JP2003305006A - Still image recordable electronic endoscope device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a still image suitably bright without repeatedly executing freeze operations, in an electronic endoscope device capable of executing the freeze operation for displaying a moving image and recording a still image. <P>SOLUTION: A monitor is connected to a processor 10 that processes an image signal read out from a CCD 54 of a videoscope 50, so as to execute the display of a moving image. As an operator operates a freeze switch button 58 provided on the videoscope 50, an aperture 33 opens three times only so that the amount of light may be doubled, based on the relationship between image signal read-out time intervals in ordinary observation and time corresponding to the electronic shutter speed in still image recording operation and on the substantially linear relationship between an aperture 33 and the amount of light to a subject. In the meantime, electronic shutter operation and recording operation of the still image are not executed. When the amount of light is doubled, electronic shutter operation and recording operation are executed, and the still image is recorded into and outputted from an image recording memory 75 and a video recorder 70. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus including a videoscope (electronic scope) having an image pickup device and a processor for performing signal processing on an image signal read from the image pickup device, and more particularly , Freezing operation for recording a still image.

[0002]

2. Description of the Related Art In a conventional electronic endoscope apparatus, a moving image can be displayed on a monitor and a freeze operation can be executed according to an operation of an operator. That is, the still image recording process is executed, and the still image is recorded in a recording device such as a memory or a video recorder.

When a still image is recorded in the electronic endoscope apparatus, the recorded still image may have resolution, color shift, etc. due to camera shake of the videoscope, movement of the observation site itself, etc., and the image quality may deteriorate. . Especially when the distance between the observation site and the tip of the videoscope is large, or when zooming using the image enlargement function,
The image quality is significantly degraded. In order to solve such a problem, in the execution of the freeze operation, there is known a configuration in which the amount of light irradiated to the subject is increased and the shutter speed of the electronic shutter is set to a high speed (Japanese Patent Laid-Open No. 6-296).
580, JP-A-11-244229 and JP-A-20
01-100111). In this case, the amount of light is increased by the fully opening operation of the diaphragm and the flash emission, and the shutter speed is set according to the increase in the amount of light.

[0004]

In the above configuration, the amount of light to be increased is determined in advance, and in order to record still images of appropriate brightness, the brightness level of sequentially recorded still images is judged. However, it is necessary to adjust the shutter speed. Further, if the aperture of the diaphragm is small immediately before the freeze operation, the amount of light to the subject will momentarily excessively increase due to the diaphragm full-open operation, and it is difficult to obtain a still image with appropriate brightness.

Therefore, it is an object of the present invention to provide an electronic endoscope apparatus and an endoscope still image recording apparatus which can quickly obtain a still image of appropriate brightness without repeatedly performing a freeze operation. And

[0006]

An electronic endoscope apparatus of the present invention is an electronic endoscope apparatus including a videoscope having an image pickup device and a processor to which the videoscope is connected. A monitor for displaying the subject image is connected. The electronic endoscope apparatus has a moving image display unit that reads an image signal corresponding to the subject from the image sensor at predetermined time intervals and processes the image signal in order to display a moving image of the subject. For example, when the NTSC system is applied as the color television system,
The image signal may be read out at intervals of 60 seconds. Further, the electronic endoscope apparatus has a light amount adjusting means for adjusting the light amount of the light emitted from the light source for illuminating the subject, and the light amount adjusting means increases or decreases the light amount according to the light amount adjusting parameter.

For example, the light quantity adjusting means is a diaphragm, and the diaphragm is arranged so as to be interposed between the light source and a light transmitting member such as a light guide. More specifically, it is preferable that the diaphragm has a shielding portion that shields the light from the light source and that the shielding portion axially rotates so as to draw an arc. The amount of light to the subject changes depending on the angle of the diaphragm. In this case, the light amount adjustment parameter is the angle of shaft rotation. A liquid crystal plate (liquid crystal shutter) or a polarizing plate may be arranged instead of the diaphragm. In this case, the light amount adjustment parameter is the voltage value. Alternatively, a light emission control control circuit may be provided as the light amount adjusting means so as to control the light emission amount of the light emitted from the light source. In this case, the light amount adjustment parameter is current.

In order to make the brightness of the moving image displayed on the monitor appropriate, the electronic endoscope apparatus controls the light amount adjusting means so that the brightness of the displayed moving image is constant. Means should be provided. For example, when the light amount adjusting unit is a diaphragm, the brightness value is calculated based on the image signals sequentially read from the image sensor, and based on the brightness value and the moving image reference brightness value indicating appropriate brightness of the subject image. Just open and close the diaphragm. The brightness value is a value of a brightness level indicating a typical brightness of the subject image, and the brightness is, for example, 1 to 2
When divided into 56 steps, it is represented by an integer value of 0 to 255. As the brightness value, for example, a brightness average value indicating the average brightness of the entire subject image is applied. In this case, the moving image reference brightness value may be set to any value of 120 to 140, for example.

The electronic endoscope apparatus has a still image recording means for executing the freeze operation. Since the still image recording means records the still image, it corresponds to the image signal read time interval in the moving image display. By the electronic shutter operation at the electronic shutter speed corresponding to a time shorter than the predetermined time interval, the image signal corresponding to the subject is read from the image sensor and processed. For example, a freeze switch is provided in a video scope or the like, and a recording device such as a video recorder is connected to the processor. Then, according to the switch operation of the operator, the still image is recorded in the memory and the recording device in the processor. The electronic shutter speed corresponding to the exposure time at the time of recording a still image may be determined in consideration of the read time interval in moving image display, the distance between the tip of the videoscope and the observed object, and the like.

The still image recording means of the present invention is characterized by including a light amount increasing means and a recording executing means. The light amount increasing means controls the light amount adjusting means by changing the light amount adjusting parameter so that the light amount to the subject reaches the reference light amount corresponding to the recording of the still image. here,
The reference amount of light indicates the amount of light necessary to obtain a still image of a desired brightness, and is set based on the set electronic shutter speed or / and the image signal read time interval (predetermined time interval) in moving image display. . It is desirable that the brightness of the still image and the brightness of the moving image be substantially equal so that the doctor can make an accurate diagnosis from the recorded still image. In this case, the reference light amount is determined based on the ratio between the time corresponding to the electronic shutter speed and the predetermined time interval. For example, when the predetermined time interval is 1/60 second and the electronic shutter speed is 1/120 second, the reference light amount is set to a light amount twice the light amount irradiated to the subject immediately before the freeze operation is performed.

The still image recording operation is not executed until the light amount to the subject reaches the reference light amount. Then, when the light quantity to the subject reaches the reference light quantity, the still image recording operation is executed to record the still image. For example, the image recording means stores an image signal of a still image in a memory provided in the processor and sends the image signal from the memory to a recording device such as a video recorder. The recording execution means may record a still image at the same time when the reference light amount is reached, or may record a still image with a delay time.

The light amount increasing means of the present invention is characterized in that the light amount adjusting means is driven by the necessary variation amount of the light amount adjusting parameter obtained from the correspondence relationship between the light amount changing parameter and the light amount to the subject. When the variation amount of the light amount adjustment parameter required to reach the reference light amount is obtained based on the correspondence, the light amount adjustment means drives according to the obtained variation amount of the light amount adjustment parameter. For example, when a diaphragm having a shaft rotation angle as a light amount adjustment parameter is applied, the light amount increasing means may set a movement angle for reaching the reference light amount, and move the shield part by the movement angle.

Since the recording operation is carried out in anticipation of the time point when the light quantity to the subject reaches the reference light quantity, a still image without image blur can be obtained at one time. Further, the electronic shutter speed can be set according to the configuration of the light quantity adjusting means, and the reference light quantity can be appropriately set according to the image signal read time interval (predetermined time interval) and the electronic shutter speed. Therefore, by appropriately setting the degree of increase in the light amount during the freeze operation, it is possible to obtain a still image with appropriate brightness.

Further, in the present invention, the light quantity adjusting means is driven by the feedforward control instead of the feedback control in order to make the light quantity to the object reach the reference light quantity. Therefore, the increase in the amount of light is quickly performed, and the freeze operation is smoothly performed.

In order that the light quantity adjusting means can quickly adjust the light quantity to the reference light quantity regardless of the light quantity to the object or the state of the light quantity adjusting means, the light quantity adjusting parameter and the light quantity to the object are logarithmic. It is desirable that the graph has a substantially linear relationship. However, the linear relationship here indicates a relationship in which the light amount to the subject changes by a constant magnification whenever the light amount adjustment parameter changes by a constant amount. For example, when the light amount adjusting means is a diaphragm that rotates about an axis, it is desirable that when the diaphragm located at an arbitrary angle is opened by a predetermined amount, the increment of the light amount corresponding to the amount is always constant.

From the start of execution of the freeze operation until the actual recording of a still image, for example, the recording execution means does not execute the electronic shutter operation and the still image recording operation until the light quantity to the subject reaches the reference light quantity. It is desirable to execute the electronic shutter operation and the still image recording operation when the light quantity to the subject reaches the reference light quantity. Alternatively,
The recording execution means may execute the transmission shutter operation while not executing the still image recording operation, and may execute the still image recording operation when the light quantity to the subject reaches the reference light quantity.

The processor of the electronic endoscope apparatus of the present invention comprises:
A processor of an electronic endoscope apparatus to which a videoscope having an image pickup device is connected, and a moving image in which an image signal corresponding to the subject is read from the image pickup device at predetermined time intervals and is processed in order to display a moving image of the subject. An image display unit, a light amount adjusting unit that adjusts the amount of light emitted from a light source to illuminate the subject, and increases or decreases the amount of light to the subject according to a light amount adjustment parameter, and a predetermined time interval for recording a still image of the subject. Still image recording means for reading and processing an image signal corresponding to the subject from the image sensor by an electronic shutter operation at an electronic shutter speed corresponding to a shorter time than To reach the reference light level corresponding to the recording of
A light amount increasing means for controlling the light amount adjusting means by changing the light amount adjusting parameter and a recording executing means for executing a still image recording operation to record a still image when the light amount to the object reaches the reference light amount. However, it is characterized in that the light amount increasing means drives the light amount adjusting means by a necessary variation amount of the light amount adjusting parameter obtained from the correspondence relationship between the light amount changing parameter and the light amount to the subject.

A still image recording apparatus for an electronic endoscope apparatus according to the present invention is an electronic endoscope apparatus including a videoscope having an image pickup element and a processor to which the videoscope is connected, and a moving image of a subject is recorded. In order to display, a moving image display unit that reads out and processes an image signal corresponding to the subject from the image sensor at predetermined time intervals, and adjusts the light amount of the light emitted from the light source to illuminate the subject, according to the light amount adjustment parameter. In a still image recording device for an electronic endoscope apparatus, which includes a light amount adjusting means for increasing or decreasing a light amount to a subject, an electronic shutter speed corresponding to a time shorter than a predetermined time interval is used to record a still image of the subject. A still image recording unit that reads and processes an image signal according to the subject from the image sensor by the shutter operation is provided, and the still image recording unit Light quantity increasing means for controlling the light quantity adjusting means by changing the light quantity adjusting parameter so that the light quantity of the object reaches the reference light quantity corresponding to the recording of the still image, and when the light quantity to the subject reaches the reference light quantity, the still image A recording execution unit that executes a recording operation to record a still image, and the light amount increasing unit adjusts the light amount by a necessary fluctuation amount of the light amount adjustment parameter obtained from the correspondence relationship between the light amount change parameter and the light amount to the subject. It is characterized in that the means is driven.

A program according to the present invention is an electronic endoscope apparatus including a videoscope having an image pickup device and a processor to which the videoscope is connected, and displays a moving image of a subject. A moving image display unit that reads out a signal from the image sensor at predetermined time intervals and processes it, and a light amount adjustment that adjusts the light amount of light emitted from a light source for illuminating the subject and increases or decreases the light amount to the subject according to a light amount adjustment parameter. Means and a still image recording means for reading and processing an image signal corresponding to the subject from the image sensor by an electronic shutter operation at an electronic shutter speed corresponding to a time shorter than a predetermined time interval in order to record a still image of the subject. A program for executing still image recording in a provided electronic endoscope apparatus, wherein the light amount to a subject is a still image. Light intensity increasing means for controlling the light intensity adjusting means by changing the light intensity adjusting parameter so that the reference light intensity corresponding to recording is reached, and when the light intensity to the subject reaches the reference light intensity, the still image recording operation is executed. The recording execution means for recording a still image is made to function, and the light quantity increasing means is operated so as to drive the light quantity adjusting means by the necessary variation of the light quantity adjustment parameter obtained from the correspondence relationship between the light quantity change parameter and the light quantity to the subject. It is characterized by

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An electronic endoscope apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the electronic endoscope apparatus according to the first embodiment.

In the electronic endoscope apparatus, CC which is an image pickup device
A video scope 50 having a D54 and a processor 10 for processing an image signal read from the CCD 54 are provided, and a monitor 60 for displaying an image of an observed region as a moving image or a still image is connected to the processor 10. The video scope 50 is detachably connectable to the processor 10, and a video recorder 70 and a video printer 80 are connected to the processor 10.

When a lamp lighting switch (not shown) is turned on, electric power is supplied from the lamp power source 36 to the light source lamp 34 to light it. The light emitted from the turned-on light source lamp 34 is incident on the incident end of an optical fiber bundle 56 provided in the videoscope 50 via a condenser lens (not shown) and the diaphragm 33. The optical fiber bundle 56 is an optical fiber that transmits the light emitted from the light source lamp 34 to the tip side of the videoscope 50 having the observation site S,
The light that has passed through the optical fiber bundle 56 is emitted from the emission end 56B. The light emitted from the emission end 56B is applied to the observation site S via a light distribution lens (not shown) which is a diffusion lens.

The light reflected at the observation site S passes through an objective lens (not shown), and a CCD (Charge-Coupled Dev)
ice) 54, and the subject image of the observation site S is formed on the light receiving surface of the CCD 54. In the present embodiment, the single-plate simultaneous type is applied as the color imaging method, and yellow (Ye), cyan (Cy), magenta (Mg), and green (G) color elements are in a checkered pattern on the light receiving surface of the CCD 54. Complementary color filters (not shown) arranged in a line are arranged so as to correspond to the respective pixels on the light receiving surface.
In the CCD 54, an analog image signal of a subject image corresponding to a color passing through the complementary color filter is generated by photoelectric conversion,
The image signal of one field (one frame) is sequentially read out at predetermined time intervals according to the color difference line sequential method.
As the color television system, for example, the NTSC system is applied, and an image signal for one field (one frame) is sequentially read for displaying a moving image at intervals of 1/60 second (1/30 second). , To the processor 10 via the signal line IC. The CCD 54 is driven by the CCD drive circuit 52, and a pulse signal for reading an image signal is output from the CCD drive circuit 52.

The image signal input to the processor 10 is
After being amplified by a pre-stage circuit (not shown), it is sent to the A / D converter 22. In the A / D converter 22, the analog image signal is converted into a digital image signal, and the digital image signal is sent to the signal processing circuit 24. Signal processing circuit 24
Then, various signal processing such as R, G, B gain processing and gamma correction is performed on the digital image signal, and a luminance signal is generated based on the image signal. Digital image signals for one frame are sequentially stored in the memory 26, which is a field memory, while luminance signals are stored in the CPU (Ce
It is sequentially sent to the system control circuit 30 including the ntral processing unit). When the digital image signal is read from the memory 26, the digital image signal is converted into an analog image signal in the D / A converter 28. The analog image signal is subjected to a predetermined signal processing in a post-stage circuit (not shown) to be an NTSC composite signal, a Y / C separation signal (S
(Video signal), RGB separation signals, and other video signals are output to the monitor 60, whereby the subject image is displayed on the monitor 60 as a moving image.

The system control circuit 30 controls the entire processor 10 and outputs a control signal to each circuit such as the signal processing circuit 24, aperture control circuit 32, and CCD drive circuit 52. A ROM (not shown) in the system control circuit 30 stores a program for executing the still image recording process during the freeze operation and controlling the operation of the entire processor. A timing control circuit (not shown) outputs a clock pulse for adjusting the signal processing timing to each circuit in the processor 10.

A diaphragm 33 for adjusting the amount of light applied to the subject S is provided between the incident end of the light guide 56 and the condenser lens, and the diaphragm 33 is opened and closed under the control of the diaphragm control circuit 32. . A control signal is output from the system control circuit 30 to the aperture control circuit 32 based on the brightness signal sent from the signal processing circuit 24 to the system control circuit 30. The diaphragm control circuit 32 drives a motor (not shown) based on the control signal, whereby the diaphragm 33 connected to the motor opens and closes. As the motor, a servo motor is applied here.

The videoscope 50 is provided with a freeze switch button 58, and when the freeze switch button 58 is pressed by the operator, an operation signal generated by the pressing operation is sent to the system control circuit 30 of the processor 10. Then, the freeze operation is executed based on the detected operation signal. That is, the image signal is read from the CCD 54 by the electronic shutter operation at a predetermined electronic shutter speed, and the A / D converter 2
2, processed in the signal processing circuit 24 and the like. The processed image signal for one frame is stored in the memory 26 for still image recording.

The image signal for one frame stored in the memory 26 is recorded in the image recording memory 75 and is also transmitted as a video signal to the video recorder 70 and the video printer 80. The video recorder 70 is a recording device for recording a still image, and the video printer 80 prints a still image based on the video signal sent during the freeze operation. While the recording of the still image is being executed, the image signal stored in the memory 26 is not updated and a new writing process is not executed. This allows
A still image is displayed on the monitor 60. When the operator releases the freeze switch button 58 from his / her finger, the freeze operation ends, and the normal observation mode for displaying a moving image is entered again.

FIG. 2 is a plan view showing a partial structure of the diaphragm 33, showing the relative positional relationship between the light flux passing between the light source lamp 34 and the incident end of the light guide 56 and the diaphragm 33. ing. 3 is a logarithmic graph showing the relationship between the angle of the diaphragm 33 and the aperture area of the diaphragm 33, that is, the aperture characteristic of the diaphragm 33. The aperture area of the diaphragm 33 and the amount of light passing through the diaphragm 33 are in a proportional relationship.

The diaphragm 33 has a tip 3 having a size capable of blocking almost all the light from the light source lamp 34.
3A and an arm portion (not shown) are integrally formed, and a motor is mechanically connected to the tip of the arm portion. When the motor rotates, the diaphragm 33 rotates about the tip of the arm as an axis, and the tip 33A has an arc C.
Move continuously along C. A notch 33C is formed at the tip 33A, and a large number of fine holes 33B are formed along the arc CC. A line BC connecting the center of the light beam BL and the rotation axis of the arm tip is a reference line for defining the angle of the diaphragm 33, and the diaphragm 33 is 0 degrees to 30 degrees.
Move within a range of degrees. In FIG. 3, the angle of the diaphragm 33 is 18
The relative positional relationship between the tip portion 33A and the light flux BL in the case of 30 degrees is shown.

In the present embodiment, the angle of the diaphragm 33 and the diaphragm 3
3 can be represented as an exponential function of the angle of the diaphragm 33, and as shown by the logarithmic graph in FIG. 3, the aperture area, that is, the object The amount of light increases by a fixed rate.
A predetermined number of fine holes 33B are formed in the tip portion 33A of the diaphragm 33 so as to maintain this linear relationship. In the present embodiment, every time the diaphragm 33 is opened three times, the aperture area of the diaphragm 33, that is, the amount of light to the subject is doubled.

FIG. 4 shows the processor 1 according to this embodiment.
9 is a flowchart showing an operation process of 0. Note that this flowchart is started when the main power supply of the processor 10 is turned on.

In step S101, the diaphragm 33, the gain coefficient in signal processing, etc. are set to initial values, and the electronic shutter speed during freeze operation is also set to a predetermined value. In step S102, normal observation, that is, processing for displaying a moving image on the monitor 60 is performed. In the normal observation mode, the automatic light adjustment processing is executed so that the brightness of the displayed subject image is constant, and here, the interrupt calculation processing is executed at intervals of 1/60 second. When step S102 is executed, the process proceeds to step S103.

In step S103, the videoscope 5
It is determined whether the 0 freeze switch button 58 has been pressed by the operator. If it is determined that the freeze switch button 58 has not been pressed, the process returns to step S102. On the other hand, if it is determined that the freeze switch button 58 has been pressed, the process proceeds to step S104. In step S104, the freeze operation process is executed, the still image is output to the video recorder 70 and the like, and is displayed on the monitor 60.

FIG. 5 is a diagram showing a subroutine of the freeze operation process in step S104 of FIG. 4, and FIG. 6 is a diagram showing the level of the luminance signal during the freeze operation in time series.

In this embodiment, when a still image is recorded, the light amount is adjusted so that the brightness of the subject image during normal observation is the same as the brightness during freeze operation.
That is, the CCD 5 when the subject image is frozen
The amount of charge accumulation in each pixel of No. 4 is adjusted so as to be the same as the amount of charge accumulation in each corresponding pixel of the CCD 54 when the same subject image is normally observed. Since the image signal is read from the CCD 54 at 1/60 second intervals during normal observation, the electronic shutter speed during still image recording is set to 1/120 second. However,
The electronic shutter speed is the CCD5 when recording a still image.
This corresponds to an exposure time of 4. Since the electronic shutter speed is twice the shutter speed of the signal readout time interval (= 1/60 seconds) of moving image display (exposure time is half),
The amount of light to be applied to the subject during the freeze operation, that is, the amount of light to be incident on the light receiving surface of the CCD 54 is twice the amount of light during normal observation.

In FIG. 6, the system control circuit 30
The levels of the brightness signals detected by the are shown in time series, and the light quantity of light passing through the diaphragm 33 (hereinafter referred to as the passing light quantity) is represented by the brightness signal level. During normal observation, the luminance signal level detected from the image signal, that is, the luminance value Y is maintained at the luminance value Y1 (hereinafter, referred to as moving image reference luminance value) indicating an appropriate brightness reference of the subject image. Has been automatically dimmed. However, the brightness value is defined as any integer value between 0 and 255 when the brightness of the subject image is classified into 256 levels. In addition, the brightness value represents the brightness average value here, and is calculated by dividing the total sum of the number of pixels in each brightness value of 0 to 255 and the multiplier of the brightness value by the number of pixels for one field.

In this embodiment, the angle of the diaphragm 33 and the logarithm of the amount of light to the subject are in a substantially linear relationship, and as described above, the aperture 33 is opened to the subject every 3 degrees from an arbitrary position (angle). The amount of light doubles. Therefore, when the freeze switch button 58 is pressed, the diaphragm 33 is driven so as to open further 3 degrees from the current angle.

In step S201, a control signal is output to the diaphragm control circuit 32 so that the diaphragm 33, which has been opened to a predetermined opening during normal observation, is opened three more times. Then, in step S202, the time from when the control signal is output to execute the aperture opening operation until the aperture 33 is actually opened three times and the control signal is output to stop the aperture opening operation after the aperture 33 is opened. After the delay time TR in consideration of the time until the actual stop occurs, the electronic shutter operation is performed at the electronic shutter speed of 1/120 seconds C
A control signal is sent to the CD drive circuit 52. The CCD drive circuit 52 outputs a charge sweep pulse signal to the CCD 54 based on a control signal from the system control circuit 30 so that the exposure time becomes 1/120 second. And
In step S206, an image signal corresponding to a still image for one frame captured at an electronic shutter speed of 1/120 seconds is stored in the memory 26 and recorded in the image recording memory 75 and the video recorder 70. The image signal for one frame once stored in the memory 26 is not rewritten during the freeze operation. When step S206 is executed, this subroutine ends, and the process proceeds to step S105 in FIG.

In step S105, it is determined whether or not the freeze switch button 58 is in the OFF state when the operator releases the freeze switch button 58 from the finger. Freeze switch button 58 is OFF
When it is determined that the state is not reached, the process returns to step S104. On the other hand, when it is determined that the freeze switch button 58 is in the OFF state, the process proceeds to step S106, the freeze operation process is canceled, and the process returns to step S103. Until the main power is turned off, step S102-
S106 is repeatedly executed.

As described above, according to the present embodiment, when the freeze switch button 58 is operated by the operator, the diaphragm 33 is opened three more times so that the amount of light on the subject becomes twice that in normal observation. During this time, the electronic shutter operation is not executed. When the diaphragm 33 is further opened by 3 degrees, the electronic shutter operation and the still image recording operation are executed, and the image signal read time interval (= 1/60) during normal observation.
Image signal is read at an electronic shutter speed (= 1/120 second) twice as fast as the second), and a still image is recorded in the image recording memory 7.
5, recorded on the video recorder 70.

At any position of the diaphragm 33 when the freeze switch button 58 is pressed, the opening angle of the diaphragm 33 is 3 degrees in order to double the light quantity. Therefore, the diaphragm 33 is always driven at the same response speed, and the freeze operation is quickly performed.

In the present embodiment, the electronic shutter speed is set to 1/120 seconds so that the brightness during normal observation and the brightness of the recorded still image coincide with each other. Accordingly, the electronic shutter speed may be set so that the image quality is not significantly deteriorated due to the camera shake of the video scope, the movement of the observation region itself, and the like. For example, as a color television system, the read time interval is 1/50.
When the PAL system of seconds is applied, the electronic shutter speed during the still image recording operation may be set to 1/100 second. In either case, based on the ratio of the image signal read time interval during normal observation and the time corresponding to the electronic shutter speed during still image recording operation, the aperture of the diaphragm 33 during normal observation The opening degree of the diaphragm 33 is determined.

The electronic shutter speed may be set so that the brightness of the still image is the brightness desired by the operator. In this case, the still image reference luminance value Y2 is set to a predetermined value according to the set shutter speed. The electronic shutter speed may be set and changed by an operator's operation. As the brightness value Y and the reference brightness values Y1 and Y2, typical values other than the brightness average value may be applied.

In this embodiment, the diaphragm 33 is used for adjusting the light amount to the subject, but the light amount may be adjusted by the liquid crystal plate. In this case, the liquid crystal plate is provided between the incident end of the light guide and the light source lamp. FIG. 7 is a logarithmic graph showing the relationship between the voltage applied to the liquid crystal plate and the amount of light passing through the liquid crystal plate, that is, the amount of light to the subject. The voltage and the amount of passing light (the amount of light to the subject) have a linear relationship in the logarithmic graph. is there. Alternatively, a light emitting diode may be applied as the light source lamp and the light emission amount of the light emitting diode may be controlled to adjust the light amount. In this case, it is possible to immediately execute the electronic shutter operation and perform the image recording operation without providing the delay time TR in FIG.

In the present embodiment, the angle of the diaphragm 33 and the amount of light to the subject have a substantially linear relationship in the logarithmic graph, but a diaphragm structure having a relationship expressed by a certain functional expression may be used. For example, let Q be the amount of light and x be the angle of the diaphragm.
= F (x) is established in the logarithmic graph, the movement angle of the diaphragm 33 may be obtained based on x = f ^-1 (Q).

Next, a second embodiment will be described with reference to FIGS. In the second embodiment, unlike the first embodiment, the electronic shutter operation is executed simultaneously with the opening operation of the diaphragm 33. Other configurations are substantially the same as those in the first embodiment.

FIG. 8 shows the subroutine of step S104 of FIG. 4 in the second embodiment, and FIG. 9 shows
It is the figure which showed the brightness signal level in 2nd Embodiment in time series. When the freeze switch button 58 is operated, the freeze operation process is started.

In step S301, a control signal is output to the aperture control circuit 32 so as to open the aperture 33 three times according to the operation on the freeze switch button 58. Then, in step S302, the electronic shutter operation is executed at the same time as the opening operation of the diaphragm 33. While the diaphragm 33 is being driven, the still image recording operation is not executed.
In step S303, the still image recording operation is executed after the opening operation time KT of the diaphragm 33 has elapsed, the image signal obtained by the electronic shutter operation is stored in the memory 26, and the still image is stored in the image recording memory 75 and the video recorder 70. Will be recorded. When step S303 is executed, this subroutine ends.

[0051]

As described above, according to the present invention, it is possible to quickly obtain a still image of appropriate brightness without repeatedly performing the freeze operation.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic endoscope apparatus according to a first embodiment.

FIG. 2 is a plan view showing a configuration of a diaphragm.

FIG. 3 is a diagram showing a logarithmic graph showing a relationship between an aperture angle and an aperture area.

FIG. 4 is a flowchart showing main operation processing of the processor.

FIG. 5 is a diagram showing a subroutine of freeze operation processing in step S104 of FIG.

FIG. 6 is a diagram showing the levels of luminance signals during a freeze operation in time series.

FIG. 7 is a diagram showing a graph showing a relationship between a voltage applied to a liquid crystal plate and a light amount to a subject.

FIG. 8 is a diagram showing a subroutine of freeze operation processing in the second embodiment.

FIG. 9 is a diagram showing the level of a luminance signal during a freeze operation in time series in the second embodiment.

[Explanation of symbols]

10 processors 24 Signal processing circuit 26 memory 30 system control circuit 32 Aperture control circuit 33 Aperture (light intensity adjustment means) 33A Tip (shielding part) 50 video scope 52 CCD drive circuit 54 CCD (imaging device) 58 Freeze Switch Button 60 monitors 70 video recorder 75 Image recording memory

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Iriyama             2-36 Maeno-cho, Itabashi-ku, Tokyo Asahikou             Gaku Kogyo Co., Ltd. F-term (reference) 2H040 BA10 CA07 GA02 GA10 GA12                 4C061 BB01 BB10 CC07 GG01 HH28                       LL03 MM05 NN01 QQ09 RR02                       RR12 RR13 RR15 RR18 RR26                       WW01 YY01 YY12

Claims (11)

[Claims] 1. An electronic endoscope apparatus comprising a videoscope having an image pickup device and a processor to which the videoscope is connected, wherein an image signal corresponding to the subject is displayed in order to display a moving image of the subject. Moving image display means for reading and processing from the image sensor at predetermined time intervals, and light quantity adjusting means for adjusting the light quantity of light emitted from the light source for illuminating the subject and increasing or decreasing the light quantity to the subject according to the light quantity adjustment parameter. In order to record a still image of the subject, a still image recording means for reading and processing an image signal corresponding to the subject from the image sensor by an electronic shutter operation at an electronic shutter speed corresponding to a time shorter than the predetermined time interval. The still image recording means includes the light amount so that the light amount to the subject reaches a reference light amount corresponding to the recording of the still image. A light quantity increasing means for controlling the light quantity adjusting means by changing an adjustment parameter; and a recording execution means for executing the still image recording operation to record a still image when the light quantity to the subject reaches the reference light quantity. Wherein the light amount increasing means drives the light amount adjusting means by a necessary variation amount of the light amount adjusting parameter obtained from the correspondence relationship between the light amount changing parameter and the light amount to the subject. Endoscopic device. 2. The light amount adjusting means is a diaphragm having a shielding part for shielding the light from the light source, and the shielding part is a diaphragm that rotates about an axis so as to draw an arc, and the light amount adjusting parameter is the It is an angle of axial rotation in a diaphragm, the light amount increasing means determines a movement angle for reaching the reference light amount, and moves the shielding part by the movement angle. Endoscope device. 3. The electronic endoscope apparatus according to claim 1, wherein the light amount adjustment parameter and the light amount to the subject have a substantially linear relationship in a logarithmic graph. 4. The reference light amount is determined based on a ratio between a time corresponding to the electronic shutter speed and the predetermined time interval so that the brightness of the still image and the brightness of the moving image are substantially equal to each other. The electronic endoscope apparatus according to claim 1, wherein the electronic endoscope apparatus is provided. 5. An automatic light control processing means for controlling the light quantity adjusting means based on a moving image reference luminance value serving as a brightness reference so that the moving image has a constant brightness. The electronic endoscope apparatus according to claim 1. 6. The recording execution means does not execute the electronic shutter operation and the still image recording operation until the light quantity to the subject reaches the reference light quantity, and the light quantity to the subject reaches the reference light quantity, The electronic endoscope apparatus according to claim 1, wherein the electronic shutter operation and the still image recording operation are executed. 7. The recording execution means executes the electronic shutter operation while not executing the still image recording operation until the light quantity to the object reaches the reference light quantity, and the light quantity to the object is The electronic endoscope apparatus according to claim 1, wherein when the reference light amount is reached, the still image recording operation is executed. 8. The electronic endoscope apparatus according to claim 1, wherein the still image recording means starts execution in accordance with an operation of an operator. 9. A processor of an electronic endoscope apparatus to which a videoscope having an image pickup device is connected, wherein an image signal corresponding to the subject is displayed at predetermined time intervals from the image pickup device in order to display a moving image of the subject. The moving image display means for reading and processing, the light quantity adjusting means for adjusting the light quantity of the light emitted from the light source for illuminating the subject, and increasing or decreasing the light quantity to the subject according to the light quantity adjustment parameter, and recording the still image of the subject Therefore, a still image recording unit that reads and processes an image signal corresponding to a subject from the image sensor by an electronic shutter operation at an electronic shutter speed corresponding to a time shorter than the predetermined time interval is provided. However, the light intensity adjustment parameter must be changed so that the light intensity on the subject reaches the reference light intensity corresponding to the recording of a still image. A light quantity increasing means for controlling the light quantity adjusting means, and a recording execution means for executing the still image recording operation to record a still image when the light quantity to the subject reaches the reference light quantity, The processor of the electronic endoscope apparatus, wherein the light amount increasing means drives the light amount adjusting means by a necessary variation amount of the light amount adjusting parameter obtained from the correspondence relationship between the light amount changing parameter and the light amount to the subject. . 10. An electronic endoscope apparatus comprising a videoscope having an image pickup device and a processor to which the videoscope is connected, wherein an image signal corresponding to the subject is displayed for displaying a moving image of the subject. Moving image display means for reading out from the image sensor at predetermined time intervals and processing, and light quantity adjusting means for adjusting the light quantity of light emitted from the light source for illuminating the object and increasing or decreasing the light quantity to the object according to the light quantity adjustment parameter. In order to record a still image of a subject in a still image recording device for an electronic endoscopic device, the electronic image pickup device responds to the subject by the electronic shutter operation at an electronic shutter speed corresponding to a time shorter than the predetermined time interval. And a still image recording means for reading and processing the image signal. A light quantity increasing means for controlling the light quantity adjusting means by changing the light quantity adjusting parameter so as to reach a reference light quantity corresponding to recording; and the still image recording when the light quantity to the subject reaches the reference light quantity. Recording execution means for executing an operation to record a still image, wherein the light amount increasing means is a necessary variation amount of the light amount adjustment parameter obtained from the correspondence relationship between the light amount change parameter and the light amount to the subject. A still image recording device for an electronic endoscope device, characterized in that the light amount adjusting means is driven. 11. An electronic endoscope apparatus comprising a videoscope having an image sensor and a processor to which the videoscope is connected, wherein an image signal corresponding to the subject is displayed to display a moving image of the subject. Moving image display means for reading out from the image sensor at predetermined time intervals and processing, and light quantity adjusting means for adjusting the light quantity of light emitted from the light source for illuminating the object and increasing or decreasing the light quantity to the object according to the light quantity adjustment parameter. A still image recording means for reading and processing an image signal corresponding to the subject from the image sensor by an electronic shutter operation at an electronic shutter speed corresponding to a time shorter than the predetermined time interval in order to record a still image of the subject. A program for executing still image recording in the provided electronic endoscope apparatus, in which the light quantity to the subject is Recording, the still image recording means for controlling the light amount adjusting means by changing the light amount adjusting parameter so as to reach the reference light amount corresponding to recording, and when the light amount to the subject reaches the reference light amount. A recording execution unit that executes an operation to record a still image is made to function, and the light amount adjustment unit is driven by a necessary variation amount of the light amount adjustment parameter obtained from the correspondence relationship between the light amount change parameter and the light amount to the subject. A program that causes the light amount increasing means to function.