displays an R color chart image on the display screen 30 a based on the video signal output from the processor 20. The color chart of each color may be displayed in the entire display area of the monitor 30, or may be displayed in a circle or rectangle in a part of the display area.

  Subsequently, it is determined whether or not the capture button 19a of the electronic endoscope 10 has been pressed by the operator (S2). This is to determine whether or not a color chart displayed on the display screen 30a of the monitor 30 has been photographed by the electronic endoscope 10. Specifically, the color chart image of R displayed on the display screen 30a of the monitor 30 by pressing the capture button 19a by placing the tip of the electronic endoscope 10 where the CCD 14 is disposed on the display screen 30a of the monitor 30 and pressing the capture button 19a. Is filmed. At this time, the lamp 23 of the processor 20 is turned off, and the display screen 30a of the monitor 30 is photographed in a state where no light is emitted from the tip of the electronic endoscope 10.

  If the capture button 19a has not been pressed (S2: No), it is determined whether or not the mode switching button 21a has been pressed (S3). If the mode switching button 21a is not pressed (S3: No), the process returns to S2, and waits until either the capture button 19a or the mode switching button 21a is pressed. When the mode switching button 21a is pressed (S3: Yes), the gain value setting process is terminated and the mode is switched from the adjustment mode to the normal observation mode. Thereafter, normal in-vivo observation is performed.

On the other hand, when the capture button 19a is pressed and an R color chart image is taken by the CCD 14 (S2: Yes), an R adjustment process is subsequently performed (S4). FIG. 4 is a flowchart showing the flow of the R adjustment process. In the R adjustment process, first, the variable n = 0 is set (S401). The variable n is a variable for counting a gain adjustment loop described later. Subsequently, the signal intensity R ₀ in the R primary color signal is detected (S 402). The R primary color signal is a signal obtained by photographing an R color chart image displayed on the display screen 30 a of the monitor 30. Specifically, when the capture button 19a is pressed as described above, an image signal corresponding to the R color chart image displayed on the monitor 30 by the CCD 14 is generated. The image signal generated by the CCD 14 is input to the matrix circuit 152 of the pre-processing circuit 15, and R, G, and B primary color signals are generated by the matrix circuit 152. In S <b> 402, the signal intensity R ₀ is detected from the R primary color signal output from the matrix circuit 152.

Subsequently, a value obtained by multiplying the detected _R0 by the R gain value rs is defined as _R0x (S403). R _0x is a variable used for calculation described later. The R gain value rs is stored in the EEPROM 17 and is read by the control unit 16. When the adjustment mode is performed for the first time in the electronic endoscope system 1, initial values set at the time of factory shipment are stored as the gain values rs, bs, gs, rws, and bws. In subsequent S404, it is determined whether or not the value of R _0x is within an ideal color (R) range in the electronic endoscope 10. Here, the ideal color range represents an allowable range that does not hinder observation regarding the color reproducibility of the subject image, and is expressed by the following equation.

R _s <R _0x <R _h (1)

The lower limit value and upper limit value of the ideal range are represented by “R _s ” and “R _h ”. These lower values _{R s} and the upper limit value _{R h} is stored in the EEPROM17 preset.

In S404, if the expression (1) is satisfied (S404: Yes), the subsequent S405, the ratio of _{R 0x} is set as R gain value rs for _{R 0,} and stores the EEPROM 17. For example, when the R adjustment process is started and R _0x is determined to be within the ideal range in the first determination in S 404, the R color chart image displayed on the monitor 30 is appropriately colored. Assuming that reproduction has been performed, the R gain value rs is set to the same value as the initial value. In S405, the flag Rf indicating whether or not the gain value has been appropriately set in the R adjustment processing is set to 0. Here, Rf is 0 when the gain value is appropriately set in the R adjustment process, and Rf is 1 when the gain value is not appropriately set.

On the other hand, when Formula (1) is not satisfied (S404: No), the process proceeds to S406. In S406, it is determined whether or not the value of the variable n is greater than 20. Here, it is determined whether or not the loop based on the determination in S404 has been executed more than the predetermined number of 20 times. When the value of the variable n is larger than 20 (S406: Yes), the ratio of R _{0x to} R ₀ at this time is set as the R gain value rs and stored in the EEPROM 17. Then, the flag Rf is set to 1 on the assumption that the gain value is not properly set in this process.

On the other hand, when the value of the variable n is 20 or less (S406: No), 1 is added to the value of n (S408), and the process proceeds to S409. In S409, it is determined whether or not the value of R _0x is larger than the lower limit value R _s of the ideal range. When the value of R _0x is equal to or lower than the lower limit value R _s (S409: No), the value of R _0x is increased by a predetermined amount as shown in the following equation (S410).

R _0x = R _0x × (1 + n / 100)

On the other hand, when the value of R _0x is larger than the lower limit value R _s (S409: Yes), the value of R _0x is decreased by a predetermined amount as shown in the following equation (S411).

R _0x = R _0x × (1-n / 100)

When the value of R _0x is increased or decreased by S410 or S411, the process returns to S404. In S404, the processing from S404 to S411 is repeated until Expression (1) is satisfied (the value of R _0x is included in the ideal range) or the value of n exceeds 20 in S406. It is. On the other hand, when the R gain value rs is set in S405 or S407, the R adjustment process ends. Then, the process returns to the gain setting process and proceeds to the subsequent process of S5.

  In S <b> 5, a video signal corresponding to the G (green) reference color chart is transmitted to the processor 20. In the processor 20, as described above, the video signal corresponding to the G color chart received from the electronic endoscope 10 is performed by the post-processing circuit 29 and output to the monitor 30. . Then, the G color chart image is displayed on the monitor 30 based on the video signal output from the processor 20.

  Subsequently, similarly to S2, it is determined whether or not the capture button 19a of the electronic endoscope 10 has been pressed by the operator (S6). If the capture button 19a has not been pressed (S6: No), it is determined whether or not the mode switching button 21a has been pressed (S7). If the mode switching button 21a has not been pressed (S7: No), the process returns to S6 and waits until either the capture button 19a or the mode switching button 21a is pressed. When the mode switching button 21a is pressed (S7: Yes), this process is terminated and the mode is switched from the adjustment mode to the normal observation mode.

On the other hand, when the capture button 19a is pressed and an image of the G color chart is captured by the CCD 14 (S6: Yes), G adjustment processing is performed (S8). In the G adjustment process, the G gain value gs is set through a process flow substantially similar to the R adjustment process. Here, illustration of the flowchart is omitted, and only the processing will be described. In the G adjustment process, first, the variable n = 0 is set as in the R adjustment process. Then, the signal intensity G ₀ in the G primary color signal is detected from the image signal photographed by the CCD 14.

Subsequently, a value obtained by multiplying the detected G ₀ by the G gain value gs is defined as G _0x . As described above, the G gain value gs in this case is also stored in the EEPROM 17, and the initial value is input when the adjustment mode is performed for the first time in the electronic endoscope system 1. Then, it is determined whether or not the value of G _0x is within an ideal color (G) range in the electronic endoscope 10. Here, the ideal range is expressed by the following equation.

G _s <G _0x <G _h (2)

The lower limit value and upper limit value of the ideal range are represented by “G _s ” and “G _h ”. These lower values _{G s} and the upper limit value _{G h} is stored in the EEPROM17 preset.

If Expression (2) is satisfied, the ratio of G _{0x to} G ₀ is set as the G gain value gs and stored in the EEPROM 17. Then, a flag Gf indicating whether or not the gain value is properly set in the G adjustment processing is set to 0. On the other hand, if the expression (2) is not satisfied, it is subsequently determined whether or not the value of the variable n is larger than 20. When the value of the variable n is larger than 20, the ratio of G _{0x to} G ₀ at this time is stored in the EEPROM 17 as the G gain value gs, and the gain value is not properly set in this processing. As a result, the flag Gf is set to 1.

Further, when the value of the variable n is 20 or less, 1 is added to the value of n. Then, it is determined whether or not the value of G _0x is larger than the lower limit value G _s of the ideal range. When the value of G _0x is equal to or lower than the lower limit value G _s , the value of G _0x is increased by a predetermined amount as in the following equation.

G _0x = G _0x × (1 + n / 100)

On the other hand, when the value of G _0x is larger than the lower limit value Gs, the value of G _0x is decreased by a predetermined amount as in the following equation.

G _0x = G _0x × (1-n / 100)

When the expression (2) is satisfied (the value of G _0x is included in the ideal range) or the loop process is repeated a predetermined number of times or more, the G gain value gs is set, and the G adjustment process is performed. finish. Then, the process returns to the gain value setting process and proceeds to the subsequent process of S9.

  In S <b> 9, a video signal corresponding to the B (blue) reference color chart is transmitted to the processor 20. In the processor 20, as described above, the video signal corresponding to the B color chart received from the electronic endoscope 10 is performed by the post-processing circuit 29 and output to the monitor 30. . Then, based on the video signal output from the processor 20 on the monitor 30, the B color chart image is displayed.

  Subsequently, it is determined whether or not the operator has pressed the capture button 19a of the electronic endoscope 10 (S10). If the capture button 19a has not been pressed (S10: No), it is determined whether or not the mode switching button 21a has been pressed (S11). If the mode switching button 21a has not been pressed (S11: No), the process returns to S10 and waits until either the capture button 19a or the mode switching button 21a is pressed. Further, when the mode switching button 21a is pressed (S11: Yes), this process is terminated and the mode is switched from the adjustment mode to the normal observation mode.

On the other hand, when the capture button 19a is pressed and a color chart image of B is photographed by the CCD 14 (S10: Yes), the B adjustment processing is subsequently performed. Also for the B adjustment process, the B gain value bs is set by a process flow substantially similar to the R adjustment process and the G adjustment process. Again, the flowchart is omitted, and only the processing is described. Also in the B adjustment process, first, the variable n = 0. Then, the signal intensity B ₀ in the B primary color signal generated by the matrix circuit 152 is detected.

Subsequently, the detected value obtained by multiplying the B gain values bs to _{B 0} and _{B 0x.} As described above, the B gain value bs in this case is also stored in the EEPROM 17, and the initial value is input when the adjustment mode is performed for the first time in the electronic endoscope system 1. Then, it is determined whether or not the value of B _0x is within an ideal color (B) range in the electronic endoscope 10. Here, the ideal range is expressed by the following equation.

B _s <B _0x <B _h (3)

The lower limit value and upper limit value of the ideal range are represented by “B _s ” and “B _h ”. For even these lower limit value _{B s} and the upper limit value _{B h,} it is stored in the EEPROM17 preset.

If Expression (3) is satisfied, the ratio of B _{0x to} B ₀ is set as the B gain value bs and stored in the EEPROM 17. Then, a flag Bf indicating whether or not the gain value is appropriately set in the B adjustment processing is set to 0. On the other hand, when Expression (3) is not satisfied, it is determined whether or not the value of the variable n is larger than 20. When the value of the variable n is larger than 20, the ratio of B _{0x to} B ₀ at this time is stored in the EEPROM 17 as the B gain value bs, and the gain value is not properly set in this processing. As a result, the flag Bf is set to 1.

On the other hand, when the value of the variable n is 20 or less, 1 is added to the value of n. Then, it is determined whether or not the value of B _0x is larger than the lower limit value B _s of the ideal range. When the value of B _0x is equal to or lower than the lower limit value B _s , the value of B _0x is increased by a predetermined amount as in the following equation.

B _0x = B _0x × (1 + n / 100)

On the other hand, when the value of B _0x is larger than the lower limit value Bs, the value of B _0x is decreased by a predetermined amount as in the following equation.

B _0x = B _0x × (1-n / 100)

When the formula (3) is satisfied (the value of B _0x is included in the ideal range) or the loop process is repeated a predetermined number of times or more, and the B gain value bs is set, the B adjustment process Ends. Then, the process returns to the gain value setting process and proceeds to the subsequent process of S13.

  In S <b> 13, a video signal corresponding to the W (white) reference color chart is transmitted to the processor 20. In the processor 20, the video signal corresponding to the W color chart received from the electronic endoscope 10 is applied to the video signal received from the electronic endoscope 10 by the post-processing circuit 29 as described above, and is output to the monitor 30. . Then, the W color chart image is displayed on the display screen 30 a on the monitor 30 based on the video signal output from the processor 20.

  Subsequently, it is determined whether or not the capture button 19a of the electronic endoscope 10 has been pressed by the operator (S14). If the capture button 19a has not been pressed (S14: No), it is determined whether or not the mode switching button 21a has been pressed (S15). If the mode switching button 21a is not pressed (S15: No), the process returns to S14 and waits until either the capture button 19a or the mode switching button 21a is pressed. If the mode switching button 21a is pressed (S15: Yes), this process is terminated and the mode is switched from the adjustment mode to the normal observation mode.

On the other hand, when the capture button 19a is pressed and a W color chart image is captured by the CCD 14 (S14: Yes), WB adjustment processing is subsequently performed. In the WB adjustment process, gain values rws and bws used in the white balance adjustment circuit 156 are set. FIG. 5 is a flowchart showing the flow of the WB adjustment process. In the WB adjustment process, first, the variable n = 0 is set (S501). The variable n is a variable for counting a gain adjustment loop described later. Subsequently, the signal intensities R ₁ and B ₁ in the R and B primary color signals are detected (S502). The R and B primary color signals are signals obtained by photographing the W color chart image displayed on the display screen 30 a of the monitor 30 by the CCD 14.

Subsequently, a value obtained by multiplying respectively the R gain values rws and B gain values bws in the white balance adjustment on the detected _{R 1} and _{B 1} and _{R 1x} and _{B 1x} (S503). R _1x and B _1x are variables used for calculation described later. As described above, the R gain value rws and the B gain value bws are stored in the EEPROM 17, and when the adjustment mode is performed for the first time in the electronic endoscope system 1, initial values are input. First, it is determined whether or not the value of R _1x is within an ideal color (R) range in the electronic endoscope 10 (S504). Here, the ideal range represents an allowable range that does not hinder observation in white balance, and is expressed by the following equation.

R _ws <R _1x <R _wh (4)

The lower limit value and the upper limit value of the ideal range are represented by “R _ws ” and “R _wh ”. These lower limit value R _ws and upper limit value R _wh are set in advance and stored in the EEPROM 17.

In S504, if the expression (4) is satisfied (S504: Yes), the subsequent S505, the ratio of _{R 1x} is set as R gain values rws in the white balance adjustment for _{R 1,} and stored in EEPROM 17. In S505, a flag Rwf indicating whether or not the gain value has been properly set in the WB adjustment process is set to 0.

On the other hand, when Expression (4) is not satisfied (S504: No), the process proceeds to S506. In S506, it is determined whether or not the value of the variable n is larger than 20. Here, it is determined whether or not the loop based on the determination in S504 has been executed more than the predetermined number of 20 times. If the value of the variable n is larger than 20 (S506: Yes), the ratio of R _{1x to} R ₁ at this time is set as the R gain value rws in the white balance adjustment and stored in the EEPROM 17. Further, the flag Rwf is set to 1 assuming that the adjustment in this process has not been properly performed. (S507).

On the other hand, when the value of the variable n is 20 or less (S506: No), 1 is added to the value of n (S508), and the process proceeds to S509. In S509, it is determined whether or not the value of R _1x is larger than the lower limit value R _ws of the ideal range. When the value of R _1x is equal to or lower than the lower limit value R _ws (S409: No), the value of R _1x is increased by a predetermined amount as shown in the following equation (S510).

R _1x = R _1x × (1 + n / 100)

On the other hand, when the value of R _1x is larger than the lower limit value R _ws (S509: Yes), the value of R _1x is decreased by a predetermined amount as shown in the following equation (S510).

R _1x = R _1x × (1-n / 100)

When the value of R _1x is increased or decreased by S510 or S511, the process returns to S504. In S504, the processing from S504 to S511 is repeated until Expression (4) is satisfied (the value of R _1x is included in the ideal range) or the value of n exceeds 20 in S506. It is.

On the other hand, in S512 following S505, the variable n is set to 0 again. Then, it is determined whether or not the value of B _1x is within an ideal color (B) range in the electronic endoscope 10 (S513). The ideal range in this case is expressed by the following equation.

B _ws <B _1x <B _wh (5)

The lower limit value and the upper limit value of the ideal range are represented by “B _ws ” and “B _wh ”. These lower limit value B _ws and upper limit value B _wh are set in advance and stored in the EEPROM 17.

In S513, if the expression (5) is satisfied (S513: Yes), the subsequent S514, sets the ratio of _{B 1x} for _{B 1} as B gain values bws in white balance adjustment, and stores the EEPROM 17. In S513, a flag Bwf indicating whether or not the B gain setting in the WB adjustment process has been appropriately performed is set to 0.

On the other hand, when Expression (5) is not satisfied (S513: No), the process proceeds to S515. In S515, it is determined whether or not the value of the variable n is larger than 20. If the value of the variable n is larger than 20 (S515: Yes), the ratio of B _{1x to} B ₁ at this time is set as the B gain value bws in the white balance adjustment and stored in the EEPROM 17. Further, the flag Bwf is set to 1 (S516), assuming that the adjustment in this process has not been properly performed.

On the other hand, when the value of the variable n is 20 or less (S515: No), 1 is added to the value of n (S517), and the process proceeds to S518. In S518, it is determined whether or not the value of B _1x is larger than the lower limit value B _ws of the ideal range. When the value of B _1x is equal to or lower than the lower limit value B _ws (S518: No), the value of B _1x is increased by a predetermined amount as shown in the following equation (S519).

B _1x = B _1x × (1 + n / 100)

On the other hand, when the value of B _1x is larger than the lower limit value B _ws (S518: Yes), the value of B _1x is decreased by a predetermined amount as shown in the following equation (S510).

B _1x = B _1x × (1-n / 100)

When the value of B _1x is increased or decreased by S519 or S520, the process returns to S513. In S513, the processing from S513 to S520 is repeated until Expression (5) is satisfied (the value of B _1x is included in the ideal range) or the value of n exceeds 20 in S515. It is. On the other hand, when the gain values rws and bws are set in S507, S514, or S516, the WB adjustment process ends. Then, the process returns to the gain value setting process and proceeds to the subsequent process of S17.

  In S17, it is determined whether or not each adjustment process of R, G, B, and WB is appropriately performed based on the values of the flags Rf, Gf, Bf, Rwf, and Bwf. When all the adjustment processes for R, G, B, and WB are appropriately performed, that is, when the values of the flags Rf, Gf, Bf, Rwf, and Bwf are all 0 (S17: Yes), The monitor 30 is instructed to display “Adjustment OK” (S18), and the process is terminated.

  On the other hand, when the adjustment process of R, G, B, and WB is not properly performed, that is, when the values of the flags Rf, Gf, Bf, Rwf, and Bwf include 1 (S17: No), the monitor 30 Is instructed to display “adjustment NG” (S19), and the operator is inquired whether or not to perform readjustment (S20). If the operator instructs to perform readjustment using an operation button or the like (S20: Yes), the process returns to the process of S1, and the gain value setting process is executed again. Further, when the readjustment is not performed (S20: No), this process ends.

  As described above, in the gain value setting process of the present embodiment, it is possible to converge all gain values within the ideal range by repeating the setting of gain values in the order of R, G, B, and WB. Then, the gain values set as described above by the gain adjustment circuit 154 and the white balance adjustment circuit 156 of the pre-processing circuit 15 for the image signal generated by the CCD 14 in the normal mode, and stored in the EEPROM 17. Gain adjustment based on the above is performed.

  As described above, in the present embodiment, first, a video signal corresponding to a reference color chart is stored in the electronic endoscope 10. When the adjustment mode is switched, the color chart image is displayed on the monitor 30. Then, the electronic endoscope 10 detects the color reproduction characteristics on the monitor 30 by photographing the color chart image reproduced in accordance with the characteristics of the monitor 30 with the electronic endoscope 10. . Then, the gain value corresponding to the characteristics of the monitor 30 can be set by setting the gain value in the pre-processing circuit 15 based on the image obtained by photographing the color chart. Thus, in the electronic endoscope system according to the present embodiment, even when the monitor characteristics are different, color reproduction due to the characteristics can be compensated for, so that an image with appropriate color reproduction can be provided. It becomes.

  The above is the embodiment of the present invention, but the present invention is not limited to this embodiment, and various modifications are possible within the scope of the technical idea of the present invention. For example, in the above-described embodiment, the gain setting process is performed in the electronic endoscope 10, but the processor 20 may perform the process. In this case, under the control of the system controller 22, the video signal corresponding to the reference color chart and the lower and upper limit values of the ideal range are stored in the EEPROM (not shown) of the processor 20, and the gain value in the post-processing circuit 29 is stored. It is good also as a structure to set. In addition, the gain value setting process may be performed in both the electronic endoscope 10 and the processor 20.

DESCRIPTION OF SYMBOLS 1 Electronic endoscope system 10 Electronic endoscope 15 Pre-processing circuit 16 Control part 17 EEPROM
20 processor 21 front panel 22 system controller 29 back-end processing circuit 30 monitor

Claims (8)

Photographing means for photographing an observation target and generating an image signal;
Storage means for storing a predetermined image;
Output means for outputting the predetermined image to the display device in order to display the predetermined image on a display device;
Reference value setting means for setting a reference value based on an image signal generated by photographing the predetermined image displayed on the display device by the photographing means;
Color adjusting means for performing color adjustment on an image signal generated by the photographing means based on the reference value;
An electronic endoscope system comprising:   The electronic endoscope system according to claim 1, wherein the predetermined image is a color chart including a reference color component.   The electronic endoscope system according to claim 1, wherein the reference values are R, G, and B gain values.   The electronic endoscope system according to any one of claims 1 to 3, wherein the reference values are R and B gain values for white balance adjustment. The storage means stores an ideal range related to color information,
The reference value setting means compares the color information in an image signal generated by photographing the predetermined image displayed on the display device by the photographing means and the ideal range, thereby comparing the reference range. The electronic endoscope system according to any one of claims 1 to 4, wherein a value is set.   A mode switching unit that switches between an adjustment mode in which the output unit outputs the predetermined image to the display device and a normal mode in which the output unit outputs an image signal generated by the imaging unit to the display unit; The electronic endoscope system according to any one of claims 1 to 5, further comprising: Photographing means for photographing an observation target and generating an image signal;
Storage means for storing a predetermined image;
Output means for outputting the predetermined image to the display device in order to display the predetermined image on a display device;
Reference value setting means for setting a reference value based on an image signal generated by photographing the predetermined image displayed on the display device by the photographing means;
Color adjusting means for performing color adjustment on an image signal generated by the photographing means based on the reference value;
An electronic endoscope comprising: A color adjustment method for an electronic endoscope system, comprising:
Displaying a predetermined image on a display device;
Photographing the predetermined image displayed on the display device by photographing means;
Setting a reference value based on an image signal generated by photographing the predetermined image by the photographing means;
Performing color adjustment on an image signal generated by the photographing unit based on the reference value.

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