JPH09258097A - Automatic focus detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a stored control from being performed again in the case of projecting auxiliary light by controlling storage operation in shorter time than the storage time calculated at the time of starting projecting the light of an auxiliary light source to a subject. SOLUTION: In the case of detecting that subject luminance is equal to or under a specified value, a control circuit 11 sets an output level to an L level, and controls an auxiliary light emission driving circuit 13 to turn on a light emitting diode so as to irradiate the subject with the auxiliary light. Since a selection switching circuit 8 sets the level of an output end Q to an H level, two switches 9 and 10 perform selective switching operation. The switch 9 gives output from a next-time storage time calculation circuit 4 to a storage time correction circuit 7, and the switch 10 selects output from the circuit 7. The circuit 7 replaces the storage time inputted from the switch 9 with the shorter storage time and outputs it. As a result, the storage time corrected to be shorter is given to a storage time control circuit 6 and a this-time storage time holding circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focus detection device for detecting a focus state by performing focus detection calculation on a subject image obtained by an accumulated charge type light receiving element, and particularly to an automatic focus detection device when the luminance of the subject is low. The present invention relates to an automatic focus detection device that emits auxiliary light to enable focus detection.

[0002]

2. Description of the Related Art The dynamic range of subject brightness is considerably wider than the dynamic range of a subject image (determined by the number of bits of an A / D converter) obtained by an accumulated charge type light receiving element such as a CCD. On the other hand, it is desired that the signal processing level after the focus detection calculation is almost constant.

Therefore, when the focus state is detected by subjecting the object image obtained by the accumulated charge type light receiving element to detect the focus state, the accumulated charge type received light should be set so that the signal level used in the focus detection calculation is substantially constant. The accumulation time of the element is adjusted one by one according to the brightness of the subject or the contrast. The methods of controlling the accumulation time of the accumulated charge type light receiving element are roughly classified into the first method of controlling the accumulation time in real time according to the accumulation amount at each accumulation time, and the next method from the accumulation time and the signal level of this time. There is a second method for controlling the accumulation time.

In the first method, since the storage time is controlled in real time, it is possible to respond to a sudden change in the brightness of the subject during storage, but on the other hand, the brightness changes independently for all the light-receiving element pixels. Is difficult to monitor, so that the storage time is often controlled so that the average signal level of a plurality of pixels becomes a desired level. on the other hand,
In the second method, it is difficult to respond to a sudden change in subject brightness or contrast during storage, but since it is software processing, all light-receiving element pixels are captured, and even one pixel, for example, can be captured. There is an advantage that fine control can be performed such that the peak level becomes a predetermined level.

In this type of automatic focus detection device,
Some methods employ a method in which auxiliary light is projected onto the subject to enable focus detection when subject brightness or contrast is low.

[0006]

The automatic focus detection apparatus to which the present invention is directed controls the storage time by the second method. As described above, in the second method, the object suddenly appears during storage. It is difficult to respond to changes in brightness. Therefore, when the subject brightness or the contrast is low, the automatic focus detection device adopting the method of projecting auxiliary light to the subject to enable focus detection is
When the auxiliary light is projected when the storage time is controlled without the auxiliary light, the following problems occur.

That is, when the storage time is controlled without auxiliary light, the storage time is naturally calculated in a dark state or a low contrast state. When the auxiliary light is projected in this state, the signal level suddenly increases and sometimes reaches a saturation level exceeding the range of the A / D converter. In such a case, conventionally, for example, the accumulation time is uniformly set to 1/4 hour and the accumulation is performed again, so that it is appropriate until the signal level becomes appropriate with the fill light projected. Since the accumulation operation of the number of times is repeated, it may take a long time to detect the focus when the auxiliary light is used.

The present invention was created in order to solve such a problem, and an object thereof is to provide an automatic focus detection device having means for avoiding re-accumulation control when projecting auxiliary light. To provide.

[0009]

A configuration will be described with reference to FIG. 1 showing an embodiment of the present invention.

An automatic focus detection device according to a first aspect of the present invention receives a subject image and outputs an output signal based on the light reception result, and a charge storage type light receiving element (1). The storage time calculation means (3, 4, 5) for calculating the storage time at the next light reception from the output signal at this time light reception and the storage time calculated based on the output signal, and the charge storage type light reception according to the calculated storage time. Storage operation control means (6) for controlling the storage operation of the element (1) and auxiliary light emitting means (11, 13) for emitting the auxiliary light source (14) when the brightness or contrast of the subject is below a predetermined level. In the automatic focus detection device including the control unit (7, 8, 9,) for controlling the accumulation operation in a time shorter than the accumulation time calculated when the projection of the auxiliary light source (14) onto the subject is started.
10, 11, 12).

According to another aspect of the present invention, the automatic focus detection device receives a subject image and outputs an output signal based on the light receiving result, and a charge storage type light receiving device (1). The storage time calculation means (3, 4, 5) for calculating the storage time at the next light reception from the output signal at this time light reception and the storage time calculated based on the output signal, and the charge storage type light reception according to the calculated storage time. Storage operation control means (6) for controlling the storage operation of the element (1) and auxiliary light emitting means (11, 13) for emitting the auxiliary light source (14) when the brightness or contrast of the subject is below a predetermined level. In an automatic focus detection device comprising: a storage time correction means (7) for correcting the storage time between the storage time calculation means (3, 4, 5) and the storage operation control means (6), and an auxiliary light source ( 14) emit light Storage time calculating means (3, 4 before,
The output of 5) is given to the storage time correction means (7), and the corrected storage time is output to the storage operation control means (6),
After light emission, switching means (8, 9, 10,) for giving the output of the storage time calculation means (3, 4, 5) to the storage operation control means (6).
11 and 12) are provided.

(Operation) In the automatic focus detection device according to the first aspect of the present invention, when the control means starts the projection of the auxiliary light onto the subject, the storage time calculated up to that time is corrected to a shorter time, and the correction is performed. The accumulation operation after light emission is performed based on the accumulated time.

As a result, the level of the signal used for focus detection does not transiently increase even if the subject brightness or the contrast increases due to the projection of the auxiliary light. The focus state can be detected as quickly as when no light is used. Specifically, the control means can be simply configured by the accumulation time correction means and the switching means as in the automatic focus detection device according to the second aspect.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration block diagram of an automatic focus detection device according to an embodiment of the present invention. In FIG. 1, the automatic focus detection device includes a charge storage type light receiving element (hereinafter referred to as “CCD”) 1, a focus detection circuit 2, an output level detection circuit 3, a next storage time calculation circuit 4, a current storage time holding circuit 5, Storage time control circuit 6, storage time correction circuit 7, selection switching circuit 8, 1-input 2-output switch 9, 2-input 1-output switch 10, control circuit 11, light emission / non-light emission recognition circuit 12, auxiliary light emission drive circuit 13, light emitting diode 14
Etc. are provided.

Under the control of the storage time control circuit 6, the CCD 1 receives a subject image within a predetermined time and outputs a signal of the received subject image to the focus detection circuit 2 and the output level detection circuit 3. The focus detection circuit 2 calculates the focus state of the subject from the output signal of the CCD 1. Also, the output level detection circuit 3
Detects the level of the output signal of the CCD 1 when the light is received this time, and outputs the detection result to the next storage time calculation circuit 4.

The next accumulation time calculation circuit 4 calculates the accumulation time at the next light reception from the output signal level of the CCD 1 at this time light reception inputted from the output level detection circuit 3 and the accumulation time inputted from the current accumulation time holding circuit 5. To do. The calculated storage time at the next light reception is output to the switching input terminal of the switch 9.

One switching output end of the switch 9 is connected to one switching input end of the switch 10, and the other switching output end of the switch 9 is connected to the input end of the accumulation time correction circuit 7. The accumulation time correction circuit 7 replaces the accumulation time input from the other switching output end of the switch 9 with a shorter accumulation time, outputs the one from the one output end to the other switching input end of the switch 10, and outputs the other output. The reset signal is output from the end to the reset end R of the selection switching circuit 8.

The switching output terminal of the switch 10 is connected to the input terminal of the current storage time holding circuit 5 and the input terminal of the storage time control circuit 6, respectively. The current storage time holding circuit 5 holds the storage time input from the switching output terminal of the switch 10 as the current storage time. The accumulation time control circuit 6 is based on the accumulation time input from the switching output terminal of the switch 10
Control the accumulation operation of D1.

In the selection switching circuit 8, the set terminal S is connected to the output terminal of the light emission / non-light emission recognition circuit 12, and the output terminal Q is connected to the switching control input terminals of the two switches 9 and 10. That is, when the set signal is input from the light emission / non-light emission recognition circuit 12, the selection switching circuit 8 sets the level of the output terminal Q to a high level (hereinafter referred to as “H level”), and the accumulation time correction circuit 7
When the reset signal is input from, the level of the output terminal Q is set to a low level (hereinafter referred to as "L level"). It should be noted that the selection switching circuit 8 has an output terminal Q in an initial state such as when the power is turned on.
Is set to L level.

When the output of the selection switching circuit 8 is L level, the two switches 9 and 10 select one switching output terminal and one switching input terminal respectively, and when the output of the selection switching circuit 8 is H level. , The other switching output end and the other switching input end are respectively selected. The control circuit 11 is provided with brightness information or contrast information from the outside. This brightness information is the output signal of a photometric sensor (not shown), or
It is a brightness value calculated from the accumulated amount of the CCD 1. The contrast information is calculated based on the output value from the CCD 1.

The control circuit 11 determines whether or not the brightness of the subject is equal to or higher than a predetermined value based on the externally input brightness information or the contrast information. If the brightness is equal to or higher than the predetermined value, the output level is set to, for example, the H level, and the predetermined level. If it is less than the value, the output level is set to L level. The output end of the control circuit 11 is connected to the input end of the light emission / non-emission recognition circuit 12 and the input end of the auxiliary light emission drive circuit 13, respectively.

The emission / non-emission recognition circuit 12 is the control circuit 1.
When the output level of 1 changes from the H level to the L level, it is recognized that the light emission has started, and the set signal is output. As a result, the selection switching circuit 8 sets the level of the output terminal Q to the H level. Then, the selection switching circuit 8 includes the accumulation time correction circuit 7
The level of the output terminal Q is set to the L level by the reset signal from.

A light emitting diode 14 for projecting auxiliary light is connected to the output terminal of the auxiliary light emission drive circuit 13. In the auxiliary light emission drive circuit 13, the output level of the control circuit 11 is L.
When the level is reached, the light emitting diode 10 is driven to light.
The operation of the automatic focus detection device according to the embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 is an operation flowchart of the automatic focus detection device according to the first embodiment of the present invention. FIG. 3 is an operation flowchart of the automatic focus detection device according to the second embodiment of the present invention.

First, the operation of the first embodiment of the present invention will be described with reference to FIG. The first embodiment shows the control operation when the brightness of the subject is low. In FIG. 2, S
In 1, the initial setting process is performed immediately after the power is turned on. That is, immediately after the power is turned on, since there is no accumulated data in the CCD 1 and the accumulated time of this time is unknown, the initial accumulated time is set in the accumulated time holding circuit 5 this time, and the output of the photometric sensor is output to the output level detection circuit 3. The predetermined value is set based on the above.

As a result, both the storage time initially set in the storage time holding circuit 5 this time and the predetermined value set in the output level detection circuit 3 are given to the next storage time calculation circuit 4, and the calculation operation of the next storage time is started. It Immediately after the power is turned on, the control circuit 11 holds the output at the H level, and the selection switching circuit 8 sets the level of the output terminal Q to the L level. Therefore, the switch 9 switches one of the switching output terminals to the switch. 10
Selects one of the switching input terminals.

Therefore, the output of the next storage time calculation circuit 4 is directly applied to the current storage time holding circuit 5 and the storage time control circuit 6 via the two switches 9 and 10. S2
Then, the accumulation time control circuit 6 controls the operation of the CCD 1 to execute the accumulation operation. Immediately after the initial setting, the storage time control circuit 6 controls the storage operation of the CCD 1 according to the storage time calculated based on the initial value set in S1, but thereafter, the CCD 1 according to the storage time calculated based on the actual measurement value. Control the accumulation operation of.

In S3, the output level detection circuit 3 is the CCD
1 is executed to extract the peak value to detect the maximum value, and the detection result is given to one input of the next accumulation time calculation circuit 4. The other input of the next accumulation time calculation circuit 4 is the output of the current accumulation time holding circuit 5. In S4, the focus detection circuit 2 reads the CCD 1 and performs focus detection calculation.

In S5, the next accumulation time calculation circuit 4 calculates the next accumulation time Tnext from the output of the output level detection circuit 3 and the output of the current accumulation time holding circuit 5, for example, according to the equation (1). Here, in Expression (1), the “target signal level” and the “actual signal level” are defined by the output value of the A / D converter. Tnext = (current accumulation time (ms) × target signal level) / actual signal level (1) For example, if shown by a concrete numerical example, the current accumulation time (ms) is, for example, 100 ms, and the target signal level is 10 The output value of the bit A / D converter is 512, and the actual signal level is 10
The next storage time Tnext is calculated by setting the output value of the bit A / D converter to 400 or the like. It is needless to say that the calculation accuracy is low because the calculation performed at the initial setting of S1 is based on the initial value.

Next, in S6, it is determined whether or not the focus detection circuit 2 has detected the in-focus state. If in focus, S6
Is affirmative (YES), and this procedure ends,
If it is not in focus, the determination in S6 is negative (NO), and the process proceeds to S7. In S7, it is determined whether or not it is dark, that is, whether or not the brightness of the subject is low enough to project the auxiliary light and the focus detection circuit 2 is in a state where focus detection cannot be performed correctly. .

If the determination in S7 is negative (NO), the brightness of the subject is so bright that focus detection can be performed correctly.
The control circuit 11 is caused to hold the output level at the H level, the switches 9 and 10 are maintained in the initial setting state, the process proceeds to S11, the lens drive circuit is activated to return to S2, and focus detection is performed in S6. , S2 → S3 → S4 → S5 → S6 →
The routine of S7 → S11 → S2 is repeatedly executed.

During this time, the next accumulation time calculated by the next accumulation time calculation circuit 4 as described above is given to the current accumulation time holding circuit 5 and the accumulation time control circuit 6 via the switches 9 and 10, and the current time of the CCD 1 is calculated. The storage operation time is controlled and the time for the next storage operation of the CCD 1 is repeatedly obtained, and the output level of the CCD 1 is controlled to a desired level. In the numerical example above, CC
The output level of D1 is controlled to be 512, and focus detection is performed.

Of course, if the shooting scene is changed, the accumulation time calculated as the next accumulation time is based on the signal level and the accumulation time before the change, so that it may deviate from the proper level, but it is a normal value. Under shooting conditions, there is no problem in followability. Next, as described above, S2 → S3 →
The accumulation time of the CCD 1 is controlled by repeating the routine of S4 → S5 → S6 → S7 → S11 → S2, and even if an appropriate output value is obtained, the accumulation time becomes longer when the brightness of the subject decreases.

Therefore, S2 → S3 → S4 → S5 → S6 →
When the control circuit 11 detects that the subject brightness has become equal to or lower than the predetermined value in the process of repeatedly executing the routine of S7 → S11 → S2, the determination in S7 becomes affirmative (YES), the process proceeds to S8, and the auxiliary light is turned on. It is determined whether the light has already been emitted. This time, the auxiliary light has not been emitted, so S
The determination of 8 is negative (NO), the auxiliary light is emitted in S9, the accumulation time is corrected in S10, and the process proceeds to S11.

Specifically, when the control circuit 11 detects that the brightness of the object has become equal to or lower than a predetermined value, the control circuit 11 sets the output level to the L level, causes the auxiliary light emission drive circuit 13 to turn on the light emitting diode 14, and causes the object to be illuminated. Irradiate auxiliary light. At the same time, when the control circuit 11 sets the output level to L level,
The light emission / non-light emission recognition circuit 12 detects that the output level of the control circuit 11 has changed from H level to L level, and outputs a set signal to the selection switching circuit 8.

Then, since the selection switching circuit 8 sets the level of the output terminal Q to the H level, the two switches 9 and 10 perform the selection switching operation, and the switch 9 corrects the output of the next storage time calculating circuit 4 to the storage time. The output of the accumulation time correction circuit 7 is selected by the switch 10 applied to the circuit 7. The storage time correction circuit 7 replaces the storage time input from the switch 9 with a storage time shorter than that, and outputs the same, and at the same time, outputs a reset signal to the selection switching circuit 8. As a result, the accumulation time corrected to a short time is given to the accumulation time control circuit 6 and the present accumulation time holding circuit 5. Further, the selection switching circuit 8 is reset to set the level of the output terminal Q to the L level, and the two switches 9, 10
The selection switching operation can be performed.

As a result, the CCD 1 starts its operation in the corrected accumulation time, the level of the output signal is given to the next accumulation time calculation circuit 4 as the signal level of this time, and the corrected accumulation time is accumulated in this time. The time is given to the next accumulation time calculation circuit 4, and the next accumulation time is calculated.

When the next storage time calculation circuit 4 calculates and outputs the next storage time based on the corrected storage time and signal level, the selection switching circuit 8 is reset,
The two switches 9 and 10 perform a selection switching operation that bypasses the storage time correction circuit 7 and are directly connected to each other. Therefore, S8 → S9 → S10 → S11 → S2 → S3
→ S4 → S5 → S6 → S7 → S8
, It is determined that the auxiliary light has been emitted, and the determination is positive (Y
ES), this time go to S11, S8 → S11 →
The focus detection operation described above is performed by repeatedly executing the routine of S2 → S3 → S4 → S5 → S6 → S7 → S8 → S11. The next accumulation time calculated by the next accumulation time calculation circuit 4 is directly the current accumulation time. Since it is given to the holding circuit 5 and the storage time control circuit 6, the storage time of the CCD 1 is
The accumulation time is preset to a short accumulation time commensurate with the increased subject brightness, and the operation can be performed based on the preset accumulation time.

In short, under the subject brightness that does not require the projection of auxiliary light, S2 → S3 → S4 → S5 → S6 → S7 →
The focus detection operation is performed by repeatedly executing the routine of S11 → S2, and in S7 of the operation process, it is always determined "whether auxiliary light should be projected." When it is determined in S7 that the brightness of the subject is lowered and it is necessary to project auxiliary light, first, S7 → S8 → S9 → S10 → S.
In the routine of 11 → S2 → S3 → S4 → S5 → S6 → S7, the auxiliary light is projected to correct the storage time, the next storage time is obtained from the corrected storage time, and the process directly proceeds from S8 to S11. Is S8 → S11 → S2 → S3 → S4 → S5 → S
The routine proceeds to the repeated execution of the routine of 6 → S7 → S8 → S11, and the focus detection based on the corrected accumulation time is performed. Next, the operation of the second embodiment of the present invention will be described with reference to FIG. The second embodiment shows the control operation when the contrast of the subject is low.

In FIG. 3, S31 to S36 correspond to S1 to S6 in FIG. 2, and the same operation is performed. In the next S37, it is determined whether the contrast is low.
If the determination in S37 is negative (NO), focus detection can be performed, but since focus is not achieved, the control circuit 11 is caused to hold the output level at the H level and switches 9 and 10 are maintained in the initial setting state. Then, the process proceeds to S41, the lens drive circuit is activated, the process returns to S32, and S32 → S33 → S34 → S35 → S36 → S37 until focus detection is performed in S36.
The routine of S41 → S32 is repeatedly executed.

During this period, the next accumulation time calculation circuit 4 executes the same operation as that of the first embodiment described above. Next, S3
If the determination of 7 is affirmative (YES), that is, if the contrast is low, the process proceeds to S38, and it is determined whether the auxiliary light has already been emitted. If the auxiliary light has not been emitted, the determination in S38 is negative (NO), the auxiliary light is emitted in S39, the accumulation time is corrected in S40, and S4
In step 1, the lens is driven based on the correction result.

At this time, the control circuit 11, switches 9 and 1
The operations of 0, the accumulation time correction circuit 7, the selection switching circuit 8, the accumulation time holding circuit 5, and the next accumulation time calculation circuit 4 are the same as those in the first embodiment described above. Then, S38 → S39
→ S40 → S41 → S32 → S33 → S34 → S35 →
In S38 after executing the operations of S36 → S37 → S38, it is determined that the auxiliary light has been emitted, and the determination is affirmative (YES).
Then, the process directly proceeds to S41.

Then, S38 → S41 → S32 → S33.
The focus detection operation described above is performed by repeatedly executing the routines of → S34 → S35 → S36 → S37 → S38 → S41, but the next accumulation time calculated by the next accumulation time calculation circuit 4 is directly the current accumulation time holding circuit 5 Therefore, even if the contrast of the subject is rapidly increased by projecting auxiliary light to the subject, the accumulation time of the CCD 1 is preset to a short accumulation time commensurate with the increased subject contrast. It Therefore, the CCD 1 can operate with the short accumulation time set in this way.

In short, under the subject contrast that does not require the projection of the auxiliary light, S32 → S33 → S34 → S3
The focus detection operation is performed by repeatedly executing the routine of 5 → S36 → S37 → S41 → S32. In S37 in the operation process, the control circuit 11 constantly determines "whether or not auxiliary light should be projected." In that S37,
When it is determined that the contrast of the subject is lowered and it is necessary to project auxiliary light, first, S37 → S38 → S39 → S.
40 → S41 → S32 → S33 → S34 → S35 → S3
The routine of 6 → S37 is executed. Similar to the first embodiment, the auxiliary light is issued in S39, and the accumulation time is corrected in S40.

From the above, in the next routine, the process proceeds from S38 to S41, and thereafter S38 → S41 → S32 → S33.
→ S34 → S35 → S36 → S37 → S38 → S41 The routine is repeatedly executed, and focus detection based on the corrected accumulation time is performed as in the first embodiment. This prevents the output level of the CCD 1 from exceeding the saturation level of the A / D converter under the projection of the auxiliary light, and corrects the accumulation time so that the output level of the CCD 1 becomes an appropriate value. The number of repetitions can be greatly reduced, and the focus state can be detected quickly.

The storage time to be corrected may be, for example, 1/2 hour of the storage time immediately before the projection of the auxiliary light.
Alternatively, the time may be shortened in a non-linear manner.

[0046]

As described above, the automatic focus detection device according to the first aspect corrects the accumulation time calculated up to that time to a shorter time when the projection of the auxiliary light on the subject is started, Since the control means for performing the accumulation operation after light emission is provided with the corrected accumulation time as a reference, the signal level used for focus detection transiently increases even if the subject brightness or the contrast is improved by the emission of the auxiliary light. This can be prevented, and even if the projection of the auxiliary light is started, the focus state can be detected as quickly as when the auxiliary light is not used.

Specifically, the control means can be simply configured by the accumulation time correction means and the switching means as in the automatic focus detection device according to the second aspect.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an automatic focus detection device according to an embodiment of the present invention.

FIG. 2 is a flowchart of the automatic focus detection device according to the first embodiment of the present invention.

FIG. 3 is a flowchart of an automatic focus detection device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 charge storage type light receiving element (CCD) 2 focus detection circuit 3 output level detection circuit 4 next storage time calculation circuit 5 current storage time holding circuit 6 storage time control circuit 7 storage time correction circuit 8 selection switching circuit 9, 10 switch 11 control Circuit 12 Light emission / non-light emission recognition circuit 13 Auxiliary light emission drive circuit 14 Light emitting diode

Claims (2)

[Claims] 1. A charge storage type light receiving element which receives a subject image and outputs an output signal based on the light receiving result, and a calculation based on the output signal of the charge storage type light receiving element at the time of current light reception and the output signal. Storage time calculating means for calculating the storage time at the next light reception from the stored storage time, storage operation control means for controlling the storage operation of the charge storage type light receiving element according to the calculated storage time, the brightness of the object, or In an automatic focus detection device including auxiliary light emitting means for emitting an auxiliary light source when the contrast is equal to or lower than a predetermined level, when a projecting operation of the auxiliary light source on a subject is started, an accumulation operation is performed in a time shorter than the calculated accumulation time. An automatic focus detection device comprising a control means for controlling the. 2. A charge storage type light receiving element which receives a subject image and outputs an output signal based on the light receiving result, and a calculation based on an output signal of the charge storage type light receiving element at the time of current light reception and the output signal. Storage time calculating means for calculating the storage time at the next light reception from the stored storage time, storage operation control means for controlling the storage operation of the charge storage type light receiving element according to the calculated storage time, the brightness of the object, or In an automatic focus detection device including auxiliary light emitting means for emitting an auxiliary light source when the contrast is equal to or lower than a predetermined level, an accumulation time correction for correcting an accumulation time between the accumulation time calculating means and the accumulation operation control means. Means, and before outputting the auxiliary light source, the output of the storage time calculation means is given to the storage time correction means, and the corrected storage time is supplied to the storage operation control hand. An automatic focus detection device comprising: a switching unit that outputs the output of the storage time calculation unit to the storage operation control unit after the light is projected.