JP2754471B2 - Focus detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detecting device such as a camera.
About the installation. 2. Description of the Related Art Conventionally, a subject image is
Obtain data information indicating the luminance distribution and process this data information.
The focus detection device that performs focus detection
Have been. Hereinafter, a conventional focus detection device will be described.
You. FIG. 17 shows a focus detection device of this type in a camera.
It is a structural example. In FIG. 17, reference numeral 1 denotes a single-lens reflex camera.
And the luminous flux from the subject is
After passing through the mirror 3, the light is reflected by the sub-mirror 4,
Focus detection optics with a detection surface at a position equivalent to the film surface 5
It is led to the system module 6. Focus detection optical system module
6 is, for example, the configuration shown inside the broken line in FIG.
ing. In FIG. 18, reference numeral 2 is the one shown in FIG.
This is the same photographic optical system. First exit pupil of imaging optical system 2
Of the luminous flux passing through the portion 28 and the second portion 29, respectively.
Each is a planned image plane 27 of the photographing optical system 2 (the
The first and second subject images are located near the image plane 5).
Each is formed. Each of the first and second subject images is
Through the field lens 22, the first and second re-imaging
First and second image sensors 2 by
Re-imaged on 5, 26. Image sensors 25, 26
Is constituted by, for example, a CCD or the like.
Accumulates charges according to the image sensors 25 and 26
A signal relating to the light intensity distribution of the subject image is output. As described above, in FIG.
The light intensity distribution of the subject image output from the system module 6
A / D converted by the A / D conversion means 8
The image data is captured by the central processing unit 9 as subject image data.
You. The central processing means 9 performs processing on the captured subject image.
By performing a predetermined focus detection calculation, the imaging surface of the photographing optical system 2 is
Focus adjustment state with film surface 5 (not detectable, front pin, rear
Pin, focus, defocus amount, etc.)
The display means 11, the photographing lens drive means 10,
Auxiliary light hand built into the electronic flash device detachable from the camera
Step 12 (specify a specific pattern on the subject when the subject is dark)
And the like. Also, the image
The central processing means 9 also controls the charge accumulation of the sensors 25 and 26.
It is done. In the above system, the central processing unit
Stage 9 is composed of a microcomputer or the like, and its operation
Sequence is a flowchart as shown in FIG.
I have. After turning on the power and starting in step 1,
In step 2, charge accumulation control of the sensors 25 and 26 is performed.
U. In this case, the central processing means 9 controls the sensors 25 and 26
Command the start of charge accumulation, and the time corresponding to the subject brightness
To stop charge accumulation and sweep the signal related to the subject image
Let out. Next, in step 3, this signal is A / D converted to 1
It is stored in the memory as the next data. How many bits of A / D conversion
May be done by default, but usually about 8 bits is sufficient.
It does not make sense to consider the noise even when performing with the above bits.
Uselessly waste memory when storing data
It will be. The primary data is a pair of (l + 1)
Data a (o) to a (l) and a '(0) to a' (l)
In other words, for a general subject, for example, as shown in FIG.
Swelling. However, a ′ (0) to a ′ (l) are shown in the drawing.
Not in. In step 4, these primary data are
The following calculation is performed, and as shown in FIG.
A pair of (m + 1) secondary data b (0) to b (b)
(M), b ′ (0) to b ′ (m) are created. [0007] The purpose of performing an operation such as equation (1) is
High frequency included in the primary data that adversely affects the detection calculation
Components and low-frequency components, and
The number of data used for focus detection calculation
However, this is to reduce the calculation time. In step 5,
A focus detection calculation is performed using the obtained secondary data,
Point adjustment status (Focus not detectable, front focus, rear focus, focus, defocus
Focus amount). In step 6, the obtained focus adjustment state is obtained.
(Not detectable, front focus, rear focus, focus, etc.)
The step controls the lens driving means. In step 7, the detection
If not, proceed to step 8;
If so, the process returns to step 2 to start the next focus detection operation.
In step 8, there is an auxiliary light means, which is ready
If there is, go to step 9;
Return to Step 2. In step 9, the auxiliary light means is operated,
Auxiliary lighting for undetectable subjects prior to the next focus detection operation
Project light or auxiliary lighting pattern and go to step 2
Return to start the next focus detection sequence. Stay
The focus detection calculation of step 5 is performed, for example, as described below.
Done in a way. First, a pair of (m + 1) secondary data b
(O) to b (m), b '(o) to b' (m)
By performing such a correlation operation, the correlation amount H (L) is changed to the shift amount L
Are sequentially changed. ## EQU2 ## The q and r in the equation (2) are the parameters of the sum operation (Σ).
It is a constant that defines the upper and lower limits of the parameter. FIG.
(A) moves L from -6 to +6 as in equation (2)
It is a graph in the case where the correlation amount H (L) was obtained while calculating.
In the figure, the correlation amount H when L is assumed to be a continuous amount
L that gives the minimum value of (L) is the relative value of a pair of secondary data
The shift amount. This relative shift amount L is determined by
Optical axes of a pair of subject images formed on the sensors 25 and 26;
It corresponds to the amount of lateral displacement in the perpendicular direction. The correlation value H (L) is different when L is an integer.
Since it is obtained sporadically, for example, as shown in FIG.
A true interpolation that gives the minimum value of the correlation value H (L) by a simple interpolation method
The shift amount Lex is obtained. For example, the shift amount Lex
The slope of the correlation function H (L) on the side (shown by straight lines 11 and 12)
Are equal, three points R-1, R, R + 1 near Lex
Correlation values H (R-1), H at an integer shift amount of
From (R) and H (R + 1), the minimum value of the correlation function H (L)
Hex and Lex are obtained. Hex and Lex are obtained by the following equations. [Equation 3] In equation (3), parameters DL and E are
It represents the quantity shown in FIG. 21 (b) and is obtained by the following equation. [Equation 4] When the shift amount Lex is obtained in this manner,
The defocus amount d (between the imaging plane of the subject image and the planned imaging plane)
The amount of displacement in the optical axis direction is: Is obtained. Where β is the image
Array pitch P of photoelectric conversion units of sensors 25 and 26, focus detection
This is a value determined by the parameters of the output optical system. Default
The front and rear focus states are detected based on the sign of the focus amount d.
And the absolute value of the defocus amount d is within a predetermined value.
It is determined that the camera is in focus. Focus examination
The detection of inability to exit is performed, for example, as follows.
Be done. When the object has low contrast,
The primary data obtained from the image sensor is also shown in FIG.
It does not change much, so it calculates the primary data
As shown in FIG. 20 (d), the obtained secondary data is
Will be a small value. For such secondary data
On the other hand, the focus detection calculation shown in equation (2)
The correlation amount H (L) is as shown in FIG.
(A) a level lower than the correlation amount H (L)
, And there is no H (R) indicating the minimum value.
In some cases, the detection amount Lex may not be obtained.
No. Even when the shift amount Lex is obtained,
Since it contains many errors and lacks reliability, it is
Set. As an example of the criterion, FIG.
Parameter E is less than or equal to a predetermined value, or
The value Hex / E standardized by the parameter E is equal to or less than a predetermined value.
Is detected and it is determined that detection is impossible. Problems to be Solved by the Invention
The focus detection device has the following disadvantages. That is,
If the focus cannot be detected, activate the auxiliary light means.
Auxiliary light means projected on the subject
Specific pattern is detected based on the relationship with the subject pattern.
In some situations, it is difficult to accurately
There was a drawback that point detection was not possible. An object of the present invention is to provide a conventional focus detection apparatus.
Suitable for auxiliary light means even for subjects for which focus cannot be detected.
Focus that can perform high-precision focus detection by performing focused focus detection processing
A detection device is provided. According to the present invention, focus detection is not performed.
Activating the auxiliary light means used when activating
Change the calculation process for focus detection
It is characterized by that. According to the present invention, there is provided an auxiliary light hand used when focus detection is impossible.
Focus on whether the step is activated or deactivated
By changing the calculation processing for detection,
Accurate focus detection becomes possible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a focus detection device according to the present invention described below will be described.
The configuration is the same as that of FIG. 17, but the operation of the central processing unit 9 is different.
Therefore, the flow will be described as an example. <First Embodiment> FIG. 1 shows a first embodiment of the present invention.
When starting in step 11, detection is not performed in step 12.
Function flag is initialized to 0. Then step 13
To set the loop counter K to 0,
Clear the data. The undetectable flag is set by the focus detection device.
This flag is used to identify that detection was impossible.
The loop counter K is based on the central processing means.
A key to count how many times the sensor output has been received.
Unta. Step 14 tests the undetectable flag.
When the undetectable flag is 1, that is, when the
Goes to step 15, and if the undetectable flag is 0,
In other words, if it can be detected, the process proceeds to step 17. Stay
In step 15, as shown in FIG.
The power of the electronic flash device is turned off because it is built into the device.
If the auxiliary light means is ready and
Proceed to step 16, otherwise proceed to step 17. In step 16, the auxiliary light means is operated,
Auxiliary light is emitted for an undetectable subject. Steps
At 17, the charge accumulation control of the sensor is performed. Step 1
8 is a signal related to the light intensity of the subject output by the sensor.
The primary data obtained by subjecting the signal to A / D conversion is stored in a memory.
For example, the primary data is a pair of (l + 1) data (a
(O) -a (l), a '(o) -a' (l))
As shown in FIG.
Data containing many minutes, but low contrast
As shown in FIG.
Data with less contrast change component than
ing. In step 19, the obtained primary data (a
(0) -a (l), a '(0) -a' (l)) to equation (1)
By the operation shown, a pair of (m + 1) secondary data
(B (o) -b (m), b '(o) -b' (m))
You. Corresponds to the primary data in FIGS. 20 (a) and 20 (c)
20 (b) and FIG. 20 (d) respectively.
As shown in the figure, contrast for general subjects
For a low-contrast subject that contains many change components
The contrast change component is small. At step 20, the loop counter K = 0.
In the case of, the tertiary data and the secondary data are equal
Thus, the pair of (m + 1) tertiary data {c (o)
~ C (m), c '(o) ~ c' (m)}
Add {b (o)-b (m), b '(o)-b' (m)}
You. In step 21, the loop counter K is incremented.
To At step 22, the tertiary data $ c (o) ~
For c (m), c ′ (o) to c ′ (m)｝, equations (2) to (5)
Perform the focus detection calculation as shown in
(Not detectable, front focus, rear focus, focus, etc.). S
If focus detection is not possible in step 23,
Go to step 25 and set the undetectable flag to 1
Proceed to 26. If focus detection is possible,
The inability flag is reset to 0, and the routine proceeds to step 27. In step 26, the loop counter K is set to the maximum
Test if count Kmax has been reached, if not
Returns to step 14 and repeats the next focus detection loop.
And add the secondary data to the tertiary data (addition mode
C). In addition, the loop counter K has a maximum count Kma.
If it has reached x, the process proceeds to step 27. Steps
27 is focus detection until the loop counter K reaches Kmax.
When it is possible to go out, it is impossible to detect even if it reaches Kmax
Display means according to the focus adjustment state,
Control the lens driving means. Then, return to step 13.
Resets the loop counter K to 0 and clears tertiary data.
To initialize the addition mode and add a new
The focus detection sequence will be repeated. With the configuration described above, the general
For the object, the tertiary data also has a contrast change component.
Since the loop counter K is 1 (ie, once
Eye) and it does not enter the addition mode.
For the contrast object, the loop counter K is set to 1
At this point, the tertiary data is controlled as shown in FIG.
The last change component is small and cannot be detected at the first time.
From step 23, go through steps 25 and 26 and go to step 14
It goes into the addition mode through the route returning to. Tertiary data is added
It is increased each time the calculation mode is repeated.
In FIG. 20 (f), the first tertiary data is approximately
The tertiary data is amplified by S times. In this way,
As the tertiary data is amplified by the mode,
The point detection level is reached, and the focus detection calculation results
It is determined that it is possible, and Steps 23 to 24 and 27
Go to step 13 and return to step 13
Get out of Therefore, in the conventional focus detection device, focus detection is performed.
For low-contrast subjects that were determined to be impossible
In the focus detection device of the present embodiment,
Since the change component of the data is amplified, focus detection becomes possible.
You. Also, even when pattern illumination is used as auxiliary light,
When the subject has some brightness with the focus detection device of
Undetectable because the pattern is buried in the surrounding luminance distribution
However, in this embodiment, the focus detection is performed by the addition mode.
It becomes possible. <Second Embodiment> Next, a second embodiment of the present invention will be described.
You. In the first embodiment, tertiary data
The focus detection calculation was performed every time.
The example shows focus detection until the loop count K reaches Kmax.
Reduces calculation time and improves responsiveness without performing calculations
There is a difference in the place where it was made. The second embodiment is similar to the first embodiment.
Steps 22, 23, 24, 25, and 26
Since this is different from the embodiment, only that part is shown in FIG. Up to step 21, the description of the first embodiment and
Since they are the same, the description is omitted. Step 21 to Step 3
Go to 1 and test if loop count K has reached Kmax
I do. If Kmax has not been reached, step 14
And repeat the addition mode until it reaches Kmax.
If Kmax has been reached, the process proceeds to step 32, where
Focus adjustment by performing focus detection calculation on the selected tertiary data
Detect state. In step 33, a test is performed to determine whether or not detection is possible.
If it cannot be detected, the process proceeds to step 35.
Set the inaccessible flag, otherwise detect in step 34
The exit impossible flag is reset to 0, and the routine proceeds to step 27.
Subsequent steps are the same as in the first embodiment. <Third Embodiment> The third embodiment is similar to the first embodiment except that
Whereas the next data was the sum of the secondary data
Tertiary data is primary data or via from primary data
Data (referred to as 1.5th order data)
Are different. The third embodiment is similar to the first embodiment.
Only steps 19, 20, 21, and 22 in the embodiment are the
3 is different from the embodiment of FIG.
Show. Step 18 is the same as that of the first embodiment.
It is omitted because it is the same. From step 18 to step 41
Advance, add primary data (1.5-order data) to tertiary data
I do. Primary data for low contrast subjects
11 (a) and 12 (a).
When adding primary data to tertiary data, tertiary data
The number of data bits should be larger than the number of primary data bits.
Need to be kept. For example, 8 bits as primary data
(1 byte) 16 bits (2 bytes) as tertiary data
(G) to secure a storage area in the memory. FIG.
(B) shows tertiary data when primary data is added S times
doing. Add 1.5-order data as tertiary data
In this case, for example, as shown in FIG.
All the primary data with the minimum value a (x) in the bias
The bias minus the 1.5 order shown in FIG. 12 (b)
Data. Tertiary data is obtained in this way
1.5th data is added, at the time of S-th addition
Is as shown in FIG. In step 42, the loop counter K is turned on.
To increment. In step 43, the obtained tertiary data
By performing the operation shown in equation (1),
Create data. Add primary data as tertiary data
In the case of using the tertiary data,
Since there are many, the minimum value in the tertiary data is biased to the tertiary data
Bias the minimum value c (x) from all data,
Data having the same number of bits as the data (FIG. 11C)
11), the calculation shown in equation (1) is performed, and FIG.
Fourth-order data d (o) to d (m), d as shown in FIG.
(O) to d '(m) are created. Also, add the 1.5th order data as the 3rd order data
When using the tertiary data,
By performing the operation of the expression (1), the fourth order as shown in FIG.
Create data d (o) ~~ d (m), d '(o) ~ d' (m)
To achieve. In step 44, the obtained fourth order data
Perform the focus detection calculation shown in equations (2) to (5), and
State is detected, and the process proceeds to step 23. The subsequent sequence is
This is the same as the first embodiment. <Fourth Embodiment> Next, a fourth embodiment of the present invention will be described.
I do. The fourth embodiment is similar to the second embodiment except that the third data
Was used as the sum of the secondary data
Then, as primary data, primary data (1.5-order data)
They use different places. The fourth embodiment is a modification of the second embodiment.
Only the steps 19, 20, 21, 31, 32 are the second implementation
Since this is different from the example, only that part is shown in FIG. S
Same as the second embodiment (first embodiment) up to step 18.
Therefore, it is omitted. In step 51, the primary data is added to the tertiary data.
Data (1.5 order data). Detailed theory of this part
The description is omitted because it is the same as that of the third embodiment. Step 52
Then, the loop counter K is incremented. Step
In step 53, whether the loop counter K has reached Kmax
Test, if not, return to step 14
Repeat calculation mode. If Kmax is reached,
Proceeding to step 54, quaternary data is created from the tertiary data.
The detailed description of this part is omitted since it is the same as that of the third embodiment.
I do. In step 55, the obtained fourth order data is
Perform focus detection calculations of equations (2) to (5) for
State is detected, and the routine proceeds to step 33. After step 33
Is the same sequence as in the second embodiment. Fourth implementation
In the case of the example, when compared with the second embodiment, 2
The operation of formula (1) that creates the next data is performed in the addition mode loop.
Since it is outside, the operation time of addition mode can be shortened and responsiveness
Is improved. <Fifth Embodiment> Next, a fifth embodiment of the present invention will be described.
You. In the first to fourth embodiments,
Focus detection calculations (2) to (5) are always performed on tertiary data
In contrast, the fifth embodiment first deals with the secondary data.
Only if the focus cannot be detected as a result
In addition mode, focus detection calculation is performed on tertiary data.
There are differences in what they do. With this configuration,
From the focus detection disabled state due to motion of the subject or camera shake.
Stable and quick even when suddenly entering the point detectable state
Can respond to FIG. 5 shows the flow of the operation of the fifth embodiment.
You. In FIG. 5, steps 61 to 69 are diagrams of the first embodiment.
Steps 1 to 19 are the same as those in step 1 and description thereof is omitted.
When the secondary data is obtained in step 69, step 70
(2) to (5) on the secondary data obtained in
Calculation is performed to detect the focus adjustment state. That is, step 7
Focus on information obtained in one sensor charge accumulation up to 0
Detects adjustment status (undetectable, front focus, rear focus, focus)
You. In step 71, as a result of step 70,
If the focus cannot be detected, the process proceeds to step 74, where
Otherwise, the undetectable flag is set to 0 in step 72.
Further, in step 73, the display hand is displayed in accordance with the focus adjustment state.
The step and the lens driving means are controlled, and the process returns to the step 63 for the next time.
Starts the focus detection sequence. On the other hand,
Is set, the mode becomes the addition mode, and the detection is not possible in step 74.
Set 1 to the flag. In step 75, the loop counter K is reset.
Increment. In step 76, 2 is added to the tertiary data.
Add the next data. A detailed description of this step
The description is omitted because it is the same as the embodiment. In step 77,
If the loop counter K is 1, the process proceeds to step 80,
If not, step 78 is executed. That is, the first time is 2
The next data and the third data are the same, and the result of the focus detection calculation is
Since the result is the same as that executed in step 70,
Therefore, the focus detection calculation for the tertiary data is omitted. In step 78, the obtained tertiary data
(To which the secondary data has been added)
The focus adjustment is performed to detect the focus adjustment state. S
In step 79, the tertiary data is focused in step 78.
If point detection is possible, exit the addition mode
Proceed to step 73 and display according to the focus adjustment state at that time.
Controlling the indicating means and the lens driving means and returning to step 63,
Start the next focus detection sequence. In Step 79
If the point cannot be detected, the process proceeds to step 80. S
In step 80, check if the loop counter K has reached Kmax
Test to see if it's reached and exit add mode
Then, the process returns to step 73. Step if not reached
Returning to 64, the addition mode is repeated. As described above, in the fifth embodiment, 1
For each time the secondary data obtained from sensor charge accumulation
First, since the focus detection calculation is performed, the subject changes suddenly.
Can respond, improving responsiveness and preventing malfunctions.
No. Also, for low contrast subjects where focus detection is difficult
However, the focus detection is possible in the addition mode.
The point is provided similarly to the first to fourth embodiments. <Sixth Embodiment> The sixth embodiment is different from the fifth embodiment in that the
3rd data every time the charge of the image sensor is stored
The focus detection calculation was
Focus detection calculation is performed until the counter K reaches Kmax
Response time was further improved by shortening the calculation time.
There are differences. The sixth embodiment is different from the fifth embodiment in that step 6
1 to 76 and steps 79 and 80 are the same,
The description is omitted, and only the differences are shown in FIG. Sixth embodiment
Then, in the case of the addition mode, 2 is added to the tertiary data in step 76.
After the next data is added, the routine proceeds to step 81, where the loop
Tests whether Unta K has reached Kmax and reaches Kmax
If not, proceed to step 64 and repeat the addition mode.
You. If Kmax has been reached, the routine proceeds to step 82, where the secondary
Focus detection for tertiary data obtained by adding data to Kmax
Performs an operation to detect the focus adjustment state, and proceeds to step 73
Exit from the forward addition mode. <Seventh Embodiment> Next, a seventh embodiment will be described. In the fifth embodiment, the tertiary data is converted to the secondary data.
However, in the seventh embodiment,
The tertiary data is the sum of the primary data or the 1.5th data
Is different. The seventh embodiment is different from the fifth embodiment in that
Steps 61 to 75 and steps 79 and 80 are the same
The description is omitted, and only the differences are shown in FIG. In the seventh embodiment, in the case of the addition mode,
After incrementing the loop counter K at step 75,
In step 91, the primary data or the 1.5th data is added to the tertiary data.
Data. The detailed description of this part is the same as that of the third embodiment.
The same operation is omitted. Next, at step 92
Test whether the counter K is 1 and if so, step 8
Go to 0. In the case other than 1, it was possible to proceed to step 93.
Create quaternary data from tertiary data. Details of this part
The detailed description is the same as the operation of the third embodiment, and will not be repeated. In step 94, the obtained fourth order data is
Then, the focus detection calculation is performed, and the routine proceeds to step 79. Later
The operation is the same as in the fifth embodiment. <Eighth Embodiment> Next, an eighth embodiment will be described. No.
The eighth embodiment is an improvement of the sixth embodiment, and is a modification of the sixth embodiment.
In the example, the data obtained by adding the secondary data as the tertiary data is used
In contrast, in the eighth embodiment, tertiary data
Is that the data obtained by adding the primary or 1.5th order data is used.
Has become. The eighth embodiment is different from the sixth embodiment in that step 6
Since 1 to 75 are the same, the description is omitted, and only the differences are illustrated.
FIG. In the case of the addition mode in the eighth embodiment,
In step 75, the loop counter K was incremented
Thereafter, in step 101, the tertiary data is converted to the primary data or 1.5.
Add the next data. A detailed description of this part
Since the operation is the same as that of the embodiment, the description is omitted. Next in step 102
Loop counter K has reached Kmax or has reached test
If not, return to step 64 and repeat the addition mode.
You. If Kmax is reached, go to step 103
The process proceeds to create quaternary data from the obtained tertiary data.
The detailed description of this part is the same as the operation of the third embodiment.
Omitted. In step 104, the obtained fourth order data
The focus detection calculation is performed for
The operation after exiting the calculation mode is the same as in the sixth embodiment.
is there. The eighth embodiment is different from the sixth embodiment in that:
To calculate the secondary data every time during the addition mode
Therefore, the operation time is shortened and the response is improved. <Ninth Embodiment> In the first to eighth embodiments, the addition mode
When entering the secondary data (or primary data, 1.5
Data) to the tertiary data and focus detection becomes possible
Exited the addition mode and cleared the tertiary data.
With this configuration, in order to be able to detect next time,
Do I have to do addition several times in addition mode again?
Was. In the tenth embodiment, a predetermined number of past times in the addition mode
Information (secondary data or
Is the primary data or 1.5-order data)
Add data from a number of times from the past to the past
To create tertiary data and focus on the obtained tertiary data
Perform detection calculations to obtain information about the focus state.
Thus, the response in the addition mode is improved. FIG. 9 shows an operation flow when applied to the fifth embodiment.
Low and the focus detection calculation does not disable detection.
The sequence (steps 121 to 134 in FIG. 9)
This is the same as the fifth embodiment (steps 61 to 73 in FIG. 5).
Therefore, the description is omitted. However, in the ninth embodiment, the third order data
Since it is not necessary to clear the
Resets the loop counter K to 0, and at step 134
If it is determined that detection is possible, a new
Thus, the loop counter K is reset to 0. Next, an addition mode which is a feature of the tenth embodiment is described.
Will be described. The secondary data obtained in step 131
The focus detection calculation result for the
In this case, the mode is set to the addition mode, and the routine proceeds to step 135 for detection.
Set the disabling flag to 1. In step 136,
Whether the loop counter K has reached a predetermined value Kmax
Is determined, and if not reached, the process proceeds to step 138.
The loop counter K is incremented, and step 1 is performed.
The secondary data obtained in step 39 is stored, and
move on. The memory for storing the secondary data is shown in FIG.
Memory areas M (1) to M (M) having a predetermined value Kmax as shown in FIG.
(Kmax), and the loop counter K is K
Step 136 → Step 138 →
Go through the routine of step 139 and loop the secondary data
Stored in the memory area M (K) corresponding to the counter K
Go. On the other hand, at step 136, the loop counter K
Has reached Kmax, the routine proceeds to step 137.
Only the memory areas M (2) to M (Kmax) shown in FIG.
(Kmax -1) sets of past secondary data are 1
The memory area is shifted sequentially one by one,
It is stored again in the storage areas M (1) to M (Kmax-1). Soshi
To step 139, and the latest secondary data is stored in the memory area.
It is stored in the area M (Kmax). Next, at step 140, the memory area M
The memory area M corresponding to the loop counter K from (1)
The secondary data stored up to (K) is expressed as in equation (6).
To create tertiary data. [Equation 6] In equation (6), c (n) and c ′ (n) are tertiary data
(Where n is 0 to l), and b (n, s) and b '(n, s) are memory
The secondary data stored in the area S is shown. Step 1
At 41, focus detection calculation is performed on the obtained tertiary data.
Focus adjustment state (not detectable, front focus, rear focus,
Is detected. In step 142, the loop counter
Determine if K has reached Kmax, and if so,
Proceeding to step 134, according to the obtained focus adjustment state
Control the display / drive means, and then proceed to step 124,
Thereafter, the sequence is the same as that of the fifth embodiment. Also, at step 142, the loop counter K
If Kmax has not been reached, proceed to step 143 to check
Only when it is determined that the display cannot be
Return to step 124, otherwise proceed to step 134.
Return to step 124 after controlling the display / drive means.
You. In the addition mode of the ninth embodiment, the above operation is performed.
Since it is a sequence, once the loop counter K
Even after reaching the predetermined value Kmax, it is cleared and returns to 0.
Each time it passes the addition mode, the
Tertiary data is created from the Kmax pairs of secondary data,
Performs focus detection calculation on the next data and enters focus adjustment state
Information on the display and drive means.
It is expected that responsiveness will be improved. In the above description, the ninth embodiment is described in the fifth embodiment.
Although the case where the present invention is applied to the embodiment, the first to eighth embodiments are described.
It goes without saying that it can be applied to the examples. The first fruit
In the embodiment to the ninth embodiment, the maximum value of the loop counter
The value Kmax may be a fixed value or may vary depending on the subject brightness.
May be changed. For example, if defined as in equation (7),
Response is poor even when the mode is set to Add
It won't be. [Mathematical formula-see original document] In the equation (7), INTT corresponds to the subject brightness.
Response time, for example, the charge accumulation time of the image sensor.
Tx represents a predetermined time. This way, low brightness
Sometimes Kmax is small and you get out of addition mode quickly
Can be Also, as a judgment to exit the addition mode
Tests whether the loop counter K has reached Kmax
Instead, the change component is amplified by addition.
Detects information about the magnitude of the change component from the next data
To exit the addition mode
The determination by the counter K may be combined. A method for detecting and judging information from tertiary data
For example, the following methods are available. Tertiary data
A pair of (m + 1) data b (o) to b (m), b
Assuming (o) to b (m), each pair of data as shown in equation (8)
Whether the value of (maximum value-minimum value) exceeds a predetermined value,
Or the absolute value of the difference between adjacent data as in equation (8),
Addition mode depends on whether the maximum value exceeds the specified value.
It is determined whether to exit. [Mathematical formula-see original document] [Mathematical formula-see original document] In equations (8) and (9), b _max , B _min Is 3
Maximum and minimum values of the next data b (o) to b (m). b '
_max , B ' _min Is the maximum of the tertiary data b '(o) to b' (m)
Value, minimum value. M1 and M2 are tertiary data contrasts
The information amount of the change component, T1 and T2 are the reference values.
is there. Also, the maximum value Kmax of the loop counter K is
The amount of information M1 and M2 when the counter K = 1 is obtained by the equation (4).
By the parameter E and the reference value T3 for E
Equations (10), (11), and (12) may be used. [Mathematical formula-see original document] [Equation 11] (Equation 12) It is necessary to exit the addition mode as described above.
The size of the contrast change component of the tertiary data
(8) to (12)
By appropriately setting the reference values T1, T2, T3 of the equation,
Responsiveness is improved without unnecessary addition mode repetition
You. In the first to ninth embodiments, the control of the auxiliary light means
Related operations, for example, step 14 in the first embodiment.
The numbers 16 to 16 are not always necessary and need not be provided. In addition,
Controlling the operation of the light assist means immediately before the start of image sensor charge accumulation
Instead of every time, once activated,
To maintain the same operation during several charge accumulations
You may comprise. Also, the operation of the auxiliary light means is not required.
It may be associated only with the object brightness at the time of operation. <Tenth Embodiment> Next, a tenth embodiment will be described.
Using a means to project a specific pattern on the subject
In this case, focus detection is performed. A specific pattern is placed on a low-contrast subject.
When projecting, if the subject brightness is relatively high, a specific pattern
Is buried in the brightness of the subject, and
In this case, focus detection became impossible. Tenth
In this embodiment, a specific pattern is formed on the subject by using the auxiliary light means.
Primary data obtained from the image sensor when
Image sensor without auxiliary light means
Primary data obtained by subtracting the primary data obtained from
By using data, small changes due to specific patterns
Is detected in the addition mode, and
Performs point detection, so relatively high-brightness low-contrast patterns
Focus detection is also possible for the The tenth embodiment is similar to the first to ninth embodiments.
Applicable to the embodiment, for example, applied to the first embodiment.
In FIG. 1, steps 11 to 11 are described.
13. Steps 19 to 27 are the same as in the first embodiment.
And steps 14 to 18 are different,
Only one is shown in FIG. At the time of step 111,
In the case of the addition mode, the undetectable flag is set to 1.
Set to 0 if not in addition mode
Have been In step 111, the undetectable flag is set to 0.
In this case, the operation proceeds to step 117 without operating the auxiliary light means.
If the undetectable flag is 1, proceed to step 112.
No. At step 112, the auxiliary light means is mounted.
If the operation is ready and the operation is ready, step 113
Otherwise, go to step 117. Step 1
At 13 the loop counter K is tested to see if it is 1 and 1
If yes, go to step 114; if zero, go to step 114
Proceed to 116. In step 114, the image sensor charge
The accumulation control is performed, and the image sensor is output in step 115.
A / D converting the force and converting the data into a pair of (l + 1)
Correction data g (o) to g (l), g '(o) to g' (l)
And store. FIG. 14A shows the correction data g (o) to g.
(L) is shown. Therefore, steps 113, 114, 115
As correction data when the auxiliary light means is not operated at
Use data of subject image when loop counter K is 1
Will be. In step 116, the auxiliary light means is activated.
And project a specific pattern on the subject. In step 117, the image sensor charge storage is performed.
Product control is performed.
A / D conversion of the force and a pair of (l + 1) primary data a
(O) to a (l) and a '(o) to a' (l)
You. FIG. 14B shows the primary data a (o) to a
(L). In step 119, the auxiliary light means is operated.
If not, go to step 120, if not
Proceed to step 19. In step 120, the auxiliary light means
From the primary data of FIG. 14B obtained by operating
The correction data of FIG. 14 (a) obtained without operating the means is
Deducted as in equation (12), and a new pair of (l + 1)
Primary data a (o) to a (l), a '(o) to a' (l)
Ask. ## EQU13 ## FIG. 14C shows the primary order obtained in this way.
Data a (o) to a (l) are shown. 1 in step 120
When the next data is obtained, the process proceeds to step 19 and thereafter the first data is obtained.
The sequence is similar to that of the embodiment. Therefore, the addition mode
From the primary data to the secondary data shown in FIG.
Is obtained as shown in FIG. 14 (d).
Tertiary data with S repeated secondary data added S times
Is projected on the subject as shown in FIG.
Focus change by increasing the contrast change component of a specific pattern
It is possible to go out. The tenth embodiment is defined as an addition mode,
The third factor that adds the primary or (1.5th) data to the data
A case where the present invention is applied to the embodiment will be described. Do not activate the auxiliary light
The correction data in the case of
The primary data when the auxiliary light is activated is shown in FIG.
The result is as shown in FIG. Primary when auxiliary light is activated
The correction data for when the auxiliary light was not activated
When the subtracted data is used as primary data again, FIG.
(C) is obtained. A pair of (l + 1) tertiary data c (o)
~ C (l), c '(o) ~ c' (l) add primary data
And when added S times, as shown in FIG.
In addition, a specific pattern projected on the subject whose variation component is amplified
It corresponds to the turn. Obtained in this way
An operation such as equation (1) is performed on the tertiary data, and a pair of (m +
1) Fourth order data d (o) to d (m), d '(o) to
When d '(m) is obtained, the focus becomes a level at which the focus can be detected sufficiently.
ing. FIG. 15E shows the state of the fourth order data. In the above description of the tenth embodiment,
The positive data g (o) to g (l) and g '(o) to g' (l) are
Gathered only when loop counter K is 1
However, even when the loop counter K is not 1, the correction data is
Can be collected and subtracted from primary data when auxiliary light is activated
No. In this case, step 113 is deleted in FIG.
You. Further, an image cell for collecting correction data is provided.
The storage time of the sensor should be equal and fixed, or the latter
A little longer. As described above, the present invention
Various modifications can be considered in the embodiment of
Embodiments when switching and using multiple embodiments
State. Normally, the first to tenth embodiments are not
Or a program written in external storage means (ROM)
It is realized by RAM (software). FIG.
And P1, P2 and P3 are different programs or different programs
Is stored in the storage means. The eleventh embodiment shown in FIG.
The ROM 3 in the device 30 including the focus detection device.
2 and write multiple programs P1, P2, P3
And the external operation means 31 is selectively switched.
Of the user from among the programs P1, P2, P3
This is to switch to the program that was used. As shown in FIG.
In the twelfth embodiment, a single program P1,
ROM with P2 written, or microcomputer containing ROM
33 and 34 to the device 30 including the focus detection device.
Remove and attach to a structure that the user can use
ROM containing the program or myco containing ROM
Attach the devices 33 and 34 to the device 30 including the focus detection device
This makes it possible to switch programs. Instead of ROM in the twelfth embodiment
Using rewritable storage means (eg, EPROM)
Focus on what you have written the desired program externally
By attaching to the device 30 containing the detection device,
The selection of the program may be switched. FIG.
In the thirteenth embodiment shown in FIG.
The storage means in the eleventh embodiment shown in FIG.
The storage means 35 is configured to be replaceable.
Desired programs P1, P2 by the writing device 36
To enable program selection switching
It was done. The structure is the same as in the twelfth and thirteenth embodiments.
If a device including a focus detection device is released, the program
Fix a bug detected above without disassembling the focus detection device
Yes, it is possible to upgrade the program at any time
It is easy to remodel. Also, the focus detection device is controlled.
Peripheral devices controlled, such as lens driving means, display means,
Auxiliary light means etc. are also configured by a program on the microcomputer,
The data communication with the microcomputer of the point detection device
If controlled, the program storage means on the peripheral device side
Can be rewritten or read as in the twelfth and thirteenth embodiments.
If it is configured to be changeable, the focus detection device and the peripheral device
Changes in part of the overall system
If you need to change some programs
However, it is easy to respond. As described above, according to the present invention, focus detection
When the auxiliary light means used when disabled is
Focus detection calculation processing for focus detection
By changing the process, conventionally, the auxiliary light
However, in situations where focus detection fails
Even if focus detection is possible,
Separate algorithm for focus detection calculation when using auxiliary light
Processing suitable for each focus detection situation
And a more accurate device can be realized. According to the embodiment, the conventional focus detecting device
Now, one focus detection operation for one image sensor output
Calculation, so the run on the image sensor output
Although it was susceptible to dam noise, the focus detection of the present invention
In the addition mode of the output device, it is obtained from the image sensor.
Since information is added multiple times, random noise is
So it is less susceptible to random noise
It also has such an advantage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a first embodiment of the present invention and shows a flowchart of a focus detection device. FIG. 2 shows a first embodiment of the present invention, and is a flowchart of a focus detection device. FIG. 3 is a flowchart of a focus detection device according to a first embodiment of the present invention. FIG. 4 is a flowchart of a focus detection apparatus according to a first embodiment of the present invention. FIG. 5 is a first embodiment of the present invention, and shows a flowchart of a focus detection device. FIG. 6 is a flowchart of a focus detection apparatus according to a first embodiment of the present invention. FIG. 7 is a flowchart of a focus detection device according to a first embodiment of the present invention. FIG. 8 is a flowchart of a focus detection device according to a first embodiment of the present invention. FIG. 9 is a flowchart of a focus detection device according to a first embodiment of the present invention. FIG. 10 is a flowchart of a focus detection apparatus according to a first embodiment of the present invention. FIG. 11 is a diagram illustrating data information of a subject image detected by an image sensor. FIG. 12 is a diagram illustrating data information of a subject image detected by an image sensor. FIG. 13 is a memory map diagram showing a memory area of a storage device of the focus detection device. FIG. 14 is a diagram illustrating data information of a subject image detected by an image sensor. FIG. 15 is a diagram showing data information of a subject image detected by an image sensor. FIG. 16 is a block diagram of a focus detection device to which the present invention is applied. FIG. 17 is a block diagram of a focus detection device. FIG. 18 is a schematic diagram showing the principle of a focus detection device. FIG. 19 is a flowchart showing an operation sequence of a conventional focus detection device. FIG. 20 is a diagram illustrating data information of a subject image detected by an image sensor; FIG. 21 is an explanatory diagram illustrating a correlation operation of the focus detection device. [Description of Signs] 1 ... Camera 2 ... Photographing lens 3 ... Half mirror 4 ... Sub-mirror 5 ... Film surface 6 ... Focus detection optical system module 8 ... A / D conversion means 9 ... Central processing means 10 ... Lens driving means 11 ... Display Means 12: auxiliary light means

Claims (1)

(57) [Claims] (1) In a focus detection device provided with focus detection means for performing focus detection by processing data information relating to luminance distribution of a subject image obtained from an image sensor, Auxiliary light means for irradiating auxiliary light to the object scene side; setting means for setting the auxiliary light means to an operating state; first arithmetic processing as arithmetic processing of the focus detection means; and the first arithmetic processing. Focus operation control means for controlling switching between different second arithmetic processing, and when the setting means sets the auxiliary light means to the operating state, the focus arithmetic control means switches to the first arithmetic processing, and Wherein the focus calculation control means switches to the second calculation processing when the setting means does not set the auxiliary means to the operating state. (2) The auxiliary light unit projects a specific pattern on the subject side, and the setting unit sets the auxiliary light unit to an operating state when it is determined that focus detection is impossible. The focus detection device according to item (1).