JPH0399587A - Automatic exposure adjusting device - Google Patents

Abstract

PURPOSE:To prevent a screen from being dark by comparing the brightness level of a priority area with that of a nonpriority area and increasing the priority of the nonpriority area when the priority area is discriminated to be in a bright forward light state to limit excess correction. CONSTITUTION:An image picking-up screen is divided into areas A1-A6, in which the area A1 is located in the center of the pattern, the area A2 is located on the outer periphery of the area A1 and further the areas A3-A6 are arranged on the circumference of the area A2. Then the highest priority is given to the area A1 where a major object exists with high possibility and the 2nd priority is placed on the area A2. When the brightness level of the area A1 having the higher brightness is larger than the brightness level of the areas A3-A6 with smaller priority, the priority of the areas A3-A6 with smaller brightness level is increased to apply the adjustment of the exposure. Thus, excess correction with respect to the area of excessive forward light is limited to prevent that the entire screen is dark.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an imaging device such as a video camera that automatically adjusts exposure.

(B) Conventional Technology In video cameras, control of the brightness level of a captured video signal using aperture, gain, etc., or so-called exposure adjustment, is a very important issue along with focus control.

Conventionally, as this automatic exposure adjustment mechanism, a method of detecting the average brightness level, peak value, etc. of the brightness level of the image capturing screen, and controlling the aperture and the gain for the captured image signal based on these levels has been popular. With this method, if there are high-brightness areas such as light sources on the screen, or if the background is dark,
The main subject may not be properly exposed due to surrounding effects.

In order to solve this problem, for example, Japanese Patent Laid-Open No. 62-11036
A technique as shown in No. 9 (HO4N5/243) has been proposed. This method takes advantage of the tendency that the main subject is likely to be located in the center of the screen, and divides the captured screen into the center and other peripheral areas, obtains the brightness level of each area, and compares the two. The aim is to adjust the exposure by adjusting the exposure to obtain an appropriate exposure for the main subject in the center of the screen.

FIG. 12 is a block diagram of a system using such a technique.

The incident light passes through a lens (1), the amount of light is adjusted by an aperture mechanism (2), and then photoelectrically converted by an imaging circuit (3) and output as a captured video signal.

This captured video signal is amplified by a variable gain amplifier (4) and then sent to a video circuit. At this time, the imaging circuit (
The output of step 3) is compared with a target brightness level by a comparator (5), and the aperture mechanism (2) is controlled using this differential voltage.

On the other hand, the captured video signal is sent to the area selection circuit (19), and the priority area signal is level-detected by the switching signal for area separation obtained by the synchronization separation and switching control circuits (12) and (18). The signal of the non-priority area is inputted to the integrating circuit (21), which is a digital integrator for each field, and is integrated for one field.

The outputs of both integration circuits are supplied to a division circuit (15), and the ratio thereof is sent to a gain control circuit (16) and a target brightness level control circuit (17) for the aperture. Both control circuits perform correction by varying the target brightness level of the aperture and the gain of the variable gain amplifier (4) based on the result obtained by the division circuit (15).

For example, if a light source exists in a backlit state, that is, in a non-priority area, and the brightness level of the priority area is three times the brightness level of the non-priority area,
Moreover, if the areas of both head regions are the same, the ratio of both horizontal outputs will be 1/3, and by setting the target brightness level to the normal 173, it is possible to obtain appropriate brightness for the subject in the priority region. become.

(c) Problems to be Solved by the Invention According to the prior art, an abnormally high brightness part such as a light source enters the non-priority area, and the background in the non-priority area is more sensitive than the main subject, which is in the priority area. This is effective in correcting so-called backlit conditions in which the main subject is extremely bright compared to the background, but it may have an adverse effect in so-called backlit conditions in which the main subject is significantly brighter than the background. That is, in general, in the direction lighting condition, if this is corrected to the same level as in the case of backlighting, the periphery of the screen where the background exists will become dark and the screen will look different from the impression received from the actual scene.

(d) Means for Solving the Problems The present invention compares the brightness levels of a priority area and a non-priority area, and when it can be determined that the priority area is in a bright front-light condition, the brightness of the priority area is determined for exposure adjustment. It is characterized by limiting the priority processing that prioritizes the level to that of non-priority areas, and by using fuzzy inference to determine the front lighting condition.

(e) Function Since the present invention is configured as described above, even if the imaging screen is in a direction light state, the amount of correction is suppressed compared to backlight correction, and unnatural sinking of the screen can be prevented.

Further, by using fuzzy inference, continuous correction amounts can be obtained according to the brightness difference between the two head regions.

(f) Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit block diagram of the device of this embodiment.

The incident light passes through a lens (1), the amount of light is adjusted by an aperture mechanism (2), and then photoelectrically converted by an imaging circuit (3) and output as a captured video signal. This captured video signal is amplified by a variable gain amplifier (4) and sent to a video circuit, and is also amplified by a variable gain amplifier (4) and sent to a video circuit.
It is fed to an integrator (80).

L P F (22) extracts the low frequency component of the luminance signal in the captured video signal and outputs it to the subsequent switching circuit (26).

The synchronization separation circuit (23) extracts vertical and horizontal synchronization signals from the imaged video signal, and the subsequent switching control circuit (25) combines these vertical and horizontal synchronization signals with the CC of the imaging circuit (3).
Based on the fixed oscillator output used to drive D, the third
A switching signal for screen division over six areas (A1) to (A6) in the figure is generated.

The switching circuit (26) receives the switching signal and switches each region (
Switches sequentially according to A1) to (A6), L P F
(22) The output is time-divided for each region by this switching circuit (26) and supplied to integration circuits (31) to (36), respectively.

The integrating circuits (31) to (36) each include an A/D converter (27) that A/D converts the output of the switching circuit (26) as shown in FIG. circuit(
28) A digital integrator consisting of an adder (29) that adds the output and a latch circuit (28) that latches the added output, and the low frequency component of the luminance signal in the corresponding area is sampled at a predetermined sampling rate. A/D converted at regular intervals,
(2) This A/D conversion data is integrated over the field period. Here, the integration circuit (31) outputs the integrated value for one field of the low frequency component of the luminance signal within the area (AI) to the memory (41), and similarly thereafter
2) The integrated value for one field of the luminance signal in (A3) (A4) (A5) (A6) is determined by the integration circuit (32) (33
)(34)(35)(36) to memory(42)(
43), (44), (45), and (46). The latch circuit (28) is reset for each field, and each memory retains the data immediately before the reset of each latch circuit, and the data is updated for each field.

By the way, the areas (A1) to (86) are respectively (Sl) to (S6), and the area (A1) is located at the center of the screen as shown in FIG. 3, and the area (A2) is located at the area (S1) to (S6). It is located on the outer periphery of A1). Furthermore, an area (A2) is formed around this area (A2).
3) to (86) are arranged.

When the integration for one field, which is one screen, is completed, the latest integrated value for one field in each area held in the memory (41) to (46) is the brightness evaluation value of each area. (Y
l) to (Y6) are the subsequent simple average circuits (68),
Each normalization circuit and each weighting are output to the circuit.

The normalization circuits (51) to (56) convert the brightness evaluation values (Yl) to (Y6) in each region into respective areas (Sl) to (S6
), and the brightness evaluation value per unit area of each region is normalized brightness evaluation value (Vl) to (V6) (however, V1=
Y1/Sl, V 2 =Y 2/S2, . . . ).

The priority determination circuit (57) determines each normalized luminance evaluation value (V
Priority (weight) of each area based on 1) to (■6)
Determine. The priority determination process in this priority determination circuit (57) is executed according to a flowchart as shown in FIG. Specifically, the following six rules are used.

[Rule (1)] rifVl and V2 are close andV 1 and v3 are not close then area (At) (A2) is given priority.'' [Rule (2)] rifVl and V2 are not close andV 1 and v3 are close then area (A ]), (A3) Priority” [Rule (3)
] rif Vl and V2 are not close and V 1 and v3 are not close then area (A1) is given priority.'' [Rule (4)] rif Vl and v2 are close a, ndV 1 and v3 are close t
hen areas (A1), (A2), (A3) have priority” [Rule (5)] rif (V1+V2+V3)/(3x simple average value) is large then all areas have the same priority” [Rule (6)] rif max ( Vi) is not small and the simple average value is small then give priority to the area below the simple average value.'' These rules are as shown in Figures 6 to 11.
Conditions such as “close” and “small” are “V2/VIJ
It is defined by a membership function for each input variable such as ``rmax (Vi)'', and has the priority (wik) of each area as a conclusion part. In addition, the inference is normal mi
This is done using the n-max method.

Next, each rule will be explained in detail.

[Rule (1)] is defined by membership functions as shown in FIGS. 6(a) and (b). FIG. 6(a) shows the membership function for the input variable (V2/Vl), which indicates the degree to which condition (1) of rule (1) "rVl and U2 are close" is satisfied. That is, in order to determine the degree of closeness indicating how close the normalized brightness evaluation value (vl) of area (A1) and the normalized brightness evaluation value (U2) of area (A2) are, the input variable is set to V2. /Vl, and the membership value (U,... ) can be found. Furthermore, V2
When /V1=1, the membership value (u,,) is maximum.

FIG. 6(b) shows the input variable (V 3
/V 1 ). That is, the normalized luminance evaluation value (Vl) of the area (A1) and the area (A
In order to determine the degree to which the normalized luminance evaluation value (U3) of 3) is not close, the input variable is set to V3.
/Vl, and by substituting the input variable (V3/Vl) in the latest field into the valley-shaped membership function that takes a minimum value when V3/V1=1, the membership value (u, ,) can be calculated. Seek. Furthermore, when V3/V1=1,
The membership value (u, ,) is the minimum. In this way, condition (1) of rule (1) is satisfied by Figure 6 (a) and (b).
(2) Membership value (u,)(u.

, ) will be calculated. Note that this calculation is based on the second
This corresponds to S T E P (100) in the flowchart in the figure.

The membership value (ul,) (u,) is STE
At P (101), the minimum value of both, that is, the smaller membership value is selected as the degree of fulfillment (Ul) of rule (1). In the example of FIG. 6, since ull<u+*, U1=u is set.

The operations of S T E P (100) and (101) described above are also executed for the remaining five rules.

[Rule (2)] is defined by valley-shaped and mountain-shaped membership functions as shown in Figures 7(a) and (b), and as in the case of Figure 6, it is a rule that "vl and U2 are not close". (2)
For condition (1), the membership value (u, ,) is closer than (a), and rVl and U3 are closer.''
2) Membership value (u, , for condition (2))
) is determined from (b), and in 5TEP (101), the smaller membership value (u, ) (u-) is selected as the degree of fulfillment (U2) of rule (2). In the example of FIG. 7, since u s + > u□, U2=us* is set.

[Rule (3)] is defined by a valley-shaped membership function as shown in Figures 8(a) and (b), and as in the case of Figure 6, rule (3) states that rVl and U2 are not close. The membership value (U, 1) for condition (1) is (a
), and the rule that rVl and U3 are not close (
3) Membership value (u, , for condition (2))
) is determined from (b), and in S T E P (101), the one with the smaller membership value (ust) (u□) is selected as the degree of fulfillment (U3) of rule (3). In the example of FIG. 8, U31<u3t, so U3=us+
is set to

[Rule (4)] is defined by a mountain-shaped membership function as shown in Figure 9 (a) and (b), and the membership value for condition (1) of rule (4) that ``rVl and U2 are close'' is u, ,) is determined from (a), and the membership value (U, ,) for condition (2) of rule (4) that "Vl and U3 are close" is determined from (b), and S T
At E P (101), the membership value (u,,)(
The smaller one of u, , ) is selected as the degree of establishment of rule (4) (U4). In the example of FIG. 9, since uH>u<t, U4=u<m is set.

[Rule (5)] is: As shown in Figure 1, the average value (Vl+V2+V
3) /3 and the simple average value (zl) + V3) / (3 The average value (Vl
+V2+V3)/3 and the simple average value (Zl) are determined to uniquely determine the membership value (u, , ). S T
In E P (101), there is only one membership value for rule (5), so after rule (5) is established, (U5) is set to U5=ui+.

[Rule (6)] is as shown in Figure 11 (a) and (b),
A membership function with a simple increasing straight line whose input variable is the maximum value max (Vi) among all normalized luminance evaluation values (Vl) to (V6), and a simple membership function whose input variable is the simple average value (Z,). It is defined by the membership function of a decreasing line. That is, Fig. 11 (
In condition (1) of rule (6) that rmax(Vi) is not small in the membership function of a), m
In order to determine the degree to which ax(Vi) is not small, if max(Vi) is determined as an input variable, membership values (u, , ) can be determined. Note that this membership value (u, ,) becomes smaller as max (Vi) becomes smaller. In addition, in the membership function of FIG. 11(b), input variables are used to determine the degree to which the simple average value (Z, ) is small in condition (2) of rule (6) that "the simple average value is small". Once the simple average value is determined, the membership value (uo) can be determined. Note that this membership value (u,,) becomes smaller as the simple average value becomes larger. In STE P (101), the smaller of the membership values (u,,) and (u,,) is selected, and the probability (U6) of rule (6) is U6=us
It is set as m.

As described above, it is determined in S T E P (102) that the calculation of the degree of establishment (Ui) (i = 1 to 6) for all rules in S T E P (100) (101) has been completed. Then, in STE P (103), the priority (Wk) (k=1 to 6) for each area is calculated. This priority (Wk) is calculated by weighted averaging of the conclusions based on the degree of establishment of each rule, as shown in the following equation.

In this formula (A), wik is the priority for each area regarding each rule, and is determined individually for each rule.

For example, regarding rule (1), "area (A1), (
In order to numerically indicate "prioritize A2)," the priorities (W, , ) to (
W,,) is wl, °w+, °3 w,, = w,, = w,, = w,, = 1
is set in advance. That is, for rule (1), the priority of area (AI) (A, 2) over other areas is 3.
It is set to double. Note that this priority setting is based on experiments conducted in advance.

Regarding rule (2), in order to indicate "prioritize areas (A1) and (A3)" as the conclusion part, the priority of each area (W, , ) to (W, ,) is w, , = w ,,=3 W go * = W t s = W t s = W *
:1 is preset.

Regarding rule (3), "give priority to area (A1)"
In order to show the conclusion part, the priority of each area (W, ,
) to (W,,) are w,,=3 w,,=w,,: w,,=w ■:w 3.
= 1 in advance.

Regarding rule (4), “area (AI), (A2),
In order to show "(A3) is prioritized" as the conclusion part, the priority of each area (W, ) to (W4.) is =4,8=4.
=w, )=3 w, , =w, , =w, , =1 are set in advance.

Regarding rule (5), "All areas have the same priority"
In order to show as a conclusion, the priority of each area (W,,)
〜(W,) is W sl= w s, = w s, = w s4°w,
, =w, , =1 is set in advance.

Regarding rule (6), in order to indicate "prioritize the area below the simple average value" as the conclusion part, the priority of each area (
If wsi) to (was) are 2=1 to 6, then w=! if Vs<simple average value (Zl). If =3Vs>simple average value (Z, ), then w1=1 is set in advance.

For example, if the normalized luminance evaluation values (Vl) to (v3) of regions (A1) to (A3) are larger than the simple average value (2,), W・4=w, 1=w, -03 w , ,: w , ,= w , 3=1. still,
The simple average value (Z,) is calculated using a simple average circuit (68
) is calculated.

Considering the priority (Wk) considering all rules using the priority of each area in each rule set in this way using the examples of FIGS. 6 to 11, for area (A1),
Formula (A) becomes. In this formula (B), =Uth゛3+u st゛3"u s+°3"ua*'3
+u, 1・l+u4m・1 =u +t”u s*÷u 1++u 4*”u sl
+u s*, so the priority (W, ) of area (A1) is
is L-(3u+++3u**”3u,++3u**”us
+”us*)/(u++”u**÷ust◆us t”
us r÷U, ). Similarly, the priorities (W,) to (W,) are calculated as follows. The priority (Wk) of each area determined by fuzzy inference for all rules is sent to the weighting circuits (61) to (66). The weighting circuits (61) to (66) give priority to each area. The weighting circuits (61) to (66) perform so-called priority processing by weighting based on the priorities (W, ) to (W,) for each area. That is,
Yi-Wi(i=
1 to 6) are calculated. All of the luminance evaluation values weighted in this way are supplied to the weighted averaging circuit (67). The weighting is performed by the average circuit (67), and the weighting is performed by the circuits (61) to (
66) Divide the added value of the output by the sum of the products of each priority and area and output the weighted average value (Z,). That is, calculate. Note that Si (i=1 to 6) indicates the area of each region.

The simple averaging circuit (68) adds up all of the respective brightness evaluation values (Yi) and calculates the added value as the area (S) of the entire screen.

+St+...S,) to obtain the simple average of the entire screen. Note that this simple average value (zl) is calculated based on each brightness evaluation value (
Y i ) is weighted by circuits (61) to (66) with priorities (W, ) to (W,) all set to "1", and weighted by averaging circuit (67) using equation This is the same value as that calculated in C).

The simple average value (Zl) and the weighted average value (z8) calculated as described above are input to the division 6 (69), and m =
z 1 / z z is divided, and this division value (m)
are a gain control circuit (70) and a target level control circuit (71).
) is entered.

The gain control circuit (70) supplies a target level (P) to a comparator (5) that controls the gain of the variable gain amplifier (4). This target level (P) is used to obtain the optimal exposure for the image capture screen when m=1, that is, when the simple average value (Zl) and the weighted average value (Z,) are equal and the brightness distribution of the image capture screen is not considered. The optimum target level (P, ) obtained is set, and the division value (m), which is a correction value, is followed so as to satisfy P = m P . Therefore, in the end, when adjusting the exposure, the average value (2,) is the optimal target level (Po
), the target level (P) will change.

The comparator (5) integrates the captured video signal over a sufficiently long time constant (for example, one field period) and outputs the output of the integrator (90) indicating the brightness level of the corresponding field and the target level (P). This comparison output is supplied to the variable gain amplifier (4) so that the integrated output reaches the target level (P).
By controlling the gain so as to match , AGC is applied to the video signal in consideration of weighting and processing.

The target level control circuit (71) supplies a target level (Q) to a comparator (72) that controls the aperture amount of the aperture mechanism (2), and this target level (Q) is equal to the target level (
Similarly to P), when the division value (m) satisfies the condition of m = 1, it is set to the optimal target level of Q = qe, and between it and the division value (m), Q = m, q o As a result, when adjusting the exposure, the weighting is changed to the average value (Z
, ) always matches the optimal target level (q6).

The comparator (72) integrates the target level (Q)! (80
) output, and this comparison output is compared with the aperture mechanism (
2), and based on this comparison output, the aperture mechanism (2)
the aperture mechanism (2) so that the integral output indicating the brightness level of the relevant field matches the target level (Q).
The aperture amount is controlled. Note that the time constant of the integrator (80) is equal to that of the integrator (90), and is set so that the aperture mechanism (2) does not follow instantaneous changes in the captured video signal.

As mentioned above, the variable gain amplifier (4) and the aperture mechanism (2)
The target level (
P )(Q ) is a variable gain amplifier (
4) and optical exposure adjustment using the aperture mechanism (2), the weighting process is fully taken into account. For example, if the simple average value (Zl) of the entire screen is "120", the average value If (2,) is 100'', sufficient brightness is obtained over the entire screen, but rules (1) to (6)
If we focus only on the areas that must be prioritized, we will not have enough brightness and the central area will be dark, so the division value (m) will be m = 1, 2. Therefore, the target level (P) (Q) is P=mP meeting, respectively.
As a result, the variable gain amplifier (4
) also increases, the aperture amount of the aperture mechanism (2) also decreases, and optimal exposure adjustment is performed for the priority area.

Next, how the rules (1) to (6) affect exposure adjustment will be explained for each rule. Rules (1) to (4) are the basics of priority processing for backlight correction, and when the brightness evaluation values are close to each other in areas (Al), (A2), and (A3), the priority of that area is determined. It acts to increase the

For example, as in the prior art, the areas (At) (A2) (A3) where the object is most likely to exist are simply given the same priority as the areas (A4), (A5), and (A6). When the subject (S) is photographed in a backlit situation as shown in Fig. 5, a bright background such as the sun appears only in the area (A2), making it impossible to correct the subject (S) appropriately. Therefore, if rules (1) to (4) are applied, both areas (A1) and (A3) are dark and only area (A2) is bright, so the normalized luminance evaluation value (Vl, ) (V2) (V3) is Vl; V3≠V2 holds, conditions (1) and (2) of rule (1), condition (2) of rule (3), and rule (4
) is difficult to hold, so only the probability of rule (2) being satisfied is extremely high, and the priority of areas (AI) and (A3) is high, and the objects that fall within these areas (A1) and (A3) (S), and the optimum exposure condition for this subject (S) is obtained. These series of rules are particularly effective when backlit.

Rule (5) is for dealing with the Douen Hikari screen.
In this route lighting condition, only the brightness levels of areas (AI) (A2) (A3) where the extremely bright main subject (S) is likely to exist are significantly high, and the normalized brightness evaluation values of these three areas ( ■1) Average value of (V2) (V3) (V1
+V2+V3)/3 becomes larger than the simple average value (Zl) of the entire screen, and accordingly, the input variable of rule (5) increases and the membership value (U5) also increases. In proportion to this increase in membership value (U5), the effect of trying to give all areas the same priority without performing priority processing becomes stronger. This action adds an element with the same priority for all areas to the corrections made according to rules (1) to (4) above.In other words, the priority processing in rules <1) to (4) is reversed. This prevents the surroundings of the subject from becoming dark and sinking when the direction light is on.

Rule (6) corresponds to the case where something extremely bright like a light source enters the screen, and the normalized brightness evaluation value (Y i
Although the maximum value of ) is not small, the simple average value (Z, )
When the screen is small and the screen as a whole is dark, priority is given to areas with low brightness. Here, if a light source, etc. is included in the screen, the simple average value (2,) will be small and the screen will be dark, even though the area containing this light source has a sufficient normalized brightness evaluation value. Put it away. In this case, by increasing the priority of areas with low normalized brightness evaluation values that do not include light sources, the influence of the light source is reduced and the exposure of the main subject is improved.

Note that the division of regions and the setting of each rule are not limited to this embodiment, and various forms can be considered. In addition, the switching circuit in Figure 1 (
It goes without saying that the operations of the divider (26) to (69) can be processed by software using a microcomputer.

In addition, in the above embodiment, the optimum target level (Po) of the imaging screen without considering the brightness distribution is set in advance, and the weighting is a division value that is the ratio of the simple average value (2,) to the average value (2,). An integrator (90) that multiplies the optimal target level (P, ) by (m) as a correction value to indicate the brightness level of the captured video signal.
Optimum exposure control is achieved by comparing with the output, but as shown in Figure 13, the optimal target level (Po)
The weighting is the average value (2,) and the target level memory (91)
The target level (po') stored in
is a value obtained by digitizing the target level (Po)) by a comparator (92), and based on the comparison result, the gain of the variable gain amplifier (4) is controlled, and the diaphragm fil (2) is It is also possible to perform electrical and optical exposure adjustment by controlling the aperture amount of ('). For example, when the average value (Z8) is smaller than the target level (Pa'), the weighting Z is determined based on the assumption that the image capturing screen is underexposed compared to the optimal exposure state after considering the brightness distribution.

The gain of the variable gain amplifier (4) is increased so that = P, °, and the aperture amount of the aperture mechanism (2) is decreased to increase the brightness. Conversely, the weighting is such that the average value (2,) is When the level is higher than the target level (Poo), it is assumed that the exposure is overexposed compared to the optimum exposure state, and the gain of the variable gain amplifier (4) is lowered so that Z, = P1'', and the aperture mechanism (
It is sufficient to reduce the brightness by increasing the aperture amount in 2).

(G) Effects of the Invention As described above, according to the present invention, excessive correction of the route light screen is restricted and the screen is prevented from becoming dark and sunken. Furthermore, by using fuzzy reasoning to determine the direction light, a continuous and natural screen can be obtained from the backlight to the direction light.

[Brief explanation of drawings]

1 to 11 relate to an embodiment of the present invention, in which FIG. 1 is an overall circuit block diagram, FIG. 2 is a flowchart, FIG. 3 is an explanatory diagram of screen division, and FIG. 4 is a main circuit. The block diagram, Figure 5 is a diagram showing an example of the imaging screen, and Figure 6 is the rule (
Figure 7 is an explanatory diagram of rule (2), Figure 8 is an explanatory diagram of rule (3), Figure 9 is an explanatory diagram of rule (4), and Figure 10 is an explanatory diagram of rule (5). 11 is an explanatory diagram of rule (6), FIG. 13 is a circuit block diagram of another embodiment of the present invention, and FIG. 12 is a circuit block diagram of a conventional example. (31) (32) (33) (34) (35) (36)・
... Integration circuit, (61) (62) (63) (64) (6
5) (66)... Weighting circuit, (70)... Gain control circuit, (71)... Target level control circuit, (57
)...priority determination circuit

Claims (2)

[Claims] (1) A brightness level detection means that divides the imaging screen into multiple areas and detects the brightness level of each area, and performs priority processing that weights the brightness level of each area based on the priority determined for each area. A priority processing means, and an exposure control means for controlling exposure by changing an exposure adjustment amount according to the output of the priority processing means, when the brightness level of the high priority area is higher than the brightness level of the low priority area. , an automatic exposure adjustment device characterized in that the weighting is limited. (2) The automatic exposure adjustment device according to claim 1, wherein fuzzy inference is used to determine whether the brightness level of the high priority area is higher than the brightness level of the low priority area.