JPH03291091A - Image pickup device - Google Patents

Abstract

PURPOSE:To attain accurate white balance control by comparing pickup outputs on a prescribed position on a pattern resulting from an image pickup output sampled by a controller and applying white balance depending on the result of comparison. CONSTITUTION:An output signal R-Y from a differential amplifier 6 is inputted to a sample-and-hold circuit 19-1 of a switch control signal leadout section 17. The circuit 19-1 samples the R-Y signal for H period of sample hold pulses SHP1-4 of a pulse generating circuit 18 and introduces a signal whose level is held for other periods. That is, when an output of the section 17 goes to H according to the output of a NOR gate NR 3, switches 15, 16 are connected to the external measurement system side being the 2nd white balance adjustment device. Moreover, when the output of the NOR gate NR 3 is L, the TTL system side being the 1st white balance adjustment device is connected to compare image pickup outputs at a prescribed position on the pattern obtained by sampling the image pickup outputs thereby implementing white balance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device, and particularly to an imaging device having a white balance adjustment means.

[Conventional technology]

Conventionally, the first white balance adjustment device for an imaging device! There are two methods: the external measurement method, in which white balance is adjusted using the output signal of an external colorimetric sensor, as shown in the figure, and the through-the-tons method (hereinafter referred to as TTL), in which white balance is adjusted by the output direction of the image sensor, as shown in Fig. 12. method)
is known. The following example will be explained using FIGS. 11 and 12.

Figure 11 is a block diagram of a conventional example of the outside method.51
A solid-state image sensor is an imaging device that converts optical information into electrical signals. 2 is a luminance ring signal processing unit that processes the output of the image sensor 1 and performs appropriate processing to derive a luminance signal Y; 3 is the image sensor 1;
A chroma signal processing unit (hereinafter referred to as a chroma signal processing unit) performs appropriate processing on the output of and derives a low-range luminance signal YL1 color signals R and B. Reference numerals 4 and 5 denote an R gain control section and a B gain control section that respectively control the levels of the outputs R and B of the chroma signal processing section 3 and output R1 and Bl. 6 is a differential amplifier that derives a color difference signal RY from Y and R1.

7 is a differential amplifier that derives a color difference signal B-Y from Yl and B. 8 is the color difference signal R-Y and B-Y from NTSC,
A modulation unit that derives a modulation signal specified by PAL, etc. 9
is an adder that derives a predetermined video signal from the output Y of the luminance signal processing section 2 and the output of the modulation section 8. 10 is a color temperature sensor which is a colorimetric sensor other than the image sensor that measures the color temperature of the light source illuminating the subject; 11 is an amplifier for the R gain control section 4s5 and the B gain control section 5 based on the output of the color temperature sensor 10; This is a control voltage derivation unit that derives a voltage for controlling the gain.

The operation will be explained below with reference to FIG.

A luminance signal processing section 2 derives a Y signal from the output of the first image sensor, and a chroma signal processing section 3 derives YL and R signals.

get B. Then, the color temperature of the light source illuminating the subject is measured by the IO color temperature sensor, and the control voltage deriving unit 11 outputs the color temperature to the R gain control unit 4 and the B gain control unit 5 in order to correct the white balance. A control voltage is derived, and color signals R, , B whose white balance has been adjusted by an R gain control section 4 and a B gain control section 5 are obtained. Below, differential amplifier 6.7. A modulator 8 and an adder 9 derive a predetermined video signal whose white balance has been adjusted from Y, YL, Rr, and B+.

Next, FIG. 12 is a block diagram of a conventional example of the TTL system, in which blocks 1 to 9 correspond to blocks with the same numbers in the conventional example of FIG.
-Y, BY It is an averaging section such as a low-pass filter that averages the signals and converts them into DC potential. Reference numeral 14 denotes a control voltage deriving section that outputs an slI control voltage to be applied to the R gain control section 4 and the B gain control section 5 in order to correct the white balance from the signals averaged by the averaging sections 12 and 13.

The operation will be explained below.

The operations of blocks 1 to 9 are similar to the conventional example shown in FIG. Then, the R-Y and B-Y signals averaged over one screen or several screens in the averaging section 12.13 are compared with a specific potential corresponding to the zero level of the color difference signal in the control voltage deriving section 14. , determines whether the level is lower or higher than the zero level, and derives a control voltage for making the RY and BY levels the closest to the zero level. Then, this control voltage is input to the R-B gain control section 4.5 to perform white balance adjustment.

In addition to the above two methods, an example of an addition method that combines the external measurement method and the TTL method is known.

FIG. 13 is a block diagram showing an example of the addition method.

In the figure, blocks 1 to 14 are shown in FIG.
This corresponds to the blocks with the same numbers in the conventional example shown in FIG. Note that hereinafter, 14 will be referred to as a first control voltage deriving section, and 11 will be referred to as a second control voltage deriving section. And 27.28 is the first
This is an adder that adds the control voltage obtained by the control voltage deriving section 14 and the control voltage obtained from the second control voltage deriving section 11 at a constant ratio. Then, white balance adjustment is performed using this added voltage.

That is, in this conventional example, by adding at a constant ratio both control voltages obtained from the signal 1υ from the image sensor 1 and the signal from the color temperature sensor, which is the colorimetric sensor 10 other than the image sensor, It is configured to perform good white balance adjustment.

In addition, Japanese Patent Application Laid-Open No. 63-3144 filed by the applicant
Publication No. 24 detects the amount of light incident on the color sensor,
There is also a description of adjusting the white balance by selectively selecting two color measurement methods depending on the detection method.

(Problems to be Solved by the Invention) However, in the conventional example described above, the external measurement method shown in FIG. At sunset, etc., the accuracy of white balance adjustment decreases significantly.

In addition, with the TTL method shown in Figure 12, when the subject is a large area of chromatic color, or when most of the screen is occupied by a single color, the accuracy of white balance adjustment may deteriorate. Put it away.

On the other hand, in the addition method shown in FIG. 13, in order to compensate for the shortcomings of the above two conventional examples, the accuracy is improved by simply adding the control voltages derived by the external measurement method and the TTL method. However, by adding them in the opposite direction, the accuracy of white balance adjustment for each scene is reduced, which is a drawback. In addition, JP-A-6
The example shown in Japanese Patent No. 3-314424 is a remedy only when the surroundings are dark, and is not suitable for white balance adjustment in bright scenes that are difficult to use.

This invention solves the above-mentioned problems of the conventional technology, and allows for distant views, variations in illumination conditions, backlighting, and imaging under dark backgrounds, which the outside measurement method is not good at, and the imaging screen, which is not good at the TTL method, is a single color. It is an object of the present invention to provide an imaging device that can perform appropriate white balance adjustment even in various types of imaging, and that can obtain appropriate effects, which is different from the adjustment that dilutes the characteristics of both of the above methods, which tends to occur with additive methods. This is the purpose.

[Means to solve the problem]

Therefore, the imaging device according to the present invention is an imaging device that performs white balance adjustment using the imaging output obtained from the imaging element, and in which the imaging output at a predetermined position on the screen obtained by sampling the imaging output is The above object is achieved by a configuration characterized in that it has a control means for comparing the two images and performing white balance according to the comparison result.

Furthermore, a first white balance adjustment means generates a white balance control signal for white balance adjustment using No. 19 obtained from the image sensor, and a white balance control signal is generated using a signal obtained from a colorimetric sensor other than the image sensor. A second white balance adjustment means that generates a white balance control signal for balance adjustment compares signals at a predetermined position on the screen obtained by sampling signals output from at least the image sensor, and compares the comparison results. According to the above 2
The present invention attempts to achieve the above object by a configuration characterized in that it has a composition means for mixing respective white balance control signals from two white balance adjustment means at a predetermined ratio.

[Effect]

With the above configuration, the control means samples the imaging outputs obtained from the imaging device and compares the imaging outputs at a predetermined position on the screen, and performs white balance adjustment according to the comparison result to capture an image.

The first white balance adjustment means generates a white balance control signal for white balance adjustment using the signal obtained from the image sensor, and the second white balance adjustment means uses a color sensor other than the image sensor to generate a white balance control signal. A white balance control signal for white balance adjustment is generated using the obtained signal. The synthesizing means compares the signals at a predetermined position on the screen 1 obtained by sampling at least the signals output from the image sensor, and outputs each white balance control signal from the two white balance adjusting means according to the comparison result. are mixed in a predetermined ratio and output.
White balance is adjusted according to this output and an image is captured.

By the above white balance adjustment, it is possible to capture images with appropriate white balance.

When the warning device that generates the photographing warning signal is incremented by 1, the photographing warning signal J is generated according to the photographing conditions.

Furthermore, if a storage means for storing a white balance control voltage is provided, an appropriate to white balance adjustment is performed using the stored white balance control voltage according to the imaging conditions, and an image is captured.

〔Example〕

(First Embodiment) FIG. 1 is a block diagram showing a first embodiment of the imaging device according to the present invention. In this embodiment, the control signals in the present invention are 3g1. This is used for switching the second white balance adjusting means. In Figure 1, 1 to 14
The book is a block corresponding to the block with the same number shown in the conventional example. Further, 15 and 16 are switches that select the white balance control voltage obtained from the control voltage deriving sections 11 and 14 and send it to the R and B gain control sections 4 and 5. 17 is a differential amplifier 6.7 that outputs (R-
A switch control signal derivation unit generates and derives a control signal for switching the switch 15.16 by comparing the Y) signal and the (B-Y) signal; 18 is the switch ff1Ja! A predetermined pulse sent to the I signal deriving section 17.

That is, it is a pulse generator that generates sampling pulses. Note that the image sensor 1, the averaging section 12, 13, and the control voltage deriving section 14 constitute a first white balance adjustment means,
The color temperature sensor 10, which is a colorimetric sensor other than the image sensor, and the control voltage deriving section 11 constitute a second white balance adjustment means, and the switch control signal deriving section 17, the switch 15, 16, and the pulse generator 18 constitute a second white balance adjustment means. It constitutes a synthesis means which is a control means.

The combining means in this embodiment selectively outputs the white balance control signals from each of the white balance adjusting means, that is, switches the combining ratio between (15100% and 15100%).

FIG. 2 is a partially omitted explanatory diagram showing an example of the switch control signal deriving section 17 of FIG. 1. In FIG.

AD1 to AD8 are adders, CP1 to cP8 are comparators, NDI to ND6 are NAND gates, NRI to NR3 are NOR gates, E is a standard voltage source, and 19-1 is a sample voltage source. This is a hold circuit (hereinafter referred to as S-H circuit). The configuration from inputting the B-Y signal from the differential amplifier 7 to another S-H circuit 19-2 to outputting it to the Nantes gate ND6 is as follows until the R-Y signal is processed and inputted to ND5. Since the configuration is the same as that of , illustration is omitted.

Further, FIGS. 3 and 4 are timing diagrams and in-screen sampling point diagrams for explaining this embodiment.

Next, the operation of this first embodiment will be explained using FIGS. 1 to 4.

First, in FIG. 1, the operations of blocks 1 to 14 are as follows:
It operates in the same way as the blocks with the same symbols in FIGS. 11, 12, and 13. The white balance control voltages derived by the control voltage deriving sections 11 and 14 are then applied to the switch 1.
5 and I6 are selected and sent to the R, B gain control section of 4.5. The switching control signals for the switches 15 and 16 are sent to the differential amplifier 6.
7 outputs R-Y, B-Y and pulses from pulse generator 18.

The operation of the switch control signal deriving section 17 will be explained in more detail below with reference to FIGS. 2 and 3.

The output signal R-Y from the differential amplifier 6 (Fig. 3a) is
It is input to the S-H circuit of 19-1.

In the S-H circuit 19-1, the sample and hold pulses 5HPI to 4 (C to h in FIG. 3) sent from the pulse generator 18 are
), sample the R-Y signal during the high level period of
During other periods, the signal SHI holds its level.
~4 (Figure 3 i~1) are derived.

Note that 1. 5HPI and 2 in this example are shown in Fig. 4 (A).
As shown in 5) (P3
, 4 are for sampling the R-Y signals on the left and right sides of the figure on the lower scanning line of the same screen, and these 5
The RY signals near the corners of the screen are sampled using HP1 to HP4.

Also, 5HPI and 2, and 5HP3 and 4 are Fig. 3g,
As illustrated in h, they are located at the front and rear sides of the - scanning line, and 5HPI and 2.5HP3 and 4 may be located on different scanning lines.

Furthermore, the derived signals SHI to SH4 are extracted two by two and compared in magnitude.

For example, pull out SHI and NR2 as one set, and
are led to adders ADI and AD2, and a positive potential E and a negative potential -E are applied to ADI and AD2. and,
Addition device AD1. The output of AD2 is connected to the ten terminal of comparator CPI and one terminal of CF2, and NR2 is connected to C
It is connected to one terminal of Pl and the ten terminal of CF2. Due to this, the CPI has announced that SH! If +E>NR2, the output will be high level, CF2 will be 0, 5HI
If -E<NR2, the output becomes high level. The outputs of cPl and CF2 are led to a Nandt gate NDI.

Therefore, the output of NDI becomes low level only when 5HI-E<NR2<SH1+E. That is, S
Only when the level difference between HI and 382 is constant and smaller than Bell E, the NDI output becomes low level.

Similarly, Nantes Gate ND2. ND3. The output of ND4 is
NR3 and SH4 of the S-H circuit respectively NR2 and SH4,S
It becomes low level only when the level difference between HI and NR3 is constant and smaller than bell E.

Further, the output of NR1 becomes high level only when the outputs of NDI and NO2 are both low level, and the output of NRZ becomes high level only when the outputs of NO3 and NO4 are both low level. And the output of NO5 is NRI, NR2
It becomes low level only when both outputs are high level.

That is, the output of the Nant gate ND5 becomes low level only when SHI to SH4 have the following relationship.

Then, the sample hold pulse 5HPI shown in FIG.
~5HP4 correspond to the upper left, upper right, lower left, and lower right on the screen shown in FIG. The output of the Nandt gate ND5 becomes low level only when the difference between the portions in the diagonal relationship is smaller than E, and the difference between the sums of the diagonal portions is smaller than 2E.

The same process is performed on the output B-Y of the differential amplifier 7, and the difference between the left and right, top and bottom parts is smaller than E, and the difference between the sums of the diagonal parts is less than 2E. Only when it is small, the output of NAND game NO6 becomes low level.

And Nantes Gate ND5. Only when both ND6 outputs become low level, that is, R-Y.

Only when both the BY signals satisfy the above conditions, the output of the NOR gate NR3 becomes high level.

With the above configuration and operation, when the output of the NOR gate NR3, that is, the output of the switch type # signal deriving section 17 is at a high level, it is determined that the difference between the color signals at each sampling point is smaller than the predetermined value E as described above. It is estimated that this is a case where most of the screen is occupied by a single color, and this is a scene where the TTL method is weak, as shown above, so switches 15 and 16 are set to Connect to the external measurement method side that is the white balance adjustment means of No.
If the output of the switch control signal deriving section 17 is at a low level, it is connected to the TTL method side, which is the first white balance adjustment means, thereby performing a white balance adjustment with higher resolution.

In particular, in this embodiment, by slightly increasing the threshold value (threshold level) for detecting color differences in parts that are diagonally related to the top, bottom, left, and right, even the same object can change color depending on the strength of light such as shadows. Also in the diagonal direction, where level differences are most likely to occur, false detection is avoided.

As described above, the TTL type first white balance adjustment means and the external measurement type second white balance adjustment means are selected by comparing color signals at predetermined sampling points on the screen. Therefore, it is possible to always perform imaging with appropriate white balance adjustment.

Incidentally, although the sampling point in the above embodiment was set near a part of the corner of the screen, it may be set at the center of the screen.

In addition, this sampling point can be changed depending on the subject. For example, when photographing a person, the sampling point is set to the center, and when photographing a wind shadow, the sampling point is set to the corner. It's okay.

(Second Embodiment) As a second embodiment, the switch control signal deriving section 17 shown in FIG. 1 of the first embodiment may be configured with an A/D converter and a microcomputer (hereinafter referred to as microcomputer).

FIG. 5 is a block diagram showing such a second embodiment. 19 is a microcomputer, 20 is an A/D converter, and other blocks that are the same as or correspond to those in the first embodiment are indicated by the same symbols.

Note that the configurations of the first white balance adjustment means and the second white balance adjustment means are the same as in the first embodiment, and include an A/D converter 20, a microcomputer 19, and a switch 15.1.
6 constitutes a selection means.

FIG. 6 is a flow chart showing the operation of this embodiment. In step (a), the A/D converter 20 converts R-Y, B
-Y signal in the first embodiment according to a command from the microcomputer 19.
It is sampled during a predetermined period corresponding to HI to SH4, A/D converted, and the digital signal is taken into the microcomputer 19.

In steps (b) to (e), R
Compare the magnitudes of SH1 to SH4 with respect to -Y and BY to check whether SHI to SH4 are within a certain level range, and if they are, proceed to step 1) and output a high level. Switches 15 and 16 are controlled by voltage derivation unit 1
1 side, select the external measurement method which is the second white balance adjustment means, and take an image.

If the level is not within the certain range, proceed to step (G), output a low level, and switch 15.
16 to the control voltage deriving section 14 side and select the TTL method, which is the first white balance adjustment means, to perform appropriate white balance adjustment imaging.

(Third Embodiment) In the above embodiment, the number of samples and sample period of each color signal of R-Y and B-Y were set to 4 points of sample and hold SHI to SH4 as shown in FIG. 4(A). ,
The number of samples and sample points may be changed. For example, as shown in Fig. 4 (B) and (C), by increasing the number of samples and validly setting the sample points, it is possible to determine whether the screen is a single color screen by appropriately switching the switches 15 and 16. can be detected more accurately, which enables accurate white balance correction, and conversely, by reducing the number of samples, it is possible to save on circuits and microcomputer programs, and the granularity of white balance adjustment is required. Appropriate design is possible within the scope and integration of other required specifications.

(Fourth Embodiment) In the above embodiments, weighting may be performed when comparing sampling values. That is, for SH5 in FIG. 4(C), the threshold level (E shown in FIG. 2) of the difference with each SH value for determining the magnitude with each SHI to 9 is lowered, and SHI The configuration is such that the threshold level for determining the magnitude of and SH9 is set high, and the threshold level is changed depending on the difference in comparison points to determine the selection of the white balance adjustment means. As a result, for example, when a single-color screen is photographed, it is possible to prevent erroneous detection due to the distance between sampling points and to select a more appropriate white balance adjustment means.

(Fifth Example) Furthermore, in the above example, the magnitudes were compared for one sampling value such as SHI to SH4, but each SH
The average value of values sampled for several fields for a point may be compared.

Furthermore, even during one field period, several points may be sampled as shown in FIG. 4(B) in the vicinity of each of SHI to SH4 on the screen, and the average values thereof may be compared.

With the above configuration, it is possible to select a more stable and appropriate white balance adjustment means in which random noise and the like are removed.

(Sixth Example) The number of samples, sample points, and weighting in the above example were determined using color temperature information, automatic exposure control (AE) information, distance information from the automatic focus control (AF) sensor, zoom lens, etc. For example, if the subject is far away and the focal length is long, the light source illuminating the external color sensor and the light source illuminating the subject may be switched based on the focal length information. Since there will be many different cases, it is best to select the first white balance adjustment method controlled by the TTL method as much as possible by increasing the number of samples and placing the sample points further on the screen than the position shown in Figure 4(A). Set it close to the four corners.

Furthermore, even if the subject is far away and the focal length is long, and the conditions of the number of samples and sample period are changed as shown in Figure 4(C), the second white balance adjustment method, which is an external colorimetry method, is selected. If this is the case, there are many cases where the white balance cannot be properly corrected. Therefore, by configuring the present invention to output a shooting warning signal in response to the control signal, it is possible to select a more appropriate white balance adjustment means. In addition, if the conditions are particularly bad, you can be notified by the photographing warning signal, so you can take appropriate action.

The block diagram of the sixth embodiment as an example of this configuration is shown in the seventh embodiment.
As shown in the figure. Note that blocks that are the same as or correspond to the blocks described above are indicated by the same reference numerals. 21 is a distance measuring sensor, 22 is a zoom lens, 23 is a counter, 24 is an ant gate, and 25 is a warning device.

In FIG. 7, when the distance sensor 21 informs the pulse generator 18 that the distance to the subject is short and the zoom lens 22 indicates that the focal length is long, the pulse generator 18 sends a signal to the switch control signal deriving section 17. The pulse that was being
The pulse number is changed from 4 to 9 toward the outside of the screen to correspond to FIG. 4(C). The switch control signal deriving section 17 is configured to send the comparison result to the switch section 15 and 16 by configuring a comparison circuit corresponding to the number of pulses. Further, a counter 23 measures the total number of pulses sent from the pulse generator 18, and when the number exceeds one predetermined level, a high level signal is sent to an AND gate 24. At this time, if the switch control pulse from the switch control signal deriving section 17 is at a high level, the output of the AND gate 24 becomes a high level,
The high level signal causes the warning device 25 to generate a photographing warning signal.

(Seventh Embodiment) In the sixth embodiment, in addition to outputting the warning signal, a configuration may be adopted in which the white balance control voltage of a previous scene in which the warning condition is not met is stored and used.

FIG. 8 is a block diagram showing this seventh embodiment, and blocks that are the same as or correspond to those described above are indicated by the same reference numerals.

26.27 is a switch that enables a high impedance output state, and 28.29 is a memory that stores a white balance control voltage. Figure 9 shows memory 28.29
30 is a buffer in the memories 28 and 29, 31 is a switch, and 32 is a logic gate circuit that generates a signal to control the switches 26 and 27 and the switches in the memories 28 and 29.

A signal indicating a situation in which white balance adjustment is difficult as described in the sixth embodiment is generated by the logic gate circuit 32 and sent to the switches 26 and 27 and the memories 28 and 29. The switches 26 and 27 are normally switched to the TTL side or the external measurement side by the output signal of the logic gate circuit 32, but if white balance adjustment is difficult, the output of the logic gate circuit 32 puts them in a high impedance output state. On the other hand, the memories 28 and 29 are configured as shown in FIG. 9, and during normal photographing, the switch 31 is switched from the output side of the buffer 30 to the input side at the same time as the power is turned on. At the same time as the power is turned off, the switch is connected to the output side. However, logic gate circuit 3
If a signal indicating difficulty in adjustment is sent from 2, the switch 31 remains connected to the output side even when the power is turned on.

Therefore, in normal times, the white balance control signal derived by the TTL method or external measurement method is sent to the R, B gain control section 4.5, and when white balance adjustment is difficult,
Capacitors C& of memories 28 and 29: A white balance control voltage based on the accumulated voltage, that is, a white balance control voltage in a previous scene that is easy to correct will be sent.

With the above configuration and operation, even under conditions where white balance adjustment is difficult, it is possible to take an image using the white balance adjustment data of the previous scene.

(Eighth Embodiment) In the above embodiment, white balance adjustment processing is performed on the image sensor 1.
Although the output of the image sensor 1 is directly stored in the image memory, the output may be directly processed. FIG. 10 is a block diagram showing this embodiment, and 33 is a frame memory.

In this case, processing for each screen becomes easier, and an improvement in white balance adjustment results can be expected.

(Ninth Embodiment) In the above embodiments, R-Y and B-Y signals were used as color signals used in the first white balance adjustment means, but R, G, B signals, etc. may also be used as color signals. .

In this case, it is possible to further improve the white balance adjustment effect.

(Tenth Example) Furthermore, in the above example, the white balance control signal was obtained by averaging the color signals of the entire screen as a signal used in the first white balance adjustment means, but the white balance control signal was obtained by averaging the color signals of the entire screen. Other methods may also be used, such as determining the control signal using

(Eleventh Embodiment) In addition, in the second embodiment, as shown in FIG.
Although the switch control signal deriving section 17 in the figure has been replaced with an A/D converter 20 and a microcomputer 19, the control voltage deriving sections 11 and 14 and switches 15 and 16 are all replaced by an A/D converter, a microcomputer, and a D/D converter. It may also be configured with an A converter.

In this case, the components can be rationalized and the functions of the microcomputer can be used effectively.

(Twelfth Embodiment) In the above embodiments, the control voltage of either the first or second white balance adjustment means was switched to be selected, but near the switching threshold, the control voltage of both means is switched. The same control voltages, such as an average value or an approximate value thereof, may be mixed at a predetermined ratio and used as the white balance control voltage, and the control voltage may be switched continuously or stepwise.

In this case, more stable and preferable imaging can be performed even near the threshold value.

Note that the control voltages of both means may be mixed at a predetermined ratio over the entire signal level range without being limited to the vicinity of the threshold value.

(Thirteenth Embodiment) In the above embodiments, the comparator and the microcomputer comparison calculation used as the means for determining the level of optical system information may be provided with hysteresis characteristics to prevent instability near the threshold level. good.

In this case, more stable and preferable imaging can be performed even near the threshold value.

(Fourteenth Embodiment) The time constant of the averaging section (integrating circuit) 12, 13 may be variably controlled using the control signal in the present invention.

That is, the integrating circuits constituting the averaging sections 12 and 13 in FIG.

For example, when the subject does not change, the accuracy of the control signal output from the control voltage deriving section 14 in TTL can be made higher by increasing the time constant; In some cases, by shortening the time constant, it is possible to reduce disturbances in the white balance due to changes in the subject.

〔Effect of the invention〕

As explained above, according to the present invention, the control means compares the imaging outputs at a predetermined position on the screen obtained by sampling the imaging outputs obtained from the imaging device, and adjusts the white balance according to the comparison result. In other words, the first white balance adjustment means uses a white balance control signal for white balance adjustment generated using the signal obtained from the image sensor, and the second white balance adjustment means uses a measurement signal other than the image sensor. The compositing means at least combines signals at a predetermined position on the screen obtained by sampling the signals output from the image sensor with a white balance control signal for white balance adjustment generated using the signal obtained from the color sensor. The comparison results are mixed at a predetermined ratio and output, and the white bass run is adjusted according to this output before image capture. Appropriate white balance adjustment can be performed even when imaging against a dark background or when the imaging screen is a single color, which is difficult to do with the TTL method. Moreover, it is possible to provide an imaging device that can obtain an appropriate effect, which is different from the adjustment that dilutes the characteristics of both of the above-mentioned methods, which tends to occur with the additive method.

If the system is equipped with a warning device that generates a shooting warning signal and performs white balance adjustment by issuing the shooting warning signal, the shooting warning signal will be emitted when the white balance adjustment is difficult to achieve. It can be used to alert people.

Furthermore, in the case of a configuration in which the storage means stores the white balance control voltages of the first white balance adjustment means and the second white balance adjustment means, and the white balance adjustment is performed using the stored white balance control voltages, When it is difficult to perform the above-mentioned white balance adjustment satisfactorily, the white balance adjustment can be performed using the white balance control voltage stored in the storage means.

As described above, it is possible to provide an imaging device that can perform appropriate white balance adjustment even under various conditions.

Furthermore, in the present invention, control is performed not based on color or brightness itself, but based on differences in sampling data.
In particular, when used for switching control of white balance control, it is possible to accurately detect whether or not the screen is a single color screen by removing the influence of the light source color, thereby realizing more accurate white balance control. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG.
The figure is a block diagram of the switch control signal deriving section, Figure 3 is a timing diagram, Figure 4 is an explanatory diagram of sampling points on the screen, Figure 5 is a block diagram showing the second embodiment, and Figure 6 is a diagram of the second embodiment. FIG. 7 is a block diagram showing the sixth embodiment, FIG. 8 is a block diagram showing the seventh embodiment, FIG. 9 is an explanatory diagram of the memory, and FIG. 10 is a block diagram showing the eighth embodiment. The block diagram shown in FIGS. 11 to 13 is a block diagram showing a conventional example. 1... Imaging device 2... Luminance signal processing unit 3 - Chroma signal processing unit 4... R gain control unit 5... B gain Control section 6.7 --- Differential amplifier 8 --- Variable section 9 --- Adder 10 --- Colorimetric sensor 11 --- Control signal deriving unit 12.13---Averaging unit 14...Control signal deriving unit 15.16---Switch 17---Switch control signal deriving unit 18...・・・
...Pulse signal generator 19...Microcomputer 20...
・A/D converter 21... Distance sensor 22... Zoom lens system 23... Counter 24 ------- A N D gate 25...・・Warning device 26.27・---3-state switch 28.2
9...Memory 30...Buffer 31...Switch 32...Logic gate circuit 33--Frame memory 34.35-0...・Adder

Claims (4)

[Claims] (1) An imaging device that performs white balance adjustment using the imaging output obtained from an imaging device, which compares the imaging outputs at a predetermined position on the screen obtained by sampling the imaging output, and uses the comparison result to An imaging device characterized by having a control means for performing white balance accordingly. (2) A first step that generates a white balance control signal for white balance adjustment using the signal obtained from the image sensor.
a second white balance adjustment means that generates a white balance control signal for white balance adjustment using a signal obtained from a colorimetric sensor other than the image sensor; a synthesizing means that compares the signals at predetermined positions on the screen obtained by sampling the signals, and mixes each white balance control signal from the two white balance adjustment means at a predetermined ratio according to the comparison result; The imaging device according to claim 1, characterized in that it has: (3) An imaging device characterized by comprising, in addition to the configuration of claim 2, a warning device that generates a photographing warning signal. (4) In addition to the configuration of claim 2, an imaging apparatus further comprising a storage means for storing a white balance control voltage, and white balance adjustment is performed using the stored white balance control voltage.