JPS6380691A - Image pick-up device - Google Patents

Abstract

PURPOSE:To obtain a suitable white balance for both the illumination by surrounding light and of a auxiliary lighting device by measuring the hue of the surrounding light, and lighting a subject by the light of the same hue as that of the surrounding light, generated by the lighting device. CONSTITUTION:The luminance of the subject is measured by a photometer circuit 8, and if the surrounding light of the subject is not so weak as it can be neglected, because the influence of the color of the light lighting the subject can not be neglected, an arithmetic operation/control circuit 11 measures the hue of the light lighting the subject through a colorimetric circuit 9. Next, on the basis of the colorimetry value, the arithmetic operation/control circuit 11 sets the white balance of a signal processing circuit 6 and color temperature (absolute temperature) of the light source 10. Next, it makes the light source 10 light and adjusts the brightness of the light source 10, then it executes a photographing operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device, and particularly to a photoelectric conversion type imaging device that is often used together with a subject illumination device.

[Conventional technology]

The sensitivity of the image sensor used in conventional imaging devices of this type cannot be said to be sufficient for all imaging conditions. This compensated for the element's lack of sensitivity. Furthermore, illumination light has also been used as auxiliary light to soften the shadows appearing on the subject.

(Problems to be Solved by the Invention) However, when preparing illumination light specifically for JMJi as described above, the following precautions were required. In other words, if the hue of the prepared illumination light is significantly different from the hue of the ambient light that is illuminating the subject, a white balance (white balance) 2 that is suitable for both is used.
This has the disadvantage that the reproduced image has an unnatural color tone as a result.

To deal with such problems, it is sufficient to prepare a light source that matches the hue of the illumination light of the subject, but in general, the types of light sources that can be practically prepared are quite limited. Therefore, not all of them have excellent portability and good luminous efficiency, and there is a problem that there are not necessarily many cases in which they can be effectively applied.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an imaging device that can obtain an appropriate white balance for both the original ambient light of the subject and the illumination of an auxiliary lighting device. The purpose is

(Means for Solving the Problems) Therefore, in the present invention, a light source capable of continuously varying the hue and a colorimetric circuit are provided to measure the hue of ambient light without a lighting device, and to measure the hue of ambient light without a lighting device. This object is achieved by configuring a lighting device to generate light of different hues to illuminate a subject.

[Effect]

With the above configuration, it is possible to obtain a reproduced image that reproduces natural colors with an appropriate white balance for both the original ambient light of the subject and the illumination light from the illumination device used.

(Example〕 The present invention will be explained below based on examples.

(Circuit Configuration) FIG. 1 shows an electric circuit block diagram showing an embodiment of a photoelectric conversion imaging device according to the present invention. 1 is an optical system for forming a subject image on the image sensor 4, and includes an optical lens and the like. 2a and 2b are respectively an aperture and its driver;
3a and 3b are a shutter and its driver, respectively. Reference numeral 4 denotes an image sensor for converting a subject image into an electrical signal, and may be, for example, an image pickup tube, a CCD (charge-coupled device), an MO3 type solid-state image sensor, or the like.

5 is a driver for driving the image sensor 4; 6 is a signal processing circuit for converting the electric signal read out from the image sensor 4 into a specified video signal; 7 is a driver for driving the image sensor 4; , magnetic tape, magnetic disk, etc.). Further, 8 is a photometric circuit for measuring the brightness of the subject, and 9 is a color embellishing circuit for measuring the hue of the light illuminating the subject. No. 10 indicates that the subject brightness is insufficient, and as will be described later, the hue (color temperature) of this light source can be adjusted. Reference numeral 11 denotes an arithmetic/control circuit for inputting signals from various parts of the imaging apparatus, performing various calculations and determinations, and controlling each part. Also, 1
2 is a clock circuit that determines the operation timing of each part;
13 is a power switch, and 14 is a release switch for the photographer to specify the shooting timing.

The photometric circuit 8, as shown in FIG. 2, can be easily constructed using a known circuit. In FIG. 2, 21 is an operational amplifier, and 22 is, for example, a silicon
The light-receiving element 23 is a diode, such as a photodiode, whose short-circuit current is proportional to the intensity of light irradiating the light-receiving element. In this circuit, the voltage generated at the output terminal 0 of the operational amplifier 21 is: k: Boltzmann constant T: ambient temperature (absolute temperature) q: charge of one electron 13: reverse saturation current of the diode 23, that is, the photometric output voltage Since v0 is proportional to the natural logarithm of the received light intensity, it increases by 18 mV every time the brightness of the subject (the received light intensity of the oc photometry circuit 8) doubles. Therefore, the subject brightness can be determined by measuring the output voltage.

The embellishing circuit 9 in FIG. 1 can be realized by a known circuit configuration as shown in FIG. 3. In Figure 3, 31
is a diffuser plate, 32, 33, and 34 are color filters that transmit only each color, for example, red (R), edge (G), and blue (B), and 35, 36, and 37 are color filters. , are photometric circuits similar to those shown in FIG.

In this circuit, if we take the difference between the outputs of the optical circuits 35 and 36 on both sides, we can find the ratio between the ¥Q (G) component and the red (R) component of the light incident on the embellishing circuit 9. .

Similarly, if we take the output difference between the optical circuits 36 and 37 on both sides, we can find the ratio between the line (G) component and the blue (B) component of the light incident on the embellishing circuit 9.

Thus, the red (R) component of the incident light: edge (G) component: blue (B) component---(5
), the hue of the incident light can be determined.

(81 Image Operation) Next, regarding the case of imaging using an illumination device that generates temporally continuous light, such as an illumination lamp, for example,
This will be explained based on the photographing operation sequence flowchart shown in FIG.

First, when the power switch 13 (FIG. 1) is turned on, the imaging device starts operating (step S1), and the photometry circuit 8
The brightness of the subject is measured (step S2). Then, it is determined in step S3 whether or not the brightness of the subject is below the specified value, and if it is below the specified value (YES),
Since the light illuminating the subject from the surroundings is so dark that it can be ignored, photography is performed using the illumination of the light source 10.

Therefore, the white balance is set to the color temperature that maximizes the luminous efficiency of the light filO, and the light source 10 is set to the mode that maximizes the luminous efficiency (step S4).
! ; Lights up jlO (step S5). Next, the photometric circuit 8 measures the subject brightness again in step S6.
), it is determined whether the imaging device is within the range where 11 images can be taken (step S7). At this time, if the shooting range of the imaging device is exceeded (too bright/too dark), the light source l
Adjust the luminous intensity of O (step S8) and repeat step S6
Return to and determine the brightness of the lighting. When the illumination of the light source 10 for the subject becomes appropriate (step S7, YES)
Then, the release switch 14 (FIG. 1) is operated (step 517).

When the release switch 14 is operated (step S17
, YES), First, the calculation/control circuit 11 narrows down the aperture 2a via the aperture driver 2b (step 818).
. After that, the arithmetic/control circuit 11 drives the shutter 3a via the shutter driver 3b, so that the shutter 3a opens for a predetermined period of time and exposes the image sensor 4 (step 519). Hey, comparison 2a here.
The aperture value and the exposure time of the shutter 3a are calculated by the calculation/control circuit 11 in step S6 based on the subject brightness information manually inputted via the photometry circuit 8.

After the exposure is completed as described above, at an appropriate timing, the subject image on the image sensor 4 is read out as an electrical signal and converted into a specified video signal by the signal processing circuit 6 (step 320), and then the recording circuit 7 is recorded on the recording medium (step 521), and the photographing operation is ended (
Step 522).

Next, in step S3 in FIG. 4, a case will be described in which the photometry result in step S2 indicates that the ambient light around the subject is not so weak that it can be ignored (step S3, No). In this case, since the influence of the color of the light illuminating the subject cannot be ignored, the calculation/control circuit 11 measures the hue of the light illuminating the subject via the photometry circuit 9 (step 510).
. Next, based on this embellishment value, the arithmetic/control circuit 11
is the white balance of the signal processing circuit 6 and the light source 10
The color temperature (absolute temperature) of is set (step 511).

Next, based on the photometric value obtained in step S2, it is determined whether the brightness allows photographing without the aid of the light source 10 (step 512). If the photograph cannot be taken without the aid of the light source 10 (NO), the light source 10 is turned on (step 513). Then, in a loop of steps S14 to S16, the brightness of the light source 10 is adjusted in the same process as steps 55 to S7 until it falls within the range that the imaging device can take, and then, in steps S17 to S21, the brightness of the light source 10 is adjusted. perform an action. In this case, each parameter value of the aperture 2a and the shutter 3a becomes a value calculated by the calculation/control circuit 11 using the photometric value in step S14.

Furthermore, as a result of the determination in step S12, the light source 10
If the brightness is such that it can be photographed without the help of (No), the process immediately jumps to step S17, and the photographing operation is executed in steps S17 to S21. In this case, the aperture 2a and shutter 3a
Each parameter value is a value calculated by the calculation/control circuit 11 based on the photometric value in step S2.

(How to set the color temperature of the light source) Next, a method for setting the color temperature of the light source 10 will be explained.

5 and 6 are detailed views of the hue (color temperature) variable light source, respectively.

In FIG. 5, 41 is a light source whose only brightness (luminous intensity) changes depending on the voltage applied between electrodes A and B;
2.43.44 are respectively red (R) and green (G).
, is a blue (B) color filter, and 45
．． Reference numerals 46 and 47 indicate colorless filters whose transmittance changes depending on the electrical signals applied to the electrodes C, D, and H, respectively.

In the light source shown in FIG. 5 having the above configuration, adapting the color temperature of the light source 10 to the embellished color value of the surrounding light of the subject means adjusting the transmittance ratio of each filter 45, 46, 47. This is done by adjusting the intensity ratio of red, green, and blue light according to
and 516) are adjusted by the voltage applied between the voltages ViUA and B.

Note that when the intensity of the ambient light is high, as in step S3 of FIG. 4, YES, each filter 42 in front of the light source 41
．． 43, ...-147 are all removed, and the light source 41
If the object is directly irradiated with the light, there will be no attenuation of the light by the filters 42 to 47, resulting in extremely high efficiency. In this case, the white balance of the imaging device is adjusted to that of the light source 41. This data may be input manually from the light source 10 to the arithmetic/control circuit 11 in a memory area of the arithmetic/control device 11 (FIG. 1).

Next, FIG. 6 is an explanatory diagram of another method for changing the hue of the light source 10. In the figure, 51.52.53 is
Each is an independent light source whose emission brightness changes by changing the voltage applied to each electrode A, B, and C, and
54.55.56 are red (R) and green (G), respectively.
), which is a blue (B) color filter. In the case of the light source shown in FIG. 6 having the above configuration, the ratio of the voltages applied to each T1 pole A, B, and C changes the red, green, and blue of the light that has passed through each color filter 54, 55, and 56, respectively. Light control is performed by adjusting the component ratio (color temperature) of the light and increasing the absolute value of the voltage applied to each electrode A, B, and C.

In addition, in the two examples of FIG. 5.6 explained above, in the case of FIG. are illuminated together and the hue (color temperature) fA is determined using the two colors.
When the filters 43 and 46 are adjusted, attenuation of the light is small, and hue adjustment is also possible.

In this regard, the same effect as shown in FIG. 6 can be obtained by omitting the color filter 55.

If it is desired to further simplify the light source, for example, the color of the light source 41 or 52 may be made closer to cyan, and the transmittance or brightness of the filter 45 or the light source 51 may be adjusted. In this case, the color filters 43 and 44 in FIG. 5 can be omitted and only one filter 46 and 47 can be used. Also, the 6th
In the figure, the color filters 55, 56 and the light source 53 can be omitted.

Also, without simplifying the above, in Figure 5.6,
Color filters 42 and 54 are magenta filters, color filters 43 and 55 are cyan filters, and color filters 44.
It is also possible to omit the light source 56 and the light source 53.

Further, in the case of FIG. 6, when a color light source is used as each light source 51, 52, the light source 53 and each color filter 54.
It is also possible to omit 55.56.

(Other imaging operations) Next, a case will be described in which imaging is performed using an illumination device that generates pulsed light, such as a strobe.

FIG. 7 shows an example of a photographing operation sequence flowchart in such a case. In this case as well, the electric circuit etc.
This can be realized by what is shown in FIG. That is, first, when the power switch 13 is turned on, this imaging device starts operating (FIG. 7, step 561), and the photometry circuit 8
The subject brightness is measured (step 562). Then, it is determined whether the brightness of the subject is below a predetermined value (step 563). If the result is less than the predetermined value (YES), the light illuminating the subject from the surroundings is so dark that it can be ignored. The arithmetic/control circuit 11 sets the value assuming that the lighting is performed under the conditions.
The white balance of the signal processing circuit 6 is set (step 564). On top of that, the parameter X that determines the case
is set to 0 (step 565).

Then, the process waits for the series switch 14 (FIG. 1) to be operated and performs step S66 (No). and,
When the release switch 14 is operated (step S66
, YES), then the case discrimination parameters are determined (step 567). In this case, since X=0, the process jumps to step 568 and sets the color temperature of the light source 10 to the maximum efficiency of the light source 10. Then, for example, 2a is narrowed down compared to the value specified by the light source 10 (step 569
), the shutter 3a is opened (step 570), and the light source 10
emits light (step 571), and after the light emission stops,
The shutter 3a is closed (step 372), and then m
The object image information is read out from the electronic element 4 in the form of an electric signal, and the signal processing circuit 6 converts it into a predetermined video signal (Step 573).The recording circuit 7 records it on the recording medium (Step 574). Ends the shooting operation.

If the ambient light has a non-negligible intensity in step S63 (step S63, No), the color temperature of the ambient light is first measured by the colorimetric circuit 9 (step 876). Based on this colorimetric value, the white balance of the signal processing circuit 6 is set (step 577).

Next, based on the colorimetric values in step S62, it is determined whether photography can be performed without the aid of the light source 10 (step 378).
). If it is determined that Ji shadow cannot be captured without the assistance of the light source 10 (No), set the value of the case determination parameter ), case discrimination parameter X
The value of is set to 1 (step 579), the release switch 14 is expected to be operated (step 566), and when the release operation is performed, the next operation is determined based on the value of the discrimination parameter X.

In this case, since X = 1 and the influence of ambient light cannot be ignored,
The color temperature of the light source 10 is set to match the color temperature of the ambient light (step 580). From then on, steps 369 to S75 are executed in exactly the same way as when x=0.

In step S78, if it is determined that photography is possible without the assistance of the light source 10 (YES), the case determination para rotor Determine some case discrimination parameter X (
step 567).

In this case, since X=2, the process jumps to step S83 and uses the photometric value in step S62 to narrow down the dust 2a to the parameter value calculated by the calculation/control circuit 11 (step 583), and drives the shutter 3a. (Step 584
) After exposure, the photographing operation is executed in steps S73 to S75, just as in the case of X=0.1.

Here, the configuration of the light source 10 includes each light source 41.
By changing 51, 52, and 53 from a continuously lit light source such as a lamp to a flash discharge tube, it is possible to maintain the configuration shown in FIGS. 5 and 6.

Furthermore, the efficiency can be improved by omitting each of the filters 46, 43, and 55, just as in the case of the continuously lit light source.

(Effects of the Invention) As described in detail above, according to the present invention, when there is no ambient light around the object, the illumination light source for the imaging device can be used with maximum efficiency, resulting in less waste. In addition, when ambient light cannot be ignored, by using the variable hue light source that comes with the imaging device that matches the ambient light, the photographer can adjust both the ambient light and the light source that comes with the imaging device without any additional operations. , it is now possible to obtain reproduced images with a well-balanced white balance and good hue reproducibility.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit block diagram of an embodiment of an imaging device according to the present invention, FIG. 2 is a photometric circuit diagram thereof, FIG. 3 is a colorimetric circuit diagram, and FIG. 4 is a photographing operation sequence of this embodiment. Flowcharts, FIGS. 5 and 6 are two examples of the light source of the present invention, and FIG. 7 is a sequence flowchart of another imaging operation. 8.-1 Photometric circuit 9-.-Colorometric circuit 32.33.34:42,43,44:54゜5
5.56---Color filter

Claims (6)

[Claims] (1) An imaging device that uses a subject illumination device is equipped with a colorimeter for measuring the hue of ambient light of the subject other than the illumination light of the illumination device, and a hue adjustment device is provided in the light source of the illumination device. An imaging device comprising: a color measuring device configured to match the hue of illumination light generated from the illumination device light source to the hue of the ambient light based on the colorimetric value obtained by the colorimetric means. (2) The imaging device according to claim 1, characterized in that the white balance of the imaging device is adjusted to match the hue of the ambient light and the illumination light adapted thereto. (3) The operation for adapting the hue of the illumination light of the lighting device to the ambient light is performed only when the intensity of the ambient light is greater than or equal to the predetermined value, and the intensity of the ambient light is equal to or greater than the predetermined value. In the following case, the lighting efficiency of the lighting device is set to the best condition, and the white balance of the imaging device is configured to match the hue of light emitted by the lighting device under the above conditions. The imaging device according to the range 1 or 2. (4) The lighting device is composed of a plurality of light emitting sections each having a different hue, and is configured to change the color of light emitted from the lighting device by changing the relative luminous intensity of each light emitting body of each light emitting section. An imaging device according to claim 1, characterized in that: (5) The means for changing the color of light emitted from each light emitting section is
Claim 4, characterized in that this is performed by changing the hue of each of the light emitters themselves or by changing the spectral transmission characteristics of each color filter disposed in front of each of the light emitters. The imaging device described in Section 1. (6) The imaging device according to claim 1, wherein the illumination device includes a single light emitting unit whose hue can be changed from the outside.