JP5850630B2 - Endoscope system and driving method thereof - Google Patents

Description

  The present invention relates to an endoscope system including an electronic endoscope in which a solid-state imaging device is mounted at a distal end portion of an endoscope, and a driving method thereof.

  In the medical field, medical diagnosis using an endoscope system is actively performed. The endoscope system includes an electronic endoscope (scope) having an insertion portion that is inserted into a body cavity, and a main body device to which the electronic endoscope is detachably connected.

  The main device includes a processor device and a light source device. The processor device receives an imaging signal output from a solid-state imaging device built in the distal end of the insertion portion of the electronic endoscope, performs image processing, and displays the obtained observation image on a monitor. The light source device generates light that illuminates the inside of the body cavity through a light guide inserted into the electronic endoscope.

  As described in Patent Document 1, as a solid-state imaging device mounted at the distal end of an insertion portion of an electronic endoscope, a CMOS (Complementary Metal Oxide) that can be driven at a low voltage and can easily achieve a large number of pixels and high-speed readout. Semiconductor) type and CCD (Charge Coupled Device) type are used.

  An electronic endoscope is used in a special environment unlike a general digital camera or the like. For example, as shown in FIG. 8 (a), the distal end portion 1 of the electronic endoscope is inserted into the body cavity 2 which is a dark place, and the affected part 3 is photographed from a distance, or as shown in FIG. 8 (b), An enlarged image of the affected part 3 is taken by bringing the distal end part 1 of the electronic endoscope closer to the affected part 3. When approaching the affected area 3 with the intensity of the illumination light in the imaging state of FIG. 8A and making the imaging state of FIG. 8B, the illumination light is too strong and the observation image of the affected area 3 is overexposed.

  Therefore, although the intensity of the illumination light generated by the light source device is reduced, this ratio is as large as 2000: 1, for example, in an electronic endoscope. That is, it is necessary to reduce the intensity of the illumination light when the shooting state of FIG. 8A is set to about 1/2000 to the shooting state of FIG.

  In this way, another problem occurs when the intensity of the illumination light is greatly changed. FIG. 9 is a graph illustrating an example of this problem. In order to capture a color image, the illumination light includes light in the wavelength bands of the three primary colors of red (R), green (G), and blue (B). The ratio of the color components contained in the RGB illumination light changes when the intensity of the illumination light is greatly changed. For example, in the example shown in FIG. 9, when the illumination light is made stronger than when the illumination light is weak, the R / G is constant, such as a light source difference in light emission efficiency, whereas the B / G is constant. May rise.

  In such a case, the doctor who has observed the observation image of the same affected part 3 while bringing the distal end portion 1 of the electronic endoscope close to the affected part 3 has the observation image in FIG. 8A and the observation image in FIG. Then, you will observe images with different colors, and you will feel uncomfortable. In particular, when surface blood vessel observation is performed, B / G needs to be constant.

JP 2009-201540 A

  An object of the present invention is to provide an endoscope system that suppresses a change in color of an observation image even when the brightness (intensity) of illumination light is changed, and a driving method thereof.

An endoscope system according to the present invention includes an electronic endoscope in which an illumination window for illuminating a subject with illumination light is provided at a distal end portion, and a solid-state imaging device that receives light from the subject is mounted on the distal end portion. ,
Equipped with different emission wavelengths plurality of semiconductor light emitting elements, a light source device for introducing the light emitted of the semiconductor light emitting element to the electronic endoscope,
Image processing means for generating observation image data based on red, green, and blue captured image signals output from the solid-state imaging device;
A memory storing characteristics indicating light amounts of the respective color components of the illumination light from the illumination window according to a drive amount for controlling the light emission amount of the semiconductor light emitting element ,
When changing the driving amount of the semiconductor light emitting element to change the intensity of the illumination light applied to the subject, the image processing unit is configured to pick up the captured image of each color based on the characteristic data stored in the memory. Correction calculation processing for increasing and decreasing the signal is performed.
Further, in the driving method of the endoscope system of the present invention, an illumination window for irradiating the subject with illumination light is provided at the distal end portion, and a solid-state imaging device that receives light from the subject is mounted on the distal end portion. An electronic endoscope,
Equipped with different emission wavelengths plurality of semiconductor light emitting elements, a light source device for introducing the light emitted of the semiconductor light emitting element to the electronic endoscope,
Image processing means for generating observation image data based on red, green, and blue captured image signals output from the solid-state imaging device;
A memory storing characteristics indicating light amounts of the respective color components of the illumination light from the illumination window according to a drive amount for controlling the light emission amount of the semiconductor light emitting element ;
A driving method of an endoscope system comprising: a light amount control unit that instructs a light amount change of the illumination light based on a captured image signal from the solid-state imaging device ;
When the light amount control unit instructs to change the light amount of the illumination light, the image processing unit is caused to perform a correction calculation process for increasing or decreasing the captured image signal of each color based on the characteristic data stored in the memory. Is.

  According to the present invention, it is possible to provide an easy-to-see image with no color change between a distant subject image and a close subject image.

1 is an overall configuration diagram of an endoscope system according to an embodiment of the present invention. It is a front end surface front view of the front-end | tip part of the electronic endoscope shown in FIG. It is a longitudinal cross-sectional view of the front-end | tip part of the electronic endoscope shown in FIG. It is a block block diagram of the control system of the endoscope system shown in FIG. It is a control system block block diagram of the endoscope system of the embodiment which replaces FIG. It is explanatory drawing of electronic shutter control when a CMOS type solid-state image sensor is used. It is explanatory drawing of electronic shutter control when using a CCD type solid-state image sensor. It is explanatory drawing of the case where the affected part is image | photographed from a distance (a), and the case where it approaches and image | photographs the affected part (b). It is a characteristic view which shows an example of the change of B / G and R / G with respect to the brightness of illumination light.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram showing a schematic configuration of an endoscope system according to an embodiment of the present invention. The endoscope system 10 according to the present embodiment includes an electronic endoscope 12, a processor device 14 and a light source device 16 constituting a main body device. The electronic endoscope 12 includes a flexible insertion portion 20 that is inserted into a body cavity of a patient (subject), an operation portion 22 that is connected to a proximal end portion of the insertion portion 20, a processor device 14, and a light source. And a universal cord 24 connected to the device 16.

  A distal end portion 26 is connected to the distal end of the insertion portion 20, and an imaging chip (imaging device) 54 (see FIG. 3) for intra-body cavity imaging is built in the distal end portion 26. Behind the distal end portion 26 is provided a bending portion 28 in which a plurality of bending pieces are connected. When the angle knob 30 provided in the operation section 22 is operated, the bending section 28 is bent / moved in the vertical and horizontal directions by pushing / pulling the wire inserted in the insertion section 20. Thereby, the front-end | tip part 26 is orientated in the desired direction within a body cavity.

  A connector 36 is provided at the base end of the universal cord 24. The connector 36 is of a composite type and is connected to the light source device 16 in addition to being connected to the processor device 14.

  The processor device 14 supplies power to the electronic endoscope 12 via a cable 68 (see FIG. 3) inserted into the universal cord 24, controls the driving of the imaging chip 54, and connects the cable 68 from the imaging chip 54. The received image signal is received, and various signal processing is performed on the received image signal to convert it into image data.

  The image data converted by the processor device 14 is displayed as an endoscopic image (observation image) on a monitor 38 connected to the processor device 14 by a cable. The processor device 14 is also electrically connected to the light source device 16 via the connector 36, and comprehensively controls the operation of the endoscope system 10 including the light source device 16.

  FIG. 2 is a front view showing the distal end surface 26 a of the distal end portion 26 of the electronic endoscope 12. As shown in FIG. 2, an observation window 40, an illumination window 42, a forceps outlet 44, and an air / water supply nozzle 46 are provided on the distal end surface 26 a of the distal end portion 26.

  The observation window 40 is arranged eccentric to the center and one side of the distal end surface 26a. Two illumination windows 42 are arranged at symmetrical positions with respect to the observation window 40, and irradiate illumination light from the light source device 16 to a site to be observed in the body cavity.

  The forceps outlet 44 is connected to a forceps channel 70 (see FIG. 3) disposed in the insertion portion 20 and communicates with a forceps port 34 (see FIG. 1) provided in the operation portion 22. Various treatment tools having an injection needle, a high-frequency knife or the like disposed at the distal end are inserted into the forceps port 34, and the distal ends of the various treatment instruments are ejected from the forceps outlet 44 into the body cavity.

  The air supply / water supply nozzle 46 is cleaned from the air supply / water supply device built in the light source device 16 in accordance with the operation of the air supply / water supply button 32 (see FIG. 1) provided in the operation unit 22. Water or air is jetted toward the observation window 40 or the body cavity.

  FIG. 3 is a longitudinal sectional view of the distal end portion 26 of the electronic endoscope 12. As shown in FIG. 3, a lens barrel 52 that holds an objective optical system 50 for taking in image light of a site to be observed in the body cavity is disposed behind the observation window 40. The lens barrel 52 is attached so that the optical axis of the objective optical system 50 is parallel to the central axis of the insertion portion 20. Connected to the rear end of the lens barrel 52 is a prism 56 that guides the image light of the site to be observed via the objective optical system 50 toward the imaging chip 54 by bending it at a substantially right angle.

  In this embodiment, the imaging chip 54 is a monolithic semiconductor (so-called CMOS sensor chip) in which a CMOS solid-state imaging device 58 and a peripheral circuit 60 that drives the solid-state imaging device 58 and inputs and outputs signals are integrally formed. And mounted on the support substrate 62. Of course, a CCD type solid-state imaging device can also be used.

  The imaging surface (light receiving surface) 58 a of the solid-state imaging device 58 is disposed so as to face the emission surface of the prism 56. On the imaging surface 58a, a rectangular plate-like cover glass 64 is attached via a rectangular frame-like spacer 63. The imaging chip 54, the spacer 63, and the cover glass 64 are assembled through an adhesive, and thereby the imaging surface 58a is protected from intrusion of dust and the like.

  A plurality of input / output terminals 62 a are arranged in the width direction of the support substrate 62 at the rear end portion of the support substrate 62 extending toward the rear end of the insertion portion 20. The input / output terminal 62a is joined to a signal line 66 for mediating the exchange of various signals with the processor device 14 via the universal cord 24. The input / output terminal 62a is a wiring formed on the support substrate 62. And a peripheral circuit 60 in the imaging chip 54 through a bonding pad or the like (not shown).

  The signal lines 66 are collectively inserted into a flexible tubular cable 68. The cable 68 is inserted through each of the insertion unit 20, the operation unit 22, and the universal cord 24 and is connected to the connector 36.

  Although not shown in FIGS. 2 and 3, an illumination unit is provided in the back of the illumination window 42. The illumination section is provided with an emission end 120a of a light guide 120 (see FIG. 4) for guiding illumination light from the light source device 16, and in this embodiment, a phosphor is provided between the emission end and the illumination window 42. 53 is provided. Similarly to the cable 68, the light guide 120 is inserted through each of the insertion unit 20, the operation unit 22, and the universal cord 24, and the incident end is connected to the connector 36.

  FIG. 4 is a block diagram showing a control system of the endoscope system 10. As shown in FIG. 4, the distal end portion 26 of the electronic endoscope 12 includes a solid-state imaging device 58, an analog signal processing circuit (AFE: analog front end) 72, a TG (timing generator) 78, a CPU 80, A data rewritable nonvolatile memory 81 is provided.

  The TG 78 generates a driving pulse (vertical / horizontal scanning pulse, reset pulse, etc.) for the solid-state imaging device 58 and a synchronization pulse for the AFE 72 based on the control of the CPU 80. The solid-state imaging device 58 is driven by a driving pulse input from the TG 78, photoelectrically converts an optical image formed on the imaging surface 58a via the objective optical system 50, and outputs it as an imaging signal.

  A large number of pixels are arranged in a matrix on the imaging surface 58a of the solid-state imaging element 58, and a photosensor (photoelectric conversion element) is provided for each pixel. Light incident on the imaging surface 58a of the solid-state imaging device 58 is accumulated as a charge in the photosensor of each pixel. The signal charge amount accumulated in the photosensor of each pixel is sequentially read out as a pixel signal by scanning in the vertical and horizontal directions by a vertical scanning circuit and a horizontal scanning circuit (both not shown), and a predetermined frame rate is obtained. Is output.

  Although not shown, the solid-state image sensor 58 is a solid-state image sensor of a single plate color imaging system provided with a color filter composed of a plurality of color segments (for example, a primary color filter with a Bayer array).

  The configuration of a signal readout circuit that reads out the accumulated charge of each photosensor of the solid-state imaging device 58 as an imaging signal is well known, and a general configuration such as a 3-transistor configuration or a 4-transistor configuration can be applied. There is no explanation here.

  The AFE 72 includes a correlated double sampling (CDS) circuit, an automatic gain circuit (AGC), and an A / D converter. The CDS circuit performs correlated double sampling processing on the imaging signal output from the solid-state imaging device 58 to remove reset noise and amplifier noise generated in the solid-state imaging device 58.

  The AGC amplifies the image signal from which noise has been removed by the CDS circuit with a gain (amplification factor) designated by the CPU 80. The A / D converter converts the imaging signal amplified by the AGC into a digital signal having a predetermined number of bits and outputs the digital signal. An imaging signal (digital imaging signal) that is digitized and output by the AFE 72 is input to the processor device 14 through the signal line 66.

  The memory 81 connected to the CPU 80 stores characteristic data of the phosphor 53 mounted on the electronic endoscope 12 and characteristic data of a color filter stacked on each pixel of the solid-state image sensor 58. This is because when it is necessary to obtain observation imaging with high accuracy, it is necessary to perform image processing in consideration of individual differences in the phosphor 53 and the solid-state imaging device 58 mounted on the electronic endoscope 12. It will be described later. The characteristic data in the memory 81 is transmitted from the CPU 80 to the CPU 82 when requested by the CPU 82 of the processor device 14 to be described later.

  The processor device 14 includes a CPU 82, a ROM 84, a RAM 85, an image processing circuit (DSP) 86, and a display control circuit 88.

  The CPU 82 controls each part in the processor device 14 and controls the entire endoscope system 10 in an integrated manner. The ROM 84 stores various programs and control data for controlling the operation of the processor device 14. The RAM 85 temporarily stores programs executed by the CPU 82 and data.

  The DSP 86 performs color interpolation, color separation, color balance adjustment, white balance correction, gamma correction, image enhancement processing, and the like on the imaging signal input from the AFE 72 based on the control of the CPU 82 to generate image data.

  The image data output from the DSP 86 is input to the display control circuit 88, and the display control circuit 88 converts the image data input from the DSP 86 into a signal format corresponding to the monitor 38 and displays it on the screen of the monitor 38.

  The operation unit 90 of the processor device 14 is provided with a mode switching button for selecting or switching the operation mode of the solid-state imaging device 58, and various buttons for receiving other user instruction inputs.

  The light source device 16 includes a main light source 100, a main light source driving circuit 101, an auxiliary light source 102, an auxiliary light source driving circuit 103, a CPU 104, and a multiplexing unit 105. The CPU 104 communicates with the CPU 82 of the processor device 14 and controls the main light source driving circuit 101 and the auxiliary light source driving circuit 103.

  The main light source driving circuit 101 controls the main light emission amount of the main light source 100 according to an instruction from the CPU 104, and the auxiliary light source driving circuit 103 controls the auxiliary light emission amount of the auxiliary light source 102 according to an instruction from the CPU 104. The combining unit 105 combines the emitted lights of the main light source 100 and the auxiliary light source 102 and outputs the combined light to the incident end 120 b of the light guide 120.

  In this embodiment, the main light source 100 is a laser diode (semiconductor element) that emits a blue laser having a wavelength of 445 nm. The main light source 100 is pulse-driven by the main light source driving circuit 101 to control the light emission amount. In this embodiment, the auxiliary light source 102 is a laser diode (semiconductor element) that emits a blue laser having a wavelength of 405 nm. The auxiliary light source driving circuit 103 drives the pulse to control the light emission amount. Blue light having a wavelength of 405 nm is used for special light observation. The light emission ratios of the light sources 100 and 102 are changed by the CPUs 82 and 104 depending on the observation mode designated by the user.

  As described above, the phosphor 53 is provided between the emission end 120a of the light guide 120 and the front end illumination window 42 of the electronic endoscope 12. The blue laser light that has passed through the light guide 120 is irradiated onto the phosphor 53 to bring the phosphor 53 into an excited state, and part of the phosphor 53 is transmitted through the phosphor 53 and emitted from the illumination window 42 as blue light.

  The phosphor 53 is mainly excited by blue laser light having a wavelength of 445 nm, and in the light wavelength band, a wide range of light (yellow as a color) from the wavelength range per blue / green boundary to the red wavelength range is used. Emits light. The yellow light and the blue light transmitted through the phosphor 53 (including part of the blue light emitted from the phosphor 53) are mixed to become white light, and the subject is illuminated through the illumination window 42.

  The reflected light from the subject (affected part) illuminated with white light including red (R) light, blue (B) light, and green (G) light is reflected by a solid-state imaging device 58 equipped with color filters of three primary colors of RGB. By receiving light, a color image of the subject is reproduced.

  When the inside of the body cavity is observed with the endoscope system 10 configured as described above, the electronic endoscope 12, the processor device 14, the light source device 16, and the monitor 38 are turned on, and the electronic internal The insertion part 20 of the endoscope 12 is inserted into the body cavity, and the image in the body cavity imaged by the solid-state imaging device 58 is observed on the monitor 38 while illuminating the body cavity with the illumination light from the light source device 16. .

  The CPU 82 of the processor device 14 determines whether or not to control the amount of illumination light from the captured image signal output from the solid-state image sensor 58. That is, when the observation image is a dark image, the amount of illumination light is increased, and when the observation image is too bright, the amount of illumination light is decreased.

  When performing this illumination light increase / decrease control, the CPU 82 issues a command to the CPU 80 to acquire the characteristic data of the phosphor 53 and outputs a command to the CPU 104 of the light source device 16 to control the light emission amount of the main light source 100.

  The main light source drive circuit 101 that has received an instruction from the CPU 104 controls the light emission amount of the main light source 100. The phosphor 53 that has received the blue laser light (wavelength 445 nm) emitted from the main light source 100 emits yellow light (green G + red R) corresponding to the laser light amount, and among the incident blue light having a wavelength of 445 nm. Transmits the required proportion of blue light.

  In the case of the phosphor 53 having the characteristic data of FIG. 9 and the main light source 100, the transmitted blue light having a wavelength of 445 nm increases as the amount of emitted light increases, that is, as the brightness increases, the proportion of blue light transmitted through the phosphor 53 increases. / G will increase.

  Therefore, in the present embodiment, when an instruction to increase the main light emission amount of the main light source 100 is issued from the CPUs 82 and 104 to the main light source driving circuit 101, the CPU 82 simultaneously performs correction processing on the DSP 86 based on the characteristic data of the phosphor 53. The DSP 86 issues an instruction, and performs image processing using this characteristic data as a parameter for correction processing. In this example, when an instruction to increase the main light emission amount is issued, the ratio of blue (B) light in the RGB color imaged image signals output from the solid-state image sensor 58 increases with respect to other colors. The picked-up image signal amount of light is reduced and corrected so that the color does not change between before the main light emission amount increase instruction and the observation image.

  In this way, in this embodiment, since the DSP 86 is instructed to reduce the bluishness simultaneously with the main light emission amount increase instruction, there is no response delay in the color change of the observation image with respect to the color change of the illumination light. Can be suppressed.

  The DSP 86 of the present embodiment performs the above-described image processing that suppresses the color change and also performs normal white balance correction. In the white balance correction, it is impossible to distinguish whether the color of the affected part of the observation image is strange or the color of the illumination light is strange. However, in the present embodiment, correction for suppressing the color change of the illumination light is performed separately from the white balance correction, so that appropriate white balance correction can be performed without being dragged by the color of the affected part. When the DSP 86 performs white balance correction, the individual difference data of the color filter of the solid-state image sensor 58 passed from the CPU 80 and CPU 82 is used.

  FIG. 5 is a control system block diagram of an endoscope system according to another embodiment of the present invention. A difference from the embodiment of FIG. 4 is a light source device 16. In the embodiment of FIG. 4, the phosphor 53 is used, but in this embodiment, the LED light source (semiconductor element) for each of the three primary colors is used as the light source device 16 without using the phosphor 53.

  The light source device 16 of this embodiment includes an R light emitting LED 100r, a G light emitting LED 100g, and a B light emitting LED 100b as light sources, and light source drive circuits 112r, 112g, and 112b that drive the light sources 100r, 100g, and 100b, respectively. A CPU 114 that outputs a control command to the light source driving circuits 112r, 112g, and 112b, and a multiplexing unit 115 that multiplexes the light emitted from each of the light sources 100r, 100g, and 100b and enters the incident end 120b of the light guide 120. Configured. The CPU 114 communicates with the CPU 82 of the processor device 14 and controls the light source driving circuits 112r, 112g, and 112b.

  In the present embodiment, the light emitting LEDs 100r, 100g, and 100b are used as the light source. However, laser diodes that emit each color may be used. The light intensity of these light sources 100r, 100g, and 100b is controlled by the light source driving circuits 112r, 112g, and 112b.

  The light combined by the multiplexing unit 115 is introduced into the incident end 120b of the light guide 120 configured by bundling a plurality of optical fibers as subject illumination light, and is directed from the emission end 120a through the illumination window 42 toward the subject. Are emitted.

  The reflected light from the subject (affected part) illuminated with white light including red (R) light, blue (B) light, and green (G) light is reflected by a solid-state imaging device 58 equipped with color filters of three primary colors of RGB. By receiving light, a color image of the subject is reproduced.

  As described with reference to FIG. 8, the brightness of the illumination light is controlled when the observation image is captured by moving the distal end portion of the electronic endoscope 12 away from the affected area, and when the observation image is captured close to the affected area. The brightness of the illumination light can be determined from the captured image signal of the solid-state imaging device 58. When the observation image becomes darker than the predetermined brightness, the light emission amount of the illumination light is increased to make it brighter, and the observation image is brighter than the predetermined brightness. When it becomes dark, lower the amount of illumination light and darken it.

  However, if the energization amount of the light emitting LEDs 100r, 100g, and 100b is controlled to increase or decrease, the individual difference between the light emitting LEDs 100r, 100g, and 100b changes, and as described with reference to FIG. 9, the R light and G light included in the illumination light. , The ratio of B light may change. In this case, the color of the observation image changes or B / G increases, making it unsuitable for superficial blood vessel observation.

  Therefore, in the present embodiment, correction processing is performed on the R, G, and B captured image signals output from the solid-state imaging device 58 so that the color of the observation image does not change, and the amount of current supplied to the light source changes. Even if the color of the illumination light changes, observation image data in which the color balance is adjusted so that the color at the point A in FIG. Is generated.

  For example, it is assumed that the energization amount control to the light source is performed and the light source is caused to emit light at a position indicated by a point B in FIG. At this B point position, B / G has already increased with respect to the A point position. When performing highly accurate surface blood vessel observation, it is necessary to perform color control with high accuracy. Therefore, for example, if the CPU 82 in FIG. 5 has the B / G characteristic data in FIG. 9 in the ROM 84 in advance, the DSP 86 is instructed, and among the R, G, and B captured image signals, the amount of the captured image signal of B light 9 can be reduced and a captured image matched with the point A position in FIG. 9 (reference position: B / G = 1, for example) can be obtained by correction calculation processing and displayed on the monitor 38.

  The characteristic data of the light sources 100r, 100g, and 100b may be stored in the memory 81 of the electronic endoscope 12, the ROM in the CPU 114 of the light source device 16, or the like. These data can be read at any time.

  In the above-described embodiment, the description has been made based on the characteristics illustrated in FIG. 9. However, when the illumination light is increased, which color light amount increases or decreases with respect to which color light amount depends on the individual light source difference. The invention is not limited to the characteristics shown in FIG. It is possible to check in advance what kind of change in the amount of light of each color occurs when the illumination light is strengthened. If the checked data is stored as table data in the ROM 84 or the like, the CPU 82 performs appropriate correction processing on the DSP 86. It is possible to instruct simultaneously with the light quantity increase / decrease instruction, and it is possible to obtain observation image data that always matches the color of the reference position without delaying the control response.

  Here, for example, it is not necessary to store data at all points on the horizontal axis in FIG. 9 as table data, but data at discrete specific positions (in the example of FIG. 9, brightness 50, 100, 150, 200,... Data between these positions) is held, and the data between them may be obtained by interpolation calculation.

  FIG. 6 is an explanatory diagram for making the exposure amount constant when capturing one frame image by controlling the shutter period (exposure period) of the electronic shutter. The CMOS type solid-state imaging device 58 basically images a subject as a moving image by driving a rolling shutter, and for each pixel row, an exposure period (from the timing of applying the reset signal 201 to a certain pixel row) The subject images are picked up in order of each pixel row while shifting (until the timing of applying the readout signal 202 for reading out the pixel signal of the pixel row).

  It is assumed that a subject image of one frame is taken in, for example, [1/30] seconds and a moving image of a subject of 30 frames is taken per second. When the tip of the electronic endoscope is gradually approached from a location far from the affected area, if the amount of illumination light emitted from the distal end of the electronic endoscope is constant, the amount of reflected light from the affected area increases as the affected area gets closer. The exposure amount of the solid-state image sensor 58 increases, and the observation image becomes gradually brighter. Therefore, as shown in FIG. 6A → FIG. 6B, the brightness of the observation image becomes constant as the reset signal 201 is brought closer to the readout signal 202 for reading out the pixel signal and the exposure period is shortened. Can be controlled. The control when moving away is reversed.

  This electronic shutter control can be performed even in a state where the energization amount to the light source is fixed and the amount of illumination light is constant (that is, the color of illumination light does not change). Therefore, it is preferable to use the brightness constant control by the electronic shutter control together with the illumination light amount control of the embodiment described with reference to FIGS. For example, when the constant brightness control is possible by the electronic shutter control, only the electronic shutter control is performed, and when it is necessary to increase or decrease the light amount of the illumination light, the light emission light amount control of the embodiment described with reference to FIGS. Switch to. Alternatively, electronic shutter control may be used in combination with the control of the embodiment of FIGS.

  FIG. 7 is a diagram illustrating an example of electronic shutter exposure control when the solid-state imaging device 58 is a CCD type. In the case of a CCD solid-state imaging device, a readout signal 205 is applied to a transfer gate provided between each pixel (photoelectric conversion device) and a vertical charge transfer path (VCCD), whereby the captured image signal is transferred to the vertical charge transfer path. read out. At this time, the readout signal 205 to be applied to the transfer gate is applied at a fixed period, but an electronic shutter pulse 206 for discarding the accumulated charge of each pixel to the substrate side and a period until the next readout signal 205 (= exposure period). By controlling, the exposure period (charge accumulation time) is controlled. In the example shown in the drawing, by applying the electronic shutter pulse 207 having a short width, the exposure period (charge accumulation time) becomes longer than the frame to which the electronic shutter pulse 206 is applied.

  Although the example using the electronic shutter control in combination has been described with reference to FIGS. 6 and 7, the electronic shutter control is not necessarily used in combination. Moreover, although the example using semiconductor elements, such as a laser diode and LED, was demonstrated as a light source, the kind of light source is not restricted to these.

  For example, a xenon lamp may be prepared as a light source in the light source device 16, a diaphragm may be provided between the xenon lamp and the incident end 120b of the light guide 120, and the light source light amount may be adjusted by the aperture amount of the diaphragm. When the light from the xenon lamp is stopped by the stop, the wavelength distribution of the light passing through the stop may change, that is, the color may change. For this reason, as in the embodiment described with reference to FIGS. 4 and 5, the color is not changed by image processing. For example, the DSP 86 performs image processing for tint control in conjunction with aperture control.

In the endoscope system and the driving method thereof according to the embodiments described above, a solid-state imaging device is mounted on the distal end portion, and an illuminating unit is provided adjacent to the solid-state imaging device, and the distal end portion is disposed in the body cavity of the subject. An electronic endoscope that illuminates a subject in the body cavity with the illuminating unit and takes an image of the subject with the solid-state imaging device,
An endoscope system including an illumination unit that generates illumination light in which three primary colors of red light, green light, and blue light are mixed and emits the light from the illumination unit to the subject, and a driving method thereof.
When processing the picked-up image data of each color of red light, green light, and blue light output from the solid-state image sensor, when the intensity of the illumination light is changed, the color of the light quantity that becomes smaller than the light quantity of other colors Image processing is performed by correcting the amount of picked-up image data to be increased or by reducing the amount of picked-up image data of a light amount that is larger than the amount of light of other colors.

  In addition, the illuminating means of the endoscope system and the driving method thereof according to the embodiment includes a phosphor that receives blue light and emits green light and red light with a part of the blue light.

  In addition, the endoscope system and the driving method thereof according to the embodiment are characterized in that the light source of the illumination unit is formed of a semiconductor element.

  In addition, the illuminating unit of the endoscope system and the driving method thereof according to the embodiment includes a plurality of light sources having different emission wavelengths, and changes a light emission ratio of each light source according to an observation mode.

  In addition, the endoscope system and the driving method thereof according to the embodiment are characterized in that the parameter for the increase correction or the decrease correction is stored in a memory in the electronic endoscope.

  In the endoscope system and the driving method thereof according to the embodiment, the increase correction or the decrease correction performed by the image processing unit using the parameter changes the intensity of the illumination light issued to the illumination unit. It is performed based on a command.

  According to the embodiments described above, the color of the observation image does not change even when the endoscope tip is photographed close to or away from the main subject, and an easy-to-see observation image without discomfort is provided. It becomes possible to do.

  The endoscope system according to the present invention is useful as an endoscope system capable of providing an easy-to-see observation image and capable of capturing a high-quality image because there is no color change between an image close to and far from an object.

DESCRIPTION OF SYMBOLS 10 Endoscope system 12 Electronic endoscope 14 Processor apparatus 16 Light source apparatus 26 Front-end | tip part 26a Front-end | tip front end surface 40 Observation window 42 Illumination window 53 Phosphor 54 Image sensor chip 58 Solid-state image sensor 80, 82, 104, 114 CPU
81 Data rewritable nonvolatile memory 100 Main light source (wavelength 445 nm)
100r R light emitting LED
100g G light emitting LED
100b B light emitting LED
101 Main light source drive circuit 102 Auxiliary light source (wavelength 405 nm: special light observation light source)
103 Auxiliary light source drive circuits 105 and 115 Multiplexer 120 Light guide 120a Light guide exit end 120b Light guide entrance end

Claims (9)

An electronic endoscope in which an illumination window for illuminating the subject with illumination light is provided at the tip, and a solid-state imaging device that receives light from the subject is mounted on the tip,
Equipped with different emission wavelengths plurality of semiconductor light emitting elements, a light source device for introducing the light emitted of the semiconductor light emitting element to the electronic endoscope,
Image processing means for generating observation image data based on red, green, and blue captured image signals output from the solid-state imaging device;
A memory storing characteristics indicating light amounts of the respective color components of the illumination light from the illumination window according to a drive amount for controlling the light emission amount of the semiconductor light emitting element ,
When changing the driving amount of the semiconductor light emitting element to change the intensity of the illumination light applied to the subject, the image processing unit is configured to pick up the captured image of each color based on the characteristic data stored in the memory. An endoscope system that performs correction calculation processing to increase or decrease signals. The endoscope system according to claim 1,
Based on a captured image signal from the solid-state image sensor, comprising a light amount control unit for instructing a light amount change of the illumination light,
The endoscope system in which the light amount control unit instructs the correction processing to the image processing unit when instructing to change the light amount of the illumination light. The endoscope system according to claim 1 or 2,
The semiconductor light emitting device includes one or more semiconductor light emitting devices that emit blue light,
A phosphor that is provided between an emission end of a light guide that guides blue light from the semiconductor light emitting element and the illumination window and that receives the blue light and emits green light and red light with a part of the blue light With
An endoscope system in which white illumination light in which blue light from the semiconductor light emitting element and green light and red light from the phosphor are mixed is emitted from the illumination window. The endoscope system according to claim 1 or 2.
The semiconductor light emitting element includes an endoscope system including a first semiconductor light emitting element that emits red light, a second semiconductor light emitting element that emits green light, and a third semiconductor light emitting element that emits blue light. . The endoscope system according to any one of claims 1 to 4, wherein
The light source device is an endoscope system that changes a light emission ratio of the plurality of semiconductor light emitting elements according to an observation mode. An electronic endoscope in which an illumination window for illuminating the subject with illumination light is provided at the tip, and a solid-state imaging device that receives light from the subject is mounted on the tip,
Equipped with different emission wavelengths plurality of semiconductor light emitting elements, a light source device for introducing the light emitted of the semiconductor light emitting element to the electronic endoscope,
Image processing means for generating observation image data based on red, green, and blue captured image signals output from the solid-state imaging device;
A memory storing characteristics indicating light amounts of the respective color components of the illumination light from the illumination window according to a drive amount for controlling the light emission amount of the semiconductor light emitting element ;
A driving method of an endoscope system comprising: a light amount control unit that instructs a light amount change of the illumination light based on a captured image signal from the solid-state imaging device ;
When the light amount control unit instructs to change the light amount of the illumination light, the image processing unit is caused to perform a correction calculation process for increasing or decreasing the captured image signal of each color based on the characteristic data stored in the memory. Driving method of endoscope system. A driving method of an endoscope system according to claim 6 ,
The semiconductor light emitting device includes one or more semiconductor light emitting devices that emit blue light,
A phosphor that is provided between an emission end of a light guide that guides blue light from the semiconductor light emitting element and the illumination window and that receives the blue light and emits green light and red light with a part of the blue light With
A driving method of an endoscope system in which white illumination light in which blue light from the semiconductor light emitting element and green light and red light from the phosphor are mixed is emitted from the illumination window. The driving method of the endoscope system according to claim 6 .
The semiconductor light emitting element includes an endoscope system including a first semiconductor light emitting element that emits red light, a second semiconductor light emitting element that emits green light, and a third semiconductor light emitting element that emits blue light. Driving method. A driving method for an endoscope system according to any one of claims 6 to 8 ,
The driving method of an endoscope system, wherein the light source device changes a light emission ratio of the plurality of semiconductor light emitting elements according to an observation mode .

Images