JP2013052022A - Dimmer and electronic endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimmer using a diaphragm, capable of performing appropriate dimming even if abnormality in dimming speed occurs in a diaphragm mechanism.SOLUTION: A diaphragm blade 26 to be driven by a motor 25 is disposed on an optical path of a lamp 27 and a light guide 29. The motor 25 is driven by a motor driver 23 based on a dimming signal generated from the luminance level of a captured image in a driver/signal processing part 16. A dummy signal is output as the dimming signal to measure a delay in response caused by the aging of the diaphragm blade 26. A correction gain of the dimming signal is calculated based on the delay in response, and the dimming signal is corrected with the correction gain to control the motor driver 23.

Description

  The present invention relates to a light control device using diaphragm blades, and more particularly to an electronic endoscope device equipped with such a light control device.

  For example, in an electronic endoscope apparatus, an aperture blade that blocks a part of light is arranged on an optical path from a light source to a light guide, and the amount of light incident on the light guide is adjusted by adjusting the position of the aperture blade. Optical devices are known. Light is emitted from the tip of the electronic endoscope through the light guide, and an image illuminated with the light is photographed by the imaging device at the tip of the electronic endoscope. The light control device adjusts the position of the aperture blade as needed so that the luminance signal of the photographed image is at an appropriate level (Patent Document 1).

Japanese Patent Laid-Open No. 10-286233

  However, in such a light control device, friction of the bearing portion of the diaphragm blade generally increases due to aging. For this reason, if the diaphragm blades are driven with the initial output after aging, a dimming speed abnormality such as a response delay occurs and proper dimming cannot be performed.

  The present invention has been made in view of the above-described problems, and it is an object of the present invention to maintain proper dimming even when a dimming speed abnormality occurs in a diaphragm mechanism in a dimming device using a diaphragm. Yes.

  The light control device of the present invention includes a light control diaphragm, diaphragm drive means for driving the diaphragm based on a light control signal, and light control to compensate for a light control delay caused by a response delay of the diaphragm that changes over time. A dimming correction means for correcting the signal is provided.

  The dimming correction unit preferably includes a delay detection unit that detects a response delay of the diaphragm, a gain calculation unit that calculates a gain of the dimming signal based on the response delay, and a gain storage unit that stores the gain. The delay detection means detects the response delay by, for example, driving the aperture in the closing direction or the opening direction, detecting the dimming speed from the image taken at that time, and comparing this with the reference dimming speed.

  It is preferable that the light control device calculates and stores gains for each of the closing direction and the opening direction. The delay detection means drives the diaphragm in the closing direction and the opening direction by outputting a dummy signal of the dimming signal. The dimming speed is calculated based on, for example, a change in the brightness level of the captured image.

  An electronic endoscope apparatus according to the present invention includes the above-described light control device.

  An electronic scope according to the present invention is an electronic scope that is attached to and detached from an electronic endoscope apparatus that includes the light control device, and is characterized in that the scope includes delay detection means, gain calculation means, and gain storage means. It is said.

  According to the present invention, in a light control device using a diaphragm, proper light control can be maintained even if a light control speed abnormality occurs in the diaphragm mechanism.

It is a block diagram which shows the structure of the electronic endoscope apparatus carrying the light modulation apparatus of this embodiment. It is a top view of the aperture blade of this embodiment. It is a block diagram which shows the electric constitution of the part in connection with the production | generation of the light control signal in a driver / signal processing part. It is a figure which illustrates the range of the field image which is preserve | saved at the image memory, and is used for calculation of a light control level, and its light control area | region. It is a flowchart which shows the flow of a process at the time of normal endoscope observation (at the time of normal operation | movement). It is the first half part of the flowchart which shows the flow of the calibration process of this embodiment. It is the latter half part of the flowchart which shows the flow of the calibration process of this embodiment. It is a time sequence of the light control dummy signal output from the light control dummy signal generator in a calibration process. It is a graph which shows an example of a time-dependent change of the luminance level when opening / closing drive of a diaphragm with a dummy signal. It is a graph which shows an example of change with time of correction gains α and β.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an electronic endoscope apparatus equipped with a light control device according to an embodiment of the present invention.

  As is well known, the electronic endoscope device 10 includes a scope 11 having a flexible tubular insertion portion, a processor device 12 to which the scope 11 is detachably connected, and a monitor 13 to which the processor device 12 is detachably connected. Consists mainly of.

  An imaging element 14 such as a CCD is provided at the distal end of the insertion portion of the scope 11, and its driving is performed based on, for example, a driver / driver in the scope 11 driven based on a clock signal from a timing controller 15 provided in the processor device 12. It is controlled by a drive signal from the signal processing unit 16. The image sensor 14 performs imaging through the imaging lens 17, and an image sensor output signal output from the image sensor 14 is sent to the driver / signal processing unit 16.

  The driver / signal processing unit 16 performs predetermined signal processing on the image sensor output signal and sends it to the previous signal processing unit 18 provided in the processor device 12 as a video signal. Further, the driver / signal processing unit 16 generates a dimming signal, which will be described later, based on the image sensor output signal, and sends this to the upstream signal processing unit 18 together with the video signal.

  The video signal sent to the upstream signal processing unit 18 is subjected to predetermined video signal processing and then temporarily held in the image memory 19 in the processor device 12 and output to the subsequent video signal processing unit 20 at a predetermined timing. Is done. The post-stage video signal processing unit 20 converts the input video signal into a video signal of a predetermined standard, and outputs the video signal from the processor device 12 to the monitor 13, for example.

  Note that a series of processing in the upstream signal processing unit 18, the image memory 19, and the downstream video signal processing unit 20 is performed based on a signal from the timing controller 15, and the timing controller 15 is a system provided in the processor device 12. It is controlled by the controller 21. A front panel (F panel) 22 is connected to the processor device 12, and the system controller 21 controls the entire processor device 12 based on an operation of the front panel 22 by the user.

  The dimming signal output from the driver / signal processing unit 16 in the scope 11 and input to the previous signal processing unit 18 is output to the motor driver 23 of the processor device 12. The motor driver 23 compares the dimming signal (voltage) with the reference voltage output from the reference voltage circuit 24, drives the motor 25 corresponding to the difference, and rotates the diaphragm blade 26. The diaphragm blades 26 are arranged so as to block the optical path from the lamp 27 to the light guide 29 through the condenser lens 28, and the position thereof is adjusted by the rotation of the motor 25. That is, the amount of light incident on the light guide 29 is adjusted by the rotational position of the aperture blade 26.

  Light that has entered the light guide 29 via the diaphragm blades 26 is transmitted through the light guide 29 disposed in the scope 11 and is irradiated through the illumination lens 30 from the distal end of the insertion portion. That is, the position of the aperture blade 26 is controlled so that the brightness of the image is constant. Note that power is supplied to the lamp 27 from the lamp power supply 31, and the lamp power supply 31 is controlled by the system controller 21.

  FIG. 2 shows the positional relationship between the diaphragm blades 26 and the luminous flux. FIG. 2 is a plan view of the diaphragm blade 26 viewed in the optical axis direction connecting the lamp 27, the condenser lens 28, and the light guide 29. A cross section of the light beam at the position of the diaphragm blade 26 is indicated by a broken line L. FIG.

  The diaphragm blade 26 is formed of a flat plate having a substantially fan shape, and is rotated about the vertex A by the motor 25. A wedge-shaped notch 32 that is curved along the arc of the fan is provided on one side of the fan shape, and the notch 32 is disposed at a position that crosses the light beam L by the rotation of the aperture blade 26. That is, light is guided to the light guide 29 through the notch 32, and the amount of light to be blocked is controlled by the positional relationship between the notch 32 and the light flux L. In FIG. 2, a notch 32 is provided on the left side of the diaphragm blade 26, and when the diaphragm blade 26 is rotated clockwise around the apex A, the diaphragm is closed to reduce the amount of light and rotate counterclockwise. The aperture is opened and the amount of light is increased.

  FIG. 3 is a block diagram showing an electrical configuration of a portion related to generation of a dimming signal in the driver / signal processing unit 16 of FIG. The dimming signal correction / calibration process of this embodiment will be described with reference to FIGS.

  An image sensor output signal (analog image signal) from the image sensor 14 is first digitally converted by the A / D converter 33 and input to the pre-stage signal processing circuit 34. In the pre-stage signal processing circuit 34, a dimming signal is generated from the luminance signal in the dimming area A2 that occupies the approximate center of the video area A1 shown in FIG. 4 and is output to the dimming signal generation circuit 35. The A2 images are sequentially output to the image memory 37 and held. In addition, a video signal including a mask area A3 surrounding the video area A1 is output from the pre-stage signal processing circuit 34 to the video signal processing circuit 36. For the dimming signal, for example, a signal corresponding to the brightness of the image such as an average luminance value of the dimming area A2 is used.

  In the video signal processing circuit 36, image processing as necessary, such as contour enhancement processing and gamma correction, is appropriately performed on the video signal, and the video signal processing circuit 36 outputs the video signal to the upstream signal processing unit 18 of the processor device 12. In addition to the dimming signal input from the pre-stage signal processing circuit 34, a dummy signal used for calibration of the dimming system can be input from the dimming dummy signal generator 38 to the dimming signal generation circuit 35. . The dimming signal generation circuit 35 dims the dummy signal in place of the original dimming signal input from the pre-stage signal processing circuit 34 when calibrating the dimming system based on a command from the system controller 39. The signal is output as a signal to the previous signal processing unit 18 of the processor device 12.

  In the present embodiment, the dimming signal generation circuit 35 has a function of correcting the dimming signal input from the pre-stage signal processing circuit 34 and is input from the correction coefficient output circuit 40 during normal endoscope observation. The dimming signal is corrected based on the gain (described later). The dimming signal is corrected, for example, for deterioration over time of the drive mechanism of the diaphragm blade 26 (for example, increase in rotational frictional force due to deterioration over time).

  During normal endoscope observation (during normal operation), the correction coefficient output circuit 40 determines the aperture based on the latest field stored in the image memory 37 and the change in the luminance level of the dimming area A2 in the past field. Is detected to be rotated in the closing direction or in the opening direction, and the correction gain (α or β) corresponding to the rotation direction is read from the memory 41 and output to the dimming signal generation circuit 35. . The dimming signal generation circuit 35 corrects the dimming signal by multiplying the dimming signal input from the previous stage signal processing circuit 34 by a gain α when controlling in the closing direction and a gain β when controlling in the opening direction, The data is output to the front signal processing unit 18 and the motor driver 23 of the processor device 12.

Here, the correction gains α and β are calculated in the calibration of the dimming system and stored in the memory 41. That is, at the time of calibration execution, the luminance level calculation circuit 42 changes the luminance level of the dimming area A2 with respect to the images of a plurality of fields stored in the image memory 37 as dimming speeds in both the closing direction and the opening direction. And these are compared with the reference dimming speed V _S stored in the memory 44. Then, the gain calculation circuit 45 obtains correction gains α and β of the dimming signal when driving in the closing direction and the opening direction, and is stored in the memory 41.

  FIG. 5 is a flowchart showing the flow of processing during normal endoscope observation (normal operation). With reference to the flow of FIG. 5 and FIGS. 1 and 3, the flow of processing during normal operation will be described.

  During normal endoscopic observation (during normal operation), that is, imaging by the imaging element 14 using the light from the lamp 27 as illumination is started, and display of the captured endoscopic image on the monitor 13 is started. In step S100, it is detected by the correction coefficient output circuit 40 whether the diaphragm blade 26 is driven in the closing direction or the opening direction, and one of the correction gains α and β is adjusted accordingly. 35. When the diaphragm blades 26 are driven in the closing direction, in step S102, the dimming signal input from the pre-stage signal processing circuit 34 to the dimming signal generation circuit 35 is multiplied by the correction gain α to obtain a corrected dimming signal. The signal is output to the previous signal processing unit 18 of the processor device 12. On the other hand, when the diaphragm blade 26 is driven in the opening direction, in step S104, the dimming signal input from the pre-stage signal processing circuit 34 to the dimming signal generation circuit 35 is multiplied by the correction gain β, and the corrected dimming is performed. The signal is output as a signal to the previous signal processing unit 18 of the processor device 12. The above process is repeated while the normal operation is continued, and the brightness of the illumination light emitted from the tip of the scope 11 is maintained substantially constant.

  Next, the flow of calibration processing of the light control system of this embodiment will be described with reference to the flowcharts of FIGS. 6 and 7 and FIGS. 6 and 7 are flowcharts showing the flow of the calibration process, and FIG. 8 is a time sequence of the dimming dummy signal output from the dimming dummy signal generator 38 in the calibration process.

  The calibration according to the present embodiment is started after the white balance adjustment is completed by, for example, the user operating the front panel 22. In the calibration process, first, an initialization process is executed in step S200, and a dummy signal for moving the diaphragm to an initial position (for example, a fully open position) is generated in the dimming dummy signal generator 38, and the dimming signal is generated. The dummy signal is output as a dimming signal from the generation circuit 35. That is, the dimming dummy signal generator 38 generates, for example, a low-level dimming signal corresponding to the darkest image as a dummy signal, and for example, a dimming signal generation circuit until the opening of the dimming diaphragm is maximized. 35 (section L1 in FIG. 8).

  When the light control diaphragm (diaphragm blade 26) is disposed at the initial position, processing for measuring the diaphragm driving speed in the closing direction is executed in steps S202 to S208. First, in step S <b> 202, a dimming dummy signal for driving the diaphragm in the closing direction is generated in the dimming dummy signal generator 38 and output from the dimming signal generation circuit 35. For example, a high-level dimming signal corresponding to the brightest image is generated as a dummy signal and output from the dimming signal generation circuit 35 (section L2 in FIG. 8).

In step S204, the luminance level calculation circuit 42 calculates the luminance level of the dimming area A2 for the image data stored in the image memory 37. In step S206, the dimming speed calculation circuit 43 performs dimming when the diaphragm blades 26 are driven in the closing direction from the temporal change in the luminance level of the continuous field (image) calculated by the luminance level calculation circuit 42. _A speed _VA is calculated. In step S208, it is determined whether or not the calibration in the closing direction has been completed. If the calibration has not been completed, the processes in and after step S202 are repeated. Note that the calibration in the closing direction is performed, for example, until the stop reaches the most closed position.

  If it is determined in step S208 that the calibration in the closing direction has been completed, the calibration in the opening direction is executed in steps S210 to S216. That is, in step S210, a dimming dummy signal for driving the diaphragm in the opening direction is generated in the dimming dummy signal generator 38 and output from the dimming signal generation circuit 35. For example, a low-level dimming signal corresponding to the darkest image is generated as a dummy signal and output from the dimming signal generation circuit 35 (section L3 in FIG. 8).

In step S210, the luminance level calculation circuit 42 calculates the luminance level of the dimming area A2 for the image data stored in the image memory 37, and the dimming speed calculation circuit 43 calculates the continuous field (image ), The dimming speed V _B when the diaphragm blades 26 are driven in the opening direction is calculated. In step S216, it is determined whether or not the calibration in the opening direction has been completed. The calibration in the opening direction is performed until, for example, the aperture reaches the most open position, and the processes in and after step S210 are repeated until then.

When the calibration in the opening direction is completed, in step S218, for example, the absolute values of the closing direction dimming speed V _A and the opening direction dimming speed V _B are converted into the reference dimming stored in the memory 44 in the dimming speed calculating circuit 43. It is compared with the absolute value of the speed V _S. The reference dimming speed V _S corresponds to the dimming speed when a dummy signal is output in a new dimming system, that is, in a state before the aging of the rotating mechanism of the diaphragm blade 26 occurs.

If any of the absolute values of V _A , V _B , and V _S is different, the gain calculation circuit 45 calculates the correction gains α and β of the dimming signal corresponding to the dimming speeds V _A and V _B in step S220. Is calculated in Then, the correction gains α and β calculated in step S222 are stored in the memory 41, and the calibration process of the present embodiment ends. In step S218, if the absolute values of V _A , V _B , and V _S are all the same, there is no need to correct the dimming signal, so the calibration process ends immediately, and is stored in, for example, the memory 41 by default. Α = β = 1 is used.

  FIG. 9 is a graph showing an example of a change in luminance level with time when the aperture is driven to open and close by a dummy signal. In FIG. 9, a curve S0 indicated by a solid line represents a change in luminance level in a new state (before deterioration with age), and a curve S1 indicated by a broken line represents a change in luminance level with time after deterioration over time. The horizontal axis represents time t, and the vertical axis represents the luminance level Y, for example, the average value of the luminance of the light control area A2 in FIG.

In the present embodiment, the dimming speed V corresponds to the time change of the luminance level Y, and corresponds to the slopes of the curves S0 and S1 in FIG. 9 illustrates the luminance levels Y1, Y2, and Y3 of the first to third fields in FIG. As shown in FIG. 9, in the curve S0 before deterioration with time, the dimming speeds V _A and V _B are substantially symmetric in both the closing direction and the opening direction, and the values are measured in advance as the reference dimming speed V _S. Yes.

In the case of FIG. 9, the dimming speed V varies depending on the position of the stop in both the closing direction and the opening direction. For example, a value at a predetermined position or an average value in each region is used as V _A , V _B , and V _S. . In this case, the dimming speed V is calculated from a difference (such as backward difference or center difference) using the luminance levels Y1, Y2, Y3, and the like. Further, when the approximate curves of the curves S0 and S1 are given in advance, the number of luminance levels necessary for obtaining the approximate curves is used. In FIG. 9, only the case where the dimming speed in the opening direction is slow is shown by the curve S1, but the dimming speed in the closing direction is usually slow as well. The light control speed is actually calculated after a necessary number of luminance levels are calculated.

When the deterioration with time progresses, as shown by the curve S1 in FIG. 9, the dimming signal V of the same level is output to the motor driver 23 (FIG. 1). The movement of 26 is not in time. Therefore, in this embodiment, by comparing V _A , V _B and V _S , correction gains α and β are obtained so that the dimming speed is maintained at V _S and applied to the dimming signal.

However, if the dimming signal is multiplied by α or β by the correction gain, the output of the motor 25 is increased and the dimming speed is maintained at the reference dimming speed V _S , but the dimming signal is always the original α times or β. Since it doubles, it will go too far from the original aperture position. Therefore, in this embodiment, the correction gains α and β are converged to 1 over time as shown in FIG.

  That is, when the dimming is started, the correction coefficient that takes the value of α (> 1) or β (> 1) gradually decreases with time and converges to 1 when the convergence time T elapses. The convergence time T is the time from the start of dimming until the aperture blade 26 (FIG. 1) reaches the target position and the dimming is completed. Thus, the use of the correction gain prevents the diaphragm position from passing the target position.

  As described above, according to the present embodiment, in the light control device using the diaphragm, it is possible to maintain proper light control even if a light control speed abnormality occurs in the diaphragm mechanism.

  In the present embodiment, since calibration is performed by outputting a dummy signal instead of the original dimming signal, the calibration can be performed without greatly changing the conventional configuration.

  In the present embodiment, the diaphragm blades are used as the dimming diaphragm, but the form of the diaphragm is not limited to the present embodiment. In the present embodiment, the dummy signal is generated on the scope side and the correction gain is stored. However, the configuration of the driver / signal processing unit on the scope side related to the calibration can be provided on the processor device side.

DESCRIPTION OF SYMBOLS 10 Electronic endoscope apparatus 11 Scope 12 Processor apparatus 13 Monitor 14 Image pick-up element 16 Driver / signal processing part 18 Previous stage signal processing part 23 Motor driver 24 Reference voltage circuit 25 Motor 26 Aperture blade 27 Lamp 29 Light guide 32 Notch 34 Previous stage signal Processing circuit 35 Light control signal generation circuit 37 Image memory 38 Light control dummy signal generator 39 System controller 40 Correction coefficient output circuit 41 Memory 42 Brightness level calculation circuit 43 Light control speed calculation circuit 44 Memory 45 Gain calculation circuit A Vertex (Rotation) axis)
L luminous flux

Claims (8)

A diaphragm for dimming,
Diaphragm driving means for driving the diaphragm based on a dimming signal;
A dimming device comprising: a dimming correction unit configured to correct the dimming signal in order to compensate for the dimming delay due to the response delay of the diaphragm that changes with time.   The dimming correction unit includes a delay detection unit that detects a response delay of the diaphragm, a gain calculation unit that calculates a gain of the dimming signal based on the response delay, and a gain storage unit that stores the gain. The light control device according to claim 1.   The delay detection means drives the diaphragm in a closing direction or an opening direction, detects a dimming speed from an image captured at that time, and detects the response delay by comparing it with a reference dimming speed. The light control device according to claim 2.   The light control device according to claim 3, wherein the gain for each of the closing direction and the opening direction is calculated and stored.   5. The light control device according to claim 4, wherein the delay detection unit drives the diaphragm in the closing direction and the opening direction by outputting a dummy signal of the light control signal.   The light control device according to claim 3, wherein the light control speed is calculated based on a change in luminance level of the captured image.   An electronic endoscope apparatus comprising the light control device according to claim 1.   An electronic scope that is attached to and detached from an electronic endoscope apparatus that includes the light control device according to claim 2, wherein the scope includes the delay detection unit, the gain calculation unit, and the gain storage unit. A featured electronic scope.

Images