JPS6296826A - Multiplex light measuring apparatus - Google Patents

Abstract

PURPOSE:To operate and take out the adequate output of light measurement in accordance with classification, by dividing an object field onto a plurality of regions, measuring light, standardizing the photoelectric outputs based on the average outputs of the obtained photoelectric outputs, and classifying the object field based on the standardized outputs. CONSTITUTION:A classifying circuit 20 receives the logic outputs from circuits 17, 18 and 19 and determines and classifies as to which specified categories these combined logics belong to. The categories are divided into three parts. A control output corresponding to each part is selectively generated. Analog switches 21, 22 and 23, which are connected between circuits 14, 15 and 16 and an apex operating circuit 24, selects the output corresponding to the classified category out of the first - third measured light outputs based on the control output of the circuit 20. The output is transmitted to the circuit 24. The circuit 24 generates an output, which corresponds to an adequate exposure value, based on the selected measured light output and other exposure factors from a data setting part 27. The output is applied to an exposure control circuit 25 and an exposure display circuit 26.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention measures the light by dividing the field into a plurality of regions, and determines the proper exposure of the entire screen from a plurality of photoelectric outputs corresponding to the plurality of regions. This invention relates to a multi-photometering device that calculates and extracts output.

Conventionally, as this type of photometric device, there is one that uses the arithmetic average value of the maximum and minimum values of multiple photoelectric outputs as the appropriate photometric output (Utility Model Publication No. 51-9271), and one that uses the arithmetic average value of the maximum and minimum values of a plurality of photoelectric outputs as the appropriate photometric output, and There is a method in which a photographer manually extracts an intermediate value and uses this intermediate value as an appropriate photometric output (Japanese Patent Laid-Open No. 17725/1983).

However, these conventional devices KFi have the following drawbacks. In other words, in the former case, the arithmetic average value is always the appropriate metering output, so in special field conditions such as backlight or when the main subject is on snow, the main subject may be underexposed or overexposed. Sometimes it becomes. In addition, even in the latter case, it not only requires skill to set the intermediate value to obtain the appropriate light output under the above-mentioned special field conditions, but because the setting operation is manual, operability is inevitably reduced. .

The object of the present invention is to analyze the situation of the photographic field based on the photoelectric output, and to provide a multi-photometering value f configured so that an appropriate photometering output can be obtained even for the photographic field under special conditions such as those mentioned above. The goal is to provide the following.

According to the present invention, a plurality of charging outputs are generated by dividing the field into a plurality of regions, photometrically measuring the field, and standardizing the plurality of photoelectric outputs based on an average output of the plurality of photoelectric outputs. A multi-photometering device is provided that classifies a field based on a standardized output and calculates and extracts an appropriate side light output based on the classified output. According to the device, multiple photoelectric outputs are normalized by the average value of multiple photoelectric outputs and the conditions of the photographic field are analyzed, so the conditions of the photographic field can be accurately detected. Therefore, it becomes possible to effectively select an appropriate photometric output according to the field conditions.

Hereinafter, the present invention is based on the first factor in which the screen and the brightness of each part of the screen are expressed as a three-dimensional figure, with the field of view (hereinafter referred to as the screen) as the bottom and the brightness of each part of the screen as the vertical axis). I will explain the basic idea. In FIG. 1 (α), considering a screen as shown on the bottom surface So, a curved surface S1 having only one brightness on the uk surface is determined. In reality, since photometry is performed using a finite number of photoelectric elements, the number of planes is equal to or less than the number of curved surface d photoelectric elements that can be captured. For example, 4 lights! When the screen is divided vertically, horizontally, and horizontally using elements, the curved surface representing the brightness of the screen is g 1 (b), (1) Figure VCSt Quantization 52~S
4 It is quantized and becomes stepwise as shown.

Doji face S! When comparing and S4, the absolute level of the brightness that makes up the quantization surface is the same, but their position on the screen is different, so the judgment for which brightness to obtain the appropriate exposure is also different. . Moreover, when comparing Dojika surface St and 53, the level difference between adjacent luminances is equal, but
Since the absolute value of the brightness between the two quantization planes is different (7+), there is also a boundary between the two quantized planes. and K into multiple categories, and determine which brightness exposure control should be applied to in each category to obtain the appropriate exposure overall.Then, for a screen under certain conditions, all exposure control The brightness to be determined can be obtained from the information regarding the brightness and the information regarding the position.

In fact, as a result of making the above correspondences for screens under various conditions, it has been found that the brightness at which fog light control should be performed in order to obtain photographs with proper exposure converges to the following three levels. That is, the first brightness level exists between the maximum value of a plurality of photometric outputs and the average value of these photometric outputs, and the second brightness level exists between the average value of these photometric outputs. It was found that a third brightness level exists between the minimum value of these photometric outputs and the average value of these photometric outputs.

This average value can be approximated by an average value, median value, or mode.

From the above, if we compare the average value of multiple photoelectric outputs with each photoelectric output and standardize the brightness in each divided screen, we can Therefore, if the screen condition is detected by pattern analysis based on this normalized output, and this detection result is correlated with the above three brightness levels experimentally or empirically, various results can be obtained. It is possible to select the brightness level at which exposure should be controlled for the screen under certain conditions.

On the other hand, the brightness level at which exposure should be controlled may be determined independently of pattern analysis. The difference between the maximum brightness and the minimum brightness is within a predetermined range, and there is little variation in brightness within the screen.

This is a case in which the maximum brightness is within a predetermined range and it can be determined that there are no bright light sources including the sun or artificial light sources such as spotlights within one screen. At this time, it has been found that good results can be obtained if K is adjusted to the second brightness level. Note that the above-mentioned standardization of multiple photoelectric outputs refers to the standardization of multiple photoelectric outputs that corresponds to the average value of multiple photoelectric outputs. The purpose of this method is to detect the magnitude relationship of one number of photoelectric outputs and convert each photoelectric output into a specific signal VCa according to the magnitude.

Hereinafter, the present invention will be explained based on examples.

FIG. 2 is a block diagram showing an embodiment of the present invention. In the same figure; the photometry circuit 10 includes a photoelectric conversion element for fully photometering each region in which the field of view is divided into a plurality of regions, and an independent analog photoelectric output Po=Pn'x corresponding to each region of the field of view:
Output. It is assumed that this photoelectric output P6 = P +s has been logarithmically compressed, and therefore the photoelectric output is expressed as an EV value. The maximum value detection circuit 11 receives the photoelectric outputs p and -p% as inputs, and detects the maximum value PaeLs'1 from these. The average value detection circuit 12 has a photoelectric output P6 ” P +%
are input, and their average value, for example, the average value Pwaa
a+% all detected. The minimum value detection circuit 13 has a photoelectric output p,
−p9 is input, and from these, the minimum value Pmani +%
Detect.

The arithmetic circuit 14 receives the maximum value PwhαX and the average value Pg−αL as input, and generates the first photometric output PH(BE”I, that is, PFIz J Py*ax+ (l −kl ) Pn
aattn --(Generates 11. Arithmetic circuit 15F
'i second photometric output PM (EV), i.e.
2), but it can actually be used as the average value detection circuit 12. The arithmetic circuit 16 calculates the minimum value Pwsin and the average value P*
Third photometric output PL (BV) as aa+% and gold input,
That is, PL-JPrfLirh+(LA!lPrmaa
n...=...(3) is generated. The circuits 11 to 16 described above constitute an appropriate III optical output generation circuit.

The binarization circuit 1T has a photoelectric output pop, and an average value Pmgα.
n is human power, and the reference output generated based on the average value Pn+-α1 and t! Compare the II original outputs p and -p to convert each photoelectric output into a logic output. At this time, ft
, the standard for standardizing the electrical output is the average value P a g
Since it is only a file, normalization and binarization are performed at four times.

The first judgment circuit 18 takes the maximum value FlcLx as all inputs, and calculates Pα≦Paα2≦Pβ (where Pα and Pβ are constants).
...Performs the judgment in (4) and generates a logical output representing the judgment result. Of course, the first determination circuit 18 uses Pα, P
It includes a circuit that generates a reference output corresponding to β. This determination operation is performed to completely identify whether the maximum value P1αX is caused by a bright light source including the sun or an artificial light source such as a spotlight. The second determination circuit 19 determines the maximum value PrR.
Using az and the minimum value PL as input, ΔP = P
aαxP□110011. Perform two calculations in (5), then α≦ΔP≦β (however, α and β are constants)...
...Performs the judgment in (6) and generates a logic output representing the judgment result. Of course, the reference output corresponding to constants α and β? The generating circuit F'i is included in the second determination circuit 19. This judgment operation judges the brightness distribution of one screen. For example, when the brightness distribution is large, the main subject is on the low brightness side, but the high brightness side is crushed, and vice versa, the main subject is on the high brightness side. This is done to prevent the phenomenon of the low brightness side being crushed.

The classification circuit 20 receives the logic outputs from one circuit 17.18.1S and determines, that is, categorizes, which of the predetermined categories the combinational logic of these logic outputs belongs to. This predetermined category is divided into three, and a control output corresponding to each category is selectively generated. circuit 14
．． Analog switches 21, 22, and 23 connected between 15 and 16 and the apex calculation circuit 24 are connected to the first to third ti5' control outputs of the classification circuit 20, respectively.
Outputs corresponding to the classified categories are selected from among the photometric outputs and transmitted to the apex calculation circuit 24.

The apex calculation circuit 24 calculates an appropriate exposure value (
It generates an output corresponding to the shutter speed and aperture value, and applies this to a known exposure control circuit 25 and exposure display circuit 26.

Next, the operation and the mode of classification by the classification circuit 20 will be described in the case where the screen is divided into three and five parts and photometry is performed. Figures 3(α) and 3(h) show how the screen is divided and the photoelectric output of each divided area.

(1) In Figure 3 (α), assuming a 6x6 camera, the screen has a central area Dc, an upper area D@L, and a lower area D.
t, and each photoelectric output is represented by Po-P.

Each photoelectric power pa −7′2 is compared with the average value Prgaesle(cs po+P, +/′2 /3 ),
Each area is represented by a logical value 1 when P, .about.Pl≧Pm@αn, and K is represented by a logical value O when Po.about.P1≦PWNgα. The classification circuit 20 determines whether the combination of logical values is (1) when the center area Da is 0 or when the lower area D
When l- is O (in this case, the main subject is area DC or D
t K), the analog switch 23 is turned on and the third photometric output PL is transmitted to the apex calculation circuit 24. (ii) When the center area DC is 1 (at this time, the main object is likely to be in area 1), the analog switch 21 is turned on and the first pick-up 1-element output PH is sent to the apex calculation circuit 24. to communicate.

011) For combinations other than the above, K turns on the analog switch 22 and transmits the second photometric output PM to the apex calculation circuit 241C.

On the other hand, the first determination circuit 18TriPα≦PmαX≦Pβ
When , the output of K logic value 1 is output, and when other than this, VC is output.
Generates Vi logic value logic power. The second determination circuit 19 generates an output of logical value 1 when α≦ΔP≦β, and generates an output of logical value O otherwise. And the first.
When the logic value 1 is applied from the judgment circuit 18.
is turned on and the photometric output PM of i@2 is transmitted to the apex calculation circuit 24.

(2) In Fig. 3(b), assuming a camera with a squid-sized screen, the center area DC1 upper right area Dr%, upper left area Dtm & lower right area Dr t, lower left area Dtt
It is divided into K, and the photoelectric output of each is represented by Po-P. Each photoelectric output P0 to P4 is the average value Pw as described above.
aaa+%, and each area is represented by a logical 1 or O.

The classification circuit 20 has this combination: (1) the central region DC is 0;
When the left and right lower regions are 0, when the left and right lower regions, l-, D, and t are 0, when the left upper region D l m and the left lower region Vtt are O,
When the upper right area D r g and the lower right area D r t are 0, or when there is some area [0 and 1 does not exist (in this case, there is a possibility that the main subject exists in the 0 area) 2), the analog switch 23 is turned on and the third photometric output PLf is transmitted to the apex calculation path 21m. Other than this, the operation is the same as described in section (1).

This five-division example takes into consideration the fact that there are vertical and horizontal shooting positions, like a squid-sized camera.

The photometric output calculated and extracted in this manner is subjected to apex calculation and sent to the exposure control circuit 25. It is applied to the exposure display circuit 26. In this embodiment, the apex calculation is performed after the photometric output is extracted, but the invention is not limited to this.
Photoelectric output? Immediately perform apex calculations and select circuits 11-13.
K may be transmitted to 17. At this time, the levels of the outputs after apex calculation of the plurality of photoelectric outputs change, but the magnitude relationship between the levels does not change, so the same operation as described above can be performed. The first to third photometric outputs increase from the beginning of BV to K to represent the TV value or AV value.

Historically, in this embodiment, the first to third group light outputs are calculated,
The calculation results are extracted, for example (1) to (3)
The same thing can be achieved by selecting the calculation formula for the expression. This is because any one of the first to third photometric outputs may be selected as a result.

Further, standardization is not limited to replacing the photoelectric output with two levels; for example, the photoelectric output near the average value may be replaced with another level.

The configuration of each block will be explained below.

FIG. 4 shows an example of a photoelectric element, in which a plurality of photoelectric elements are lined up, and can be constructed from a photodiode array, a vicD, or the like. However, it does not necessarily have to be in a matrix form. By combining the outputs of the photoelectric elements, the photoelectric output in the above-mentioned divided regions is obtained.

FIG. 5 shows an example of a receiving optical system. 31 is a plurality of photoelectric elements shown in FIG. 4, 32 is a photographing lens, 33 is a midge, 34 is a film surface, 35 is a finder screen, and 36 is a finder screen imaged on the photodetector surface of the subject Shinkin Bank. This lens is used to re-image the image.

With the above configuration, it is possible to measure the brightness of each part of the scene to be photographed, and to extract a plurality of independent photometric information.

@6 (e) Figure H An example of the maximum value detection circuit 11.

Fig. 6(h) shows the Fi minimum value detection circuit 13. These circuits use OP amplifiers and ideal diodes and are known per se.

Figure 7 shows resistance r% r/n and op amp A.

The average value detection circuit 12 is entirely configured with p. +p,...P1/,%e=P.
An output of 4α is obtained.

FIG. 8 shows an example of the arithmetic circuits 14, 15, and 16.
It is composed of a follower +o-A port and voltage dividing resistors R, -R4, and the first to third photometric outputs P〃, PM, PLV'i
By adjusting the partial pressure ratio, equations (1), (2), and (3) can be satisfied.

FIG. 9 shows a binarization circuit 11 and a classification circuit 2.

This is an example of a circuit. The figure shows the screen as shown in Figure 3(b).
This is an example in the case of division.

The in-phase input terminal of the comparator CI has an input corresponding to the constant Pa, and the comparator C! Inverting input terminal VC#
-i inputs corresponding to the constant Pβ are respectively applied. On the other hand, the in-phase input terminal of comparator CS. key constant α
An input corresponding to the constant β is applied to the inverting input terminal of the comparator c4. Photoelectric output p. Comparator C with −p, as the in-phase input
, −C-th inversion input is applied with a reference input of P1α to δL phase. The purpose of lowering the level of the δL phase diagram is to more reliably perform binarization on the low luminance side of the optical purchasing power Po−P. Photoelectric output P. A basic yarn input corresponding to Pnraα+δH is applied to the inverting input of the comparator c6, which serves as an all-in-phase input. This level increase equivalent to 6g is due to the high brightness side pressure of the photoelectric output po.
This is to ensure more reliable value conversion.

The maximum value PgαX is input to the inverting input terminal of the comparator C1 and the in-phase input terminal of the comparator C. Brightness difference ΔP
' is the inverting input terminal of comparator cI and the comparator c
Input to the in-phase input terminal of No.4. Comparators C1-c4
The output of Fi7 is output from the ANDI gate. When the output of the 7nd gate AND becomes 1, the comparator C
When the outputs of 1 to C4 all indicate 1, Pα≦Pwhax≦
Pβ・・・・・・(7)(g8katsu, α≦ΔP′≦β・
River...(7Xa) is established. AND GATE AN
Let it be the output fM flag of Dl. When the M flag is 1, it becomes the output Vii of the OR gate OR1, and the analog switch 2
2 is turned on to select the second photometric output PM. This is because equation (7) b holds true, which indicates that there is a certain degree of f4 degree difference, but if equation (7) 4 holds true, that is, when the maximum value falls within a certain range, This is because there is no backlight condition and the appropriate exposure level exists near the average value. Note that this holds true even if the photoelectric output on the high-brightness side or the low-brightness side is blocked. The photoelectric output P, is inputted to the in-phase input terminals of the comparators C- and C7, and the following photoelectric outputs p1%p, , p, and the PaVi comparator Ca%Cl*'IOs and the C-th in-phase input terminal are inputted. In addition, the inverting input terminal of the comparator C6 has an output Pwtaa which is a level-up of the average value by a certain value.
n+δg is input. The output of the comparator Ca becomes IK when the photoelectric output Pa in the central area Da is discernibly higher (by δH) than the average value P@aα, indicating that the central part of the photographic screen has a bright area pressure. ing. On the other hand, the output Pnigα4-δL obtained by lowering the average value by a certain value is input to the inverting input terminals of the comparators C7 to Cth. When the outputs of the comparators Ca to C11 become O, the photoelectric outputs po-p, are lower than the average value Pmmal by a discernible amount (by δL), and the photoelectric outputs Po to P4
This indicates that the corresponding screen is under dark pressure.

AND gate ANDIKii comparator C6, c,
, inverter INF of M flag on output of CIO,
The output inverted by is input.

The output of the AND gate A7'/D becomes 1 when is satisfied and the M flag is O. In such a state, the central region Dc is bright and the upper half region Dr u
, When Dlu is dark, it is like a spotlight. Therefore, equation (8) becomes a condition for determining that the main subject is in a bright area. The 6g flag is the output of the AND gate AND. Now, when the H flag is 1, that is, the comparators Ce and C+o output 1, and the inverter INV
, is outputting 1, the analog switch 21 is turned on and the first photometric output pH is extracted.

The output of C7 enters inverter INF3. Now, P 6
(P ws, * a - δL (the central area DC is the dark part)...If (9) holds true, the comparator C
Output of I #-i.

Then, the output dlK of the inverter INF becomes. Also, the outputs of comparators C6 and C9 enter a NOR gate.

holds, the outputs of comparators C, , C, are both IC
At O, the output of the NOR gate becomes 1. Similarly, if and holds true, the Noah gates N ORt and NOR
The output of , becomes 1. Inverter INF's and NOR gate NORt~NOR.

The output of is input to the OR gate ORB K, and if any output is 1, the OR gate OR, and the output becomes 1. That is, if any of the expressions (9) to @ is satisfied, the output of the OR gate ORs becomes 1. (9)
If the formula holds true, this means that the center of the screen, where there is a high probability that the main subject is located, is a dark trap, and it is better to adjust the exposure to the low brightness side. However, even if the center of the screen is bright, it is often due to the brightness of the background, and it cannot necessarily be determined that the main subject is in the bright area. In fact, in backlit situations, the brightness of the main subject will be close to the brightness of the lower part of the screen. Therefore, if the αυ formula holds true, it is better to judge that the main subject is in a dark area and select the 43 slant light output PL. This may be due to the fact that the photo was taken at a different angle.
Each of Uni (9) to Kan style is a condition for determining that the main subject is in a dark area. At this time, the output of the OR gate OR becomes 1. At this time, AND gate A N
If the M flag of D t is O, that is, (7)
(4) If formula (A) is not fully satisfied, inverter INF,
outputs 1. Therefore, the AND gate AND outputs 1, turns on the analog switch 23, and extracts the third photometric output PM.

The y%L and t flags are input to the Nant gate HAND, and become 1 if both are 0.

This is a case where it is determined that the main subject is neither in a bright area nor in a dark area. At this time, OR gate OR+
The output becomes 1, and the second photometric output PM is selected 6.

According to the present invention as described above, it is possible to obtain a multi-photometering device that can obtain appropriate exposure even under special field conditions such as backlighting and spotlight illumination.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the f4 degree of each part of the field (screen) in a three-dimensional figure, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is an example of how the drawing is divided. 4 is a diagram showing an example of a photoelectric element 7 ray, FIG. 5 is a diagram showing an example of a receiving optical system, FIG. 6 is a diagram showing an example of a maximum value and minimum value detection circuit, and FIG. 7 is a diagram showing an example of a maximum value and minimum value detection circuit. 8 is a diagram showing an example of an average value detection circuit, FIG. 8 is a diagram showing an example of an arithmetic circuit, and FIG. 9 is a diagram showing an example of a classification circuit. [Lord S! Explanation of part symbols〕

Claims (1)

[Claims] 1. Dividing the field into a plurality of regions and performing photometry, generating a plurality of photometry outputs corresponding to the plurality of regions, and calculating an average output from the plurality of photometry outputs, means for generating a first output that is higher than the average output, a second output that matches the average output, and a third output that is lower than the average output; A multi-photometering device characterized by obtaining appropriate photometering output. 2. The multi-photometering device according to claim 1, wherein the first output is between a maximum value and an average output of the plurality of photometering outputs. 3. The multi-photometering device according to claim 1, wherein the third output is between a minimum value and an average output of the plurality of photometering outputs.