JPS6011475Y2 - Multi photometer - Google Patents

Description

[Detailed explanation of the invention] This invention divides the field into multiple areas, measures the light, and extracts the appropriate photometric output for determining the appropriate exposure of the entire screen from the multiple photoelectric outputs corresponding to the areas. This paper relates to improvements to multi-photometering devices.

Conventional multi-metering devices divide the field into multiple areas,
Appropriate exposure information was simply obtained from the maximum value, minimum value, etc. of the plurality of photoelectric outputs corresponding to the plurality of regions.

However, as described above, it is difficult to obtain a sufficiently appropriate exposure even if the appropriate exposure is simply determined from a plurality of photoelectric outputs.

This invention solves these shortcomings and obtains proper exposure by identifying the brightness distribution in the subject and determining the proper exposure based on this result. , which performs more appropriate exposure control.

Further, when identifying the brightness distribution state in this way, it is conceivable to compare each photoelectric output with a reference value to identify the distribution state.

However, if the reference value is fixed to a certain value, if the entire object is bright (or dark), each area of the object will be brighter (or darker) than the corresponding brightness of the standard value. Therefore, there is a possibility that it becomes impossible to identify the brightness distribution state in the object field.

The present invention also solves these drawbacks.

Furthermore, in order to solve this drawback, it is conceivable to change the reference value depending on the brightness of the field.

However, if the standard value is simply changed according to the brightness of the subject, if there is a very bright (or dark) part of the subject, that is, if there is an extremely bright (or dark) part of the subject, If there are bright areas (or extremely dark areas such as shadows), the reference value will shift accordingly, making it impossible to discern the brightness distribution in the subject. .

The present invention also solves these drawbacks.

As is clear from the above description, the purpose of the present invention is to identify the brightness distribution of the subject based on a plurality of photoelectric outputs, and to obtain appropriate exposure information according to the identification results. It is an object of the present invention to provide a multi-photometering device that can properly perform this discrimination even when the entire field is bright (or dark) and when a part of the field is very bright (or dark).

Hereinafter, the present invention will be explained with reference to Figure 1, which represents the screen and the brightness of each part of the screen as a three-dimensional figure, with the field of view (hereinafter referred to as the drawing) as the bottom and the brightness of each part of the screen as the height (M1 axis). This section describes the basic concept of multi-photometry.

In FIG. 1a, the bottom surface S.

When considering a screen as shown in , the brightness of the screen determines one curved surface S□.

In reality, since photometry is carried out using a finite number of photoelectric elements, the curved surface that can be captured is a collection of planes with a number equal to or less than the number of photoelectric elements.

For example, if the screen is divided vertically, horizontally and horizontally using four photoelectric elements, the curved surface representing the brightness of the screen is shown in Figures 1b and 1c.
It is quantized and becomes stepwise as shown by 2 to S.

When comparing quantization planes S2 and 34, the absolute level of the luminance that makes up the quantization planes is the same, but their positions on the screen are different, so it is difficult to obtain the appropriate exposure for which luminance. The judgment is also different.

Further, when comparing the quantization planes S2 and S3, although the level difference between adjacent luminances is the same, the absolute value of the luminance between the two quantization planes is different, so that the judgment for obtaining appropriate exposure also differs.

Now, we classify the shooting screen under all conditions into multiple categories based on information regarding brightness and information regarding position, and determine which brightness should be controlled for exposure in each category to obtain an overall appropriate exposure. Attach the correspondence.

Then, on a screen under certain conditions, the brightness at which exposure control should be performed 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 exposure control should be performed in order to obtain properly exposed photographs 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 is approximately equal to the average value of these photometric outputs. A matching level and a third brightness level was found to lie between the minimum value of these photometric outputs and the average value of these photometric outputs.

This average value can be approximated by the average value, the median value (the value located between the maximum value and the minimum value), or the mode value (the value that appears most frequently among each photoelectric output). can.

From the above, if we compare the average value of multiple photoelectric outputs with each photoelectric output and standardize the brightness on each divided screen, we can simultaneously obtain information on the position and brightness of each screen. You will be able to do this.

Therefore, if the state of the screen is detected by pattern analysis based on this normalized output, and this detection result is correlated experimentally or empirically with the above three nobleness levels, exposure control for the screen under various conditions should be performed. Brightness level can be selected.

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, there is little variation in brightness within the screen, and the maximum brightness is within a predetermined range. This is a case where it can be determined that no artificial light source exists.

In this case, it has been found that good results can be obtained by adjusting the exposure for the second brightness level.

On the other hand, if there is a high brightness area represented by the sun or a low brightness area below the photometry lower limit in the screen, when setting the levels of the first to third brightness levels described above, the maximum value corresponding to the high brightness area,
If you ignore the minimum value corresponding to the low brightness area below the photometry lower limit, or replace these maximum and minimum values with other brightness values that exist within the screen, you can obtain proper photometry information that is not affected by extreme high and low brightness. It will be done.

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, a photometry circuit 10 includes a photoelectric conversion element for photometering each region of the field of view divided into a plurality of regions, and outputs an independent analog photoelectric output P corresponding to each region of the field of view.

62 photoelectric output P which outputs -p n-1. ~P"'
n''l corresponds to the absolute value of luminance mentioned in the explanation of FIG.

The first maximum value detection circuit 100 has a photoelectric output P.

- Maximum value Pmax original from Pn-1
Detect.

The first minimum value detection circuit 9j is also P.

-Minimum value Pm1n original from Po-1
Detect.

Further, as will be described later in the description of the blocking circuits 101 and 102, the second maximum value detection circuit 11 outputs the photoelectric output P via the analog switches 103 and 104.

~Pn-1, those that do not exceed a threshold level (Pthl or pth2, which will be described later) are input, and the maximum value Pmax is detected from these.

The average value detection circuit 12 is an analog switch '105,1
Photoelectric output P via 06.

- Between multiple good price levels of Pn-1 (pt
The input is between h□ or pth2 and PthO, and the average value of these, for example, the average value Pmean
Detect.

The second minimum value detection circuit 13 includes an analog switch 107,
Photoelectric output P via 108.

-Pn-□, dark value level (pthO described later)
As input, the minimum value P among these is
Detect min.

The arithmetic circuit 14 calculates the maximum value Pmax and the average value Pmean
As input, the first photometric output PH (EV), that is, PH = kIPmax + (1-) Pmean
= (1) is generated (here, □ is a constant).

The arithmetic circuit 15 generates the second photometric output PM (EV), that is, PM = Pmean = (2), and can actually be used as the average value detection circuit 12.

The arithmetic circuit 16 inputs the minimum value Pm1n and the average value Pmean and outputs the third photometric output PL (EV), that is, PL=2Pmin+ (1-2) Pmean
-...-(3) is generated (here, 2 is a constant).

The circuits 11 to 16 described above constitute an appropriate photometric output generation circuit.

Arithmetic circuit 110 receives photometric outputs PH and P from circuits 14 and 15.
M is applied, and the fourth photometric output, that is, PHM=(P
Output H+PM)/2.

Arithmetic path 111 receives photometric outputs PM and PL from circuits 15 and 16, and outputs a fifth photometric output, namely PLM=(
PM+PL)/2 is output.

The binarization circuit 17 is a part that performs standardization, and the photoelectric output P
.

-Pn-1 and the average value Pmean, and the average value Pm
The reference output and photometric output P generated based on ean.

-Pn-□ to convert each photoelectric output into a logic output.

Specifically, in the embodiment, the output Pi of the i-th position and the average value Pmean are compared, and if Pi≧Pmean, it is set to 1, and if Pi (Pmean), it is set to 0.

If the normalized output is 1, it indicates that the i-th position is a brighter-than-average portion, and if it is 0, it indicates that it is a darker portion.

That is, under the above-mentioned standard, it is in the form of binarization.

Alternatively, you can do the following.

In order to divide the overall brightness into a bright part, a dark part, and an intermediate part, Pmean + δ8 and Pmemn - δ'L are set as reference outputs based on the average value Pmean, and for these two reference levels, This is a method of performing binarization.

In other words, when Pi)Pmean+δ8 stands out, it is 1
, Pi≦Pmean+δH is 0, and P
Set to 1 when i≧Pmemn-δ2, and 0 when Pi(Pmean-δL(7)).

In this case, the binarized output at the i-th position is two (2 bits).
become.

When the outputs are arranged in the order of comparison of Pmean + δ8 and Pmean - δ, if it is for output power, the bright part is shown, and 0
If it is 0, it indicates a dark part, and if it is 01, it indicates a part close to the intermediate average value (if it is 10, it does not exist).

By dividing the brightness at that position into three levels in this way, more advanced pattern analysis becomes possible.

Of course, it is possible to divide the binarization circuit into four or more stages, and the number of stages may be changed depending on the position.

Next, the first determination circuit 18 inputs the maximum value Pr1iax and calculates Pa≦Pmax≦Pβ (where Pa and Pa are constants)
. . . The judgment in (4) is made and a logic output representing the judgment result is generated.

Of course, the first determination circuit 18 includes a circuit that generates reference outputs corresponding to Pα and Pβ.

This determination operation is performed to identify whether the maximum value Pmax is caused by a bright light source including the sun or an artificial light source such as a spotlight.

The second judgment circuit 19 determines the maximum value Pmax and the minimum value Pm.
1n as input, calculate Δp = Pmax - Pmin = (5), then perform the judgment of α≦∆P≦β (however, α and β are constants) (6), and show the judgment result. Generates a logical output.

Of course, the second determination circuit 19 includes a circuit that generates reference outputs corresponding to the constants α and β.

This judgment operation determines the brightness distribution of the screen, and for example, if the brightness distribution is large and the main subject is on the low brightness side, if you adjust the exposure to the low brightness side, the high brightness side will be off, or vice versa. This is done to prevent the phenomenon in which the main subject is on the bright side, but when the exposure is set on the high brightness side, the low brightness side is crushed.

The classification circuit 20 receives as input the logic outputs from the circuits 17, 18, and 19, the n flag from the third determination circuit 170 (described later), and the 1 flag from the second blocking circuit 102 (described later).
It is determined, ie, classified, to which predetermined category the combinational logic of these logic outputs belongs.

This predetermined category is divided into five, and a control output corresponding to each category is selectively generated.

The analog switches 21, 22, 23, 112 and 113 connected between the circuits 14, 15, 16, 110 and 111 and the apex calculation circuit 24 output the first to fifth photometric outputs according to the control output of the classification circuit 20. Outputs corresponding to the classified categories are selected from among them and transmitted to the apex calculation circuit 24.

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

First minimum value detection circuit 99, first maximum value detection circuit 1
00 is photoelectric output P.

~Pn-1 is input, and the minimum value Pm1n is selected from among these.
* original, maximum value Pmax・origi
nal is detected respectively.

The third determination circuit 170 inputs the maximum value Pmax - original from the first maximum value detection circuit 100 and Pm1n * original from the first minimum value detection circuit 99 and calculates Pmax @ original - Pmin.
It is determined that @original≦γ (where γ is a constant).

Of course, this determination circuit 170 includes a circuit that generates a reference output corresponding to the constant γ and a comparison circuit.

This determination operation is for determining whether to extract the fourth or fifth photometric output.

The output of this circuit is applied to classification circuit 20 as an n flag.

The first blocking circuit 101 inputs the photoelectric outputs Po to P, -□ and compares them with two threshold levels pth and Pth2.

The first threshold level pth□ is set to be equivalent to approximately 16 EV assuming that the daytime sun is present on the screen, and the second
The threshold level Pth2 is set to be equivalent to about 15 EV assuming that the sun at dusk is present on the screen.

First, when there is a photoelectric output equal to or higher than the threshold level pth□, the analog switches 103, 105, and 107 are controlled to prevent the photoelectric output from being transmitted to the circuits 11, 12, and 13.

However, when all the photoelectric outputs are equal to or higher than the threshold level Pth1, the analog switches 103, 105, and 1
Controls 07.

The reason for this will be explained later. Next, when there is a photoelectric output equal to or higher than the threshold level pth2, the analog switches 103, 105,
107 and its photoelectric output circuits 11, 12, 13
transmission is prevented, but the number of inhibitions is kept below a certain number.

This is because when photographing at dusk, the sun itself may be the subject of the photograph, and if all that information is blocked, the photographer's intentions may not be reflected.

The second blocking circuit 102 has a photoelectric output P.

-Pn-□ is input, and the threshold level Pth corresponding to the lower limit of photometry.

Compare with.

If there is a photoelectric output below PthO, the analog switches 104, 106, and 108 are controlled to prevent the photoelectric output from being transmitted to the circuits 11, 12, and 13.

Then, a 1 flag indicating whether the number of inhibitions is above or below a certain value is generated and applied to the classification circuit 20.

The first and second blocking circuits 101 and 102 transmit the blocking number to the next stage circuit to the average value detection circuit 12,
When calculating the average value, the photoelectric output whose transmission to the average value detection circuit 12 is blocked by these blocking circuits 101 and 102 is excluded from the calculation target.

Next, the operation and classification mode of the classification circuit 20 will be described in the case where the screen is divided into three and five parts.

Figures 3a and 3b show how the screen is divided and the photoelectric output of each divided area.

(1) In Fig. 3a, assuming a 6x6 camera, the screen is divided into a central area (2), an upper area (Du), and a lower area (D1), each with a photoelectric output of P.

−P2.

Each photoelectric output P.

-P2 is the average value Pmean (=(PO+P1+P2)
/3) and each area is compared with P.

When ~P2≧Pmean, it is represented by a logical value of 1, and P.

-P2 (Pmean is represented by a logical value O.

The classification circuit 20 determines that the combination of logical values is (i) when the central region ■ is O or when the lower region DI is 0 (in this case, there is a high possibility that the main subject exists in the region Dc or DI) The analog switch 23 is turned on and the third photometric output PL is transmitted to the apex calculation circuit 24.

(1[) When the central area pc is 1 (because the main subject is likely to exist in the area Dc at this time), the analog switch 21 is turned on and the first photometric output PH is transmitted to the apex calculation circuit 24.

(!! When the n flag is 1, that is, Pmax * ori
When ginal −Pmin −original≦γ, if the screen is in the state (1), the third photometric output P
I turned on the analog switch 113 to extract the fifth photometric output (PM + PL)/2 instead of L, and the screen changed to (
If the state is i[), the analog switch 112 is turned on to extract the fourth photometric output (PM+PH)/2 instead of the first photometric output PH.

This means that when the first or third photometric output is extracted, the maximum photoelectric output, Tenyu Pmax @
original and minimum value Pm1n 41 original
This is because when the difference from nal is small, that is, when the subject has relatively uniform brightness, correcting toward the average value often results in a more desirable photograph.

qv On the other hand, the first determination circuit 18 determines that Pα≦Pmax≦Pβ
When , an output of logical value l is generated, and at other times, an output of logical value O is generated.

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.

Then, when the logic value l is applied from the first and second judgment circuits 18 and 19, the classification circuit 20 changes the screen to the above (i).
Even in the state t (ii), the analog switch 22 is turned on and the second photometric output PM is transmitted to the apex calculation circuit 24 with priority.

(2) In Figure 3b, the screen is assumed to be a Leica camera, with a central area ■, an upper right area Dru, and an upper left area D.
lu, a lower right region Drl, and a lower left region Dll, each having a photoelectric output of P.

It is represented by ~P.

Each photoelectric output P. -P4 is the average value Pmea as above
n, and each area is represented by a logical value l or o.

The classification circuit 20 calculates the following combination: (1) When the center area Dc is O, when the lower left area Dll and the lower right area Drl are O, when the upper left area Dlu and the lower left area Dll are 0, the upper right area When the area Dru and the lower right area Drl are O,
At this time, the analog switch 23 is turned on and the third photometric output PL is transmitted to the apex calculation circuit 24 (because there is a high possibility that the main subject exists in the area O at this time).

(ii), riii), qv) The operations are the same as those described in section 1 (7).

This five-division example takes into consideration the fact that there are vertical and horizontal photographing positions, such as in a Leica camera.

Now, in terms 1 and 2 above, if there is a high brightness part above the threshold level pth□ in a certain area of the screen, the photoelectric output of that area, for example, P, is blocked and the average value is Prnean.
'=(PO+P2)/2 or Pmean' :=
(po 10 p, 10 P3 + P4) / 4.

Therefore, using this average value, the circuit 17, the arithmetic circuit 14.
15. 16 will work.

That is, the circuit 17 converts each photoelectric output into a logical output based on this average value Pmean', and the arithmetic circuits 14, 15, 1
6 is the photometric output PH, PMX based on this Pmean'
Generates PL.

This photometric output is selectively extracted by the classification circuit 20 in the same manner as described above.

So, when the entire screen has high brightness and the same brightness ρ, for example when photographing clouds, the maximum photoelectric output @P m
Only one ax is printed on the circuits 11, 12, and 13.

Then, the maximum value, average value, and minimum value all match Pmax.

At this time, PH, PM. Regardless of which of PL, PHM, and PLM is selected, since Pmax is selected, exposure control is performed for high brightness.

Next, the photoelectric outputs above the threshold level PtFI2 are prevented from being transmitted to the circuits 11, 12, and 13 within a certain number, and the average @
'mean is also a constant average value Pmea depending on the number of inhibitions.
n''.

Then, based on this average value Pmean'', it operates in the same manner as the previous stage.

As described above, correction for the presence of a high brightness area is performed when generating a photometric output.

On the other hand, if there is a photoelectric output below the threshold value Ptho, this photoelectric output, for example P□, is blocked from being transmitted to the circuits 11, 12, and 13, so the average absolute level increases.
Pmean"' = 5p.

10P2)/2 Pmean ”' = (Po+
P2+P3+P, )/4.

Therefore, the first to fifth photometric outputs PH, PM, PL, PHM, PLM ignore the photoelectric output below the photometric lower limit.
is obtained.

This photometric output is selected by the classification circuit 20 in the same manner as described above.

In this way, correction is performed when a low brightness portion exists within the screen.

In FIG. 2, element 10 constitutes a photometric circuit that generates a plurality of photoelectric outputs corresponding to a plurality of divided regions of the field.

When the reference value for normalizing the brightness of the plurality of areas is set to Pmean, element 12 is used, and when the reference value is set to Pmean + δ8 or Pmean - δL, element 12 outputs Pmean. And this output is 8
The first means for generating a reference value corresponding to the plurality of photoelectric outputs includes means for adding or subtracting 8 or δ.

Further, elements 14 to 24, 110 to 113, and 170 identify the brightness distribution state of the subject from the magnitude relationship between the photoelectric outputs and the reference value, and generate appropriate exposure information based on the results. The second means and the elements 101 to 108 respectively constitute a third means for disabling outputs exceeding a predetermined threshold among the plurality of photoelectric outputs from being involved in the calculation of the reference value.

In this embodiment, the predetermined threshold values are Pthl and Pth2.
(threshold value on the high brightness side), Pt)'io (threshold value on the low brightness side).

Also, the standard values for normalizing brightness are Pmean, P
It may be other than mean + δ, Pmean-δ.

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 photo diode array, CCD, or the like.

However, it does not necessarily have to be in a matrix form.

The photoelectric output in the above-mentioned divided areas is obtained by the output of the photoelectric element.

FIG. 5 shows an example of a light receiving optical system.

31 is a plurality of photoelectric elements shown in FIG. 4, 32 is a photographing lens, 33 is a mirror, 34 is a film surface, 35 is a finder screen, and 36 is a device that reproduces the subject image formed on the finder screen onto the light receiving element surface. This is a lens for forming an image.

With the above configuration, the brightness of each part of the scene to be photographed can be measured, and a plurality of independent photometric information can be extracted.

FIG. 6a shows an example of the maximum value detection circuit 11, 100, and FIG. 6b shows an example of the minimum value detection circuit 13.99.

These circuits are known per se, using OP amplifiers and ideal diodes.

FIG. 7 shows an average value detection circuit 12 configured with a resistor rX r/n and an OP amplifier A□, and the output of the OP amplifier is (Po+P,...Pn-t)/n=Pm
An output of ean is obtained.

FIG. 8 is a circuit example of the arithmetic circuits 14, 15, and 16,
The first to fifth photometric outputs PH are composed of followers A1o-A1° and partial pressure resistors R1 to R1.

PM, PL, PHM, and PLM can be obtained by adjusting the partial pressure ratio to satisfy equations (1), (2), and (3).

FIG. 9 shows an example of the first blocking circuit, in which the number of blocking circuits described above is two.

In the same figure; comparator C100, and gate A
ND I Q Q, ANDIOI, flip-flop F
Circuit blocks consisting of FIQ, FF1l, diode D100, and analog switch AS100 are prepared in correspondence with the number of photoelectric outputs.

Here, the photoelectric output P.

-Five blocks are prepared corresponding to P4, and block B1 is shown as a representative.

However, the AND gate AND99 and the AND97 flip-flops FFi2 and FF13 are dedicated to the block B1.

Now, a clock pulse of a constant period is applied to the ring counter RC, and the output terminal q is applied to the ring counter RC.

v ql? Q3? q51q79 Q9? Outputs are sequentially generated on qIO according to the number of clock pulses.

Terminals q□ to q9 are provided every other bit, and a time lag of one bit is provided between each output.

Binary counter BCI is q of ring counter RC.

Let the output be the input, and the Q output and q. The output is A with AND118
ND was taken q.

A pulse is generated every two periods of output.

When the Q output is 1, the Q output outputs 0, turns off the transistor Tt, and applies a voltage corresponding to the above-mentioned threshold level pth to the inverting input terminal of the comparator of each block.

Further, when the Q output is 0, the Q output becomes 1, the transistor Tr is turned on, and a voltage corresponding to the above-mentioned threshold level Pth2 is applied to the inverting input terminal of the comparator of each block.

These comparators are 1 when Pi>pth (where Pi is each photoelectric output and pth is pth□ or pth2).
Output.

Next, 1÷describe the operation. ■Binary counter BC1ψQ
When the output is 1; this is a mode for detecting Pi)Pthl.

Since the output of OR gate 0RIIO is 1, block B
When the AND gate AND I Q Q receives the 91 output of the ring counter RC, it
The output of is applied to the S input of flip-flop FF lO.

Here P. > pthl, the comparator C100 outputs 1, so the flip-flop FF IQ is Q
Output l to the output.

At the same time, the flip-flop FF l l outputs 1 to the Q output, turning off the analog switch AS100 and outputting P.

is not transmitted to the next stage circuit. This operation is time-divided by the outputs q1 to q9 of the ring counter RC and sequentially moves toward the block that receives the photoelectric output P4 as an input.

As a result, the photoelectric output from the block inputting the photoelectric output of the Pi
The maximum value detection circuit 11 is not transmitted to the average value detection circuit 12 and the second minimum value detection circuit 13.

On the other hand, the output of the AND gate AND100 is input to the AND gate AND110 which inputs the output of the ring counter RC(7) (1), and when both the output and the output of q1 are 1, the AND gate ANDllQ outputs 1. , binary counter BC2 via OR gate 0R111
is input.

Similarly, an azt of the AND gate of each block
23w a<output is q3t qst q7? The signals are input to the binary counter BC2 in synchronization with the qs outputs.

Therefore, the binary counter BC2 is also ~a4 output l
Count.

However, since the Q output of binary counter BC1 is 1, the output of OR gate OR110 is
It is 1 regardless of the count value of 2.

Therefore, when Po-P,〉Pth□, all photoelectric outputs are blocked from being transmitted to the next stage circuit, but when the count value of binary counter BC2 is 5, that is, "101" in binary code, binary counter BC
2's Q10 output and Q1□ output become 1, and gate AND98 outputs 1, and flip-flop FF12
1 enters the set input of flip-flop FF 13, the output Q becomes 1, and l enters the set input of flip-flop FF 13, the output Q becomes 1.
and Q becomes 0.

(The reset timing relationship is the same as FF IO and FFII.) Therefore, the output of the AND gate AND99 is set to O, and the analog switch AS1QO is turned on.

As a result, the photoelectric output P. is the next stage circuit (11~ in Figure 2)
13).

Here, if the anode terminal of the diode D100 is made higher than the voltage equivalent to Pth2 by the amount of the drop caused by the diode using the variable resistor R100, the photoelectric output P.

is limited to a voltage equivalent to Pth2.

This is based on the consideration that when the entire screen is bright, overexposure can produce more realistic photos.

Note that when the count value of the binary counter BC2 is less than 1, the output of the NOR gate NORIQ is 1, and the AND gate AND99 is the Q of the flip-flop FF1l.
Transmit the output as is to the analog switch ASIGO.

Also, when the count value of binary counter BC2 becomes 2 or more, Q11 output, Q2 output or AND gate AND
l l The output of 5 becomes l, and at this time 21 agate N
0RIQQ outputs O.

Then, the AND gate AND116 outputs the ring counter R.
C's q engineering.

Since the binary counter function 1 is reset when the output becomes 1, the Q output becomes 1 when the q1 output becomes 1 again, and as a result, the mode does not shift to the mode for detecting Pi) pth2.

(2) When the Q output of the binary counter BCI is O; in this case, the mode is to detect P i'>pth2.

When the output of the NOR gate N0RIQQ is 1, the output of the OR gate 0RIIO becomes 1.

That is, when the count value of the pinary counter 9BC2 is 1 or less, that is, when the Q1o output is 1.

Now, if the count value of the binary counter BC2 is O, the NOR gate NOR100 and the OR gate 0R110 output 1, so the comparator of each block is at the threshold level P.
tFL2 and photoelectric output P.

- Compare with P4 respectively.

When the photoelectric output is Pth2 or more, for example, P.

, pl, also when p2>pth2. The outputs of al and a2 become 1.

Then, by applying the q□9 q3y Qs output, each AND gate ANDllQ to AND112 outputs 1, which is counted by the binary counter BC2.

Therefore Q10? Since the Q11 output becomes 1, the AND gate ANDl15 outputs 1 and the NOR gate NORI Q Q
, the OR gate 0RIIO outputs 0.

As a result, if two or more photoelectric outputs are blocked, no more will be blocked.

In other words, the programs operating subsequently in chronological order do not perform blocking operations.

Note that due to the limitations of the blocking operation, there is a possibility that photoelectric output of pth2 or more will be transmitted to the next stage circuit, but this is a problem because it is limited to a voltage equivalent to pth2 by the action of diodes D100 to D104 and resistors R100 to R104. It is not.

Furthermore, the AND gate AND 117 and AND l 1 g
generates a reset pulse for flip-flops FFI O and FFI 1, and after AND l l 7 generates output 1, AND l l f3 generates output l, and the reset timing of FFIQ and FFI l is determined. Adjustments are being made.

FIG. 10 shows an example of the second blocking circuit, which is set to the above-mentioned constant number of blocking circuits, 3.

In the figure; the voltage corresponding to the threshold level Ptl''IO is generated by the resistor R200, and the voltage corresponding to the threshold level Ptl''IO is generated by the comparator C20
It is applied to the common mode input terminals of 0 to C2O4.

A photoelectric output P is provided to the inverting input terminals of the comparators C200 to C2O4.

~P is applied, and each comparator has Pi〈Ptho(
However, Pi is any P.

-P4) is satisfied, output 1 is generated.

Analog switches AS200 to AS204 provided corresponding to each comparator block transmission of the photoelectric output to the next stage circuit at output 1 of the corresponding comparator.

The analog switches AS200 to AS204 each include the analog switches AS1 of each block described in FIG.
00 to ASI 04 (ASI O1 to AS104 are omitted in FIG. 9) are connected in series.

Analog switch blocks BIG and Bll are circuits 103, 105, 107 and circuits 104, 106, 1 in Fig. 2.
08 respectively.

The ring counter RC200 is sequentially incremented by q by applying a clock pulse.

t QU Q31 Q5? Q7? q9? Generates Q□0 output.

The outputs q□ to q9 are output with a time lag of one minute of l-hif of the counter.

Now, q of ring counter RC200.

When the output becomes 1, the binary counter BC3 is reset.

q□When the output becomes l, the gate of the AND gate AND200 opens and the output of the comparator C200 is ORed.
200.

At this time, the output of comparator C200 is 1 (po<pt
ho), then the binary counter BC3 outputs this output l
Count.

Thereafter, as the q1 to q9 outputs of the ring counter RC200 sequentially become 1, a similar operation is performed by the AND gate AND2.
01 to AND204, and if any of the photoelectric outputs P□ to P4 satisfies Pi(PthO), the binary counter BC3 advances the count by that number.

When the count value of binary counter BC3 becomes 3, both Q20 output and Q21 output become 1, and the output of AND gate AND205 becomes 1, and OR gate 0R201
Q output of flip-flop FF20 by output 1 of
That is, 1 flag becomes 1.

Similarly, the 1 flag is 1 when the count value of the binary counter BC3 is 4.5.

As the operation progresses and the qIO output of the ring counter RC200 becomes 1, when the count value of the binary counter BC3 is 3 or more, the output of the AND gate AND 206 to which the output O is applied from the inverter lNV2O0 is 0, so the flip-flop FF20 is not reset.

The l flag remains 1.

If the number of inhibitions is 2 or less in the next cycle, the inverter lNV
Since the output of 2O0 is 1, the 1 flag becomes O.

Note that when Q2r and output Q2° of the binary counter BC3 are both 1, the number of blocking is 5, and the entire screen is below the lower limit of photometry.

Therefore, if this is detected by the AND gate AND207,
By lighting up the light emitting diode LED, it is possible to indicate that photography is not possible.

FIG. 11 shows an example of the average value detection circuit.

In the same figure; since the blocking operation by the first blocking circuit (high brightness side) and the blocking operation by the second blocking circuit (low brightness side) cannot occur at the same time in normal photographing conditions, the adding circuit 40 is an OR gate. It was composed of

Each field effect transistor FET is conductive when its gate is at 1.

- When the blocking number is O, all gates are 1 and all FETs are conductive, so the composite feedback resistance R is 3, that is, however, Pa1l is the sum of unblocked photoelectric outputs.

- When the number of blocking is l, FET0 becomes non-conducting. - When the number of blocking is 2, FETI becomes non-conducting. - When the number of blocking is 3, FET0゜1 becomes non-conducting. - When the number of blocking is 4, FET0 is non-conductive. When, FETI.

There are two valve grooves connected, and FIG. 12 shows the binarization circuit 17 and the first to third judgment circuits 18.
, 19, 170 are circuit examples of the classification circuit 20.

This figure shows an example in which the screen is divided into five parts as shown in Fig. 3b.

An input corresponding to the constant Pα is applied to the inverting input terminal of the comparator C1, and an input corresponding to the constant Pβ is applied to the in-phase input terminal of the comparator C2.

On the other hand, an input corresponding to the constant α is applied to the inverting input terminal of the comparator C3, and an input corresponding to the constant β is applied to the in-phase input terminal of the comparator C4.

An input corresponding to the constant γ is applied to the in-phase input terminal of the comparator C5.

Photoelectric output P. - Comparator C7 with P4 as in-phase input
A reference input corresponding to Pmean-δ is applied to the inverting input terminal of ~C1l.

This level reduction equivalent to δL is the photoelectric output P.

- It is a light type that more reliably performs binarization on the low luminance side of P4.

Photoelectric output P. A reference input equivalent to Pmean + δH is applied to the inverting input of the comparator C6, which has as the in-phase input.

This level-up equivalent to 88 is to ensure more reliable binarization on the high-brightness side of the photoelectric output P0.

The maximum @P max is input to the in-phase input terminal of comparator C1 and the inverting input terminal of comparator C2.

The luminance difference ΔP is input to the in-phase input terminal of the comparator C3 and the inverting input terminal of the comparator C4.

The output of comparators C1 to C4 is AND1
Enter.

When the output of the AND gate ANDl becomes 1, the outputs of the comparators C1 to C4 all indicate 1, and Pα≦Pmax≦Pβ (7), (a) and α≦ΔP≦β (7), (b ) is true.

The output of the AND gate AND l is set as the M flag.

When the M flag is 1, the output of the OR gate OR1 becomes 1, and the analog switch 22 is turned on to output the second photometric output P.
M is selected.

That is (7). The fact that Equation (b) holds true indicates that there is a certain degree of brightness difference, but if Equation (7) and (a) hold true, that is, when the maximum value falls within a certain range, then the condition is backlit. This is because 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.

Photoelectric output P. is input to the in-phase input terminals of comparators C6 and 07, and the following photoelectric outputs P1w P2y P4 and P
3 is input to the common mode input terminals of comparators C8, C9, CIO and C1l.

Further, an output Pmean+δH obtained by increasing the level of the average value by a certain value is input to the inverting input terminal of the comparator C6.

The output of the comparator C6 becomes 1 at the photoelectric output P of the central region Dc.

is clearly higher than the average value Pmean (by δH), indicating that the central part of the photographic screen is a bright part.

On the other hand, an output Pmean-δL obtained by lowering the average value by a certain value is input to the inverting input terminals of the comparators C7 to C1l.

When the outputs of the comparators C7 to C11 become 0, the photoelectric output is P.

-P is lower than the average value Pmean by a discernible amount (by δ), indicating that the screen corresponding to the photoelectric outputs P0 to P4 is a dark area.

Furthermore, as is clear from comparators C6 and C7, Po
For this, standardization is performed by binarizing two reference levels near the average value.

AND gate AND2 has comparator C6゜C9,C
The output of IO and the output of M flag inverted by inverter INv1 are input.

The reason why the output of the AND gate AND2 becomes 1 is Po) Pmean + δH (the central area Dc is the bright part) P2
≧Pmean-δL (Lower half area Drl, Dll is not a dark area) Do≧
(8) When the command is raised and the M flag is 0.

In such a state, the central region Dc is bright and the upper half regions Dru and Dlu are dark, which is a spotlight-like state.

Therefore, equation (8) becomes a condition for determining that the main subject is in a bright area.

The output of the AND gate AND2 is set as the H flag.

If the H flag is 1 and the inverter INV2 is 1, the analog switch 21 is turned on and the first photometric output P
H is selected.

The output of C7 enters inverter INV3.

Now, when Po(Pmean-δL (central area Dc is dark) (9) stands out, the output of the comparator C7 is 0 and the output of the inverter INV3 is 1.

Also, the outputs of comparators C8 and 09 are NOR gates N0R
Enter 1.

Pl(Pmean-δ.

(Left half areas Dlu and Dll are dark areas) P2〃 (When 1G rises, the outputs of comparators C8 and C9 are both 0.
The output of the NOR gate NORl becomes 1.

Similarly below P2(Pmean-δ Lower half area Drl, Dll is the dark part) PK 〃 (11) and P3(Pmean-δ.

(Right half area Dru, Drl are dark areas) P, (Pme
an-δ.

(12) If holds, respectively, the Noah gate NOR2.

The output of NOR3 becomes 1.

Inverter INV3 and NOR gate N0R1~NOR
The output of 3 is input to the OR gate OR3, and if any of the outputs is 1, the output of the OR gate OR3 becomes 1.

That is, if any of the equations (9) to (12) is satisfied, the output of the OR gate OR3 becomes 1.

When equation (9) stands out, it means that the center of the screen, where there is a high probability that the main subject is located, is a dark area, 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 equation (11) is valid, it is better to determine that the main subject is in a dark area and select the third photometric output PL.

If Equations (11 and (12)) hold true, it is considered that the camera was held in a vertical position to take a picture.

As described above, each of equations (9) to (12) becomes a condition for determining that the main subject is in a dark area.

At this time, the output of the OR gate OR3 becomes 1.

If a certain number of photoelectric outputs are below the photometry lower limit, the 1 flag becomes 1.

Then, the output of the OR gate OR2 becomes 1 and the first photometric output PH is selected.

This is because when there are many photoelectric outputs that are below the photometric lower limit, there is a high probability that photometry is possible due to some bright areas of the photoelectric element, and it is better to select the high brightness side.

ΔP′ or Pmax −original −Pm1n
・Original is input to the inverting input terminal of comparator C5, and Δp'<γ (however, r is a constant)...
13), the output of comparator C5 becomes 1.

This is a case where the measured luminance difference is relatively small, and correcting it toward the average value will bring the exposure closer to the correct exposure.

The output of comparator C5 is inverted by inverter INV2.

The output of inverter INV2 and the H flag are AND gate A
Input to ND3.

The reason why the output of the AND gate AND3 becomes 1 is (13)
This is when the formula does not hold and the H flag is 1.

That is, when the high brightness side is selected and the brightness difference is large, the output of the OR gate OR2 becomes 1 and the first photometric output PH is selected.

The 1 flag is input to the inverter INV4 and inverted, and the outputs of the inverter INV4 and the comparator C5 and the H flag are input to the AND gate AND4.

The output of AND gate AND 4 becomes 1 (13)
This is when the expression is valid, the H flag is 1, and the 1 flag is O.

That is, when the high brightness side is selected and the brightness difference is small, the fourth photometric output PHM, that is, (PH+PM)/2 is selected.

The outputs of the OR gate OR3, the inverters INV, l, and INV4 are input to the AND gate AND7.

The reason why the output of the AND gate 7 becomes l is 1. This is when the M flag is 0 and the output of OR3 is 1.

That is, this is a case where the low luminance side is selected. Now, let's set the output of AND 7 as the L flag.

AND gate AND5 has L flag and comparator C5
is input, the low luminance side is selected, and when the luminance difference is small, the output is l, and the fifth photometric output PLM, that is (P
M+PL)/2 is selected.

AND gate AND6 has L flag and inverter I'N
When the output of V2 is input and the low luminance side is selected, and the luminance difference is large, the output becomes 1 and the third photometric output PL is selected.

H, L, l flags are input to NOR gate N0R4,
Both become 1 when O.

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, the output of the OR gate OR1 becomes 1, and the second photometric output PM is selected.

As described in detail above, according to the present invention, the second means (elements 14 to 24, 110 to 113, and 170 in the embodiment) each correspond to a photometric circuit (the same element) corresponding to each divided area of the field. a plurality of photoelectric outputs of element 10) and a first means (element 12);
), the brightness distribution state in the subject is identified, and appropriate exposure information is output according to this result. More appropriate exposure information can be output than when determining appropriate exposure simply from the photoelectric output, that is, when determining appropriate exposure without identifying the distribution of brightness in the object field.

Further, according to the present invention, the reference value outputted by the first means changes according to the plurality of photoelectric outputs outputted by the photometric circuit, so even if the entire field becomes bright (or dark), the reference value outputted by the first means is changed accordingly. The value changes, and the second means can identify the brightness distribution state in the field based on this reference value.

Furthermore, according to the present invention, the third means (the same element 101
~108) works so that photoelectric outputs exceeding a predetermined threshold among the plurality of photoelectric outputs output by the photometric circuit are not involved in the calculation of the reference value in the first means, so that even if the subject is very bright, The reference value output by the first means does not change significantly due to (or dark) portions.

Therefore, the second method is to place a part of the scene very bright (
Even if there are dark portions, the brightness distribution state in the object field can be more appropriately identified.

As described above, the present invention is capable of identifying the brightness distribution state in the object field and outputting more appropriate appropriate exposure information.

[Brief explanation of drawings]

Figure 1 is a diagram showing the brightness distribution of the field (screen), Figure 2 is a block diagram showing an embodiment of the present invention, Figure 3 is a diagram showing how the screen is divided, and Figure 4 is a photoelectric element array. A diagram showing an example of
Figure 5 shows an example of a light receiving optical system, Figure 6 shows an example of a maximum value or minimum value detection circuit, Figure 7 shows an example of an average value detection circuit, and Figure 8 shows an arithmetic circuit. 9 is a diagram showing an example of the first blocking circuit, FIG. 10 is a diagram showing an example of the second blocking circuit, FIG. 11 is a diagram showing an example of the average value detection circuit, and FIG. 12 are diagrams showing examples of a binarization circuit and a classification circuit. Explanation of symbols of main parts, 10...Photometering circuit, 1
2...First means, 14-24, 110-11
3.170...Second means, 101-108.
...Third method.

Claims (1)

[Claims for Utility Model Registration] 1. A photometry circuit that divides the field into multiple regions and measures the light, and generates multiple photoelectric outputs corresponding to the multiple regions; the brightness of each of the regions in the field. a first means for generating a reference value according to the plurality of photoelectric outputs in order to standardize the output;
a second means for identifying the brightness distribution state in the object field from the magnitude relationship between the respective photoelectric outputs and the reference value, and generating appropriate exposure information according to the result; and A multi-photometering device characterized by comprising a third means for disabling photoelectric outputs exceeding a predetermined threshold value from being involved in calculating the reference value. 2. The multi-photometering device according to claim 1, wherein in the third means, the threshold value is a threshold value set on the high luminance side. 3. The third means counts the number of photoelectric outputs that exceed a darkness value set on the high brightness side among the photoelectric outputs, and transfers the photoelectric output to the first means until the number reaches a predetermined number. According to claim 2 of the utility model registration claim, the utility model registration method is characterized in that when a predetermined number is exceeded, the excess value is replaced with a predetermined value and input to the first means. The multi-photometering device described. 4. The multi-photometering device according to claim 1, wherein in the third means, the predetermined threshold value is a threshold value set on the low luminance side. 5. The multi-photometering device according to claim 1, wherein in the first means, the reference value is an average value, a median value, or a mode value of the plurality of photoelectric outputs.