JPH07194527A - Endoscope system - Google Patents

Abstract

PURPOSE:To perform secure observations and treatments by preventing malfunctioning regarding dimming during observations. CONSTITUTION:An iris signal computing means 34 comprises a detector circuit 41 which calculates a dimming control signal matching the level of an image signal, from the image signal that has been converted from analog to digital form by an A/D converter 19, the dimming control signal being inputted thereafter from the detector circuit 41 via a filter 42 to a CPU 32, which then judges the dimming control signal according to the ID data of a light source device 12 stored in a ROM 31 and the ID data of a scope 13 stored in a ROM 33; and a nonlinear conversion circuit 43 which converts the dimming control signal from the detector circuit 41 into a nonlinear form according to the judgment result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope device for automatically adjusting the illumination light applied to a subject.

[0002]

2. Description of the Related Art In recent years, there has been an electronic endoscope apparatus in which a CCD is arranged at the tip of a scope to convert a subject image into an electric signal, perform signal processing, and display it on a monitor. Such an electronic endoscope device incorporates an automatic light control device that automatically controls the amount of irradiation light with which a subject is irradiated.

The above-mentioned electronic endoscope apparatus is composed of a processor 11, a light source device 12 and a scope 13 in FIG. A xenon lamp 14 is provided inside the light source device 12.
There is a lens 15, and the light emitted from the xenon lamp 14 is condensed by the lens 15 and passes through the light guide 16 and is emitted from the tip of the scope 13 toward a subject (not shown).

CCD arranged at the tip of the scope 13
17 is driven by a drive signal from a signal generation circuit (not shown) inside the processor 11, converts the subject image into an electrical video signal and outputs it. This video signal is sent to the processor 11
Correlation 2 in CDS (correlation double sampling circuit) 18
After the double sampling, the A / D converter 19 performs A / D conversion and the signal processing circuit 20 performs processing, and the D / A converter 2
In step 1, D / A conversion is performed and output to a monitor (not shown). This output can be displayed on a monitor, for example NTS.
It complies with the C standard.

The video signal output from the CDS 18 is input to the detection circuit 22, and the detection circuit 22 determines the control amount according to the level of the video signal by the photometric method instructed by the instruction section 26 provided on the front panel. It is calculated, and after passing through the filter 23, is output as a dimming control signal.

The dimming control signal is sent to the CPU 2 of the light source device 12.
5 and the difference signal corresponding to the dimming level instructed by the instructing unit 26 provided on the front panel of the light source device 12 is given to the motor 27, and the xenon lamp 14 and the lens 15 are supplied.
By controlling the diaphragm 30 placed approximately in the middle, the amount of light emitted from the tip of the scope 13 toward the subject is properly controlled.

[0007]

However, in the above-mentioned conventional example, the operator has switched the photometry method of peak photometry and average photometry by judging the display on the monitor. This imposes a heavy burden on the operator. Therefore, JP-A-5-16
Japanese Patent No. 4976 proposes a technique for switching the photometric method using a histogram of image data.

However, when a treatment tool called a cannula 41 is used as shown in FIG.
In the image when observing the stomach corner 42 as described above, the strong reflection from the cannula 41 and the stomach corner 42 is regarded as the same, and the processing is performed. Therefore, when the cannula 41 is used, dimming of the cannula 41 is performed. The reaction may darken the affected part in the background and may interfere with the operation of the treatment tool.

Although a plurality of types of light source devices can be used for the electronic endoscope device, the reaction speed of the aperture is different for each type of light source device. Therefore, the characteristics of the filter in the processor that optimizes the dimming control system differ depending on the type of light source. However, it is disadvantageous in terms of cost and circuit scale to have a filter for each type of light source in the processor.

Further, the response characteristic to the EE signal which is the control signal for the diaphragm shown in FIG. 14 (a) is such that the diaphragm opens as shown in FIG. 14 (b) compared to the speed in the closing direction of the diaphragm. There is also the drawback that the speed in the direction is slower.
For this reason, the light control operation is unnatural during observation.

The present invention has been made in view of the above circumstances, and prevents malfunction of dimming during observation by detecting a pattern of a subject and performing dimming control according to the characteristics of the image. It is an object of the present invention to provide an electronic endoscope that enables safe observation and treatment.

Another object of the present invention is to provide an electronic endoscope which enables stable dimming control by changing the calculation contents of dimming control according to the combined light source device.

Another object of the present invention is to provide an electronic endoscope having a good followability of a diaphragm by changing the calculation content of the dimming control according to the change of the amount of light emitted from the light source device.

[0014]

An endoscope apparatus according to the present invention is an endoscope including a light source means for supplying illumination light for illuminating a subject in a lumen and an image pickup means for picking up the subject. In the mirror device, based on an image pickup signal from the image pickup means, a light amount control amount calculation means for calculating a control amount for controlling the light amount of the illumination light supplied by the light source means, and the illumination based on the control amount. And a light quantity control means for controlling the light quantity of light, wherein the light quantity control quantity calculation means calculates the control quantity according to the type of the light source means, thereby preventing malfunction of dimming during observation. However, safe observation and treatment are possible.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 10 relate to a first embodiment of the present invention, FIG. 1 is a block diagram showing the configuration of an electronic endoscope apparatus, and FIG. 2 is a block diagram showing the configuration of the detection circuit of FIG. 3 is an explanatory diagram for explaining the block luminance average calculation circuit of FIG. 2, FIG. 4 is a pattern diagram showing a screen pattern stored in the ROM of FIG. 2, and FIG. 5 is a luminance distribution by the electronic endoscope apparatus of FIG. FIG. 6 is a configuration diagram showing the configuration of the filter of FIG. 1, FIG. 7 is a configuration diagram showing the configuration of the lag lead filter of FIG. 6, and FIG. 8 is a diagram of FIG. 7 is a characteristic diagram showing the characteristics of the LUT of FIG. 7, and FIG. 9 is the LUT of FIG.
FIG. 10 is a first explanatory diagram for explaining the operation of FIG.
It is a second explanatory diagram for explaining the action of.

As shown in FIG. 1, the electronic endoscope apparatus of the first embodiment has a processor 11, a light source device 12, and a scope 1.
It is composed of 3. A xenon lamp 14 and a lens 15 are provided inside the light source device 12, and the light emitted from the xenon lamp 14 is condensed by the lens 15 and passes through the light guide 16 to be emitted from the tip of the scope 13 toward a subject (not shown).

CCD arranged at the tip of the scope 13
17 is driven by a drive signal from a signal generation circuit (not shown) inside the processor 11, converts the subject image into an electrical video signal and outputs it. This video signal is sent to the processor 11
Correlation 2 in CDS (correlation double sampling circuit) 18
After the double sampling, the A / D converter 19 performs A / D conversion and the signal processing circuit 20 performs processing, and the D / A converter 2
In step 1, D / A conversion is performed and output to a monitor (not shown). This output can be displayed on a monitor, for example NTS.
It complies with the C standard.

The ROM 31 in the light source device 12 connected to the scope 13 stores ID data indicating the type of the light source device 12, which is stored in the CPU in the processor 11.
It is determined by 32. RO in the scope 13 to be connected
ID data indicating the type of the scope 13 is stored in the M33, and this is discriminated by the CPU 32 in the processor. Data based on these determination results is sent from the ROM (not shown) in the CPU 32 to the iris signal calculation means 34.

The iris signal calculation means 34 detects the video signal A / D converted by the A / D converter 19 by a method described later and calculates a dimming control signal according to the level of the video signal, and a detection circuit 41. The dimming control signal from the circuit 41 is input through the filter 42, and R (not shown) in the CPU 32 is input.
A non-linear conversion circuit 43 that performs non-linear conversion of the dimming control signal from the detection circuit 41 based on the data output from the OM.

The non-linearly converted dimming control signal is D / A
The CPU 25 of the light source device 12 is D / A converted by the converter 45.
Is input to the motor 27, and a difference signal corresponding to the dimming level instructed by the instructing unit 26 provided on the front panel of the light source device 12 is applied to the motor 27. 30 is controlled to properly control the amount of light emitted from the tip of the scope 13 toward the subject.

As shown in FIG. 2, the detection circuit 41 of the iris signal calculation means for calculating the dimming control signal outputs the video signal A / D converted by the A / D converter 19 to the block luminance average calculation circuit 51. input. The block luminance average calculation circuit 51 divides the signal for one screen into 16 blocks as shown in FIG. 3, and calculates the average luminance value for each block. Then, returning to FIG. 2, the output of the block brightness average calculation circuit 51 is output to the data calculation circuit 52, and this data calculation circuit 52 calculates the maximum value and the minimum value from the brightness average value for each block in FIG. value,
The average value, the median value, and the number of blocks belonging to the vicinity of the average value are calculated, and (1) the average value and the median value are compared in the buffer 53. Each data of the number of blocks belonging to is output.

On the other hand, a screen pattern as shown in FIG. 4 is previously stored in the ROM 54 as data, and the image pattern discriminating circuit 55 stores the screen pattern and the pattern of 16 blocks which is the output of the block luminance average calculating circuit 51. Comparison is made to determine what screen pattern the subject belongs to.

Then, stored in the buffer 53 (1)
The microcomputer 56 is based on the magnitude relationship between the average value and the median value, (2) the average value, the deviation of the median value, (3) the number of blocks belonging to the vicinity of the average value, and (4) the image pattern determined by the image pattern determination circuit 55. Determines and determines the coefficient k. The coefficient k is uniquely stored in advance in the ROM 57 with respect to the above four determination data, and the coefficient of the multiplier is controlled by the microcomputer. The values in the ROM 57 are controlled by the CPU 32, and the stored data is changed for each type of connected scope.

On the other hand, the video signal A / D converted by the A / D converter 19 has an average photometric detection circuit 5 for calculating the average amount of light.
8 and the peak photometric detection circuit 59 for calculating the peak light amount are also output, and the multiplier 60 multiplies the average light amount calculated by the average photometric detection circuit 58 from the microcomputer 56 by (1-k) times. The peak light amount calculated by the peak photometric detection circuit 59 is multiplied by k in the multiplier 61, and then added and output to the filter 42 as the detection circuit output. Note that FIG. 5 shows an example of the luminance distribution state and images belonging to it.

Next, the filter 42 of the iris signal calculation circuit 34 will be described.

As shown in FIG. 6, a detection circuit 41 in the iris signal calculation circuit 34 calculates a detection output corresponding to the video signal and outputs it to the filter 42. This output value is input to the multiplier 71 in the filter 42, and also to the low-pass filter (LPF) 72 and the 1-frame delay unit 73 that delays 1 frame. Then, the subtractor 74 subtracts the detection output from the LPF 72 output to obtain the deviation between the detection output and its average value. Further, the subtractor 75 subtracts the detected output and the output of the one-frame delay unit 73 to obtain the luminance change between frames.

Based on this deviation and the change in luminance, the control circuit 7
At 6, the coefficient of the multiplier and the time constant of the digital filter are calculated, and the control circuit 76 controls the multiplier 71 and the lag lead filter 77 by the coefficient of the multiplier and the time constant of the digital filter. The output of the multiplier 71 is passed through the lag lead filter 77 to the filter 4 of the iris signal calculation circuit.
2 output. Table 1 shows an example of control of the coefficient of the multiplier and the time constant of the filter depending on the deviation and the change in luminance. Where T
A is a deviation threshold value, and TB is a luminance change threshold value.

[0029]

[Table 1] Next, the lag lead filter 77 will be described.

As described above, the iris signal calculation circuit 3
A detection circuit 41 in 4 calculates and outputs a detection output according to the video signal. This output is input to the lag lead filter 77 shown in FIG. This lag lead filter 77 has the following characteristics.

[0031]

[Equation 1] Coefficients a and b that determine the characteristics of the lag lead filter
Is the ID from the ROM 31 in the connected light source device 12.
Depending on the type of the light source device 12 identified by the data,
The data is read from the ROM (not shown) in the CPU 32 in the processor 11 as data, supplied to the microcomputer and set. The coefficients a and b are constants for optimizing the dimming control system of the light source device, and are stored in advance as CP data in the processor 11
It is stored in a ROM (not shown) in U32.

The output of the lag lead filter 77 is used as a lookup table (LU
T) 43a performs non-linear conversion and becomes the output of the iris signal calculation means.

Here, the LUT 43a for nonlinear conversion
Has the characteristics as shown in FIG. 8, for example, and the characteristics of the conversion table can be rewritten depending on the type of the light source device 12.

The operation of the LUT 43a will be described. FIG. 9 shows the characteristics of the detection circuit 41 and shows that its output value is linear according to the value of the brightness of the screen. On the other hand, FIG. 10 shows the relationship between the dimming signal control amount of the light source device 12 and the irradiation light amount controlled by the diaphragm 30. In the small dimming signal range, the irradiation light amount corresponds to a slight signal change. Shows a non-linear characteristic that the change of the irradiation light amount is small with respect to a slight signal change in a large range of the dimming signal.

Therefore, in the LUT 43a having the conversion table as shown in FIG. 8, the output of the detecting means is non-linearly converted so that the relationship between the brightness of the screen and the irradiation light amount becomes linear. As a result, when the target brightness level of the screen is set to a high level by the light amount setting instructing unit 26 on the front panel of the light source device 12, the light amount change with respect to the change of the control signal increases and the dimming response speed improves. Further, when the brightness level is set to be low, the change in light amount is reduced and hunting is less likely to occur.

According to the filter 42, when the aperture opening direction and the light amount change are large, the gain of the detection output is increased and the time constant of the filter is reduced, which is the control signal of the aperture shown in FIG. 14 (a). For the EE signal, FIG.
As shown in (c), tracking of the aperture is improved.

The coefficient of this lag lead filter, L
The conversion table of the UT is read from the ROM in the processor according to the type of the light source device, but the present invention is not limited to this, and the lag lead filter for each type or individual light source device is stored in the ROM provided in the light source device. Coefficient, LUT
The conversion table of is stored and the RO in this light source device is stored.
Data may be read from M.

As described above, according to the electronic endoscope apparatus of the present embodiment, by adding the image pattern discrimination result to the parameter of the dimming control, even when a bright spot appears in the subject, for example, it is a cannula. It is possible to determine whether it is a corner of the stomach or another observation target, and for example, the problem that the dimming works properly for the cannula and the affected part to be treated becomes dark, and the optimal adjustment according to the observation target can be solved. Can do light.

Further, since the contents of the ROM in which the image pattern and the coefficient are stored are changed according to the scope to be connected, the difference in the position of the treatment tool and the angle of view appearing on the screen depending on the type of scope are taken into consideration. It is possible to control the amount of illumination light.

Although the coefficient k is obtained by using the microcomputer in this embodiment, fuzzy control using a membership function may be performed.

Next, the second embodiment will be described. Figure 11
FIG. 6 is a configuration diagram showing a configuration of a detection circuit according to a second embodiment. Since the second embodiment is almost the same as the first embodiment, only different configurations will be described, the same configurations will be denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 13, in the detection circuit 41a of the second embodiment, the A / D converted video signal is converted by the block luminance average calculation circuit 51 into a signal for one screen as shown in FIG. The blocks are divided into blocks, and the average value of the brightness for each block is calculated. Further, by the image pattern discrimination circuit 55, ROM is previously stored as data.
The screen pattern as shown in FIG. 4 stored in 54 and the 16-block pattern obtained here are compared to determine which screen pattern the subject belongs to.

Based on this judgment result, the microcomputer 56 determines the weighting coefficient k for the average value of the brightness of 16 blocks. The coefficient k is uniquely stored in the ROM in advance for the determination result of the image pattern, so that the coefficient of the multiplier is controlled by the microcomputer. These R
The value of OM is controlled by the CPU, and the stored data is changed for each type of connected scope. The average value Xi of the brightness of 16 blocks and the coefficient ki are multiplied by the multiplier 81 to obtain an addition average, which is used as the detection means output.

The image pattern weighting coefficient ki will be described below. Here, when the corner of the stomach is imaged, FIG.
(D), classified into image patterns as shown in FIG. 8 (e),
3e, f, g, h or d, g, h, j, k,
Set equal coefficients only for m and n blocks. Also,
When the cannula is used, the same pattern is set for blocks other than j and m in FIG. 7 classified into the image pattern shown in FIG. 8C.

Other configurations and operations are the same as those in the first embodiment.

As described above, according to the second embodiment, as in the first embodiment, the image pattern is discriminated and the dimming operation is performed based on this information. Therefore, the observation by the dimming control suitable for each image is performed. Is possible.

[0047]

As described above, according to the present invention, since the light amount control amount calculating means calculates the control amount according to the type of the light source means, malfunction of dimming during observation is prevented, and safety is ensured. There is an effect that various observations and treatments can be performed.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a configuration of a detection circuit of FIG.

FIG. 3 is an explanatory diagram illustrating a block luminance average calculation circuit of FIG.

4 is a pattern diagram showing a screen pattern stored in the ROM of FIG.

5 is an image / luminance distribution chart showing an example of an image belonging to the luminance distribution state by the electronic endoscope apparatus of FIG.

6 is a configuration diagram showing a configuration of the filter of FIG.

FIG. 7 is a configuration diagram showing a configuration of the lag lead filter of FIG.

FIG. 8 is a characteristic diagram showing characteristics of the LUT of FIG.

FIG. 9 is a first explanatory diagram illustrating an operation of the LUT of FIG.

FIG. 10 is a second explanatory diagram illustrating the operation of the LUT of FIG.

FIG. 11 is a configuration diagram showing a configuration of a detection circuit according to a second embodiment.

FIG. 12 is a configuration diagram showing a configuration of an electronic endoscope apparatus according to a conventional example.

FIG. 13 is an explanatory diagram for explaining light control by the conventional electronic endoscope apparatus of FIG.

FIG. 14 is a characteristic diagram for explaining a reaction characteristic of the diaphragm with respect to a control signal of the diaphragm.

[Explanation of symbols]

 11 ... Processor 12 ... Light source device 13 ... Scope 14 ... Xenon lamp 15 ... Lens 16 ... Light guide 17 ... CCD 18 ... CDS 19 ... A / D converter 20 ... Signal processing circuit 25, 32 ... CPU 26 ... Instruction unit 30 ... Diaphragm 31, 33 ... ROM 34 ... Iris signal calculation means 41 ... Detection circuit 42 ... Filter 43 ... Non-linear conversion circuit 45 ... D / A converter

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[Procedure amendment]

[Submission date] February 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

The image pattern weighting coefficient ki will be described below. Here, when the corner of the stomach is imaged, FIG.
(D), classified into image patterns as shown in FIG. 8 (e),
3e, f, g, h or d, g, h, j, k,
Equal weighting is applied only to m and n blocks ,
The light control is performed on the corner of the stomach. When the cannula is used, it is classified into the image pattern shown in FIG.
Weight the coefficients equal to blocks other than j and m in
Control the dimming of parts other than the cannula.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (1)

[Claims] 1. An endoscope apparatus comprising: a light source means for supplying illumination light for illuminating a subject in a lumen; and an image pickup means for picking up an image of the subject, based on an image pickup signal from the image pickup means. A light amount control amount calculation unit that calculates a control amount that controls the light amount of the illumination light supplied by the light source unit; and a light amount control unit that controls the light amount of the illumination light based on the control amount. The endoscopic device characterized in that the control amount calculation means calculates the control amount according to the type of the light source means.