JP2001154232A - Photometric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an easy-to-observe picked up image having no halation even in the case of picking up the image of a treatment tool. SOLUTION: A gate signal generation circuit 29 outputs a gate signal for performing peak photometry at a center part and average photometry at a periphery part in an image pickup range. A clip circuit 33 clips an inputted video signal only in terms of an average photometry area and gives it to an integration circuit 34. The circuit 34 integrates the video signal equivalent to a peak photometry area by a comparatively large coefficient and the video signal equivalent to the average photometry area by a comparatively small coefficient. Thus, little influence is exerted on photometric results by luminance by the treatment tool at the periphery part, and a high-luminance affected part at the center part can be observed with sufficient brightness by the peak photometry. Furthermore, when the existence of the treatment tool is shown by a color discrimination signal in the peak photometry area, a mask circuit 31 masks such a part. Thus, the photometry is not adversely influenced by the treatment tool in the peak photometry area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometric device suitable for an electronic endoscope device capable of automatic dimming.

[0002]

2. Description of the Related Art In recent years, a solid-state imaging device (CC)
2. Description of the Related Art Electronic endoscope apparatuses equipped with D) and projecting an observation image captured using a CCD on a television monitor by a video processor have become widespread. In an electronic endoscope device, a light source device for enabling a subject to be observed brightly and a light amount for irradiating the subject are automatically measured in order to easily observe a body cavity and perform a treatment. (Automatic dimming) function is indispensable.

In order to achieve an automatic light control function, an electronic endoscope apparatus conventionally has a built-in photometric circuit for calculating the brightness of a subject. The light amount is automatically adjusted by controlling the aperture of the light source device according to the brightness calculated by the photometry circuit.

As a photometric method, for example, Japanese Patent Publication No. 7-108
No. 278 discloses an average photometry method and a peak photometry method. The average photometry method adjusts the amount of light irradiated to the subject based on the average value of the reflected light from the subject, whereas the peak photometry method irradiates the subject based on the peak value of the reflected light from the subject. This adjusts the amount of light to be emitted.

The average photometry is an advantageous method when the output from the image pickup device is integrated to obtain an average value of the reflected light, and when the luminance distribution of the subject is uniform. In the average photometry method, a clipping circuit for clipping a video signal of a predetermined level or more is provided so that a region of interest can be prevented from being darkened by a high-luminance, small-area object such as a treatment tool. Provided.

However, when observing a prominent high-luminance subject such as a stomach angle, the halation occurs when the average photometry method is adopted. Therefore, in such a case, a peak photometry method is adopted.

[0007] The peak metering is for detecting the peak value of the output from the image sensor and controlling the light amount, and is used when the luminance difference of the subject is large. However, if a treatment tool is used when the peak photometry method is adopted, the entire screen becomes dark, and it becomes difficult to observe the region of interest.

That is, the peak photometry method is effective when there is an attention area in a high luminance portion of a subject having a large luminance difference, and the average photometry method is effective when the luminance distribution is uniform or when observation is performed using a treatment tool. It is.

[0009]

However, conventionally,
In the electronic endoscope apparatus, the observer has to perform observation while switching between the average photometry method and the peak photometry method according to the observation scene, and there is a problem that the usability is poor.

The present invention has been made in view of the above circumstances, and automatically switches and sets the peak photometry and the average photometry without requiring the observer to switch between the peak photometry and the average photometry. It is an object of the present invention to provide a photometric device capable of always performing observation in an optimal dimming state.

[0011]

According to a first aspect of the present invention, there is provided a photometric device for measuring the brightness of an image based on an image signal for displaying the image on a display device. Input means for inputting an image, an area dividing means for dividing an image displayed on the display device into at least a first area and a second area based on the image signal input from the input means, Based on the video signal corresponding to the first area divided by the dividing means,
A first photometry unit that performs photometry of the first area using a first photometry method, and the first photometry method based on a video signal corresponding to the second area divided by the area division unit. A second photometric unit that performs photometry using a different second photometric method, a luminance calculation unit that calculates the luminance of the video signal based on photometric results of the first photometric unit and the second photometric unit, and the display device A color identification unit for identifying a specific color from a video signal for displaying an image on a specific region; a specific region extraction unit for extracting a specific region having a specific color identified by the color identification unit; Input prohibiting means for prohibiting a video signal corresponding to the specific portion from being input to the first and second photometric means based on the specific area extracted by the extracting means. In claim 1 of the invention , Video signals inputted by the input means, by the region dividing means is divided into at least a first region and a second region on the display region. The first metering means measures a video signal corresponding to the first area by a first metering method, and the second metering means measures a video signal corresponding to the second area by a second metering method. I do. The brightness calculation means calculates the brightness of the video signal based on the photometry results of the first photometry means and the second photometry means, thereby enabling photometry utilizing the advantages of the first and second photometry methods. The color identifying means identifies a specific color from a video signal for displaying an image on a display device, and the specific area extracting means extracts a specific area having the identified specific color. For the video signal corresponding to this specific area, the input to the first and second photometric means is prohibited by the input prohibiting means,
The effectiveness of the photometry by the second photometry method is maintained.

According to a second aspect of the present invention, there is provided a photometric device for measuring the brightness of an image based on an image signal for displaying an image on a display device, the input means for inputting the image signal; Area dividing means for dividing an image displayed on the display device into at least a first area and a second area based on the image signal input from the input means; Based on the video signal, a predetermined area specified by the video signal is
A first photometric unit that performs photometry using the photometric method, and a second photometer that is different from the first photometric method based on the video signal that is input from the input unit. A second photometric unit that performs photometry by a method, a luminance calculating unit that calculates the luminance of the video signal based on photometric results obtained by the first photometric unit and the second photometric unit, and the area dividing unit. Switching means for selectively switching and outputting each of the divided video signals corresponding to the first area and the second area to each of the first light metering means or the second light metering means; .

According to a second aspect of the present invention, the first area divided by the area dividing means is measured by the first light measuring means using the first light measuring method, and the second area is measured by the second light measuring method. Is measured by a second photometric means using
The luminance calculating means calculates the luminance of the video signal based on the photometric results obtained by the first and second photometric means. The switching means selectively switches each of the video signals corresponding to the first area and the second area to the first photometric means or the second photometric means, and outputs the video signal, so that the validity of photometry is obtained. Plan.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 relate to a first embodiment of the present invention. FIG. 1 is a block diagram showing an electronic endoscope device in which a photometric device according to the first embodiment is incorporated. FIG. 2 is a photometric circuit in FIG. FIG. 3 is a block diagram specifically showing the configuration of FIG.
FIG. 4 is a waveform diagram for explaining the color detection circuit 25 in FIG. 4, FIG. 4 is an explanatory diagram for explaining the gate signal, and FIGS.
FIG. 6 is an explanatory diagram for explaining the operation of the embodiment, and FIG. 6 is a timing chart for explaining the operation of the first embodiment.

In this embodiment, the peak photometry and the average photometry are switched and set in accordance with the position and the color in the imaging range, so that the observer does not need to switch the photometry method.

As shown in FIG. 1, the electronic endoscope apparatus includes an electronic endoscope 1, a video processor 2, a light source device 3, and a television monitor 4. The electronic endoscope 1 has a flexible elongated insertion portion, and a CCD 6 is built in the distal end side of the insertion portion. An objective lens 5 is provided at the tip of the insertion section, and an optical image from a subject (not shown) is formed on the imaging surface of the CCD 6. The insertion section is provided with a forceps channel 8 for inserting a treatment tool such as forceps and a light guide 9 for transmitting illumination light from the light source device 3 and irradiating the object with the illumination light.

The light source device 3 includes a light source lamp 21, a rotary filter 22, an aperture 20, an aperture control circuit 19, and a brightness control button 23. The light emitted from the light source lamp 21 passes through a rotary filter 22 on which red (R), green (G), and blue (B) color transmission filters are attached, and the diaphragm 2
The light is guided to the light guide 9 through 0. Light guide 9
Transmits the incident light to the tip of the electronic endoscope 1 and outputs red,
Light of each wavelength of green and blue is sequentially emitted toward a subject (not shown).

The CCD driver 7 of the video processor 2
Outputs a drive signal for driving the CCD 6. This drive signal is transmitted to the CCD 6 via a signal line provided in the insertion section.
Supplied to Thus, the CCD 6 photoelectrically changes the optical image from the subject, and supplies the video signals of the R, G, and B fields to the analog processing circuit 10 of the video processor 2 via the signal lines in the insertion unit. .

The analog processing circuit 10 includes a preamplifier (not shown) for amplifying a CCD output signal, a CDS circuit for performing correlated double sampling, and the like. After amplifying the CCD output signal, the analog processing circuit 10 double-samples and holds. This CD
By the S process, 1 / f included in the output signal of the CCD 6
Noise and reset noise are removed, and a signal with an improved S / N ratio is obtained. The signal subjected to the CDS processing is A /
It is supplied to the D converter 11.

The A / D converter 11 converts an input signal into a digital signal. The output of the A / D converter 11 is supplied to a digital processing circuit 12. Digital processing circuit 12
Performs predetermined signal processing such as clamp processing, white balance processing, electronic zoom processing, gamma conversion processing, and edge enhancement processing on an input video signal, and then performs synchronization memories 14 a to 14 14c.

The outputs of the digital processing circuit 12 are R, G,
This is a time series signal of the B image signal. The selector 13 separates the sequentially input R, G, B image signals, and separates the R, G, B image signals.
Image signals are respectively stored in three-axis synchronization memories 14a to 14a.
output to c.

The three-axis synchronization memories 14a to 14c are:
By storing the R, G, and B image signals, respectively, and reading them out at the same time, plane-sequential images are synchronized, and the three-axis D /
Output to the A converters 15a to 15c. The three-axis D / A converters 15a to 15c respectively input R, G,
Converts B image signal into analog signal and converts it into 75Ω driver 1
6 The 75Ω driver 16 supplies an analog video signal to the television monitor 4. TV monitor 4
Are designed to display an image based on an input video signal.

The signal A / D converted by the A / D converter 11 is also supplied to a photometric circuit 17. Photometric circuit 17
Is controlled by the CPU 24 to calculate the brightness of the subject based on the input signal, and generate a dimming signal for controlling the aperture control circuit 19 of the light source device 3 based on the calculation result. .

Further, in the present embodiment, the photometric circuit 1
7, the output of the color detection circuit 25 is also supplied. The R, G, and B image signals are input to the color detection circuit 25 from the three-axis synchronization memories 14a to 14c. The color detection circuit 25 detects the luminance, hue, and saturation of the image from the values of the input R, G, and B image signals, and based on the detection result,
A color determination signal for determining whether or not to be a photometric object is output.

FIG. 3 is a waveform diagram for explaining the operation of the color detection circuit 25.

FIG. 3 shows a video signal for one horizontal period, and FIGS. 3A to 3C show R, G, and B signals, respectively. For example, forceps are nearly achromatic and have high brightness. Therefore, when the levels of the R, G, and B signals are r, g, and b, respectively, the color detection circuit 25 determines that r = g = b and that r, g, and b are equal to or greater than a predetermined level.
In the case of the broken line parts in (a) to (c), the input R,
The G and B signals are determined to correspond to the forceps portion.

The color detection circuit 25 outputs a color discrimination signal in order to exclude the forceps portion and the like from the object of photometry.
The color detection circuit 25 outputs a high-level (hereinafter, referred to as “H”) color discrimination signal during a period excluded from the photometry target, and a low-level (hereinafter, referred to as “L”) color discrimination during the photometry target period. Output a signal. The color discrimination signal is a photometric circuit 1
7 is supplied.

It should be noted that the color detection circuit 25 may perform color determination based on a color difference signal. In this case, the color detection circuit 2
Step 5 may detect a portion where RY, GY, and BY become almost zero.

The photometric circuit 17 uses the photometric result of the period indicated by the color discrimination signal as the photometric target period,
A light control signal is generated based on a comparison between the photometric result and the set value of the brightness control button 23 of the light source device 3. This dimming signal is provided to the D / A converter 18. The D / A converter 18
The dimming signal is converted into an analog signal and output to the aperture control circuit 19.

The stop control circuit 19 controls the stop 20 to output the light from the lamp 21 to the rotary filter 2.
The light amounts of the R, G, and B lights that have passed through 2 are adjusted. For example,
During the photometry target period, the brightness of the subject is compared by comparing the brightness of the subject calculated by the photometry circuit 17 with the set value of the brightness control button 23 provided on the front panel (not shown) of the light source device 3. If it is brighter, the aperture 20 is closed to reduce the amount of light irradiated on the subject. Conversely, if the photometric result is darker than the signal output from the brightness control button 23, the aperture 20 is opened to increase the amount of light to irradiate the subject.

FIG. 2 is a block diagram showing a specific configuration of such a photometric circuit 17.

In FIG. 2, the photometry circuit 17 has a programmable gate signal generation circuit 29. The gate signal generation circuit 29 generates a gate signal for setting a peak photometry area and an average photometry area in advance in the imaging range. For example, the gate signal generation circuit 29 sets the center of the imaging range to a peak photometry area, sets the periphery of the imaging range to an average photometry area, and sets a high level (peak photometry period) during a period corresponding to the peak photometry area (peak photometry period). Hereinafter, the gate signal is output at a low level (hereinafter, referred to as “L”) in a period (average photometric period) corresponding to the average photometric region.

A clip level setting signal is supplied from the CPU 24 to the photometric circuit 17. The clip level setting signal is determined by the CPU 24 based on a setting value of a brightness control button 23 to be described later, in order to exclude the brightness of a high-luminance, small-area object such as a treatment tool from the object of photometry. Has become.

The digital signal from the A / D converter 11 is
The signal is supplied to the clip circuit 33 via the mask circuit 31 and the sub-sampling circuit 32 of the photometry circuit 17. The sub-sampling circuit 32 performs sub-sampling of the input video signal and supplies the video signal to the clip circuit 33. The circuit scale can be reduced by subsampling.

The clipping operation of the clipping circuit 33 is controlled by a gate signal from the gate signal generating circuit 29. That is, the clipping circuit 33 clips the video signal at the level based on the clip level setting signal during the average photometry period in which the gate signal “L” is output, and
4 is output to the integrating circuit 34 without clipping the input video signal during the peak metering period in which the gate signal “H” is output.

The gate signal from the gate signal generation circuit 29 is also supplied to a coefficient output circuit 35. Coefficient output circuit 35
Outputs a relatively small coefficient during the average photometry period in which the gate signal is "L", outputs a relatively large coefficient during the "H" peak photometry period, and outputs the coefficient to the integration circuit 34. ing.

The integration circuit 34 converts the R, G, and B images sequentially output from the clipping circuit 33 into relatively small coefficients and gates during the average photometry period in which the gate signal "L" is output for each field. In the peak photometry period in which the signal “H” is output, integration is performed using a relatively large coefficient. The integration result is supplied to the luminance calculation circuit 36.

The luminance calculation circuit 36 calculates R,
The luminance of the subject is calculated based on the integrated output for each of the G and B fields. That is, the luminance calculation circuit 36 multiplies the integrated outputs of the R, G, and B fields by 0.30 and 0.59, respectively.
After multiplying by 0.11 and then multiplying by 0.11, the luminance of the subject is obtained.

During the peak photometry period in which the gate signal is "H", the A / D-converted video signal is directly supplied to the integration circuit 34 without being clipped, and is integrated by a relatively large coefficient. During the average photometry period in which the gate signal is “L”, the A / D-converted video signal is clipped and supplied to the integration circuit 34, where it is integrated by a relatively small coefficient.

Therefore, the photometric circuit 17 calculates the luminance from the output of the integrating circuit 34 and obtains the photometric result. The photometric result largely depends on the luminance at the center of the imaging range and the luminance of the high luminance portion in the peripheral portion. The video signal is clipped, and only the average brightness of the periphery is reflected in the photometric result.

Therefore, even when a treatment tool such as a forceps is imaged around the imaging range, the effect of the high luminance portion of the treatment tool on dimming is extremely small. By using an optical signal, it is possible to observe a high-luminance portion of a subject having a large luminance difference with sufficient brightness even at the time of observation using a treatment tool.

Further, in the present embodiment, the CDS signal from the A / D converter 11 is masked by the mask circuit 31 so as not to be reflected on the photometric result.
That is, the output of the gate signal generation circuit 29 is
Is also supplied. A color discrimination signal is also input to the AND circuit 30, and the AND circuit 30 obtains a logical product of two inputs and outputs the logical product to the mask circuit 31 as a mask signal.

The AND circuit 30 outputs a mask signal which becomes "H" only when both the gate signal and the color determination signal are "H". That is, when the mask signal includes, for example, a forceps portion or the like determined by the color detection circuit 25 to be excluded from the photometry target in the peak photometry region,
It becomes "H".

The mask circuit 31 converts the video signal input only during the “L” period of the mask signal into the sub-sampling circuit 3.
Output to 2. Thus, photometry is not performed during the “H” period of the mask signal.

The photometric result from the luminance calculation circuit 36 is supplied to the D / A converter 18 as a dimming signal. The D / A converter 18 converts the input dimming signal into an analog signal and supplies the analog signal to the aperture control circuit 19.

The light source device 3 is provided with a brightness control button 23 for controlling brightness in a plurality of steps on a front panel (not shown). A signal based on the operation of the brightness control button 23 by the observer is supplied to the CPU 24,
The PU 24 controls the aperture control circuit 19 using the brightness based on the input signal as a set value (not shown).

The aperture control circuit 19 controls the aperture 20 so that the brightness set by the CPU 24 based on the operation of the brightness control button 23 matches the brightness indicated by the dimming signal.

Next, the operation of the embodiment configured as described above will be described with reference to FIGS.

The insertion portion of the electronic endoscope 1 is inserted into a body cavity (not shown), and the illumination light from the light source device 3 is guided into the body cavity via the light guide 9 to illuminate the subject. Light source device 3
Is, for example, one rotation of the rotary filter 22 in a three-field cycle, and R in a field cycle (1/60 second).
(Red), G (green), and B (blue) illumination light are emitted.

The reflected light from the subject forms an image on the imaging surface of the CCD 6 via the objective lens 5 provided at the tip of the insertion section. The CCD 6 is a CCD driver 7 for the video processor 2.
, The optical image of the subject formed on the imaging surface is fetched in a frame-sequential manner and subjected to photoelectric conversion.

The video signal from the CCD 6 is subjected to predetermined preprocessing such as amplification and correlated double sampling by the analog processing circuit 10 of the video processor 2 and then subjected to A / D conversion.
It is supplied to the converter 11. The A / D converter 11 converts the input image signal into a digital signal and outputs the digital signal to the digital processing circuit 12 and the photometric circuit 17.

The video signal input to the digital processing circuit 12 is subjected to predetermined signal processing such as clamp processing, white balance processing, electronic zoom processing, gamma conversion processing and contour emphasis processing, and then to the synchronization memories 14a to 14a. It is supplied to 14c and a synchronization process is performed. Synchronized R,
The G and B image signals are returned to analog signals by the D / A converters 15a to 15c. D / A converters 15a to 15
The output of 5c is output to the television monitor 4 via the 75Ω driver 16.

The brightness of the endoscope image displayed on the display screen of the television monitor 4 is automatically adjusted according to the operation of the brightness control button 23 based on the photometry result of the photometry circuit 17. In the present embodiment, the gate signal generation circuit 29 in the photometry circuit 17 performs peak photometry in the center of the imaging range and generates a gate signal for performing average photometry in the periphery.

That is, the gate signal generation circuit 29 sets a peak photometry area at the center of the imaging range of the CCD 6 for obtaining the endoscope image 26 displayed on the display screen 27 of the television monitor 4 shown in FIG. The gate signal of “H” is output for setting the average photometry area.
Output the gate signal.

Now, it is assumed that the endoscope image 26 on the display screen of the television monitor 4 is as shown in FIG. In FIG. 5, the stomach angle is displayed at the center from the upper left to the lower right of the screen, and the forceps are displayed at the lower left of the screen. The portion enclosed by the broken line in FIG. 5 indicates the peak photometric region, and the other portions indicate the average photometric region. The forceps are in the average photometric area.

In this embodiment, the color detection circuit 25 detects whether or not a display such as forceps is present in the endoscope image 26. The color detection circuit 25 detects that the levels of the input R, G, and B signals are substantially equal and are equal to or higher than a predetermined level in the forceps portion, and detects that the forceps and the like are being imaged. . The color detection circuit 25 outputs an “H” color discrimination signal when a forceps or the like is detected.

The color discrimination signal and the gate signal are supplied to the AND circuit 3
Input to 0. The AND circuit 30 calculates a logical product of two inputs. In the example of FIG. 5, the color determination signal becomes “H” only at the timing corresponding to the portion outside the portion surrounded by the broken line. At this timing, the gate signal is "L" and A
The output of the ND circuit 30 is always "L".

Therefore, in the example of FIG.
Supplies the input video signal to the sub-sampling circuit 32 as it is. The video signal is thinned out by the sub-sampling circuit 32 and supplied to the clipping circuit 33.

A gate signal is also input to the clipping circuit 33. The clipping circuit 33 clips the video signal at the clip level set by the CPU 24 during a period corresponding to the average photometry area around the imaging range, and sets a peak at the center of the imaging range. During the period corresponding to the photometry area 24, the video signal is output to the integration circuit 34 without clipping.

As a result, even when the forceps are imaged around the imaging range, the high-luminance portion of the video signal by the forceps is clipped and does not affect light control.

The integrator circuit 34 converts the input signal into a large coefficient during the period when the gate signal “H” is output in units of fields and a small coefficient during the period when the gate signal “L” is output. Is integrated and output. Integration circuit 34
Is supplied to the luminance calculation circuit 36, and the luminance of the subject is calculated. The luminance calculation circuit 36 outputs the calculation result to the aperture control circuit 19 of the light source device 3 as a dimming signal.

On the other hand, the observer operates the brightness control button 23 provided on the light source device 3 to set the brightness of the endoscope image 26 to a desired brightness. A signal based on the operation of the brightness control button 23 is supplied to the CPU 24,
Sets the brightness based on the input signal in the aperture control circuit 19.

The aperture control circuit 19 is provided with a light control signal from the light measurement circuit 17, and the brightness based on the light control signal is C
The aperture 2 is adjusted to match the brightness set in the PU 24.
Control 0. That is, when the brightness of the subject given by the light control signal is brighter than the set brightness, the aperture control circuit 19 closes the stop 20 to reduce the amount of light radiated to the subject, and provides the light control signal. If the brightness of the subject is darker than the set brightness, the aperture 20 is opened to increase the amount of light irradiated on the subject.

As a result, the brightness of the subject is automatically adjusted to the brightness based on the operation of the brightness control button 23 by the observer. Since the peak photometry is performed at the central portion of the imaging range and the average photometry is performed at the peripheral portion, the dimming signal substantially depends on the peak photometry at the central portion of the imaging range, and the average photometry result at the peripheral portion of the imaging range is also reflected. .

That is, as shown in FIG. 5, even when the forceps are imaged around the imaging range, the effect of dimming due to the brightness of the forceps is small, and the observation site at the center of the imaging range does not become dark. . In addition, the stomach angle that causes halation in the average photometry is imaged in the center of the imaging range, so that optimal automatic light adjustment can be performed for the brightness of the subject, and the subject having a large difference in luminance can be sufficiently captured. It can be observed in brightness.

Next, it is assumed that the endoscope image 26 on the display screen of the television monitor 4 is as shown in FIG. Also in FIG. 7, a portion surrounded by a broken line indicates a peak photometric region,
The other part shows the average photometry area. In FIG. 7, the forceps are displayed extending from the average photometry area to the peak photometry area at the center of the screen.

FIGS. 6A to 6C show a color determination signal, a gate signal, and a mask signal in this case, respectively.

The "H" of the color discrimination signal corresponds to the position of the forceps, and is a gate signal indicating the peak photometry area (FIG. 6).
"B") and "H" in the color discrimination signal (FIG. 6A).
And overlap in some periods. As shown in FIG. 6C, the mask signal from the AND circuit 30 becomes “H” when both the color determination signal and the gate signal are “H”.

When the mask signal is “H”, the mask circuit 31 masks the video signal, and converts the video signal input only during the “L” period of the mask signal into the sub-sampling circuit 3.
Output to 2.

Therefore, photometry is not performed on the portion where the forceps is imaged in the peak photometry area. That is, the automatic dimming is not affected by the forceps imaged in the center of the imaging range, and optimal automatic dimming is possible.

As described above, in the present embodiment, the center of the imaging range is the peak photometry area and the periphery is the average photometry area, so that the observer does not need to switch between the average photometry and the peak photometry. Even when an image is taken, the observation site can be observed with sufficient brightness, and the operability is extremely excellent. In addition, even when the forceps and the like are imaged in the peak photometry area, since this portion is excluded from the photometry target, optimal automatic light control can always be performed.

The gate signal may be changed for each electronic endoscope by reading information of the electronic endoscope 1 from a setting storage circuit (not shown) provided in the electronic endoscope 1.

FIGS. 8 to 11 relate to a second embodiment of the present invention. FIG. 8 is a block diagram showing a video processor in which the photometric device of the second embodiment is incorporated. FIG. 9 is a photometric circuit 39 in FIG. FIG. 3 is a block diagram showing a specific configuration of FIG. FIG.
Is a flowchart for explaining the operation of the embodiment, and FIG. 11 is an explanatory diagram for explaining the operation of the embodiment. 8, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The video processor 28 of this embodiment employs a photometric circuit 39 instead of the photometric circuit 17 of the video processor 2 of the first embodiment, and omits the color detection circuit 25 and adds a photometric method determination circuit 38. This is different from the first embodiment.

A digital video signal is supplied from the A / D converter 11 to the photometric method determining circuit 38 and the photometric circuit 39. The photometric method determining circuit 38 determines a photometric method based on the input video signal. For example, if halation occurs due to the presence of a high-luminance observation site in the average photometry area, the photometry method determination circuit 38 detects an area where halation occurs from the input video signal, and It is determined that the area should be the peak metering area up to the area. The photometry method determination circuit 38 transmits the result of the determination to the photometry circuit 39 by a photometry method determination signal. Note that “H” of the photometry method determination signal indicates peak photometry, and “L” indicates average photometry.

FIG. 9 shows the photometric circuit 39. 9, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The photometric circuit 39 differs from the photometric circuit 17 of FIG. 2 in that the mask circuit 31 is omitted and an OR circuit 40 is used instead of the AND circuit 30.

The video signal from the A / D converter 11 is supplied to the clip circuit 33 via the sub-sampling circuit 32. The OR circuit 40 receives the gate signal and the photometric method determination signal. The OR circuit 40 calculates the logical sum of the two inputs and outputs the result to the clipping circuit 33 and the coefficient output circuit 35.
In addition, the gate signal indicates peak photometry at “H”,
“L” indicates average photometry.

The output of the OR circuit 40 becomes “H” during the “H” period of the gate signal and the photometry method determination signal. Therefore,
The peak photometry is performed not only in the area where the peak photometry is specified by the gate signal but also in the area specified by the photometry method determination circuit 38.

Next, the operation of the embodiment configured as described above will be described with reference to FIGS.

Gate signal generating circuit 29 of photometric circuit 39
Generates a gate signal for instructing peak photometry in the center of the imaging range and instructing average photometry in the periphery of the imaging range. As a result, when the power of the video processor 28 is turned on, the photometry method in the periphery of the imaging range is the average photometry (step S1 in FIG. 10). In the present embodiment, the A / D converter 11
The digital video signal from is input. In step S2, the photometry method determination circuit 38 detects a portion where halation occurs in the video signal in the periphery of the imaging range of any of R, G, and B fields (G field in this embodiment), The number of the pixels is counted. For example, assuming that the video signal level is 255 at the maximum,
It is determined that halation has occurred for pixels having the above video signal level, and the number of pixels is counted.

The photometric method determining circuit 38 determines in the next step S
At 3, the count value is compared with a threshold value M. This threshold value M is, for example, １ ／ of the number of pixels in the periphery of the imaging range.
If the count value is smaller than 1/3 of the number of peripheral pixels, the process returns to step S1 to maintain the average photometry method. In this case, the photometry method determination circuit 38 outputs an “L” output indicating average photometry to the photometry circuit 39 as a photometry method determination signal.

The OR circuit 40 of the photometric circuit 39 obtains the logical sum of the photometric method determination signal and the gate signal. Since the photometric method determination signal is “L”, the OR circuit 40 outputs the gate signal as it is. The gate signal is supplied to the clip circuit 33 and the coefficient output circuit 35. Accordingly, in this case, the photometric circuit 39 operates in the same manner as the photometric circuit 17 of FIG. 2 and adjusts the luminance calculation result obtained from the peak photometric result at the center of the imaging range and the average photometric result at the peripheral portion. Output as a signal.

Now, as shown in FIG.
It is assumed that the subject is projected only in the average photometric area in the peripheral portion of. In this case, there are many high-luminance pixels in the periphery of the imaging range. As a result, the count value exceeds the threshold value M, and the photometry method determination circuit 38 detects in step S3 that there are many pixels having halation in the peripheral portion, and changes the peripheral portion to peak photometry in step S4.

That is, the photometry method determination circuit 38 outputs a “H” photometry method determination signal to the photometry circuit 39. The OR circuit 4 of the photometry circuit 39 is output by the photometry method determination signal of “H”.
0 outputs “H” even while the gate signal is “L”. As a result, the photometric circuit 39 outputs a dimming signal based on peak photometry even in the periphery of the imaging range.

Next, in step S5, the photometric method determining circuit 38 determines the peak value of the video signal, and sets, for example, 60% of the peak value as the threshold value of the video signal. Note that the threshold value may be obtained from an average value instead of the peak value. Then
The photometric method determining circuit 38 counts the number of pixels at a level equal to or higher than the threshold value (step S6). In the next step S7, the photometry method determination circuit 38 determines whether to maintain the peak photometry method or return to the average photometry method based on the ratio of pixels having a level equal to or higher than the threshold to the peripheral area. For example, the photometry method determination circuit 38 maintains the peak photometry when the number of pixels having a level equal to or higher than the threshold value is more than 1/6 (= N) of the total number of pixels in the peripheral portion. Return to the average metering method.

The photometry method determination signal from the photometry method determination circuit 38 is supplied to a photometry circuit 39, and the photometry method in the periphery of the imaging range is determined.

As described above, in the present embodiment, even when a treatment tool such as forceps is used in the periphery of the imaging range, automatic dimming is not performed in accordance with the brightness of the treatment tool. Average photometry such as the stomach angle causes halation and makes it possible to perform optimal automatic dimming for the brightness of an object that is difficult to observe, and even when halation occurs in the periphery of the imaging range, The optimum automatic light control is performed by changing to the peak light measurement.

It is clear that the color detection circuit 25 may be applied to the present embodiment.

[Supplementary Notes] (1) In a photometric device that measures the brightness of an image based on an image signal for displaying the image on a display device,
A photometric unit that performs photometry of a predetermined area specified by the video signal based on a predetermined photometric method, and a color identification unit that identifies a specific color from the video signal for displaying a video on the display device, A specific region extracting unit that extracts a specific region having a specific color identified by the color identifying unit; and a video signal corresponding to an outer specific portion based on the specific region extracted by the specific region extracting unit. 1. A photometric device, comprising: input inhibiting means for inhibiting input to the second photometric means.

[0091]

As described above, according to the present invention, there is an effect that the observation can always be performed in an optimal dimming state without the observer switching between peak photometry and average photometry.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electronic endoscope apparatus in which a photometric device according to a first embodiment of the present invention is incorporated.

FIG. 2 is a block diagram specifically showing a configuration of a photometric circuit in FIG. 1;

FIG. 3 is a waveform chart for explaining a color detection circuit 25 in FIG. 1;

FIG. 4 is an explanatory diagram for explaining a gate signal.

FIG. 5 is an explanatory diagram for explaining the operation of the first embodiment.

FIG. 6 is a timing chart for explaining the operation of the first embodiment.

FIG. 7 is an explanatory diagram for explaining the operation of the first embodiment.

FIG. 8 is a block diagram showing a video processor in which the photometric device according to the second embodiment is incorporated.

FIG. 9 is a block diagram showing a specific configuration of a photometric circuit 39 in FIG. 8;

FIG. 10 is a flowchart for explaining the operation of the embodiment.

FIG. 11 is an explanatory diagram for explaining the operation of the embodiment;

[Description of Signs] 1 ... Electronic endoscope, 2 ... Video processor, 3 ... Light source device, 4 ... TV monitor, 6 ... CCD, 10 ... Analog processing circuit, 17 ... Photometry circuit, 25 ... Color detection circuit, 19 ...
Aperture control circuit, 20 ... Aperture, 23 ... Brightness control button,
24 ... CPU.

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[Procedure amendment]

[Submission date] December 8, 1999 (1999.12.
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction contents]

A gate signal is also input to the clipping circuit 33. The clipping circuit 33 clips the video signal at the clip level set by the CPU 24 during a period corresponding to the average photometry area around the imaging range, and sets a peak at the center of the imaging range. During the period corresponding to the photometry area, the video signal is output to the integration circuit 34 without clipping.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takayuki Hanawa, Inventor 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industry Co., Ltd. (72) Tatsuhiko Suzuki 2-43-2, Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Katsuichi Imaizumi, Inventor Katsuichi Imaizumi 2-43-2 Hatagaya, Shibuya-ku, Tokyo F-term (reference) 2H002 DB02 DB06 DB14 DB17 DB23 JA13 4C061 AA01 BB02 CC06 DD00 FF40 GG01 NN01 NN05 QQ09 RR02 RR15 RR22 RR23 RR30 TT01 WW02 XX01

Claims (2)

[Claims] 1. A photometric device that measures the brightness of an image based on an image signal for displaying the image on a display device, wherein: an input unit that inputs the image signal; Area dividing means for dividing at least into a first area and a second area; and a first photometry based on a video signal corresponding to the first area divided by the area dividing means. A first light metering unit that performs light metering by a method, and a second light metering method that is different from the first light metering method based on a video signal corresponding to the second area divided by the area dividing unit. 2 photometric means, luminance calculating means for calculating the luminance of the video signal based on photometric results of the first photometric means and the second photometric means, and a video signal for displaying video on the display device. Specific from inside A color identification unit that identifies a color; a specific region extraction unit that extracts a specific region having a specific color identified by the color identification unit; and the identification based on the specific region extracted by the specific region extraction unit. An input prohibiting unit that prohibits a video signal corresponding to a part from being input to the first and second photometric units. 2. A photometric device for measuring brightness of an image based on an image signal for displaying an image on a display device, wherein: an input unit for inputting the image signal; Area dividing means for dividing into at least a first area and a second area; and, based on the video signal input from the input means, photometry of a predetermined area specified by the video signal by a first photometry method A first photometric unit that performs photometry using a second photometric system different from the first photometric system based on the video signal input from the input unit, based on the video signal. 2 is divided by the area dividing means; a luminance calculating means for calculating luminance of the video signal based on photometric results obtained by the first and second photometric means; Switching means for selectively switching and outputting each video signal corresponding to the first area and the second area to each of the first light metering means or the second light metering means. A photometric device, characterized in that: