Image processing device, image processing method, and program

Abstract

Provided are an image processing device, an image processing method, and a program capable of improving visibility of a lesion portion appearing in an observation image. A color balance adjustment unit (317) performs, on an image signal (SC), color balance adjustment processing for increasing a ratio of G component signal / R component signal and a ratio of B component signal / R component signal. A display image generation unit (316) allocates, to respective RGB channels, image signals of RGB color components in a display image corresponding to the image signal (SC) and outputs the allocated image signals to a display device.

Description

Image processing device, image processing method and program

[0001] The present disclosure relates to an image processing device, an image processing method, and a program.

[0002] Conventionally, in the medical field, endoscope systems are used to observe the organs of a subject, such as a patient. Generally, endoscope systems perform color balance adjustment processing on in-vivo images captured inside the subject, making the images suitable for observation by an operator, and then display the images. For example, Patent Literature 1 (JP-A-2005-102626) discloses a technology that allows selection between color balance adjustment processing using preset color balance parameters for an imaging signal and color balance adjustment processing in which color balance parameters are calculated based on signals of color components detected from an imaging signal that has undergone color balance adjustment processing on the imaging signal.

[0003] Patent No. 6242552

[0004] However, in the above-mentioned Patent Document 1, the color balance is suitable for the surgeon's observation, and the color balance is not adjusted for the purpose of improving the visibility of the lesion shown in the observation image, and there is a need for technology that can improve the visibility of the lesion area shown in the observation image.

[0005] The present disclosure has been made in view of the above, and aims to provide an image processing device, an image processing method, and a program that can improve the visibility of a lesion area shown in an observation image.

[0006] In order to solve the above-mentioned problems and achieve the object, the image processing device according to the present disclosure is an image processing device including a processor, which acquires an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band, performs adjustment processing on the image signal to increase the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal, and outputs the R component signal, G component signal, and B component signal in the image signal that has undergone the adjustment processing to the R channel, G channel, and B channel, respectively, of a display device.

[0007] Moreover, an image processing device according to the present disclosure is an image processing device including a processor, wherein the processor acquires a first image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band, generates a second image signal by extracting a base component signal and a detail component signal based on the first image signal, performs a gradation compression process on the base component signal of the second image signal, combines the base component signal of the second image signal after the gradation compression process with the detail component signal of the second image signal to generate a third image signal, outputs the third image signal to a display device, and performs an adjustment process on any one of the first image signal, the second image signal, and the third image signal to increase the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal.

[0008] Moreover, the image processing method according to the present disclosure is an image processing method executed by an image processing device having a processor, and includes the steps of: acquiring an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; performing an adjustment process on the image signal to increase the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal; and outputting the R component signal, G component signal, and B component signal in the image signal after the adjustment process to an R channel, a G channel, and a B channel of a display device, respectively.

[0009] Moreover, an image processing method according to the present disclosure is an image processing method executed by an image processing device having a processor, the image processing method including the steps of: acquiring a first image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band, by the processor; generating a second image signal by extracting a base component signal and a detail component signal based on the first image signal; performing a gradation compression process on the base component signal of the second image signal; generating a third image signal by combining the base component signal of the second image signal after the gradation compression process with the detail component signal of the second image signal; outputting the third image signal to a display device; and performing an adjustment process on any one of the first image signal, the second image signal, and the third image signal to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal.

[0010] Furthermore, a program according to the present disclosure is a program to be executed by an image processing device having a processor, and causes the processor to execute the following steps: acquiring an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; performing an adjustment process on the image signal to increase the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal; and outputting the R component signal, G component signal, and B component signal in the image signal that has been subjected to the adjustment process to an R channel, a G channel, and a B channel of a display device, respectively.

[0011] Furthermore, a program according to the present disclosure is a program to be executed by an image processing device having a processor, and causes the processor to execute the following steps: acquiring a first image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; generating a second image signal by extracting a base component signal and a detail component signal based on the first image signal; performing a gradation compression process on the base component signal of the second image signal; generating a third image signal by combining the base component signal of the second image signal after the gradation compression process with the detail component signal of the second image signal; outputting the third image signal to a display device; and performing an adjustment process on any one of the first image signal, the second image signal, and the third image signal to increase the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal.

[0012] The present disclosure provides an advantage of improving the visibility of a lesion in an observation image.

[0013] FIG. 1 is a schematic configuration diagram of an endoscopic system according to a first embodiment of the present disclosure. FIG. 2 is a block diagram showing the functional configuration of a main part of the endoscopic system according to the first embodiment of the present disclosure. FIG. 3 is a block diagram showing the functional configuration of an image processing unit 31 including a control unit included in a processing device according to the first embodiment of the present disclosure. FIG. 4 is a flowchart showing an outline of processing performed by the processing device according to the first embodiment of the present disclosure. FIG. 5 is a flowchart showing an outline of color balance adjustment mode processing performed by the processing device according to the first embodiment of the present disclosure. FIG. 6 is a diagram schematically showing an example of an observation image subjected to conventional image processing. FIG. 7 is a diagram schematically showing an example of an observation image subjected to color balance adjustment mode processing by the processing device according to the first embodiment of the present disclosure. FIG. 8 is a block diagram showing the functional configuration of an image processing unit including a control unit included in a processing device according to a second embodiment of the present disclosure. FIG. 9 is a flowchart showing an outline of color balance adjustment mode processing performed by a processing device according to the second embodiment of the present disclosure. FIG. 10 is a block diagram showing the functional configuration of an image processing unit including a control unit included in a processing device according to a third embodiment of the present disclosure. FIG. 11 is a flowchart showing an outline of color balance adjustment mode processing performed by a processing device according to the third embodiment of the present disclosure.

[0014] Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. Furthermore, each drawing referred to in the following description merely shows a schematic representation of the shape, size, and positional relationship to the extent that the contents of the present disclosure can be understood. In other words, the present disclosure is not limited to only the shape, size, and positional relationship exemplified in each drawing. Furthermore, in the description of the drawings, identical parts are denoted by the same reference numerals. Furthermore, an endoscopic system equipped with a flexible endoscope will be described as an example of an endoscopic system according to the present disclosure.

[0015] (First embodiment) [Configuration of endoscope system] Fig. 1 is a schematic configuration diagram of an endoscope system according to a first embodiment of the present disclosure. Fig. 2 is a block diagram showing the functional configuration of a main part of the endoscope system according to the first embodiment of the present disclosure.

[0016] 1 and 2 is inserted into the body of a subject such as a patient, and displays a display image based on an image signal (image data) generated by capturing an image of the inside of the subject's body. A user such as a doctor observes the displayed image to check for the presence or absence of bleeding areas, tumor areas, and abnormal areas, and to measure their size.

[0017] In the first embodiment, the endoscope system 1 will be described as an endoscope system using a flexible endoscope as shown in Fig. 1 , but the present invention is not limited to this and may be, for example, a medical system equipped with a rigid endoscope. Furthermore, the endoscope system 1 may also be applied to a medical microscope or a medical surgical robot system that performs surgery or treatment while displaying an image based on an image signal (image data) captured by an endoscope on a display device. In Fig. 2, the solid arrows indicate the transmission of electrical signals related to the image signal (image data), and the dashed arrows indicate the transmission of electrical signals related to control.

[0018] The endoscope system 1 shown in FIGS. 1 and 2 includes an endoscope 2, a processing device 3, and a display device 4.

[0019] [Configuration of Endoscope] First, the configuration of the endoscope 2 will be described.

[0020] The endoscope 2 captures an image signal (RAW data) of a subject by inserting a tip thereof into the subject. The endoscope 2 includes a flexible, elongated insertion section 21, an operation section 22 connected to the base end of the insertion section 21 and receiving input of various operation signals, and a universal cord 23 extending from the operation section 22 in a direction different from the direction in which the insertion section 21 extends and incorporating various cables connected to the processing device 3.

[0021] The insertion section 21 has a distal end section 24 incorporating an image sensor 244 in which pixels are arranged two-dimensionally and which generate image signals by receiving light and performing photoelectric conversion, a bending section 25 which is freely bendable and is made up of a plurality of bending pieces, and a long flexible tube section 26 which is connected to the proximal end side of the bending section 25. The insertion section 21 is inserted into a body cavity of a subject, and uses the image sensor 244 to capture an image of a subject such as biological tissue in a position where external light cannot reach.

[0022] The tip portion 24 has a light guide 241 made of glass fiber or the like and forming a light guide path for light emitted by the light source portion 32, an illumination lens 242 provided at the tip of the light guide 241, an optical system 243 for collecting light, and an image sensor 244 provided at the imaging position of the optical system 243, which receives the light collected by the optical system 243, photoelectrically converts it into an electrical signal, and outputs an image signal.

[0023] The optical system 243 is configured using one or more lenses and prisms, and has an optical zoom function for changing the angle of view and a focus function for changing the focus.

[0024] The imaging element 244 photoelectrically converts light from the optical system 243 to generate an electrical signal (image signal). Specifically, the imaging element 244 includes a matrix of pixels, each of which includes a photodiode that accumulates a charge corresponding to the amount of light and a capacitor that converts the charge transferred from the photodiode into a voltage level. The imaging element 244 includes a light-receiving unit 244a, which photoelectrically converts light from the optical system 243 to generate an electrical signal, and a readout unit 244b, which sequentially reads out electrical signals generated by pixels arbitrarily selected as readout targets among the pixels of the light-receiving unit 244a and outputs them as image signals. The light-receiving unit 244a is also provided with a color filter, and each pixel receives light in one of the wavelength bands of red (R), green (G), and blue (B) color components. The imaging element 244 controls various operations of the tip unit 24 in accordance with a drive signal received from the processing device 3. The imaging element 244 is configured using, for example, a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD) image sensor.

[0025] The operation unit 22 has a bending knob 221 for bending the bending portion 25 in the up-down and left-right directions, a treatment tool insertion portion 222 for inserting treatment tools such as biopsy forceps, an electric scalpel, and an examination probe into the subject, and a plurality of switches 223 which are an operation input portion for inputting operation instruction signals for peripheral devices such as an air supply means, a water supply means, and a screen display control in addition to the processing device 3. The treatment tool inserted from the treatment tool insertion portion 222 passes through a treatment tool channel (not shown) in the tip portion 24 and emerges from an opening (not shown).

[0026] The universal cord 23 incorporates at least a light guide 241 and an assembly cable 245 that combines one or more signal lines. The assembly cable 245 includes signal lines for transmitting image pickup signals, signal lines for transmitting drive signals for driving the image pickup element 244, and signal lines for transmitting and receiving information including unique information related to the endoscope 2 (image pickup element 244). Note that, although the present embodiment will be described as using signal lines to transmit electrical signals, they may also be used to transmit optical signals, or may be used to transmit signals between the endoscope 2 and the processing device 3 via wireless communication.

[0027] [Configuration of Control Device] Next, the configuration of the processing device 3 will be described.

[0028] The processing device 3 supplies illumination light to the endoscope 2 for illuminating the subject, receives image signals generated by the endoscope 2, performs predetermined image processing on the received image signals, and outputs the processed signals to the display device 4. The processing device 3 includes an image processing unit 31, a light source unit 32, an input unit 33, a recording unit 34, and a control unit 35.

[0029] The image processing unit 31 is configured using a memory and a dedicated processor, such as a general-purpose processor such as a CPU (Central Processing Unit) or various arithmetic circuits that execute specific functions, such as an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), and a GPU (Graphics Processing Unit). Under the control of the control unit 35, the image processing unit 31 performs predetermined image processing on the image signal generated by the endoscope 2 and outputs the image signal to the display device 4. The detailed functional configuration of the image processing unit 31 will be described later.

[0030] The following describes the configuration of the light source unit 32. The light source unit 32 includes an illumination unit 3211 and an illumination control unit 3221.

[0031] The illumination unit 3211 emits illumination light to the subject (subject) under the control of the illumination control unit 3221. The illumination unit 3211 has a light source 3211a and a light source driver 3211b.

[0032] The light source 3211a is configured using an LED light source that emits white light, one or more lenses, etc., and emits light (illumination light) by driving the LED light source. The illumination light generated by the light source 3211a passes through the light guide 241 and is emitted from the tip of the tip portion 24 toward the subject. Note that the light source 3211a may be configured using a red LED light source, a green LED light source, and a blue LED light source to emit illumination light (field sequential type). The light source 3211a may also be configured using a laser light source or a lamp such as a xenon lamp or a halogen lamp.

[0033] The light source driver 3211b, under the control of the illumination control unit 3221, supplies a current to the light source 3211a, thereby causing the light source 3211a to emit illumination light.

[0034] The illumination control unit 3221 controls the amount of power supplied to the light source 3211a based on a control signal from the control unit 35, and also controls the drive timing of the light source 3211a.

[0035] The input unit 33 is realized using a keyboard, a mouse, a switch, and a touch panel, and receives input of various signals such as operation instruction signals that instruct the operation of the endoscope system 1. Note that the input unit 33 may include a switch provided on the operation unit 22 or an external portable terminal such as a tablet computer.

[0036] The recording unit 34 records various information related to the endoscope system 1. The recording unit 34 is configured using RAM (Random Access Memory), ROM, flash memory, SSD (Solid State Drive), HDD (Hard Disk Drive), etc. The recording unit 34 also has a program recording unit 341 that records various programs for operating the endoscope system 1, data including various parameters necessary for operation of the endoscope system 1, and identification information of the processing device 3. Here, the identification information includes unique information (ID), model year, specification information, etc. of the processing device 3. The program recording unit 341 records graph data used by the image processing unit 31 to perform image processing, and enhancement processing information such as brightness thresholds, upper limits, and functions used when performing enhancement processing.

[0037] The control unit 35 is configured using a general-purpose processor such as a CPU, or a dedicated processor such as an ASIC, FPGA, or other various arithmetic circuit that executes specific functions, and performs drive control of each component including the image sensor 244 and the light source unit 32, and controls input and output of information to each component. The control unit 35 references control information data (e.g., read timing, etc.) for image capture control recorded in the recording unit 34, and transmits it as a drive signal to the image sensor 244 via a predetermined signal line included in the cable assembly 245.

[0038] [Configuration of Display Device] Next, the display device 4 will be described.

[0039] The display device 4 displays an image corresponding to the image signal generated by the processing device 3 (image processing unit 31) via a video cable. The display device 4 is configured using a monitor such as a liquid crystal or organic EL (Electro Luminescence) monitor.

[0040] [Functional Configuration of Image Processing Unit] Next, the functional configuration of the image processing unit 31 described above will be described in detail.

[0041] Fig. 3 is a block diagram showing the functional configuration of the image processing unit 31 including the control unit 35. As shown in Fig. 3, the image processing unit 31 has an image signal acquisition unit 311, a pre-image processing unit 312, a switching unit 313, a gradation compression processing unit 314, a post-image processing unit 315, a display image generation unit 316, a color balance adjustment unit 317, a gradation compression processing unit 318, and a post-image processing unit 319.

[0042] The image signal acquisition unit 311 receives the image signal S output from the image sensor 244 of the endoscope 2. C Specifically, under the control of the control unit 35, the image signal acquisition unit 311 acquires an image signal S generated by the imaging element 244 capturing illumination light irradiated onto the living tissue and light returning from the living tissue. C Get.

[0043] The pre-image processing unit 312 performs signal processing such as noise removal, A / D conversion, and demosaic processing (for example, performed when image signals for each color component are obtained using a color filter, etc.) on the image signal SC acquired by the image signal acquisition unit 311, and outputs the signal.

[0044] Under the control of the control unit 35, the switching unit 313 switches the image signal S output by the pre-image processing unit 312. C The switching unit 313 outputs the image signal S output from the pre-image processing unit 312 to either the gradation compression processing unit 314 or the color balance adjustment unit 317. Specifically, when the observation mode of the endoscope system 1 is the normal observation mode using white light, the switching unit 313 outputs the image signal S C When the observation mode of the endoscope system 1 is a normal observation mode using white light, the output destination of the image signal S output by the pre-image processing unit 312 is switched to the gradation compression processing unit 314. C The output destination is switched to the color balance adjustment unit 317.

[0045] The gradation compression processing unit 314 converts the image signal S input from the pre-stage image processing unit 312 via the switching unit 313 into C The gradation compression processing unit 314 performs known gradation compression processing on the signal of each color component of the image signal S input from the previous image processing unit 312 and outputs the signal to the next image processing unit 315.C The gradation compression processing unit 314 performs gradation compression processing on the signal of each color component by nonlinear conversion of the image signal S C Alternatively, a plurality of functions may be preset and selected according to a selection signal input via the input unit 33 under the control of the control unit 35. The function used in this case takes the luminance value of the image signal as an input value and outputs a luminance value after compression corresponding to this luminance value. As a result, the gradation compression processing unit 314 adjusts the white balance while compressing the gradation-corrected image signal S C can be generated.

[0046] The post-stage image processing unit 315 converts the image signal S input from the gradation compression processing unit 314 into C The image signal S1 is subjected to post-stage image processing such as contour correction for the image signal S1, and is output to the display image generating unit 316. For example, the post-stage image processing unit 315 outputs the image signal S1 to the display image generating unit 316. C The image signal S1 is subjected to post-stage image processing such as noise reduction processing, including coring processing, and is output to the display image generation unit 316.

[0047] The display image generation unit 316 assigns the image signals of each RGB color component in the image signal S1 input from the subsequent image processing unit 315 or the image signal S2 input from the subsequent image processing unit 319 described later to each RGB channel and outputs them to the display device 4.

[0048] The color balance adjustment unit 317 adjusts the image signal S input from the pre-image processing unit 312 via the switching unit 313. CThe image signal S2 that has been subjected to color balance adjustment processing for the image signal S is output to the gradation compression processing unit 318. Generally, the brightness of each spectrum of the gastrointestinal mucosa is an R component signal, a G component signal, and a B component signal (R>>G>B), and even if there is sufficient contrast between the lesion and its surroundings in the G component signal (G channel) and the B component signal (B channel), if information with low contrast and high brightness in the R component signal (R channel) is included in the observation image (RGB image), the contrast between the lesion and its surroundings may deteriorate when the observation image (RGB image) is converted. For this reason, the color balance adjustment unit 317 adjusts the image signal S C The color balance adjustment unit 317 performs color balance adjustment processing to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal for the R component signal. Specifically, the color balance adjustment unit 317 performs color balance adjustment processing to suppress the signal value of the R component signal. For example, the color balance adjustment unit 317 performs suppression processing to multiply the signal value of the R component signal by a coefficient smaller than 1. This increases the ratio of G component signal / R component signal and the ratio of B component signal / R component signal. Note that the color balance adjustment unit 317 may also perform color balance adjustment processing to emphasize the signal value of the G component signal and the signal value of the B component signal. Specifically, the color balance adjustment unit 317 performs emphasis processing to multiply the signal value of the R component signal by a coefficient greater than 1. This increases the ratio of G component signal / R component signal and the ratio of B component signal / R component signal.

[0049] The gradation compression processing unit 318 performs gradation compression processing similar to that performed by the gradation compression processing unit 314 described above on the image signal S2 input from the color balance adjustment unit 317, for example, performing known gradation compression processing on the signals of each color component, and outputs the resulting image signal S2 to a subsequent image processing unit 319.

[0050] The subsequent image processing unit 319 performs signal processing such as contour correction on the image signal S2 input from the gradation compression processing unit 318, and outputs the resulting image signal S2 to the display image generation unit 316. For example, the subsequent image processing unit 319 performs signal processing similar to that performed by the above-mentioned subsequent image processing unit 315, for example, noise reduction processing such as coring processing on the image signal S2, and outputs the resulting image signal to the display image generation unit 316.

[0051] [Processing of the Processing Device] Next, a description will be given of the processing executed by the processing device 3. Fig. 4 is a flowchart showing an outline of the processing executed by the processing device 3.

[0052] As shown in FIG. 4, first, the image signal acquisition unit 311 receives the image signal S output from the image sensor 244 of the endoscope 2. C is acquired (step S101).

[0053] Next, the pre-image processing unit 312 converts the image signal S acquired by the image signal acquisition unit 311 into C The image is subjected to pre-stage image processing (step S102).

[0054] Thereafter, the control unit 35 determines whether the endoscopic system 1 is set to the normal observation mode (step S103). If the control unit 35 determines that the endoscopic system 1 is set to the normal observation mode (step S103: Yes), the processing device 3 proceeds to step S103, which will be described later. On the other hand, if the control unit 35 determines that the endoscopic system 1 is not set to the normal observation mode (step S103: No), the processing device 3 proceeds to step S105, which will be described later.

[0055] In step S103, the image processing unit 31 generates a normal white image and outputs it to the display device 4. Specifically, under the control of the control unit 35, the image processing unit 31 switches the image signal S C to the gradation compression processing unit 314, and the gradation compression processing unit 314 converts the image signal S input from the previous image processing unit 312 via the switching unit 313 into C The image processing unit 31 performs gradation compression processing on the image signal S input from the gradation compression processing unit 314 and outputs the result to the subsequent image processing unit 315. C The display image generating unit 316 performs post-stage image processing on the image signal S CThe image signals of each RGB color component in the image signal are assigned to each RGB channel and output to the display device 4. This allows the user to observe an image observed in normal observation under white light. After step S103, the processing device 3 proceeds to step S104.

[0056] Next, the control unit 35 determines whether or not to end the observation of the subject in accordance with the input signal input from the input unit 33 (step S104). If the control unit 35 determines to end the observation of the subject (step S104: Yes), the processing device 3 ends this process. On the other hand, if the control unit 35 determines not to end the observation of the subject (step S104: No), the processing device 3 returns to the above-mentioned step S101.

[0057] In step S105, the image processing unit 31 receives the image signal S C Then, the processing device 3 executes a color balance adjustment mode process for adjusting the color balance of the image and outputting the adjusted image. The color balance adjustment mode process will be described in detail later. After step S106, the processing device 3 proceeds to step S104.

[0058] [Color Balance Adjustment Mode Processing] Next, details of the color balance adjustment mode processing described in step S106 of Fig. 4 will be described. Fig. 5 is a flowchart showing an outline of the color balance adjustment mode processing.

[0059] As shown in FIG. 5, the color balance adjustment unit 317 adjusts the image signal S input from the pre-image processing unit 312 via the switching unit 313. C The color balance adjustment unit 317 performs color balance adjustment on the image signal S CThe color balance adjustment unit 317 performs color balance adjustment processing to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal (step S201). Specifically, the color balance adjustment unit 317 performs color balance adjustment processing to perform suppression processing on the signal value of the R component signal. Note that the color balance adjustment unit 317 may also perform color balance adjustment processing to perform emphasis processing on the signal value of the G component signal and the signal value of the B component signal.

[0060] Thereafter, the gradation compression processing unit 318 converts the image signal S input from the color balance adjustment unit 317 into C The image data is then subjected to the same gradation compression processing as that performed by the gradation compression processing unit 314 described above, for example, a known gradation compression processing for each color component signal, and output to the subsequent image processing unit 319 (step S202).

[0061] Next, the post-stage image processing unit 319 converts the image signal S input from the gradation compression processing unit 318 into C The image data is subjected to signal processing such as contour correction and output to the display image generating unit 316 (step S203).

[0062] Thereafter, the display image generating unit 316 converts the image signal S C (step S204), and assigns image signals of each RGB color component in the display image to each RGB channel and outputs them to the display device 4 (step S205). After step S205, the processing device 3 returns to the main routine of FIG.

[0063] Here, an observation image generated by the above-described color balance adjustment mode processing and an observation image generated by conventional image processing in normal observation mode will be described. FIG. 6 is a diagram schematically illustrating an example of an observation image subjected to conventional image processing. FIG. 7 is a diagram schematically illustrating an example of an observation image subjected to color balance adjustment mode processing. FIGS. 6 and 7 show an observation image P1 obtained by performing conventional image processing and color balance adjustment mode processing on image signals (RAW data) captured at the same observation location. In the observation image P1 in FIGS. 6 and 7, region R1 indicates the area within the lesion, and region R2 indicates the area within the surrounding mucosa. Furthermore, in FIG. 7, the coefficient α of the suppression process for the signal value of the R component signal in the color balance adjustment process performed by the color balance adjustment unit 317 on the R component signal is set to 0.5, while the conventional coefficient α in FIG. 5 is set to 1.0.

[0064] As shown in Figures 6 and 7, the ratio of the hue difference ΔE between region R1 and region R2 (image P1 after color balance adjustment processing / image P2 after image processing using conventional technology) is 1.72 (ΔE = 1.72). Therefore, as shown in Figures 6 and 7, the difference in hue between the lesion and its surroundings is increased. As a result, the visibility of the lesion in the observation image can be improved.

[0065] According to the first embodiment described above, the color balance adjustment unit 317 adjusts the image signal S C In contrast, a color balance adjustment process is performed to increase the ratio of G component signals to R component signals and the ratio of B component signals to R component signals, thereby improving the visibility of the lesion (lesion area) in the observation image, which has a color impression similar to that of a normal observation image using white light.

[0066] In the first embodiment, the color balance adjustment unit 317 performs color balance adjustment processing on the image signal before the gradation compression processing by the gradation compression processing unit 314, but this is not limited to this, and color balance adjustment processing may also be performed on the image signal after the gradation compression processing.

[0067] In addition, in the first embodiment, the color balance adjustment unit 317 performs color balance adjustment processing to increase the ratio of G component signals to R component signals and the ratio of B component signals to R component signals of the image signal. However, this is not limited to this. The ratio of G component signals to R component signals and the ratio of B component signals to R component signals of the image signal may be increased by adjusting the light in the red wavelength band emitted by the light source unit 32. In this case, the light source 3211a may be configured using a red LED light source, a green LED light source, and a blue LED light source, and the illumination control unit 3221 may control the light source driver 3211b to control the amount of light emitted by the red LED to perform suppression processing to suppress the R component signal. Of course, the illumination control unit 3221 may also control the light source driver 3211b to control the amount of light emitted by the blue LED to perform emphasis processing to emphasize the B component signal.

[0068] (Embodiment 2) Next, embodiment 2 will be described. The endoscope system according to embodiment 2 differs not only in the functional configuration of the image processing unit 31 according to embodiment 1 described above, but also in the color balance adjustment mode processing executed by the processing device. Specifically, embodiment 2 further includes brightness adjustment processing in addition to the configuration of the image processing unit 31 according to embodiment 1. Below, the configuration of the image processing unit according to embodiment 2 will be described, and then the color balance adjustment mode processing executed by the processing device will be described. Note that the same components as those in the endoscope system 1 according to embodiment 1 described above will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0069] [Functional Configuration of Image Processing Unit] Fig. 8 is a block diagram showing the functional configuration of an image processing unit including a control unit according to embodiment 2. Image processing unit 31A shown in Fig. 8 further includes a brightness correction unit 320 in addition to the configuration of image processing unit 31 according to embodiment 1 described above.

[0070] The brightness correction unit 320 performs brightness adjustment processing on the image signal S2 input from the color balance adjustment unit 317 to adjust the brightness, and outputs the resulting image signal S3 to the gradation compression processing unit 318. Specifically, the brightness correction unit 320 performs brightness adjustment processing on the image signal S2 input from the color balance adjustment unit 317, such as gamma correction processing and correction processing that moves the peak position of the histogram of the luminance values ​​of each pixel of the image corresponding to the image signal. Note that, for example, the brightness correction unit 320 may perform brightness correction processing on the image signal S2 input from the color balance adjustment unit 317 to adjust a tone curve that raises dark areas.

[0071] [Color Balance Adjustment Mode Processing] Next, the color balance adjustment mode processing executed by the control unit 35 according to the second embodiment will be described in detail. Fig. 9 is a flowchart showing an outline of the color balance adjustment mode processing. In Fig. 9, step S301 and steps S303 to S306 correspond to steps S201 to S205 in Fig. 5, respectively, with only step S302 being different. Therefore, only step S302 will be described below.

[0072] In step S302, the brightness correction unit 320 performs brightness adjustment processing on the image signal S2 input from the color balance adjustment unit 317 to increase the brightness of the entire image, and outputs the result to the gradation compression processing unit 318. Specifically, because the color balance adjustment processing reduces the R component signal, making the entire observed image dark, the brightness correction unit 320 performs gamma correction processing on the image signal S2 input from the color balance adjustment unit 317 as brightness adjustment processing to increase the brightness of the entire image, and outputs the result to the gradation compression processing unit 318. After step S302, the control unit 35 proceeds to step S303.

[0073] According to the second embodiment described above, the brightness correction unit 320 performs brightness adjustment processing on the image signal S2 after the color balance adjustment processing by the color balance adjustment unit 317, and outputs the signal to the gradation compression processing unit 318. Therefore, even if the R component signal is reduced by the color balance adjustment processing, it is possible to improve the visibility of the lesion area shown in the observation image with a color impression close to that of a normal observation image taken with white light, and to obtain an observation image with appropriate brightness.

[0074] In the second embodiment, when the color balance adjustment unit 317 performs color balance adjustment processing to apply emphasis processing to the signal values ​​of the G component signal and the B component signal, in order to prevent the entire observed image from becoming too bright, the brightness correction unit 320 performs brightness adjustment processing on the image signal S2 after the color balance adjustment processing to reduce the brightness of the entire image, and outputs the result to the gradation compression processing unit 318.

[0075] In addition, in the second embodiment, the color balance adjustment unit 317 performs color balance adjustment processing on the image signal before the gradation compression processing by the gradation compression processing unit 314, but this is not limited to this, and color balance adjustment processing may also be performed on the image signal after the gradation compression processing.

[0076] (Embodiment 3) Next, embodiment 3 will be described. The endoscope system according to embodiment 3 differs in functional configuration from the image processing unit 31 according to embodiment 1 described above, and also differs in the color balance adjustment mode processing performed by the processing device. Specifically, in embodiment 3, the image processing unit performs color adjustment processing on the image signal, and then performs image processing (TXI: Texture and Color Enhancement Imaging) that enhances contrast based on the Retinex theory. Below, the configuration of the image processing unit according to embodiment 3 will be described, and then the color balance adjustment mode processing performed by the control unit will be described. Note that the same components as those in the endoscope system 1 according to embodiment 1 described above will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0077] [Functional Configuration of Image Processing Unit] Fig. 10 is a block diagram showing the functional configuration of an image processing unit including a control unit according to embodiment 3. In addition to the configuration of the image processing unit according to embodiment 1 described above, an image processing unit 31B shown in Fig. 10 further includes a base component extraction unit 321, a base component adjustment unit 322, a detail component extraction unit 323, a detail component emphasis unit 324, a brightness correction unit 325, a gradation compression unit 326, a synthesis unit 327, and a color emphasis unit 328.

[0078] The base component extraction unit 321 performs base component extraction processing to extract components with weak visual correlation from the image components of the image signal S2 input from the color balance adjustment unit 317. The image components referred to here are components for generating an image, and are composed of base components and / or detail components, as described below. The extraction processing can be performed using, for example, the technology (Retinex theory) described in "Lightness and Retinex Theory," E.H.Land, J.J.McCann, Journal of the Optical Society of America, 61(1), 1 (1971). In extraction processing based on Retinex theory, components with weak visual correlation correspond to the illumination light components of an object. Components with weak visual correlation are generally called base components. On the other hand, components with strong visual correlation correspond to the reflectance components of an object. Components with strong visual correlation are generally called detail components. The detail components are components obtained by dividing the signals constituting an image by the base components. The detail component includes contrast components such as contour (edge) components of an object and texture components.

[0079] The base component extraction unit 321 extracts a signal including a base component from the image signal S2 (hereinafter referred to as the base component signal S2). B") to the base component adjustment unit 322. When image signals for each RGB color component are input, the base component extraction unit 321 performs extraction processing for each color component signal. In subsequent signal processing, similar processing is performed for each color component. The extraction processing by the base component extraction unit 321 is not limited to extraction processing based on the above-mentioned Retinex theory, and can be performed using, for example, the Edeg-aware filtering technique described in "Temporarily Coherent Local Tone Mapping of HDR Video," TOAydin et al., ACM Transactions on Graphics, Vol. 33, November 2014. The base component extraction unit 321 may also extract base components by dividing the spatial frequency into multiple frequency bands. The extraction processing method by the base component extraction unit 321 may also be adjusted for each RGB color component in the image signal S2. For example, the base component extraction unit 321 may extract the G color component from the image signal S2 by slightly reducing the emphasis of the G color component in the detail component enhancement process described later. More specifically, similar to the component correction unit 322b described later, the image signal S2 may be extracted by adding together the R, G, and B color components assigned a weight (w).

[0080] The bass component adjustment unit 322 adjusts the bass component extracted by the bass component extraction unit 321. The bass component adjustment unit 322 includes a weight calculation unit 322a and a component correction unit 322b. The bass component adjustment unit 322 adjusts the bass component signal S after the component adjustment. B_1 to the detail component extraction unit 323 and the brightness correction unit 325.

[0081] The weight calculation unit 322a calculates the weight used to adjust the base component. Specifically, the weight calculation unit 322a first calculates the weight used to adjust the base component of the image signal S CRGB of the image is converted to YCrCb from the weight calculation unit 322a to obtain a luminance value (Y). Thereafter, the weight calculation unit 322a refers to the recording unit 34 to obtain a numerical value (function) and a numerical value table for weight calculation, and also obtains a threshold value and an upper limit value for the luminance value according to the input result from the input unit 33. Note that although the third embodiment will be described as using the luminance value (Y), a reference signal other than the luminance value, such as the maximum value of the signal values ​​of each color component of RGB, may also be used. Specifically, the weight calculation unit 322a refers to a preset weight calculation line and calculates the weight of the input image signal S C The weight calculation unit 322a calculates a weight according to the luminance value of each pixel. The weight calculation unit 322a calculates a weight for each pixel position, for example. As a result, a weight map is generated in which a weight is assigned to each pixel position. Note that a luminance value equal to or less than the threshold is weighted to zero, and a luminance value equal to or greater than the upper limit is weighted to an upper limit value (for example, 1). The threshold and upper limit values ​​may be recorded in advance in the recording unit 34, or values ​​input by the user via the input unit 33 may be used.

[0082] The component corrector 322b corrects the bass component based on the weight map calculated by the weight calculator 322a. Specifically, the component corrector 322b corrects the bass component signal S extracted by the bass component extractor 321. B For example, the base component signal S extracted by the base component extractor 321 is added to the image according to the weight. B The base component of PreBase , image D InRGB , the corrected base component is D C-Base , and the weight is w, the corrected base component is obtained by the following equation (1): D C-Base = w x D PreBase + (1-w) x D InRGB ...(1) As a result, the larger the weight, the greater the input bass component signal S B For example, when the weight is 1, the corrected bass component is B In this way, the base component adjustment unit 322 adjusts the image component of the image signal S2 and the base component signal S2 extracted by the base component extraction unit 321. BThe bass component signal S containing the bass component corrected by the component corrector 322b is adjusted by alpha-blending it with the bass component S. B_1 is generated.

[0083] The detail component extraction unit 323 extracts the image signal S2 input from the color balance adjustment unit 317 and the base component signal S2 input from the base component adjustment unit 322. B_1 Specifically, the detail component extractor 323 extracts the base component signal S from the image signal S. B_1 The detail component extraction unit 323 extracts the detail component from the signal containing the detail component (hereinafter referred to as the “detail component signal S D ") to the detail component emphasis unit 324.

[0084] The detail component emphasis unit 324 extracts the detail component signal S D The detail component emphasis unit 324 refers to the recording unit 34, acquires a preset function, and performs gain-up processing to increase the signal value of each color component at each pixel position based on this function. Specifically, the detail component emphasis unit 324 performs an emphasis process on the detail component signal S D Among the color component signals included in Detail , the signal value of the green component is G Detail , and the signal value of the blue component is B Detail When this is done, R Detail α , G Detail β , B Detail γwhere α, β, and γ are parameters that are set independently of each other and are determined based on a preset function. For example, a luminance function f(Y) is set for each of the parameters α, β, and γ, and the parameters α, β, and γ are calculated according to the input luminance value Y. This function f(Y) may be a linear function or an exponential function. The detail component emphasis unit 324 calculates the signal value of each color component after the emphasis process using the detail component signal S D_1 to the synthesis unit 327. The parameters α, β, and γ may be set to the same value, or may be set to arbitrary values. The parameters α, β, and γ are set via the input unit 33, for example.

[0085] The brightness correction unit 325 corrects the adjusted bass component signal S generated by the bass component adjustment unit 322. B_1 For example, the brightness correction unit 325 performs a brightness correction process on the base component signal S after the correction process using a preset correction function. The brightness correction unit 325 performs a correction process to increase the brightness value of at least the dark portion. B_2 is output to the gradation compression unit 326.

[0086] The gradation compression unit 326 converts the base component signal S B_2 The gradation compression section 326 performs a known gradation compression process such as a gamma correction process on the base component signal S after gradation compression. B_3 is output to the synthesis unit 327.

[0087] The synthesis unit 327 synthesizes the detail component signal S D_1 and the base component signal S after the gradation compression process generated by the gradation compression unit 326. B_3 The synthesis unit 327 synthesizes the detail component signal S D_1 and the base component signal S B_3 By combining these, a composite image signal S can be obtained, which can improve visibility. S Generate.

[0088] The color tone enhancement unit 328 enhances the synthesized image signal S S Specifically, the color enhancement unit 328 performs color enhancement processing to expand the color tone of the synthesized image signal S S The image signal S is processed to extend the color tone range in a predetermined Lab color space. Ｈ and outputs it to the subsequent image processing unit 319.

[0089] [Color Balance Adjustment Mode Processing] Next, a description will be given of details of the color balance adjustment mode processing executed by the control unit 35 according to embodiment 3. Fig. 11 is a flowchart showing an outline of the color balance adjustment mode processing.

[0090] As shown in FIG. 11, first, the color balance adjustment unit 317 adjusts the image signal S input from the pre-image processing unit 312 via the switching unit 313. C The color balance adjustment unit 317 performs color balance adjustment processing on the image signal S (first image signal) to generate the image signal S2 (step S401). C For example, the color balance adjustment unit 317 performs color balance adjustment processing to suppress the signal value of the R component signal, thereby generating an image signal S2, and outputs this image signal S2 to each of the base component extraction unit 321, the base component adjustment unit 322, and the detail component extraction unit 323. C Alternatively, color balance adjustment processing may be performed to enhance the signal values ​​of the G component signal and the B component signal.

[0091] Next, the base component extraction unit 321 extracts the base component from the image signal S2 input from the color balance adjustment unit 317, and generates a base component signal S B (second image signal) and outputs it to the base component adjuster 322 (step S402).

[0092] Thereafter, the weight calculation unit 322a calculates the weight of the image signal S input from the color balance adjustment unit 317.C Based on the luminance component of B Specifically, the weight calculation unit 322a refers to a preset weight calculation line recorded in the recording unit 34, and calculates a weight to be used for adjusting the input image signal S C Based on the luminance values ​​of the image signal S C The weight of each pixel position is calculated, and a weight map indicating the weight of each pixel position is generated.

[0093] Next, the component corrector 322b corrects the bass component based on the weight map calculated by the weight calculator 322a (step S404). Specifically, the component corrector 322b corrects the bass component signal S B That is, the component corrector 322b adds a signal value according to the weight to the image signal S2 and the base component signal S extracted by the base component extractor 321. B and a bass component signal S containing the corrected bass component by adjusting the bass component by α-blending the bass component. B_1 and outputs it to the detail component extraction unit 323 and brightness correction unit 325.

[0094] Thereafter, the brightness correction unit 325 corrects the adjusted base component signal S B_1 is subjected to brightness correction processing to obtain the base component signal S B_2 and generates the base component signal S B_2 to the gradation compression unit 326 (step S405). Specifically, the base component signal S B_1 Since the R component signal in becomes dark (smaller), the brightness correction unit 325 B_1 For example, the brightness correction unit 325 performs a correction process to increase the luminance value of at least the dark portion of the base component signal S B_1 More specifically, the brightness correction unit 325 performs brightness correction processing on the base component signal S B_1The brightness correction process is performed to increase the brightness while maintaining the color balance of the R component signal, the G component signal, and the B component signal in the image.

[0095] Next, the gradation compression unit 326 converts the base component signal S B_2 is subjected to gradation compression processing to obtain the base component signal S B_3 and generates the base component signal S B_3 to the synthesis unit 327 (step S406). Specifically, the gradation compression unit 326 outputs the base component signal S B_2 Then, a known gradation compression process such as gamma correction is performed on the image data.

[0096] Thereafter, the detail component extraction unit 323 extracts the image signal S2 input from the color balance adjustment unit 317 and the base component signal S2 input from the base component adjustment unit 322. B_1 Specifically, the detail component extraction unit 323 extracts the detail component using the image signal S2 input from the color balance adjustment unit 317 and the base component signal S2 input from the base component adjustment unit 322 (step S407). B_1 and based on the image signal S2, the base component signal S B_1 The base component of the signal S is subtracted to obtain a detail component signal S D and outputs it to the detail component emphasis unit 324.

[0097] Next, the detail component emphasis unit 324 extracts the detail component signal S D (Step S408). Specifically, the detail component emphasis unit 324 refers to the recording unit 34, acquires a preset function, and based on this function, performs emphasis processing on the detail component of the detail component signal S D The detail component emphasis unit 324 performs gain-up processing to increase the signal value of each color component at each pixel position for the detail component signal S D_1 is output to the synthesis unit 327.

[0098] Thereafter, the synthesis unit 327 synthesizes the detail component signal SD_1 and the base component signal S after the gradation compression process generated by the gradation compression unit 326. B_3 The composite image signal S S The third image signal is generated and output to the color enhancement unit 328 (step S409).

[0099] Next, the color tone enhancement unit 328 converts the synthesized image signal S S The image signal S H and outputs it to the subsequent image processing unit 319 (step S410).

[0100] Thereafter, the subsequent image processing unit 319 converts the image signal S input from the color tone enhancement unit 328 into H The image data is subjected to signal processing such as contour correction and output to the display image generating unit 316 (step S411).

[0101] The display image generating unit 316 receives the image signal S T The image signal for display is generated by processing the image signal so as to be a signal that can be displayed on the display device 4 (step S412), and the image signal for each RGB color component of the displayed image is assigned to each RGB channel and output to the display device 4 (step S413). After step S413, the processing device 3 returns to the main routine of FIG.

[0102] According to the third embodiment described above, the image processing unit 31B converts the image signal S C A color balance adjustment process is performed on the image signal S2, which increases the ratio of G component signals / R component signals and the ratio of B component signals / R component signals, and the image processing of TXI described above is performed on the image signal S2 that has undergone the color balance adjustment process. As a result, in the case of a mucous membrane with severe inflammation (a mucous membrane that is reddish overall) that appears in the observation image, the contrast between the lesion area captured by the B component signals and the surrounding mucosa can be emphasized and displayed with a color impression close to white light.

[0103] In the third embodiment, the image processing unit 31B converts the image signal S CIn the above example, a color balance adjustment process is performed on the image signal S2 that has undergone the color balance adjustment process, increasing the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal, and the image signal S2 that has undergone the color balance adjustment process is subjected to the above-described image processing by TXI. However, the present invention is not limited to this, and the color balance adjustment unit 317 may perform the color balance adjustment process after the image processing by TXI. Specifically, the color balance adjustment unit 317 performs the color balance adjustment process on the detail component signal S2 that has undergone the enhancement process by the detail component enhancement unit 324 in the synthesis unit 327. D_1 and the base component signal S after the gradation compression process generated by the gradation compression unit 326. B_3 The composite image signal S S A color balance adjustment process may be performed on the image.

[0104] In the third embodiment, after the base component is extracted from the image signal S2 by the base component extraction unit 321, the detail component signal S2 is extracted by the detail component emphasis unit 324. D The color balance adjustment unit 317 may perform color balance adjustment processing before and during the processing for enhancing the detail component.

[0105] In the third embodiment, the synthesis unit 327 generates a synthesis image signal S S The color balance adjustment unit 317 may perform color balance adjustment processing between the processing after generating the color balance adjustment signal .gamma. and the processing before the color enhancement unit 328 performs color enhancement processing to expand the color tones.

[0106] In addition, in the third embodiment, the color balance adjustment unit 317 performs color balance adjustment processing to increase the ratio of G component signals to R component signals and the ratio of B component signals to R component signals of the image signal, but the present invention is not limited to this, and the ratio of G component signals to R component signals and the ratio of B component signals to R component signals of the image signal may be increased by adjusting the light of the red wavelength band emitted by the light source unit 32. In this case, the light source 3211a may be configured using a red LED light source, a green LED light source, and a blue LED light source, and the illumination control unit 3221 may control the light source driver 3211b to control the amount of light emitted by the red LED.

[0107] Other Embodiments In the endoscope systems according to the first to third embodiments of the present disclosure, the light source 3211a is configured as a white LED light source and emits white light. However, the present disclosure is not limited to this. For example, the light source unit 321a may be configured to emit at least one of white light and narrowband light having a predetermined wavelength band. In this case, the light source unit 321a may be configured using a white LED light source and a narrowband light source capable of emitting narrowband light including a predetermined wavelength band, for example, 390 to 445 nm and 530 to 550 nm, for narrowband imaging (NBI). The illumination control unit 3221 may control the light source driver 3211b to control the amount of light emitted by the white LED light source and the narrowband light source and the timing of light emission. In this case, the color balance adjustment unit 317 may perform color balance adjustment processing on an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band, thereby increasing the ratio of the G component signal / R component signal and the ratio of the B component signal / R component signal.

[0108] Various inventions can be formed by appropriately combining multiple components disclosed in the endoscopic systems according to the above-described first to third embodiments of the present disclosure. For example, some components may be omitted from all of the components described in the endoscopic systems according to the above-described embodiments of the present disclosure. Furthermore, the components described in the endoscopic systems according to the above-described embodiments of the present disclosure may be appropriately combined.

[0109] Furthermore, in the endoscope systems according to the first to third embodiments of the present disclosure, the above-described "unit" can be read as "means," "circuit," etc. For example, a control unit can be read as control means or a control circuit.

[0110] In addition, the programs to be executed by the endoscopic systems according to the first to third embodiments of the present disclosure are provided as file data in an installable or executable format recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), a USB medium, or a flash memory.

[0111] In addition, the programs to be executed by the endoscopic systems according to embodiments 1 to 3 of the present disclosure may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network.

[0112] In the description of the flowcharts in this specification, expressions such as "first," "then," and "continue" are used to clearly indicate the order of processing between steps, but the order of processing required to implement the present invention is not uniquely determined by these expressions. In other words, the order of processing in the flowcharts described in this specification can be changed within a consistent range. Furthermore, programs are not limited to those consisting of simple branching processing, and branching can be achieved by comprehensively determining more judgment items.

[0113] Although some of the embodiments of the present application have been described in detail above with reference to the drawings, these are merely examples, and the present invention can be implemented in other forms that have undergone various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in the disclosure of the present invention.

[0114] REFERENCE SIGNS LIST 1 Endoscope system 2 Endoscope 3 Processing device 4 Display device 31, 31A, 31B Image processing unit 32 Light source unit 33 Input unit 34 Recording unit 35 Control unit 311 Image signal acquisition unit 312 Pre-stage image processing unit 313 Switching unit 314, 318 Gradation compression processing unit 315 Post-stage image processing unit 316 Display image generation unit 317 Color balance adjustment unit 318 Gradation compression processing unit 320, 325 Brightness correction unit 321 Base component extraction unit 322 Base component adjustment unit 322a Weight calculation unit 322b Component correction unit 323 Detail component extraction unit 324 Detail component emphasis unit 326 Gradation compression unit 327 Synthesis unit 328 Color emphasis unit 341 Program recording unit

Claims

1. An image processing device having a processor, wherein the processor acquires an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band, performs adjustment processing on the image signal to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal, and outputs the R component signal, G component signal, and B component signal of the image signal that has been adjusted to the R channel, G channel, and B channel of a display device, respectively.

2. An image processing device according to claim 1, wherein the adjustment processing is processing for performing suppression processing on the signal value of the R component signal.

3. An image processing device according to claim 1, wherein the adjustment processing is processing for performing enhancement processing on the signal values ​​of the G component signal and the B component signal.

4. An image processing device according to claim 1, wherein the processor, after the adjustment processing, divides the image signal on which the adjustment processing has been performed into a base component signal and a detail component signal, performs gradation compression processing on the base component signal, performs synthesis processing to synthesize the base component signal and the detail component signal after the gradation compression processing, and outputs the R component signal, G component signal, and B component signal of the image signal after the synthesis processing to the R channel, G channel, and B channel, respectively, of a display device.

5. An image processing device according to claim 4, wherein the processor performs enhancement processing on the detail component signal.

6. An image processing device according to claim 4, wherein the processor performs brightness correction processing on the base component signal after the gradation compression processing to raise dark areas, and the brightness correction processing is processing to adjust a tone curve.

7. An image processing device according to claim 4, wherein the processor performs color enhancement processing on the image signal after the synthesis processing to expand the hue difference in a predetermined color space, and outputs the R component signal, G component signal, and B component signal of the image signal after the color enhancement processing to the R channel, G channel, and B channel of a display device, respectively.

8. An image processing device according to claim 1, wherein the processor, after acquiring the image signal and before the adjustment processing, divides the image signal into a base component signal and a detail component signal, performs gradation compression processing on the base component signal, performs synthesis processing to synthesize the base component signal and the detail component signal after the gradation compression processing, and performs the adjustment processing on the image signal after the synthesis processing.

9. An image processing device according to claim 1, wherein the processor divides the image signal into a base component signal and a detail component signal before the adjustment process.

10. An image processing device according to claim 1, wherein the processor, before the adjustment processing, divides the image signal into a base component signal and a detail component signal, performs gradation compression processing on the base component signal, performs synthesis processing to synthesize the base component signal and the detail component signal after the gradation compression processing, and performs the adjustment processing on the image signal after the synthesis processing.

11. An image processing device comprising a processor, wherein the processor: acquires a first image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; generates a second image signal by extracting a base component signal and a detail component signal based on the first image signal; performs gradation compression processing on the base component signal of the second image signal; generates a third image signal by combining the base component signal of the second image signal after the gradation compression processing with the detail component signal of the second image signal; outputs the third image signal to a display device; and performs adjustment processing on any one of the first, second, and third image signals to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal.

12. An image processing method executed by an image processing device equipped with a processor, comprising the steps of: acquiring an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; performing adjustment processing on the image signal to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal; and outputting the R component signal, G component signal, and B component signal of the image signal after the adjustment processing to the R channel, G channel, and B channel of a display device, respectively.

13. An image processing method executed by an image processing device having a processor, the image processing method comprising the steps of: acquiring a first image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; generating a second image signal by extracting a base component signal and a detail component signal based on the first image signal; performing a gradation compression process on the base component signal of the second image signal; generating a third image signal by combining the base component signal of the second image signal after the gradation compression process with the detail component signal of the second image signal; outputting the third image signal to a display device; and performing an adjustment process on any one of the first, second, and third image signals to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal.

14. A program to be executed by an image processing device having a processor, causing the processor to execute the following steps: acquiring an image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; performing adjustment processing on the image signal to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal; and outputting the R component signal, G component signal, and B component signal of the image signal after the adjustment processing to the R channel, G channel, and B channel of a display device, respectively.

15. A program to be executed by an image processing device having a processor, causing the processor to execute the following steps: acquiring a first image signal having an R component signal, a G component signal, and a B component signal obtained by capturing an image of a subject illuminated with at least one of white light and narrowband light having a predetermined wavelength band; generating a second image signal by extracting a base component signal and a detail component signal based on the first image signal; performing a gradation compression process on the base component signal of the second image signal; generating a third image signal by combining the base component signal of the second image signal after the gradation compression process with the detail component signal of the second image signal; outputting the third image signal to a display device; and performing an adjustment process on any one of the first, second, and third image signals to increase the ratio of G component signal / R component signal and the ratio of B component signal / R component signal.

Images