JPS61280530A - Colorimetric sensor - Google Patents

Abstract

PURPOSE:To obtain an image near to visual sensation even when the color temp. of a light source is extreme, by controlling the output of a color sensor having received predetermined adjustment so as to allow the change in the output of said sensor to gradually become small when the color temp. information obtained by applying operational processing to said output is out of a predetermined level range. CONSTITUTION:The output photocurrents of the R-color colorimetric sensor and B-color colorimetric sensor of a colorimetric sensor 4 and the temp. measuring output current of a current dividing part 8 are selectively supplied to be converted to voltages logarithmically compressed by a logarithmic amplifier part 5 to be stored in a memory 12 through an A/D converter 11. An operation circuit 13 calculates color temp. information on the basis of the memory 12 and, when the calculated result is out of a predetermined level, memories M1-M3 or memories M4-M6 are referred to through a system controller SC and color temp. information controlled so as to become small as a level becomes higher or lower is outputted to adjust the image pickup signal from an image sensor 15. Therefore, even when the color temp. of a light source is extremely high or low, the image approaching the visual sensation of a person is obtained.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a colorimetric sensor device, and in particular to obtaining an image close to the sense seen by the human eye even when the color temperature is extremely high or low. We will take measures to make this possible.

(Prior Art) A conventional so-called automatic tracking type color balance adjustment device converts an image of a subject under a light source with a color temperature in a certain range (for example, 2500"K to 10000"K) to a color temperature of a constant color temperature (for example, 5400"K). The image was adjusted to be equal to the image of the subject under a light source of "K".In other words, since the human eye has a function to correct color temperature, the imaging device should also have this function. be.

On the other hand, the present applicant has filed Japanese Patent Application No. 59-64969 (Showa 5
(filed on March 30, 2009), the offset of the output of each color sensor is adjusted according to the output level of a plurality of color sensors that respectively detect different color signals, so that the output of each color sensor falls within a predetermined level range. We proposed a colorimetric sensor device that can accurately measure the color of light with a wide range of brightness.

(Problem to be solved by the invention) By the way, when the intensity of one color is extremely high or extremely low, the color temperature correction function of the human eye is not very effective. When viewed with a camera, the subject appears reddish or blue-colored, but with the color balance adjustment device described above, the color temperature is completely corrected within a certain color temperature range. For example, even though a sunset is taken in the sky, it looks as if it was taken in the middle of the day.

Furthermore, according to the offset adjustment means, when the range of color temperatures is extremely wide, the difference in the outputs of the color sensors (for example, the R sensor that detects a red signal and the B sensor that detects a blue signal) becomes large. , under the same offset value,
In order to accurately process the output of the color sensor, it is no longer within the input range of the A/D converter that converts it into a digital quantity, and in order to reduce errors when performing offset adjustment, the outputs of the R and B sensors are set to the same offset. Even if you try to import the values, as mentioned above, there are cases where the re-output difference is so large that the same offset value cannot be used. Although it is possible to solve this problem with the system controller program, it takes some processing time. This takes time and can be an obstacle when taking still images, where instantaneousness is important.

Therefore, the present invention eliminates the above-mentioned drawbacks of the prior art and obtains an image that is closer to the sense seen by the human eye even when the color temperature of the light source is extremely high or low. The object of the present invention is to provide a colorimetric sensor device that can perform color measurement.

(Means for Solving the Problems) In order to solve the above problems, the colorimetric sensor device of the present invention includes a plurality of color sensors that respectively detect different color signals, and offset adjustment of the output of the color sensor. and a means for calculating and processing the output of the color sensor subjected to the offset adjustment to form color temperature information, wherein when the color temperature information is outside a predetermined level range, the output changes gradually. It is a device that is controlled to be small.

(Function) Based on the above configuration, the colorimetric sensor device of the present invention gradually reduces the output change of color temperature information when the color temperature of the light source is extremely high or low. The degree of color temperature correction is weakened as the color temperature becomes higher or lower than a predetermined range, and color temperature correction that is closer to the characteristics of the human eye is performed in the color temperature range where the color temperature correction function of the human eye is not very effective. It is something.

(Example) An example of the colorimetric sensor device of the present invention will be described below with reference to the drawings. The following description describes the overall configuration of the embodiment of the colorimetric sensor device of the present invention, the offset adjustment means in the same embodiment, the output level detection means of the color sensor, and the order of operation of the embodiment of the colorimetric sensor device of the present invention. Do it with

(Overall configuration of an embodiment of the colorimetric sensor device of the present invention) (FIG. 1) FIG. 1(A) shows an embodiment of the colorimetric sensor device of the present invention.
The overall configuration of the example is shown. In the figure, 1 is a decoding section, 2 is an input terminal to which a selection signal is input from the system controller SC to the decoding section 1, 3 is a switch section, and 4 is an R for detecting red color, for example. 5 is a log amplifier section, 6 is a final amplifier section, and the decoder 1 receives signals from the final amplifier section 6 according to a select signal input to the input terminal 2. Controls which signal is output to the A/D converter 11. The switch section 3 selects whether or not to transfer the photocurrent output from the colorimetric sensor 4 to the log amplifier section 5 under the control of the decoder section 1 . Note that when the photocurrent is not transferred to the log amplifier unit 5, the sensor is short-circuited to remove excess electron-hole pairs. The log amplifier section 5 converts the photocurrent outputted from the colorimetric sensor 4 via the switch section 3 into a logarithmically compressed voltage and outputs it.
The output of the log amplifier section 5 is amplified to match the input level of the A/D converter 11 at the next stage.

Reference numeral 7A denotes a reference current control section, which adjusts the magnitude of the reference current Irat using, for example, an external resistor R, and cancels the offset of the final amplifier section 6, etc. A reference voltage setting section 7B sets a reference voltage Vref for the log amplifier section 5 and the final amplifier section 6. Reference numeral 8 denotes a current shunt section, which sets a current for canceling temperature fluctuations in voltage in the log amplifier section 5. 9
is an offset unit serving as a signal source and offset adjustment means, and is an offset unit that converts the R signal and B signal into the A/D converter 11.
A current is generated to apply an offset voltage to the output Vout of the final amplifier section 6 in order to convert the signal into a convertible range. The details will be described later with reference to FIG. 2. Reference numeral 10 denotes a mode setting input terminal for controlling the offset value of the offset section 9, into which a mode setting signal from the system controller Sc is input.

11 is an A/D converter for converting the output of the final amplifier section 6 into a digital signal; 12 is a memory for storing the output; and 13 is an arithmetic unit for forming color temperature information based on the output of the memory 12. circuit, memory M1
~M6 is connected.

Reference numeral 14 denotes a level detection circuit which is an example of level detection means, which detects in what range the level of the output V out of the final amplifier section 6 is, and outputs the detection signal to the system controller SC. For details, please refer to Part 5.
This will be described later with reference to the drawings.

The system controller SC controls the operation and operation timing of each part of this colorimetric sensor device as shown in the figure.
The details will be described later with reference to FIG.

15～. 18 schematically shows an imaging device whose gain is controlled by this colorimetric sensor, 15 is an image sensor, and 16.17 shows the gains of R, G, and B signals, which are the color signals output from the image sensor 15. This is a gain control amplifier that controls relatively, and in this example, it is provided for each R and B signal, and the gain is controlled by the output of the arithmetic circuit 13.This adjusts the level of each color signal according to the color temperature of the subject. will be held. A process encoder 18 forms a standard television signal, for example, an NTSC signal, based on the R, G, and B signals.

Next, the operation of the colorimetric sensor device shown in FIG. 1(A) will be explained. A photocurrent generated by the colorimetric sensor 4 consisting of an R sensor and a B sensor is selectively sent to or shunted to a log amplifier section 5 by a decoder section 1 and a switch section 3. The photocurrent sent to the log amplifier section 5 is converted into a voltage, logarithmically compressed, and then amplified by the final amplifier section 6 and output. The above flow is called signal acquisition mode. Also, under the control of the decoding section l, the colorimetric sensor 4
No current is sent from the current to the log amplifier section 5, but a constant current (described later) is passed from the current shunting section 8 to the log amplifier section 5, and is outputted from the final amplifier section 6 in the same manner as described above. Since the ambient temperature is measured by this, the above flow is set as the temperature measurement mode. That is, when a (0, 0) signal is sent from the system controller SC to each input terminal A, B of the select signal input terminal 2, the output of the B sensor is outputted from the final amplifier section 6 via the log amplifier section 5, and ( When the 0, 1) W signal is sent, the output of the R sensor is output, and when the (1, 0) signal is sent, the current shunt section 8
When the output current 11 of (1°1) is sent, the output current 1611 of the current shunt section 8 is similarly outputted from the final amplifier section 6. Therefore, each sensor and the current shunt section 8 as a constant current source Since time-division processing is performed on the output of , the circuit configuration can be simplified.

In this way, according to the select signal from the system controller SC, the outputs of the R sensor, the B sensor, and the current shunt section 8 are sent to the A/W converter 11 through the log amplifier section 5 and the final amplifier section 6 in time series, respectively. It is A/D converted and supplied to the memory 12, and the memory 12 has an R sensor and a B sensor.
The outputs of the sensor and current shunt section 8 are each temporarily stored. The calculation circuit 13 calculates the output ratio of the R sensor and the B sensor, excluding the influence of temperature fluctuation, based on these stored values, and this output ratio corresponds to the color temperature at a ratio of 1:1.

In the embodiment of the present invention, the signal outputted as color temperature information from the arithmetic circuit 13 and used to control the gain of the gain control amplifiers 16 and 17 has output characteristics as shown in FIG. 1CB) and FIG. 1C. In other words - human power nogR/B=
If X is in a predetermined range (for example, the range of α3 to β3 in CB in the same figure), the output logR/B=Y will change in proportion to X, but if X is α3 or more or β3 or less, A characteristic is provided in which the change in Y gradually becomes smaller. For this purpose, the memories M1 to M6 are connected to the arithmetic circuit 13, and if X>α1, the value stored in the memory M1 is output as color temperature information, and if α1>x>α2, the value stored in the memory M2 is output as the color temperature information. If α2>x>α3, the value stored in the memory M3 is output. Similarly, if x x βl, the value stored in memory M4 is stored, and if βl <x<β2, the value stored in memory M5 is
If the stored value is β2 x β3, the stored value of M6 is output as a memo. As a result, as the color temperature increases, the color balance gradually changes and becomes bluish, and as the color temperature decreases, the color balance gradually changes and becomes reddish. This allows you to take pictures of extremely bright objects with a sense of realism, making it possible to obtain images that are closer to the senses of the human eye. In reality, it is possible to further increase the numbers of α1 to α3 and β1 to β3, and to provide more memories for storing the above-mentioned specific values. The control procedure for providing the above characteristics will be explained in more detail with reference to FIG.

Instead of having the characteristic that the output Y changes stepwise as shown in Figure 1CB), Y changes continuously in response to changes in the input X, as shown in Figure 1ffl (C), and It is also possible to provide a characteristic in which the change in Y gradually decreases as it approaches . To do this, a memory containing a table for performing the conversion shown in FIG.
The arithmetic circuit 13 may output a signal representing the value of Y corresponding to a change in X.

Furthermore, in the colorimetric sensor device of FIG. 1(A), R
When the outputs of the sensor and the B sensor are outside the range that can be A/D converted by the A/D converter II, the information is stored in the memory M1 instead of the above-mentioned arithmetic processed information by the means described later with reference to FIG. Or output the time saving information stored in M4.

(Offset adjustment means in the embodiment of the present invention) (Figs. 2 to 4) Next, the main points of the offset adjustment means in the above embodiment will be explained with reference to the specification of the above-mentioned Japanese Patent Application No. 59-64966. do. FIG. 2 shows an example of a specific circuit configuration of the final amplifier section 6 and offset section 9 in FIG. 1(A). In the final amplifier section 6, 21 is an operational amplifier whose (+) The potential of (V
s+Vref), and the potential at the other end of the resistor R1 connected to its (-) input end is Vref. In the offset section 9, CMI, 0M2.0M3 are current mirror circuits, and C, D, and E are input terminals forming the mode setting input terminal 10 of FIG. 1(A). IO is the output current of the offset section 9 for adjusting the offset of the output voltage Vout of the final amplifier section 6, and its value is controlled by signals input to input terminals C, D, and H as described later. Output current of each mirror circuit 11. I2. It is determined by the combination of I3. And 11. I2. The ratio of I3 is set to approximately 4:2:l, the details of which will be described later. Also, I2 is l2=Ic for constant current IC.
is set to

Here, a mode of adjusting the offset of the final amplifier section 6 will be explained. In FIG. 2, the current Is- flowing through the resistor R1 is Is = (Vs +Vref -Vref)
/R1=Vs/R1 On the other hand, Is is expressed as Is=Is'-IO, where Is' is the current flowing through the resistor R2, so Is'=Vs/R1+IO. Therefore, the output voltage Vout is expressed as Vout=Vs+Vref+(Vs/R1+I0)IR2=Vs''(R1+R2)/R1+Vref+IOR21111* (1).

Therefore, by changing the magnitude of Io, V
The offset of out can be adjusted. For example, as shown in Fig. 3, when IoR2=0, EV5~
It can only handle light intensity up to EVIO, but IO@R2=1.
When it is 5V, EV2.5~EV7.5. I□-R2=3
When it is V, it is possible to handle a light amount of E V O to EV5. That is, by adding the offset l0eR2, the light amount from EVO to EVIO can be handled. Therefore 11. I2. I3 is set as described above and the second
The output current IO and offset voltage change as shown in Table 1 depending on the combination of 1 or O signals input to the input terminals C-H in the figure.

Here, in order to form color temperature information in the apparatuses shown in FIG. 1(A) and FIG. 2, as V's in equation (1), R sensor,
All you have to do is read the output signal of the B sensor and find the ratio, but since the offset I4 of the sensor mentioned above is adjusted, it is necessary that the two types of signals are both in the same mode. Otherwise, an error effect will occur.

That is, when redundancy is not provided to the offset as shown in FIG. 4(a), the above two types of signals are set to R.

B, it is good when R and B are in the same mode as in 22 in the same figure, but R is in the upper mode and B is in the lower mode as in 23 in the same figure. When the mode is set, even if the ratio between R and B is calculated in this state, a completely incorrect result will be calculated.

Therefore, in this device, this drawback is prevented by providing an overlapping portion between each mode as shown in FIG. 4(b). However, this overlapping portion is set to be larger than the difference between R and B.

In this way, for example, even if R is in mode (2) and B is lower than its lower limit, if (b) is set to mode (2), both R and B will be in this mode.

The mode setting procedure is automatically performed by the system controller SC, and details thereof will be described later with reference to FIG. 6, but an example of the mode setting procedure will be briefly described here. First, the mode as a reference mode■
and check whether R is in that range.

If R is larger than the L limit (-5V) of ■, go to mode ■.

(If it is smaller than the lower limit (-9V) of ■, it goes to mode ■ and then goes to ■.The upper and lower limits of ■ are compared with R, and the mode moves to mode ◎ or mode ■.

In this way, we search for a mode in which R can fit, and once we find a mode in which R can fit, we check whether B can fit in it. Here, if B is also in that mode, in order to give an offset corresponding to that mode, a code signal is input from the system controller SC to the mode setting input terminal 10 to give a predetermined offset, and in this state, R sensor output,
The B sensor output and the output of the current shunt section 8 are each sequentially processed under the control of a select signal, A/D converted, stored in the memory 12, and then arithmetic processed to form color temperature information. Here, the current mirror circuit CMI~CM3
If the current values of the outputs 11 to 3 have an error, the offset voltage will also include the error, making it impossible to cover the target light brightness range. The difference between R and B is
Assume that there are 5 stages of EVO.

Two problems arise in this case. $1 is the lower limit (mode ■
), it is necessary to provide a sufficient margin for error so that the range of target light brightness can be covered.
Assuming that there is an error of Ic=100μA, I1=200A→220~180ILAI2=10
0 ru A → 110 to 90 舊 A l3 = 50 ru A → 55 to 45 ru A.

If the maximum error occurs in mode (2), what should be 350 ILA becomes 385 ILA or 3154A. In this case, the problem is 315JLA, but this problem can be solved by determining the lower limit EV value of mode (2) in consideration of the error voltage obtained by multiplying the error amount 35ILA by R2. If the error voltage is 1V, it corresponds to an EVI stage, so if the lower limit of mode (2) is set to EVI, it is possible to guarantee up to EV2.

The second problem occurs in the following cases. That is,
Suppose that in FIG. 4 (b), R is in mode ■, but B is found to be smaller than the lower limit of mode ■. In this case, it jumps to mode (2), and in mode (2), both R and B should be present due to the overlap, but at this time, due to an error, mode (2) becomes too high by (15V), and mode (2) becomes 0. If the voltage drops by 5V, the overlap mentioned above will disappear.In other words, even if the error is subtracted, if the overlap is not larger than the difference between R and B, R
A problem arises in that B and B are not covered in the same mode.

To deal with this problem, if the constant currents 1 to I3 for offset adjustment are set at equal intervals, the maximum error between each mode will vary even if the setting takes the error into account. Moreover, a very large maximum error may occur.

Therefore, it is necessary to provide an extra amount of overlap between each mode, and as a result, the configuration and control of the constant current source for forming the IO become complicated.

Therefore, in this embodiment, in order to reduce this error, the output of each reference signal source is set so that the above-mentioned error is averaged.

This can be explained theoretically as follows. That is, in order to minimize the conversion error to the adjacent mode, the ratio of the output current of each signal source is set to 1 instead of 1:2:4:・Φ・
+ α: 2 + β: 4 + γ: 1・, 11=X1, l2=X2, l3=X13X1=
4X-Z x2=2x+ (z-Z') X3=2X+Z' xl+x2+x3=7x so that the value considering the error in each mode approaches the specified value. Here, assuming that X has an error of ±y%, the above formula is xl' = (4x-z) (1±y) X2' = (2x+z-z') (L±y)X3'
= (x+z') (t±y), and the difference from the adjacent mode is (x+z') (1+y) =X+Xy+z'+zy @II meeting (2) (between modes ◎ and ■) (2x+z=z )(1+y)−(x+z”)*(1
-y)=x+3xy+z-2z/÷zy-・#(3) (between modes ■ and ■) (4x-z)(1+y)-((2x+z-z')+
(x+z'))(1-y)=x+7xy-2z...
(4) (Between modes ■ and ■)
', so from equations (2) and (3), 2xy-3
z'+z+zy□-z' y=0・Fist・(5) From equations (3) and (4), 4xy-3z+2z' −zy=0* *Fist (6) Expressions (5) and (6) as z, Solve for z' and get 4XY
(4+y) and z=11.06. z' = 7.152, and from this x1 = 200-11.06 = 188.94X2 = 100
+ (11,06-7,152)=103.908 x3=50+7.1.52=57.152, so
11=189JLA, l2=104, A, l3=57J
If it is LA, even if there is an error of ±10% in each current, 11 = 189 ± 10% = 207.9 to 170. ll2=
104±10%=114.4~93°6I3=57
±10% = 82.7 to 51.3 Table 2 Within the range of each ILA, the difference between each mode is as shown in Table 2 even in the worst case, and the maximum error is between modes ■, ■ and between modes ■, ■ It is significantly reduced to 13.1 between the two.

(Output level detection means of color sensor in the embodiment of this invention) (FIG. 5) FIG. 5 shows the output level of the final amplifier unit 6 input to the A/D converter 1 of FIG. Details of the level detection circuit 14 that detects the output level of the color sensor 4 of the color measurement sensor 4 are shown in detail. In the figure, 31 and 32 are comparators, and the output of the final amplifier section 6 is input to the A/D converter 1. and the (=) input terminal of the comparator 31 and the comparator 32
is input to the (+) input terminal of The (+) input terminal of the comparator 31 and the (-) input terminal of the comparator 32 are a reference potential source v corresponding to the upper and lower limits convertible by the A/D converter 1.
H and vL, respectively. The outputs of the comparators 31 and 32 are input to the AND gate 33.
3 and the output of the comparator 31 are input to the NOR gate 34,
The output of the AND gate 33 and the comparator 32 is the NOR gate 3
5, and the AND gate 33 and the NOAH gate 34
．． The output of 35 is input to the system controller SC.

Therefore, if the output of the final amplifier section 6 is within the convertible range of the A/D converter 11, the comparator 31.3
Both outputs of the AND gate 33 become high, and the output of the AND gate 33 also becomes high. On the other hand, the output of the final amplifier section 6 is A
If the level is higher than the convertible upper limit of the /D converter 11, the comparator 31, the comparator 32 and the AND gate 3
3 become low, high, and low, respectively, and the high output is supplied only from the NOR gate 34 to the system controller SC. Furthermore, if the output of the final amplifier section 6 is at a level lower than the lower limit of convertible output of the A/D converter 11,
Similarly, a high output is supplied only from the NOR gate 35 to the system controller SC. Thereby, it is determined whether the output of the final amplifier section 6 is within the convertible level range of the A/D converter 11, or whether the level is higher or lower than this range.

As a modification of the above, the output of the A/D converter 11 may be input to the system controller SC as shown by the broken line in FIG. 1 (A, ), and the level of the color sensor output may be detected by the system controller SC itself. In this case, the level detection circuit 14 shown in the figure can be omitted.

(Operation of the embodiment of the colorimetric sensor device of the present invention) (Figs. 1 and 6) By performing the offset adjustment of the output of the color sensor by the above-mentioned means, the output of each color sensor is brought within a predetermined level range. Although it is possible to obtain highly accurate color temperature information at low cost using an A/D converter with a simple configuration, the above-mentioned method also allows the color temperature information to fall within a predetermined level range (for example, If it is outside the range α3 to β3 in FIG. 1(B), the image captured by the imaging device will be very different from the sense of the eye and will look unnatural, as described above.

Therefore, the present invention is designed to gradually reduce the change in the output of the means for forming color temperature information in the above case, and the specific procedure thereof will be explained below mainly with reference to FIG. 6.

In FIG. 6, first, the count value fli of a setting counter (not shown) is set to 1, the select signal input to the input terminal 2 of the decoder 1 is set to (0, 1), the output of the R sensor is read, and this is sent to the log amplifier. Set R mode for input to section 5, and set offset to mode ■ (step 1O1). In this state, check whether the input signal (data) is higher than the switch/D convertible range (step 103).
Or it is determined whether it is lower than this range (step 104), and if the data is M a

In step 105, it is determined whether the select signal input is (0°1). Since the answer is YES in this case, the process proceeds to step 106, and the data (R data in this case) is stored in the memory 1z.

Next, the select signal input is set to (0, 0).

As a result, the B mode is set to read the output of the B sensor, and the process returns to step 102 (step 107). This time, the output of the B sensor is taken in via the switch section 3.
Similarly to the above, if M a x > data > M i , proceed to step 105 (steps 102 to 104)
.

In step 105, it is determined whether the select signal input is (0°1), but in this case, it is (0, 0), so the process advances to step 108, where the select signal input is (0, 1).
0), and since it is yes, step 10
9, the B data is stored in the memory 12 via the A/D converter 11.

Next, set the select signal input to (1, 0) and set the constant current to 11
etc. (step 110). Here, in step 111, constant current 11 and 16i1
A mode setting signal is input to the input end 10 so as to set an offset value that can be input to the A/D converter 11, and then the process returns to step 102 again, where the constant current 11 is taken in via the switch section 3, and MaX>il data >Min, proceed to step 105, step 105.108
Since both determination results are NO, the process advances to step 112. In step 112, the select signal input is (i, o
), and since the answer is YES, the process proceeds to step 113, where data 31 is stored in the memory 12.

Next, the select signal input is set to ct, 1), step 114), thereby setting the mode for reading the constant current 1611, and then returning to step 102, reading the 16i1 data via the switch section 3, Max> 16i
If 1 data>Min, the process proceeds to step 105. Since all the determination results in step 105, 108, and 112 are negative, the process proceeds to step 115, and the 16i 1 data is stored in the memory 12.

Through the above operations, the R, B, t 1 and 16 [□ data are temporarily stored in the memory 12, and the ratio of the outputs of the R sensor and the B sensor is calculated from these data, excluding the influence of temperature fluctuations. In other words, the arithmetic circuit 14 (Q o
gR−no gB) is calculated (step 116), and no gR−(Lo gB=A o gR/B=X
As for the change in X in Figure 1 (B), is it X〉α1?
(Step 117a) Is cxl>X>β2? (Stella7'117b) Is α2>x>α3? (Step 11
7C) Is x x β1? (Step 118a) Is β1 x x β2? (Step 118b) Is β2 x x β3?
(Step 118c) is determined, and if all are negative, it is considered to be within the appropriate range of α3>x>β3.
Based on this value of X, the arithmetic circuit 13 derives color temperature information (step 121), and outputs this color temperature information to control the gains of the amplifiers 16 and 17 (step 122).

On the other hand, if the determination is YES in either steps 117a-117c or steps 118a-118c, the memories M1 to M3 or the memory M
The values stored in M4 to M6 are respectively output (steps 119a to 119c, 120a to 120c). That is, in the predetermined range α3 to β3, Y changes linearly with respect to X, but In the region α3 and x β3,
As shown in FIG. 1(B), it is set so that the change in Y with respect to X gradually becomes smaller. In other words, the predetermined range α
In both the upper region and the lower region outside of 3 to β3, the change in Y gradually decreases step by step.

Based on the above-mentioned characteristics, this colorimetric sensor device can obtain an image that is closer to the sense of the human eye even when the density of one color is extremely high or low as described above. . In addition, as mentioned above, Figure 1 (
It is also possible to provide the characteristic shown in C) so that the change in Y with respect to X becomes gradually smaller continuously outside the predetermined range α3 to β3.

The flow up to step 122 described above is such that the outputs of the R sensor and B sensor are converted into A/D converter 11.
If the value is within the range in which D conversion is possible, but if it is outside the range, in the embodiment of the present invention, specific information that can be set as color temperature information is output by the following operation. This corresponds to step 103 or 10 in FIG.
If the determination result in step 4 is YES, and the determination result in step 103 is yes, step 123
The process proceeds to step 124, where it is determined whether it is iwl or not. In this case, the answer is YES, so the process proceeds to step 124, where the offset mode is changed from the reference mode ■ to ■. This is to quickly find the optimal offset value.Next, set the count value i to i+1=2 and return to step 102 (step 125).As a result of the mode change, if a negative determination result is obtained in step 103, The above-mentioned operation continues, but if the determination result is still YES, the process goes to step 123 again, and since i=2 here, the process goes to step 126, where it is determined whether or not i=4. Therefore, the process proceeds to step 127, where the mode is changed from ■ to ■, and the count value jli+1 is set to 3 (step 125), and the process returns to step 102. In this way, if the determination result in step 103 is YES, step 12
6, the offset mode is switched until i=4 is obtained. When i=4 is obtained in step 126, the process proceeds to step 120a, and the value stored in the memory M4 is output from the arithmetic circuit 13 as color temperature information.

This means that even after offset adjustment, the A/D converter 1
This is a case where the output of the R sensor or the B sensor is so small that it does not fall within the A/D convertible range according to 1, and the color temperature is determined to be extremely low. In this case, Figure 1C
This is a case where the value deviates further to the left and right than the range of α3 to β3 in B), but for the sake of simplicity, it is assumed that the value stored in the memory M4 is output as color temperature information even in this case. Note that the values stored in the memory M4 can be variably set depending on the brightness of the subject and the like. This also applies to the values stored in the memory M1, which will be described later.

Next, a case where the determination result in step 104 is YES will be described. If a yes determination result is obtained in step 104, the process proceeds to step 128, where it is determined whether i=1, and if yes, the offset mode is changed from reference mode ■ to ■step 129).
After setting the count value i to f+1=2, the process returns to step 102 (step 125), and if a negative determination result is obtained in step 104, the above-mentioned normal operation proceeds, but if a positive determination result is still obtained, the process returns to step 102 (step 125). Proceed to step 128, and since i=2 here, proceed to step 130. Here, a yes determination result is obtained, so proceed to step 131, change the offset mode from ■ to 0, and further... -i+1=3 (step 125) Return to step 02. and step 10
If the result in step 4 is not negative, the result in steps 128 and 130 is negative, and the process proceeds to step 119a, where the value stored in the memory M1 is output as color temperature information.

This is a case where the output of the R sensor or B sensor is so large that even if the offset mode is set to ◎, it does not fall within the A/D convertible range by the A/D converter 11, and the color temperature is judged to be extremely high. . In this case, as in the case where the color temperature is extremely low, for the sake of simplicity, it is assumed that the value stored in the memory Ml is output as the color temperature information.

Therefore, in the apparatus shown in FIG.
When the color temperature is outside, the values stored in the memories M1 to M6 are output as color temperature information, and this controls the gain of the gain control amplifier 16.17, so if the color temperature is extremely high or low, In this case, it is possible to obtain an image that is closer to the sense of the human eye. Furthermore, when the output of the color sensor is outside the range that can be A/D converted by the A/D converter 11, specific information (Ml or M4 in the above example) is output as color temperature information, making color measurement impossible. For example, it eliminates the time required for the calculation time of the microcomputer as a control and calculation means, the time required for switching the photocurrent of the color sensor and the current for temperature correction, etc., and enables virtually instantaneous photography. The output difference between R sensor and B sensor is very large, and A/
If it does not fall within the input range of the D converter 11,
It is determined that the color temperature has already exceeded the level corresponding to α1 or β1 in FIG. 1(B), and the above-mentioned specific information is output.

As a modified embodiment of the colorimetric sensor device of the present invention, when the color temperature information is outside the predetermined range α3 to β3, the input io
In addition to gradually reducing the change in output fLogR/B=Y with respect to the change in gR/B=X, even if the color temperature is within the predetermined range above, the degree of correction is changed without completely correcting the color temperature. By reducing the amount of light (approximately 95% in quantitative terms), it is possible to bring it even closer to the sense of the eye. This is because color temperature correction is considered to be incomplete due to the characteristics of the human eye even for color temperatures within the above-mentioned predetermined range.

Furthermore, in addition to the case where two color filters, R and H, are used as the colorimetric sensor 4 of the apparatus shown in FIG. 1(A), when three color filters, R, G, and H are used,
) It is possible to expect the same effect as in the case of using two colors by outputting the specific stored value shown in FIG.

(Effects of the Invention) As described above, according to the present invention, offset adjustment is performed on the outputs of a plurality of color sensors that detect mutually different color signals, and the outputs of the color sensors subjected to the offset adjustment are subjected to arithmetic processing. Color temperature information is formed, and when this color temperature information is outside a predetermined level range, the output of the color temperature information forming means is controlled to gradually decrease, so the color temperature of the subject is extremely high or low. In this case, it is possible to obtain an image that is closer to the sensation seen with the human eye.

[Brief explanation of the drawing]

FIG. 1(A) is a block diagram showing the overall configuration of an embodiment of the colorimetric sensor device of the present invention, and FIG. 1(B) is the same diagram (A).
A diagram showing an example of the output characteristics of color temperature information in the embodiment, FIG. 2 (C) is a diagram showing another example, and FIG. 2 shows the final amplifier section and offset section in FIG. A circuit diagram showing an example, FIG. 3 is an explanatory diagram showing the principle of off-top-2-t adjustment in an embodiment of the present invention, and FIG. 4 (a) is an explanatory diagram showing a comparative example of the offset adjustment method. (B) is an explanatory diagram showing an example of the offset adjustment method in the embodiment of the present invention, FIG. 5 is a circuit diagram showing an example of the level detection circuit in the embodiment of FIG. 1(A), and FIG. Figure 1 (A
) is a flowchart illustrating the operation of the embodiment. Explanation of symbols 1: Decode section, 2: Select input terminal, 3: Switch section, 4: Colorimetric sensor, 5: Log amplifier section, 6: Final amplifier section, 8: Current shunt section, 9: Offset section, 10: Mode setting input terminal, 11: A/D converter, 12: memory,
13: Arithmetic circuit, 14 two-level detection circuit, 16, 17:
Gain control amplifier, Ml to M6: memory, SC system controller. Figure 1 (B) Figure 3 Figure 5

Claims (4)

[Claims] (1) A plurality of color sensors that detect mutually different color signals, a means for adjusting the offset of the output of the color sensor, and arithmetic processing of the offset-adjusted output of the color sensor to generate color temperature information. A colorimetric sensor device comprising: means for forming color temperature information, the output change of which is controlled to gradually become smaller when the color temperature information is outside a predetermined level range. (2) When the color temperature information is outside a predetermined level range, means for controlling the output change to gradually decrease over a plurality of stages in an upper region and a lower region outside the predetermined level range, respectively. A colorimetric sensor device according to claim (1). (3) When the color temperature information is outside a predetermined level range, the measurement device includes means for controlling the output change so that it continuously decreases in an upper region and a lower region outside the predetermined level range, respectively. Color sensor device. (4) The colorimetric sensor device according to any one of the above claims, wherein the color temperature correction is adjusted so that the degree of color temperature correction is weakened even when the color temperature information is within a predetermined level range.