JPH0553218B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention provides data output means for spectral sensitivity correction that measures the intensity of blue, green, and red regions of an incident light beam, and corrects the spectral sensitivity of a photosensitive means based on the measured values. Regarding.

2. Description of the Related Art For example, a color meter is a known device for determining the intensity of incident light in the blue, green, and red regions in order to obtain correction data for matching the color balance of an illumination light source with that of a photosensitive means. There is.

Problems to be Solved by the Invention By the way, if the intensity of the incident light is absolutely insufficient, there is a risk that correct correction data cannot be obtained, and the reliability of the correction data will decrease.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a data output device for spectral sensitivity correction that can easily determine whether the obtained correction data is highly reliable.

Means for Solving the Problems In order to achieve the above object, the data output device for spectral sensitivity correction of the present invention has the following features as shown in FIG.
A first photometric circuit 1001 outputs a signal corresponding to the incident light intensity in the red region of the incident light beam, a second photometric circuit 1002 outputs a signal corresponding to the incident light intensity in the green region, and a second photometric circuit 1002 outputs a signal corresponding to the incident light intensity in the blue region. a third photometric circuit 1003 that outputs a signal corresponding to the intensity of the incident light;
a calculation means 1004 for calculating correction data for correcting the spectral sensitivity of the photosensitive means based on the signals from the first, second and third photometry circuits, and based on the output of the second photometry circuit; determining means 10 for determining whether the incident light intensity is below a predetermined value.
05, and signal output means 1006 for outputting a signal indicating that the correction data is unreliable when the determination means determines that the incident light intensity is less than a predetermined value. There is.

Function In the data output device for spectral sensitivity correction of the present invention having the above configuration, the first, second and third photometric circuits 1
Based on the signals from 001, 1002, and 1003, calculation means 1004 calculates correction data for correcting the spectral sensitivity of the photosensitive means. At the same time, based on the signal corresponding to the incident light intensity in the green region from the second photometric circuit 1002, the determining means 1005 determines whether the incident light intensity is below a predetermined value, and as a result of the determination, the incident If the light intensity is below a predetermined value, the signal output means 1006 outputs a signal indicating that the correction data is unreliable.

Correspondence with Embodiments The following is a correspondence between the means constituting the present invention shown in FIG. 5 and the embodiments of the present invention described later.

That is, the analog circuit 10 shown in FIG.
2,1003, more specifically, the photometric circuit 2 for the red area, the photometric circuit 3 for the green area, and the photometric circuit 1 for the blue area shown in FIG.
are the first, second, and third photometric circuits 100, respectively.
1,1002,1003. The microcomputer 300 in FIG. 3 corresponds to the calculation means 1004, the discrimination means 1005, and the signal output means 1006.
~ Steps #17, #19, #69, #71, #73 and #75 ~ of the flowchart shown in Figure 4-4
#79 is sent to the calculation means 1004, step #43 is sent to the discrimination means 1005, and step #45 is sent to the signal output means 1.
Corresponds to 006.

Example The following example shows an LB filter used for color correction in photography (which corrects the deviation between the overall color balance from red to blue in a light source and that in the film used), and a CC filter used for color correction in photography.
It is configured as a color meter that obtains information for determining a filter (a device that locally corrects the discrepancy between the color balance of a specific color area for red in the light source and that in the film used). Here, before explaining the embodiments, preliminary matters regarding color correction for color balance will be explained first.

Regarding black body radiation, the difference between the intensity of light rays with arbitrary two wavelengths λ ₁ and λ ₂ , I ₁ and I ₂ , and the photographic color temperature (Tx Kelvin) determined by the intensity of these two wavelengths is 10 ⁶ /Tx = 1 /k ₂ · {1n (I ¹ /I ² )−k1} ...(1) It is known that the following relationship exists. Here, k ₁ =5·1n(λ ₂ /λ ₁ ), k ₂ =(1/λ ₂ −1/λ ₁ )·C C; are constants. It is also well known that Mx=10 ⁶ /Tx is expressed in Mrd (milled) units. Here Mrd is Micro
It is an abbreviation of Reciprocal Degree.

Note that with an actual measuring device, it is difficult to measure the intensity of a light beam of only one wavelength, and in reality, the output In of the measuring device is In=∫I·Sn·dλ. Here, Sn is the spectral sensitivity of the measuring device. Also, the wavelength λn compatible with this measurement device
is also expressed as λn=∫λ・Sn・dλ.

The above relationship is expressed as the intensity of light in the blue region at the light source.
Applying Ib to the intensity Ir of the light ray in the red region, we get the following:
Mb is obtained. This is called the BR ratio.

M _b = 10 ⁶ /T _b = 1/k _2b・(1nI _b / _9r −k _1b ) ...(1-1) k _1b = 5・1nλ _r /λ _b , k _2b = (1/λ _r − 1/λ _b )・
C I _b =∫I・S _b・dλ, I _r =∫I・S _r . dλ λ _b =∫S _b ． λ.dλ, λ _r =∫S _r・λ・dλ S _b ; Spectral sensitivity of the photometric circuit in the blue region S _r ; Spectral sensitivity of the photometric circuit in the red region Similarly, the intensity I _r of the light ray in the red region at the light source and The following M _g can also be obtained for the intensity I _g of the light ray in the green region. This is called the GR ratio.

M _g = 10 ⁶ /T _g = 1/k _2g・(1nI _g /I _r −k _1g ) ...(1-2) K _1g = 5・1n(λ _r /λ _g ), k _2g = (1 /λ _r −1/λ _g )・C I _g =∫I・S _g・dλ, λ _g =∫λ・S _g・dλ S _g = Spectral sensitivity of the photometric circuit in the green region The difference between the LB filter and the CC filter In the case of correction by combination, the value M _f corresponding to the color temperature of the film type used, the above B-R ratio M _b and G-R ratio
Based on M _g , M _b −M _f = LB (milled) ……(2) M _g −(M _b −M _f )−M _f = M _g −M _b = CC ……(3) ( milled) is obtained. Here, M _f =10 ⁶ /T _f ... (4) T _f is the color temperature of the film used. The above LB is called a light balancing factor, and indicates the difference between the BR ratio suitable for the film used and the BR ratio of the measured illumination light source. In addition, the CC mentioned above is called a color compensating factor, which is a combination of the G-R ratio suitable for the film used and the G-R ratio corrected based on the measured illumination light source and LB factor. This shows the deviation.
As mentioned above, the measurer uses this LB factor, CC
By using a color filter (LB filter, CC filter) suitable for the factor, it is possible to take pictures with a color balance suitable for the film being used.

FIG. 1 is a circuit diagram showing a first embodiment of the invention. Circuit 1 consisting of a filter F ₀ that passes only the blue region of the incident light rays, a light receiving element PD ₀ , a logarithmic compression diode D _{0 and} an operational amplifier OA ₀
is a blue region photometry circuit that outputs a voltage V _b obtained by logarithmically compressing the incident light intensity in the blue region of the incident light beam. A filter that only passes rays in the red area
A circuit 2 consisting of F ₂ , a light receiving element PD ₂ , an operational amplifier OA ₂ , and a logarithmic compression diode D ₂ generates a voltage that logarithmically compresses the incident intensity of the red region of the incident light beam.
This is a photometric circuit for the red region that outputs _Vr . Filter F ₃ that passes only light in the green region, light receiving element
PD ₄ , logarithmic compression diode D ₄ , operational amplifier OA ₄
The circuit composed of outputs a voltage V _g that is logarithmically compressed the intensity of the green region of the incident light.
This is a photometric circuit for green areas.

E ₀ is the voltage corresponding to k ₁ b in equation (1-1)
A constant voltage source that outputs V _1b , E ₂ is the equation (1-2)
It is a constant voltage source that outputs a voltage V _1g corresponding to k _1g . The circuit 40 composed of resistors R ₀ to R ₁₀ and operational amplifier OA _b is a subtraction circuit in which the resistance values of resistors R ₀ , R ₂ , and R ₄ are equal, and the resistance values of resistors R ₆ , R ₈ , and R ₁₀ are equal. are becoming equal. The circuit 42 composed of resistors R ₁₂ to R ₂₂ and operational amplifier OA ₈ is a subtraction circuit, and includes resistors R ₁₂ , R ₁₄ ,
The resistance value of R ₁₆ is equal, and the resistance values of resistors R ₁₈ , R ₂₀ , and R ₂₂ are equal. The circuit 50 composed of resistors R ₂₄ and R ₂₆ and operational amplifier OA ₁₀ is an inverting amplifier circuit, and the ratio R ₂₆ /R ₂₄ of resistors R ₂₄ and R ₂₆ is 1/|k _2b | in equation (1-1). Compatible. The circuit 52 composed of resistors R ₂₈ and R ₃₀ and operational amplifier OA ₁₂ is an inverting amplifier circuit, and the ratio R ₃₀ /R ₂₈ of resistors R ₂₈ and R ₃₀ is (1-2).
It corresponds to the equation 1/|k _2g |.

Means amplifier OA ₁₄ , OA ₁₆ , transistor BT ₀ ,
BT ₂ , BT ₄ , resistor R ₃₂ , constant voltage source E ₄ , diode
The circuit 60 composed of D ₆ is a reciprocal calculation circuit that performs the calculation T _b (Kelvin) = 10 ⁶ /M _b (5). operational amplifier
OA ₁₈ , OA ₂₀ , transistor BT ₁₀ , BT ₁₂ ,
The circuit 62 composed of BT ₁₄ , resistor R ₃₄ , constant voltage source E ₆ , and diode D ₈ is a reciprocal calculation circuit that performs the calculation of T _g (Kelvin)=10 ⁶ /M _g (6).

Constant voltage source E ₈ , operational amplifier OA ₂₂ , transistor
The circuit composed of BT ₆ , BT ₈ and the light emitting diode LD ₀ is a warning circuit indicating that the photographic color temperature Tb based on the outputs of the photometric circuits 1 and 2 cannot be determined. The circuit composed of the constant voltage source E ₁₀ , operational amplifier OA ₂₄ , transistors BT ₁₆ , BT ₁₈ , and light emitting diode LD ₂ cannot determine the photographic color temperature T _g based on the outputs of the photometric circuits 2 and 3. This is a warning circuit that indicates that

The variable voltage source _E12 outputs a voltage VM _f corresponding to M _f (milled) in equation (4), which corresponds to the manually set color temperature of the film. The circuit 7 composed of the resistors R ₃₆ to R ₄₂ and the operational amplifier OA ₂₆ is a subtraction circuit that calculates the LB factor, and the resistors R ₃₆ and R ₃₈
The resistance values of resistors R ₄₀ and R ₄₂ are equal. Circuit 8, which is composed of resistors R ₄₄ to R ₅₀ and operational amplifier _{OA 28} , is a subtraction circuit that calculates _the CC factor.
The resistance values of R ₄₈ and R ₅₀ are equal.

M ₀ is a meter that displays T _b (Kelvin) as shown in formula (5), M ₂ is a meter that displays T _g (Kelvin) as shown in formula (6), and M ₄ is a meter that displays T g (Kelvin) as shown in formula (2). Meter that displays LB factor, M ₆ is CC shown by formula (3)
This is a meter that displays factors.

Next, the operation will be explained. The photometric circuits 1, 2, and 3 output the intensities of the light beams incident on the respective light receiving elements PD ₀ , PD ₂ , and PD ₄ as I _b , I _r , and I _g . Then, the outputs of the photometric circuits 1 and 2 and the voltage V _1b corresponding to K _1b from the constant voltage source E ₀ are input to the subtraction circuit 40, and the voltage V _b −V _r −V _1b =V ₆ is obtained by the subtraction circuit 40. is output from. this voltage
V ₆ corresponds to In(I _b /I _r )−k _1b .

On the other hand, the outputs of the photometric circuits 2 and 3 and the constant voltage source E ₂
A voltage V _1g corresponding to k _1g from the subtraction circuit 42 is inputted to the subtraction circuit 42, and a voltage of V _g −V _r −V _1g =V ₈ is outputted from the subtraction circuit 40 . This voltage V ₈ corresponds to 1n(I _g /I _r )−k _1g .

The output voltage V ₆ from the subtraction circuit 40 is input to the inverting amplifier circuit 50, and this output voltage V _Mb is expressed as follows: V _Mb = −R ₂₄ /R ₂₆ · V ₆ = −R ₂₄ /R ₂₆ · (V _b − V _r −V _1b ), and furthermore, R ₂₄ /R ₂₆ = 1/|k _2b |, so V _Mb is M _b = 1/k _2b・{1n(I _b /I _r )−k _1b } ( 1-1). On the other hand, the output voltage V ₈ from the subtraction circuit 42 is input to the inverting amplifier circuit 52, and this output voltage V _Mg is expressed as follows: V _Mg = −R ₃₀ /R ₂₈・V ₈ = −R ₃₀ /R _{28 g} −V _r −V _1g ), and furthermore, R ₃₀ /R ₂₈ = 1/|K _2g |, so V _Mg is M _g = 1/k _2g {1n(I _g /I _r )−k _1g }
...(1-2) is supported.

The output V _Mb of the inverting amplifier circuit 50 is output from the reciprocal calculation circuit 6
It is input to 0. In this reciprocal calculation circuit _{60 ,} first, _the input voltage V _Mb is
is converted into a current I _Mb proportional to this. this current
I _Mb is the collector current of the current mirror transistor BT ₂ , and is connected to the diode D ₆ , constant voltage source E ₄ ,
It flows into a circuit for logarithmic compression consisting of an operational amplifier _OA16 . Therefore, the output voltage of constant voltage source E ₄ is V ₂
Then, the output V ₄ of the operational amplifier OA ₁₆ becomes a constant: V ₄ =V ₂ −β·1nI _Mb =V ₂ −β ₂ ·1nV _Mb β ₁ ·β ₂ ; This output V ₄ is logarithmically expanded into a current by the transistor BT _4. If the collector current of the transistor BT ₄ is I _Tb , then I _Tb = β ₃ · exp (V ₄ ) = β ₃ · exp {V ₂ − β ₂・1nV _Mb } = β ₄・exp(V ₂ )/V _Mb β ₃ , β ₄ are constants, and if the output voltage V ₂ of the constant voltage source E ₄ is selected appropriately, I _Tb is T _b = 10 ⁶ /M _b ...(5), the photographic color temperature determined by the B-R ratio has been established, and the photographic color temperature T _bK (Kelvin) is displayed by the meter M ₀ .
The reciprocal calculation circuit 62, which has the same configuration as the reciprocal calculation circuit 60, outputs an input V _Mg and a constant voltage source _E6.
Based on V ₁₀ , the collector current I _Tg of the transistor BT ₁₄ is I _Tg = β ₄ exp (V ₁₀ )/V _Mg , and this current value corresponds to T _g = 10 ⁶ /M _g ……(6) value, and the photographic color temperature T _gK (Kelvin) determined by the G-R ratio has been established.
This is displayed on meter _M2 .

When the output V _Mb of the inverting amplifier circuit 50 is higher than the output voltage V ₁₄ of the constant voltage source E ₈ , the output of the operational amplifier OA ₂₂ becomes “high”, the transistor BT ₆ becomes non-conductive, and the reciprocal calculation circuit 60 Then, the meter M ₀ becomes inoperative, and at the same time, the transistor BT ₈ becomes conductive and the light emitting diode LD ₀ lights up to issue a warning. This is because the photographic color temperature determined from the measured B-R ratio will be less than zero Kelvin K, but if the color temperature becomes less than zero Kelvin K, it cannot be defined as a color temperature, so this is a warning. It is something. Similarly, when the photographic color temperature determined from the G-R ratio measured by the constant voltage source E ₁₀ , operational amplifier OA ₂₄ , transistors BT ₁₆ , BT ₁₈ , and light emitting diode LD ₂ becomes less than zero Kelvin K, The reciprocal calculation circuit 62 and the meter _M2 are made inoperable, and a warning is given by the light emitting diode _LD7 .

The subtraction circuit 7 receives the output voltage V _Mf from the constant voltage source E ₁₂
and the output V _Mb of the inverting amplifier 50 are input, and a voltage of V _LB = V _Mb - V _Mf is output. V _Mf corresponds to M _fMrd (milled), which corresponds to the color temperature of the film used, shown in equation (4), and V _Mb corresponds to M _bMrd (milled), so V _LB is (2 ) corresponds to the LB factor shown in the formula, and this is displayed by meter M ₄ .

The subtraction circuit 8 receives V _Mb and the inverting amplifier circuit 52.
V _Mg is input and a voltage of Vcc = V _Mb - V _Mg is output. This is because V _Mg corresponds to M _gMrd (milled), so the voltage Vcc corresponds to the CC factor shown in equation (3), which is the meter
Displayed by M ₆ .

In this embodiment, a circuit is provided to issue a warning when the outputs V _Mb and V _Mg of the inverting amplifiers 50 and 52 exceed V ₁₄ and V ₁₆ , respectively. It is also possible to add a circuit that similarly issues a warning when a light source that becomes too large is measured. To realize this, a warning may be issued when the outputs of the inverting amplifiers 50 and 52 fall below a predetermined value, and a circuit configuration similar to the warning circuit shown in FIG. 1 may be used.

Fig. 2 is an external view of a color meter to which this invention is applied, Fig. 3 is an internal circuit diagram of this color meter, and Figs. This is a flowchart showing the operation of a computer (hereinafter referred to as μ-com). First, the configuration shown in FIG. 2 will be explained, as well as its general functions. 12 is a light receiving section in which three filters and a light receiving element are provided. SS is a slide switch that sets the film type.When it is in the B position, the B type (tungsten type, color temperature 3200K) is set, and when it is in the A position, the A type (tungsten type, color temperature 3200K) is set.
3400K) is set. D when in position D
The type (daylight type, color temperature 5500K) is set. Further, when it is in the V position, the set color temperature of the film becomes variable.

FS is a button that is pressed when you want to change the film, and when this button is pressed, the display section 22 will be
Film and K are displayed to indicate that it is a Film setting operation, the data corresponding to the position of the slide switch SS is read, the color temperature is displayed on the display section 24, and the color temperature is set on the display section 28. Displays the film type B, A, D or V indicating that it is variable. Also, when the film type is variable, press the UP button at the same time as the FS button.
When the US or DOWN button DS is pressed, the color temperature of the film, which is set at regular intervals while the two buttons are pressed, changes, and the set value is displayed on the display section 24. When the UP button US is pressed, the set color temperature increases, and when the DOWN button is pressed, the set color temperature decreases.
When you release the UP or DOWN button, the current color temperature display is fixed, and that value is stored as the film's color temperature setting. Note that the color temperature to be set has an upper limit and a lower limit, and when this value is reached, the set value and display value do not change even if the buttons US and DS are pressed. Further, even if only the buttons US and DS are pressed, the set values and displayed values do not change.

LS is the button you press when you want to know the LB factor. When measured values are being taken in, LB is displayed on the display section 22, and the display section 24 shows LB.
Factors are displayed. Furthermore, when no measured value has been taken in, nothing is displayed on the display section 24, but when the measurement button MS is pressed and a measured value is taken in, the LB factor is displayed on the display section 24 based on that value. be done. CS is a button to press when you want to know the CC factor, and when this button is pressed, CC is displayed on the display section 22. Also,
Similar to the LS button, the CC factor is displayed on the display 24 when the measured value is being captured.
If the measurement value has not been imported, press the measurement button.
Nothing is displayed on the display section 24 until MS is pressed and the measured value is taken in. KS is B-R
This button is pressed when you want to know the photographic color temperature determined from the ratio.When this button is pressed, the display section 2
2, K is displayed, and as with LS and CS, the photographic color temperature is displayed on the display 24 when measured values are being captured, and nothing is displayed on the display when no measured values are being captured. is not displayed either. Incidentally, no matter which button is pressed, a display indicating the set film type is displayed on the display section 26.

When the measurement button MS is pressed, a measurement is performed except when the film type setting mode is selected, and as long as this button MS is pressed, the measurement is repeated and the new measurement value is used. The actual LB factor or CC factor or photographic color temperature is displayed. When the FS button is pressed and the mode is set to set the film type, no measurement is performed even if the measurement button MS is pressed. Furthermore, when the brightness of the light source to be measured becomes less than a predetermined value, the calculated data is unreliable, so the display section 24 displays the calculated data in a blinking manner. Further, in the case of displaying photographic color temperature, when the calculated data reaches the upper limit or lower limit, the display section 24 blinks and displays the upper limit or lower limit value. Further, the entire display remains the same for a certain period of time when a button is operated (if it is blinking, it continues to blink), and after a certain period of time, nothing is displayed.

Next, the configuration of FIG. 3 will be explained. 300 is a one-chip μ-com whose circuit is composed of, for example, a C-MOSFET, has low power consumption, and is constantly supplied with power from the battery _E20 . This μ-com30
0 contains RAM302 and accumulator
ACC, 304, carry flag CY, 306, logical operation circuit ALU, 308, address counter
Ad・Cou・,310, ROM312, frequency divider
DIV, 314, clock generator 31
6. Input port IP ₁ ~ ID ₃ , output port OP ₁ ~ _{OP 6}
There are various other circuit blocks, but they are omitted because they are not directly related to the explanation.

Within RAM 302 are registers with various labels. The functions of these registers will be explained below. MTC is a register that counts the time from the end of a button operation until the display disappears. MRD is a register for setting color temperature data of a set film type, and in this embodiment, Mf=10 ⁶ /T _fMrd is set. Fixed data for B type is K ₄ , fixed data for A type is K ₅ , fixed data for D type is K ₆
It is shown. The MDD is set with data to be displayed on the display section 24, and the data when it is blankly displayed (nothing is displayed) is indicated by _K3 . Further, among the color temperature display limit values, data corresponding to the upper limit is shown as K ₁ , and the lower limit is shown as K ₂ . MDM is a register that sets the determination result of the operation mode; 8 is in film type setting mode, 4 is in LB factor calculation mode, 2 is in CC factor calculation mode, and 1 is in color temperature calculation mode. Set. MFL is a register that becomes 1 when all measurement data has been captured, and becomes 0 when no measurement data has been captured. MRN indicates which of the outputs V _Mb , V _Mg , and V _g from the analog circuit 10 is output to the A-D converter circuit 20.
This register is input with a signal to switch whether to input it to V _Mb when it is 4, and V _Mg when it is 2.
When it is 1, V _g is input. MGF is a register that becomes 1 when the measurement button MS is pressed to perform a measurement operation, and becomes 0 otherwise. MFJ is
This register is set to 1 when the level of V _g is below a predetermined value (when the amount of incident light is small) and it is necessary to flash the display to issue a warning, and otherwise set to 0. MFC is a register that is set to 1 when performing a blinking display or a blank display, and is set to 0 when displaying data. MRA is
This is a register that takes in data α from input port IP ₁ , and when the set film type is B, it is 8,
This register is 4 when it is A, 2 when it is D, and 1 when it is variable. MUD is a register that becomes 2 when the down button DS is pressed, 1 when the up button US is pressed, and 0 when neither is pressed. MJU is a register that becomes 1 when the calculated color temperature exceeds the limit, and becomes 0 otherwise. Furthermore, MSJ is a register that takes in data from the input port (IP ₂ ) by button operation. #W is input port IP ₃
This is a register that takes in A-D conversion data from. #X is a register to which data is set when the data in register #W corresponds to M _b . #Y is a register to which data is set when the data in register #W corresponds to M _g . #Z is the data of register #W
When the data corresponds to V _g , this data is set in the register.

A strobe signal is always output from output port OP ₁ , and switches FS, LS, CS, KS,
Scanning is performed for US, DS, BSS, ASS, DSS, and VSS. In addition, the function of this 1-chip μ-com is that when a switch input or a 1 second elapsed signal from the frequency divider 314 is received in the inactive state (CEND state), a specific address of the ROM 312 (0 Execute the command from address).

The transistor BT ₂₀ is a transistor that controls power supply to the analog circuit 10 and the AD converter 20 using a signal from the μ-com 300 via the inverter IN. 10 is the photometric circuit 1, 2, shown in FIG.
3. An analog circuit consisting of constant voltage sources E ₀ , E ₂ , subtraction circuits 40 , 42 , and inverting amplifiers 50 , 52 .The output is from the inverting amplifiers 50 , 52 .
V _Mb , V _Mg and V _g from the photometric circuit 3 are output.
FETFT ₀ , FT ₂ , FT ₃ are analog switches,
From the output port OP ₃ of μ-com300 to the above
The data in the MRN register is output, and when it is 4, the FET (FT ₀ ) is conductive, and V _Mb is input to the A-D converter 20, and when 2 is output, the FET (FT 0 ) is turned on.
(FT ₂ ) is conductive and V _Mg is input, and when 1 is output, FET (FT ₄ ) is conductive and V _g is input. Note that V _g is used to determine whether the incident light is greater than or equal to a predetermined value. 20 is an A-D converter, which starts operating with a signal from the output port OP ₃ of μ-com300, and the A-D conversion result is sent to the input port.
Incorporated into μ-com from IP ₃ . 22 is the second
The display sections 22 and 24 in the figure are the display sections 24 and 2 in FIG.
Reference numeral 6 corresponds to the display section 26 in FIG. 2, and is made of, for example, liquid crystal.

MSW is a switch that is closed when you press the photometry button MS in Figure 2, FSW is a switch that is closed when you press the film type setting button FS in Figure 2,
LSW is a switch that is closed when you press the LB calculation button LS in Figure 2, CSW is a switch that is closed when you press the CC calculation button CS in Figure 2, and KSW is for color temperature calculation in Figure 2. The switch that is closed when the button KS is pressed, USW is the switch that is closed when the button US is pressed to increase the set color temperature of the film shown in Figure 2, and the DSW is the switch that is closed when the button US is pressed to increase the set color temperature of the film shown in Figure 2. This is a switch that is closed by pressing down on the button DS, which is pressed when decreasing the color temperature. BSS is the switch that is closed when the slide switch SS in Figure 2 is in position B, and ASS
is a switch that is closed when slide switch SS in Figure 2 is in position A, DSS is a switch that is closed when slide switch SS in Figure 2 is in position D, and VSS is a switch that is closed when slide switch SS in Figure 2 is in position D.
This is a switch that is closed when SS is in the V position.

Next, the operation shown in FIG. 3 will be explained according to the flowcharts shown in FIGS. 4-1 to 4-4. In addition, the fourth
Figures 1 and 4-2 mainly show flowcharts for measurement, calculation, and display operations, Figure 4-3 mainly shows flowcharts for button discrimination and setting operations, and Figure 4-4. The figure shows a flowchart of the display operation when no button operations are performed.

When an input from a button or a 1 second signal from the frequency divider 314 is received, the μ-com 300 starts operating from an instruction at a specific address in the ROM 312.
In step #2, it is determined whether the start of operation is due to a 1-second signal or a signal from a button.
If it is a 1 second signal, move to step #81 in Figure 4-4. If it is not a 1 second signal, in order to determine which button is pressed in step #3,
Data from input port IP ₂ is taken into register MSJ in RAM 302. Next, in step #4, the switch MSW is activated based on the contents of the register MSJ that has taken in the button signal in the RAM 302).
It is determined whether or not the button is closed, and if it is not pressed, the process goes to step #51 in Figure 4-3, and if it is pressed, the process goes to step #5.
In step #5, the contents of the register MDM are determined, and if MDM=8, that is, in the film type setting mode, the state is changed to CEND and the operation is stopped. That is, measurements are no longer performed when the film type is in the setting mode.

If it is determined in step #5 that it is not in the film type setting mode, in step #6, a "high" signal is output from output port OP ₃ to the inverter (IN), making transistor BT ₂₀ conductive. Then, power supply to the analog circuit 10 and the AD converter 20 is started. Then, in step #7, set register MGF to indicate that measurement is in progress.
is set, and since no measured values have been imported yet, the register becomes 1 when three measured values are imported.
MFL is set to 0, and register MRN, which specifies the data to be captured, is set to 4 to specify the data M _b to be captured first. In step #8, it is determined whether register MFL is 1 or 0. At this time, if the measurement switch MS is closed and the three measurement data have not yet been captured, register MFL is 0, so the process moves to step #21 and register MDD is blank. Set data _K3 for register MRA,
The MDM is determined, the set film type is displayed on the display section 26, the set calculation mode is displayed on the display section 22, and the process moves to step #24.

If the measurement switch MS is closed and all three pieces of measurement data are complete at step #8, or after the button discrimination operation described below according to Figure 4-3, the measurement data is When all are present, move on to step #9 and register.
The calculation mode is determined by determining the contents of the MDM. When register MDM is 1, BR ratio M _b
The mode shifts to a mode for calculating the resulting photographic color temperature (step #10), and the following calculation is performed: T _b =10 ⁶ /M _b (5). Next, in step #11,
Determines whether the calculated data exceeds the display limit value, and if it does not, stores the display data corresponding to the calculated data in the register MDD.
and set the register so that the blinking display is not performed.
Set MJU to 0 and move to step #24.
If it is determined in step #11 that the display limit is exceeded, the upper limit data is displayed in step #14 or #15.
Set _K1 or lower limit data _K2 in register MDD, set register MJU to 1 so that a blinking display is performed, and proceed to step #24.

If the contents of register MDM are 2 in step #9, move to CC calculation, and in step #17 calculate CC = M _g × M _b ... (3) and set the display data to register MDD. Then move on to step #24.

When the contents of register MDM are 4 in step #9, it is the LB calculation mode, and in step #19, the calculation LB=M _b − M _f ...(2) is performed and the display data is transferred to register MDD. Set it and move on to step #24.

In step #24, it is determined whether photometry is in progress by checking the register MGF. If photometry is not in progress, the process moves to step #26. If photometry is in progress, an A-D conversion start signal is sent in step #25. Output from output port OP ₃ . Note that the time required from step #6 to step #25 is longer than the time required for the analog circuit 10 to stabilize.

In step #26, register MFJ is determined to be 1 when the output level of the photometric circuit is below a predetermined value in steps #42 to 45, which will be described later.If MFJ is not 1, then register MJU is determined to be 1 or not. If this value is also not 1, the process moves to step #32 and displays based on the MDD data. When register MFJ or MJU is 1,
In step #28, determine whether register MFC is 1, and if it is 1, set blank display data _K3 in register MDD and set MFC to 0.
In step #32, a blank is displayed on the display section 24. Also, register MFC is set to 1 in step #28.
If not, set MFC to 1 and display the contents of register MDD on the display section 24 in step #32. That is, the operations #26 to #32 are MFJ, MJU
When is 1, the calculated data and blank are alternately displayed on the display section 24 each time this step is passed, thereby producing a blinking display.

In step #33, it is determined whether measurement is in progress or not. If measurement is not in progress, that is, if an operation is performed by pressing a button other than the measurement button, in step #38, the display is displayed for a certain period of time. Reset the timer register MTC for continuation and stop the operation.

When it is determined in step #33 that measurement is in progress, the A-D converted data is sent to input port IP _3.
Load it into register #W from
Determine whether the MSW is closed. When the measurement switch MSW is not closed,
Move to step #36 and set register MGF to 0.
as a transistor for powering analog circuits
Turn off BT ₂₀ and proceed to step #38 above. At step #35, turn on the measurement switch.
When it is determined that the MSW is closed,
Proceed to step #39 and determine the contents of register MRN. When the contents of register MRN are 4, the input voltage to the AD converter 20 is V _Mb , and the data taken into register #W is set to register #X. When MRN is 2, the AD converted data corresponds to M _g , and this data is set in the #Y register. Furthermore, when MRN is 1, the A-D converted data corresponds to the output V _g of the photometric circuit 3 in Fig. 1, and this data is set in the #Z register, and then this data is Determine whether the value is below the value. This is to warn you that when the amount of incident light is less than a predetermined value, the calculated data is unreliable. Then, when it is less than a predetermined value, 1 is set in register MFJ, and when it is more than a predetermined value, it is set to 0. This MFJ is set to 1, and when it is equal to or greater than a predetermined value, 0 is set. This MFJ is the aforementioned #26
It is used in step #87 and step #87 described below to determine whether or not to blink the display. In addition,
The time required from step #25 to step #34 is longer than the time required for AD conversion.

In step #46, the bit in register MRN that is set to 1 is shifted one bit to the lower side.
That is, when it is 4, it is set to 2, when it is 2, it is set to 1, and when it is 1, 1 is sent to the carry 306. In step #47, it is determined whether the carry 306 is 1 or not. If it is not 1, the process moves to step #50, outputs the contents of MRN to output port _OP2 , and returns to step #8. Also, carry 3 in step #47.
When 06 is 1, it means that three pieces of data have been taken in, so 1 is set in register MFL, 4 is set in register MRN, and the process moves to step #50 described above.

The above is the main operation when the measurement button MS is pressed, and while the measurement button MS is pressed, three data are repeatedly acquired in order, and each time based on these data, Calculation and display are performed according to the set calculation mode, and when the measurement button MS is released, the operation shifts to a time counting operation that continues the display.

Next, the operation when a button other than the measurement button is operated will be explained according to FIG. 4-3. #3
The data loaded into register MSJ in step #51, 54, 57, and 60 is determined, and when calculating K, set register MDM to 1 and display on display 2.
Display K to 2 and when in CC calculation mode,
Set MDM to 2 to display CC on the display section 22, set MDM to 4 to display LB when in LB calculation mode, and set MDM to 8 to display Film when in film type setting mode. Show #63
Move on to the next step.

In step #63, the contents of the register MDM are determined, and if MDM≠8, the calculation mode is entered, so the process moves to step #8 described above, and if the measurement value acquisition is completed, the set calculation is performed. After performing calculations and display according to the mode, the operation is stopped and the operation shifts to a constant time counting operation. Also, if measurement values are not being imported, #21
Through the following steps, the display section 26 displays the information and then stops the operation.

If MDM=8 in step #63, the process moves to step #64 and subsequent steps for film type setting mode. In step #64, data α corresponding to the states of switches BSS, ASS, and VSS from input port IP ₁ is taken in and set in register MRA. Next, it is determined whether the contents of the register MRA are 1 or not. If it is not 1, it is necessary to set the type of B, A, or D, so the process moves to step #68. If it is 1, the set color temperature of the film is selected. Since is variable, move to step #75.

In step #68, the contents of register MRA are determined, and when MRA = 8, data K ₄ (data in millets) corresponding to B type film is set in register MRD, and B is displayed on display section 26. Display and move on to step #10. When MRA=4 in step #68, data K ₅ (milled) corresponding to the A type film is set in the register MRD, A is displayed on the display section 26, and the process moves to step #10. When MRA=2 in step #68, data K ₆ corresponding to D type film
Set (Milled) to MRD and display D.
Move to step #10.

When the process moves from step #67 to step #75, the set color temperature of the film is variable. In this case, determine the contents of register MUD, and MUD =
If it is 0, neither the UP nor DOWN button has been pressed, so the process moves to step #80 and display section 2 is pressed.
Display V at 6 and move to step #10.
When MUD = 1, compare the contents of MRD with the lower limit value, and if the lower limit has been reached, proceed to step #80; if the lower limit has not been reached, register
Subtract 1 from the contents of MRD and move to step #80. In step #75, when MUD = 2, compare the contents of MRD with the upper limit value in step #78, and if the upper limit has been reached, proceed to step #80; if the upper limit has not been reached, proceed to step #80. Add 1 to the contents of MRD and move to step #80.

When returning from steps #70, #72, #74, and #78 to step #10, T _f =10 ⁶ /M _f ...(4) is calculated based on M _f set in register MRD. , performs a display, and then stops the operation. When the operation reaches the CEND state, Film
Button FSW and UP button USW or DOWN button
If DSW is pressed, the operation will be performed again and the set value will be changed. That is, while this button is pressed, the set value is changed at regular intervals.

FIG. 4-4 is a flowchart regarding the operation of continuing the display for a certain period of time after the button operation is completed. Frequency divider 314 in CEND state
When there is a 1 second signal from , the μ-com 300 starts operating, moves to step #81, adds 1 to the timer register MTC, and determines whether an overflow has occurred. When it overflows,
Set the register MFL, which indicates that the measurement value has been captured, to 0, set the registers MFJ and MJU, which indicate that a blinking display is to be performed, to 0, and set the blank display data _K3 to the display data register MDD. Eliminate the display on the display sections 22 and 26,
Outputs MDD data _K3 and enters CEND state. Therefore, nothing will be displayed on the display section from now on unless a button operation is performed.

If there is no overflow in step #82, it is determined whether the display is blinking in steps #87 and 88, and if it is not a blinking display, the process moves to step #94 and the display is continued. When it is determined in #87 and 88 that the display is blinking, it is determined in step #89 whether the register MFC is 1 or not. If it is 1, MFC is set to 0 and a blank display is displayed in the MDD. data and move on to step #94.

If MFC is 0, set MFC to 1,
Set the display data in the MDD and proceed to step #94. Therefore, when the operation related to the button operation is completed, the display continues for a certain period of time, and if blinking for warning is necessary, blinking is performed at a cycle of 1 second.

In addition, in the above embodiment, first the BR ratio and the G
-R ratio is determined and calculations are performed based on this ratio, but the present invention is different from the B ratio as in conventional color meters.
-The purpose is not to find the R ratio and the G-R ratio, but to find the light balancing factor and color compensating factor, so we use the above B-R ratio and G-R ratio. The present invention is not limited to embodiments that perform calculations. In other words, the light balancing factor is essentially a value that is uniquely determined by giving the light intensity in the blue region, the light intensity in the red region, and the color temperature of the film, while the color compensating factor , green, and red light intensity and the color temperature of the film, so any intermediate calculation process is possible; This is because there is no need to ask for it.

Also, the explanation so far is based on the LB with the following effect.
This was done on the premise of using a filter and a CC filter. That is,
The LB filter has the function of matching the entire slope of the characteristic curve of the color balance of the blue source with that of the film using red as the reference light, and the CC filter has the function of matching the entire slope of the characteristic curve of the above characteristic curve between the light source and the film. This is based on the premise that it has the effect of correcting local deviations in the characteristic curve, particularly in the green area, under conditions where the values match. A color meter was used to select the appropriate correction strength for each of the LB and CC filters.

However, color correction is not limited to the combination of an LB filter and a CC filter as described above, and the following methods are also available.
That is, first, the CC filter that has a local correction effect in the green area is used to correct only the green area (in this case, the LB filter is not used), and then the second CC filter that has a local correction effect in the blue area is used. In this method, by correcting only the blue region using CC filter 2, the overall color balance characteristic curve from red to blue is matched between the light source and the film.

In this case _, when expressed using _the B-R ratio M _b and the _G - _R ratio M _{g , CC 1 and} CC ₂ serves as an index for local correction in the green area and local correction in the blue area (both are color convensating factors). Therefore, the present invention is not limited to displaying the combination of the light balancing factor LB and the color compensating factor CC as in the above embodiment, but is also applicable to the display of the color compensating factor CC ₁ and the color compensating factor CC. It may be configured to display combinations of factors CC ₂ . This is possible by slightly modifying the above embodiment. In addition, in this case as well,
As can be seen from the definitions of CC ₁ and CC ₂ , the color convensating factor CC ₁ is essentially a value that is uniquely determined given the light intensity of the green and blue regions and the color temperature of the film. , On the other hand, the color compensating factor CC ₂ is also a value that is uniquely determined given the light intensity of the blue and red regions and the color temperature of the film, so as in the case of the above embodiment, Not necessarily B-
There is no need to go through the steps of determining the R ratio M _b and the G-R ratio M _g , and the calculation process in the middle is optional.

Note that the present invention is applicable not only to silver halide color films but also to a wide range of general photosensitive means (e.g. electronic imaging devices).
Needless to say, this method can be applied to a photographing device using a . In this case, the "film type or color temperature corresponding thereto" in the embodiments is understood to be "information corresponding to the spectral sensitivity of the photosensitive means."

Effects of the Invention As described above, according to the present invention, spectral sensitivity correction data is calculated from the incident light intensity in each of the red, green, and blue regions, and even if the incident light intensity in the green region is below a predetermined value, For example, since a signal indicating that the correction data is unreliable is output, it is possible to easily determine whether the obtained correction data is highly reliable. And this discrimination is the second
Since this is carried out based on the output of the photometric circuit, there is no need to provide a separate photometric circuit for measuring the intensity of incident light in order to determine reliability, and the number of parts and cost can be reduced. In addition, since the green region occupies almost the middle region of the incident light beam, it is less affected by changes in the spectral sensitivity of the light source than the red and blue regions, and therefore the output of the green region is It can represent the intensity of the incident light beam. Therefore, based on the output in the green region, compared to the red and blue regions,
Reliability can be determined more accurately.

Note that the device of the present invention can also be used as a data output device for spectral sensitivity correction for an automatic white balance adjustment device in a video camera, and its utility value is high.

[Brief explanation of the drawing]

Fig. 1 shows a first embodiment of the present invention, Fig. 2 is an external view of a color meter to which the invention is applied, and Fig. 3 shows a color meter according to the present invention.
The figures show the second embodiment of this invention, Nos. 4-1 to 4-4.
This figure is a flowchart showing the operation of μ-com in FIG. 3, and FIG. 5 is a block diagram showing the data output device for spectral sensitivity correction of the present invention. 1001...First photometric circuit, 1002...Second photometric circuit, 1003...Third photometric circuit, 1004
...Arithmetic means, 1005...Discrimination means, 1006...Signal output means.

Claims (1)

[Claims] 1. A first photometric circuit that outputs a signal corresponding to the incident light intensity in the red region of the incident light beam, a second photometric circuit that outputs a signal corresponding to the incident light intensity in the green region, and a second photometric circuit that outputs a signal corresponding to the incident light intensity in the green region. a third photometric circuit that outputs a signal corresponding to the light intensity; and a calculation that calculates correction data for correcting the spectral sensitivity of the photosensitive means based on the signals from the first, second, and third photometric circuits. means for determining whether the intensity of the incident light is less than or equal to a predetermined value based on the output of the second photometric circuit; 1. A data output device for spectral sensitivity correction, comprising: signal output means for outputting a signal indicating that the correction data is unreliable when the correction data is unreliable.