JPH08211284A - Focus detector - Google Patents

Abstract

PURPOSE: To obtain a focus detector capable of detecting the relative displacement of the optical images of nearly identical object respectively formed on a pair of photoelectric element arrays. CONSTITUTION: A pair of photoelectric element arrays 105 and 106 consisting of an image sensor such as a CCD is juxtaposed in a photoelectric conversion part 201. The identical subject image is formed on each photoelectric element array by a focus detecting optical system. An image deviation arithmetic means 205 calculates the relative deviation of the optical images on a pair of arrays based on a pair of image output. A correction data storage means 207 stores correction data for correcting the output from the arithmetic means 205. The relative positional deviation of every corresponding image point of the optical images on the arrays 105 and 106 in a focusing state is measured and stored in the storage means 207 as the relative positional deviation of every image point on the array.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detecting device for detecting relative displacement of light images of substantially the same object formed on a pair of photoelectric element arrays. In particular, it is used for focus detection devices such as cameras and distance measuring devices. 2. Description of the Related Art FIG. 1A shows an optical system of a focus detecting device such as a general camera.
By 01, an image is formed in the vicinity of the field lens 102. The primary image of the subject 100 is formed as a secondary image on the first and second photoelectric element arrays 105 and 106 by the first and second re-imaging lenses 103 and 104, respectively.
The relative positional relationship of the secondary images on the arrays 105 and 106 is detected from the image output of the arrays. In order to perform such focus detection with high accuracy, each point of the light image distributed on the photoelectric element array 105 and each corresponding point of the light image distributed on the photoelectric element array 106 are combined. It is necessary that they are relatively completely coincident with each other at the time of focusing, and are deviated by the same amount corresponding to the amount of non-focusing from each corresponding point at the time of non-focusing. Of course, it is also possible to determine that the corresponding points at the time of focusing deviate by a certain amount. However, the above conditions are not satisfied due to aberrations or insufficient adjustment of the focus detection optical system including the field lens 102 and the re-imaging lenses 103 and 104. When focused, the image points 107a, 1a of the center point 100a of the subject 100 as shown in FIG.
08a forms an image at the same position (for example, the center) of each array 105 and 106, but the image point 107 of the peripheral point 100b.
b and 108b are imaged relatively displaced. Therefore, there is a difference between the focus detection result based on the point images 107a and 108a and the focus detection result based on the point images 107b and 108b, and correct focus detection cannot be performed. In order to eliminate such a difference in the relative position between each array and the light image on the array depending on the position of the array (hereinafter, referred to as position shift), a focus detection optical system with extremely small aberration is adopted. In addition, the optical adjustment must be performed very carefully, which leads to an increase in the cost of the focus detection optical system and a significant decrease in mass productivity. The above problem is not limited to the pupil division type focus detection device of FIG. 1, but in a device for photoelectrically detecting a pair of optical images of the same object and performing distance measurement or focus detection from the relative position thereof, photoelectric image displacement. This is common when performing detection.
An object of the present invention is to provide a highly accurate focus detection device (distance measuring device) that is easy to optically adjust and has high mass productivity. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, a pair of photoelectric element arrays 105 and 106 each including an image sensor such as a CCD are arranged in parallel in the photoelectric conversion unit 201. An image of the same subject is formed on each photoelectric element array by the focus detection optical system similar to that shown in FIG. The image outputs a1 ... aN from the array 105 are A / D converted by the A / D converter 202 sequentially in time series, stored in the data memory means 204 in the microcomputer 203, and just like the image output b1 from the array 106. ... bN is also stored in the data memory means 204 via the A / D converter 202. The image shift calculating means 205 calculates the relative shift amount of both image outputs, that is, the relative shift amount of the optical image on the pair of arrays, based on the pair of image outputs a1 ... aN, b1 ... bN. Of course, the data used for the image shift calculation need not necessarily be the direct image output of the array, but may be the image output obtained by appropriately filtering or sampling these outputs. The correction data storage means 207 stores correction data for correcting the output of the image shift calculation means 205. This correction data is defined as follows.
That is, after the focus detection optical system is temporarily adjusted during the manufacture of the focus detection apparatus, the array 10 in the focused state is obtained.
5, the relative displacement amount of each corresponding image point of the optical image on 5, 106 is measured, and the relative displacement amount of each image point on this array is stored in the storage means 207 as the correction amount. As a concrete example, as shown in FIG. 1B, when the position in the array direction of the photoelectric elements of the arrays 105 and 106 is x and the center xo of each array 105 and 106 is the array 105, the array 105 is arranged. , 106, it is relatively easy to adjust so that the corresponding image points of the light image on the focus at the center xo of the array. Therefore, when adjusted in this way, the relative positional deviation amount of each point has the characteristic S (x) shown by the solid line at the in-focus point and the characteristic Z (x) at the out-of-focus point as shown in FIG. Here, the characteristic S (x) at the time of focusing indicates that the relative displacement amount is zero at the array center xo by the above adjustment and increases linearly from here to the array periphery. The focus characteristic Z (x) is translated from the characteristic S (x) by an amount ZT according to the degree of out-of-focus. The position shift S (x) of the in-focus point is stored in the correction data storage unit 207. It is not preferable to store all the values of S (x) for each position x of the array as the way of storing because the number of stored data increases. Therefore, when the positional shift amount S (x) can be approximated by a straight line passing through the origin xo as shown in FIG. 3, the positional shift amount S (x) is obtained only by the inclination of this straight line.
Since (x) can be specified, the storage unit 207 may store data indicating this inclination. In this case, the correction data storage means 207 can be extremely simplified, and the value of the potentiometer 401 can be changed to the characteristic straight line S as shown in FIG.
The output of the potentiometer 401 can be input to the microcomputer 203 via the A / D converter 402 by adjusting the inclination of (x). The correction data storage means 207 shown in FIG.
You may use ROM which memorize | stored the said inclination like (a). In this ROM, the output terminals P1 to P8 are also connected to the power supply line Vcc and the ground line Et, respectively, and the output terminals P1 to P8 are set according to the data to be stored.
Is processed so that it is connected to only one of the power supply line and the ground line. Further, the correction data storage means 2
A ROM in the microcomputer 203 can be used as 07. When the correction data S (x) is not a straight line but a curved line as shown in FIG. 5, this curved line is approximated by an n-th order equation and specified by (n + 1) numerical values. Good. Alternatively, correction data for several predetermined positions xi may be stored, and if correction data for intermediate positions are required, for example, Lagrangian interpolation may be used. Returning to FIG. 2 again, the correction calculation means 206 corrects the output Z (x) of the image shift calculation means 205 with the correction data S (x) of the correction data storage means 207, and specifically, Z (x ) -S (x) is calculated to calculate the corrected image shift amount ZT. The corrected image shift amount ZT is converted into a defocus amount (a shift amount between the subject image and a predetermined image formation of the photographing lens) by the correction calculation unit 206 and sent to the display drive unit 208. This means 208 displays the focus adjustment state based on the defocus amount and drives the taking lens to the in-focus position. This operation will be described below. A pair of arrays 1
Image output from 05 and 106 a1 ... aN, b1 ... b
N is stored in the data memory means 204 after A / D conversion. Image outputs a1 ... aN stored in the data memory means 204 are illustrated in FIG. 6 (a). Image shift calculation means 2
Reference numeral 05 designates this image output as shown in FIG. 6B or 6C, for example, five areas X-2, X-1, X0, X.
1 and X2, and image output b1 ... bN in exactly the same way
Is divided into five regions X-2, X-1, X0, X1, and X2, and the partial region Xi is output from the image output of each partial region X1.
The partial image shift amount Z (xi) with respect to the center xi of is calculated individually. The correction calculation means 206 calculates the partial correction amount S (xi) at the location xi from the contents of the correction data storage means 207. This partial correction amount S (xi) is obtained by substituting x = xi into the function S (x) as shown in FIG. Thereafter, the correction calculation unit 206 subtracts the partial correction amount S (xi) from the partial image shift amount Z (xi) to obtain the corrected partial image shift amount Z.
Get T (xi). That is, ZT (xi) = Z (xi)-
Get S (xi). In this way, the correction calculation means 206 obtains the corrected partial image shift amount ZT (xi) for each partial area Xi, and, for example, the simple average ΣZT (xi) / 5 of these values.
Is calculated as the final image shift amount, converted into a defocus amount, and sent to the display drive unit 208. There are various methods for obtaining the final image shift amount ZT from the partial image shift amount ZT (xi) for each partial region Xi, depending on the purpose, but some examples will be shown below. (A1) Corrected partial image shift amount ZT (xi) as described above
The average value of is the final image shift amount ZT. (A2) An average value of the remaining corrected partial image shift amounts excluding the maximum and minimum corrected partial image shift amounts ZT (xi) is set as the final image shift amount ZT. (A3) When the corrected partial image shift amounts ZT (xi) are arranged in descending order, the central one is set as the final image shift amount ZT. (A4) The corrected partial image shift amount ZT related to the partial area having the maximum information amount E (x) described later is set as the final image shift amount ZT. (A5) The final image shift amount Z is obtained by adding the average value of the corrected partial image shift amounts ZT (xi) relating to the plurality of partial regions having a relatively large amount of information or the weighted addition of the average value according to the information amount
Let T. As an algorithm for calculating the partial image shift from the data of each partial region Xi, for example, means for performing Fourier transform on the image output and comparing the phases (Japanese Patent Laid-Open No. 54-54).
No. 104859) or a means for calculating a shift amount that gives a maximum correlation by performing a correlation calculation (Japanese Patent Laid-Open No. 57-45510). When the number of photoelectric conversion elements included in the partial region Xi is small, it is more accurate to use the Fourier transform method. When a deep subject is imaged on the array, if the image shift amount is calculated using the image output of the entire area of the array, it is completely unknown which part of the depth subject is automatically focused. Becomes The problem regarding such a depth subject can be solved as follows by calculating the partial image shift amount Z (xi) for each partial region Xi as described above. (B1) If the image shift amount having the smallest image shift amount is selected from the plurality of partial image shift amounts Z (xi) and the final image shift amount ZT is obtained based on this, the defocus amount for the portion closest to the depth subject is calculated. On the contrary, by selecting the one having the largest partial image shift amount, the defocus amount for the distant portion can be obtained, and by selecting the intermediate one, the defocus amount for the intermediate distance portion can be obtained. (B2) If a plurality of partial image shift amounts Z (xi) have almost the same value, the value is selected and the final image shift amount ZT is calculated based on the selected value. Can be obtained. (B3) A partial image shift amount in the partial area Xi having the largest amount of information, which will be described later, is selected and the final image shift amount ZT
Is obtained, it is possible to obtain the defocus amount for the subject having the most information for focus detection, generally, the subject having the best contrast. Next, a specific example of calculating the partial image shift amount as described above will be described with reference to a flowchart. Figure 7
In step (2), the image shift calculating unit 205 calculates the partial image shift amount Z (xi) and the information amount E (xi) in each partial region Xi. Here, the information amount E (xi) represents the reliability of the corresponding partial image shift amount Z (xi). The larger the value of this information amount, the higher the accuracy of the corresponding partial image shift amount. Specifically, if the image shift calculation is performed by the phase comparison after the Fourier transform as the information amount, the values related to the amplitude after the Fourier transform (r1, r1 ′ in JP-A-55-98710). , R2, r2 '
Is applicable. ) Can be used, and when the image shift calculation is a correlation method, an autocorrelation value Wm described later can be used. In the step, each of the partial areas Xi
The information amount E (xi) of is compared with a predetermined threshold Eth, and the partial area Xi having the information amount E (xj) having a value larger than this threshold is selected. In the step, the correction data storage means 2
The partial correction amount S (xj) in the selected partial area xj is calculated from the content S (x) of 07, and the partial image deviation amount Z (xj) in the selected partial area Xj is calculated as the partial image deviation amount Z (xi. ) To choose from. In step, the corrected partial image shift amount ZT (xj) for the selected area Xj is ZT (xj) =
It is calculated from Z (xj) -S (xj). In step, the corrected partial image shift amount ZT (x
j) whether the variation is smaller than a predetermined value ΔZ, specifically, whether the difference between the maximum value and the minimum value of the corrected partial image displacement amount ZT (xj) is smaller than a predetermined value. If it is small, the process proceeds to the step because the subject has no depth, and if it is not small, the subject is determined to have the depth and the process proceeds to step. In the step, for example, the above (A1)-
The final shift amount ZT is obtained by any of the processes in (A5). In the step, for example, the above (B1) to (B3)
The final image shift amount ZT is obtained by any one of the processes. In the above embodiments, a plurality of partial image shift amounts are calculated from a pair of image outputs, but a second embodiment for calculating a single image shift amount will be described next. FIG. 8A shows the data memory means 20 of FIG.
A pair of data strings A1 ... AN, B1 ... BN stored in No. 4
Shows one of. This data string may be the image output itself of the photoelectric element array as described above, or the image output obtained by filtering or sampling it. In FIG. 2, the image shift calculation means 205 is a pair of data strings A1 stored in the data memory means 204.
... AN, B1 ... BN, and one data string A1 ... AN
While shifting the other data string B1 ... BN by a predetermined amount, the correlation amount C (L) for each shift amount L is obtained. That is, ## EQU1 ## The shift amount L that minimizes this function C (L)
m is obtained as the image shift amount. Since the image shift amount Lm thus obtained by the correlation calculation includes an error caused by insufficient adjustment of the optical system as described above, the image shift amount Lm must be corrected by the correction data S (x). I won't. However, this image shift amount is determined by the data strings A1 ... AN, B1 ... B.
Since the calculation is made from all N areas, it becomes a problem which area of the correction data S (x) is used as the correction amount. This problem is solved as follows. The data strings A1 ... AN, B1 ... BN do not all contribute equally to the correlation amount C (L), and
As shown in (a), the portion Y in which the data string changes drastically contributes greatly, and the portion in which the change changes gently contributes little. That is, it depends on the size of the contrast of each part. Therefore, if the degree of the above contribution (hereinafter referred to as the degree of contribution) for each place x of the data strings A1 ... AN, B1 ... BN is obtained, and the correction amount is obtained from the contribution correction data S (x) corresponding to this place Good. The contribution Wm can be obtained, for example, from the difference between adjacent data in the data string. That is, Wm = | Am-Am + 1 | or | Bm
-Bm + 1 |. This value Wm is shown in FIG. Of course, | Am-Am + 1 | + | Bm-Bm + 1 | can be used as Wm. The correction amount ST is as follows: Here, Sm is s when x = m
(X). Therefore, the corrected image shift amount ZT is obtained from the following equation. ZT = Lm-ST It should be noted that the positional deviation amount according to the location between the relative position between the first photoelectric element array and the optical image on it and the relative position between the second photoelectric element array and the optical image on it. When is extremely large, it may be difficult to correct the image shift amount with high accuracy using the correction data S (x). Therefore, the positional deviation amount is corrected in advance to some extent by changing the pitch of the photoelectric elements of the first and second photoelectric element arrays according to the location, and the remaining positional deviation amount is stored as correction data. It is desirable to do. As is apparent from the above description, according to the present invention, the relative position between the first photoelectric element array and the optical image thereon due to the insufficient adjustment of the optical system and the like, Since the correction data relating to the positional deviation generated according to the position of the relative position between the photoelectric element array and the optical image on the photoelectric element array is stored, and the image deviation amount is corrected by this correction data, the photoelectric deviation is corrected. The fine adjustment of the optical system of the dynamic image displacing device is not required, and the volume balance can be greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is an optical diagram showing a relationship between a general focus detection optical system and a photoelectric element array. FIG. 3B is a front view showing the position of an optical image on the photoelectric element. FIG. 2 is a block diagram showing an embodiment of the present invention. FIG. 3 is a graph showing an example of a relative positional deviation amount. 4A and 4B are circuit diagrams showing a specific configuration example of a correction data storage unit. FIG. 5 is a graph showing another example of the relative positional deviation amount. FIG. 6A is a graph showing an example of image output.
FIGS. 9B and 9C are diagrams showing how the image output is divided into a plurality of areas. FIG. 7 is a flowchart showing a specific operation of the first embodiment. FIG. 8A is a graph showing another example of image output.
(B) is a graph showing the intensity of change in image output. [Description of Signs of Main Parts] 105, 106 ... Photoelectric element array 205 ... Image shift calculation means 206 ... Correction calculation means 207 ... Correction data storage means

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[Procedure Amendment] [Date of submission] July 3, 1991 [Procedure Amendment 1] [Document name for amendment] Specification [Item name for amendment] Claims [Amendment method] Change [Amendment content] [Patent] (1) A focus detection optical system that forms two images having parallax for a plurality of different regions of the object field, and a plurality of image shift amounts for the plurality of regions from the photoelectric output for each of the two images. And a focus detection device that performs display or lens drive based on the image shift amount corresponding to the shortest distance among the plurality of image shift amounts. (2) A focus detection optical system that forms two images having parallax for a plurality of different regions of the object field, and a calculation that calculates a plurality of image shift amounts for the plurality of regions from photoelectric outputs of the two images. And a focus detection device that performs display or lens drive based on an image shift amount corresponding to a subject occupying a wide area with respect to the plurality of image shift amounts. (3) The focus detection optical system forms two images having a parallax with respect to a substantially continuous predetermined area of the object scene, and the computing means divides the photoelectric output of the two images into a plurality of parts to obtain the two images. Claim (1) characterized in that it calculates a plurality of image shift amount related to the area and
The focus detection device according to item (2). [Procedure correction 2] [Document name to be corrected] Specification [Item name to be corrected] 0003 [Correction method] Change [Details of correction] Focus detection is performed from the relative positional relationship of the detected secondary image. [Procedure Amendment 3] [Name of Document to be Amended] Specification [Name of Item to Amend] [Correction Method] Change [Content of Amendment] [Problem to be Solved by the Invention] In the case of performing focus detection in this way In the past, focus detection was performed only on one part of the subject, so the places where focus detection was possible were limited. Further, if there is no detectable subject in the detection area, focus detection is impossible. If the focus detection area is widened in order to avoid such a situation, there is a problem that focus detection becomes impossible because the subject with a depth is often present in one focus detection area. [Procedure Amendment 4] [Document Name for Amendment] Specification [Correction Target Item Name] 0005 [Correction Method] Deleted [Procedure Amendment 5] [Correction Target Document Name] Specification [Correction Target Item Name] 0006 [Correction Method] Change [Details of correction] The above problem is not limited to the pupil division type focus detection device of FIG. 1, but in a device for photoelectrically detecting a pair of optical images of the same object and performing distance measurement or focus detection from their relative positions, This is common when performing photoelectric image displacement detection.
It is considered that the object of the present invention enables focus detection for a plurality of parts of a subject, and considers the presence of the depth of the subject from the obtained plurality of image shift amount detection results, and reflects the intention of the photographer most. The focus is on the subject. To achieve this object, in the present invention,
As a first method, a subject closest to the camera is selected from the detection results of a plurality of image shift amounts, and the subject is focused. Further, as a second method, an object having a substantially equal value from the detection results of a plurality of image shift amounts, that is, an object occupying a wide range is focused. [Procedure Amendment 6] [Name of Document to be Amended] Specification [Name of Item to Amend] [Method of Amendment] Change [Content of Amendment] Returning again to FIG. The output Z (x) is corrected by the correction data S (x) of the correction data storage unit 207, and specifically, the calculation Z (x) -S (x) is performed to calculate the corrected image shift amount ZT. To do. The corrected image shift amount ZT is converted into a defocus amount (a shift amount between the subject image and a predetermined image forming surface of the photographing lens) by the correction calculation unit 206 and sent to the display drive unit 208. This means 208 displays the focus adjustment state based on the defocus amount and drives the taking lens to the in-focus position. [Procedure Amendment 7] [Name of Document to Amend] Specification [Name of Item to Amend] 0024 [Correction Method] Change [Content of Amendment] In the step, for example, (A1)-
The final shift amount ZT is obtained by any of the processes in (A5). In the step, for example, the above (B1) to (B3)
The final image shift amount ZT is obtained by any one of the processes. This final image shift amount is converted into a defocus amount, and display and drive are performed. Since the image shift amount and the defocus amount are in a proportional relationship, a plurality of image shift amounts are converted into a plurality of defocus amounts, the above comparison and selection are performed, and display and driving are performed based on the result. You may do it. Next, a correction method in the case where the correction amount S (x) greatly changes in one detection area will be described. [Procedure Amendment 8] [Name of Documents to Amend] Specification [Name of Items to Amend] 0027 [Method of Amendment] Change [Content of Amendment] [0027] [Equation 1] [Procedure Amendment 9] [Name of Document to be Amended] Specification [Name of Item to Amend] 0028 [Correction Method] Change [Content of Amendment] [Shift amount L that minimizes this function C (L)]
Obtain _m as the image shift amount. Since the image shift amount L _m thus obtained by the correlation calculation includes an error due to insufficient adjustment of the optical system as described above, the image shift amount L _m is corrected by the correction data S (x). There must be. However, this image shift amount is determined by the data strings A1 ... AN, B1 ... B.
Since the calculation is made from all N areas, it becomes a problem which area of the correction data S (x) is used as the correction amount. [Procedure Amendment 10] [Name of Document to Amend] Specification [Name of Item to Amend] 0029 [Method of Amendment] Change [Content of Amendment] [0029] This problem is solved as follows. The data strings A1 ... AN, B1 ... BN do not all contribute equally to the correlation amount C (L), and
As shown in (a), the portion Y in which the data string changes drastically contributes greatly, and the portion in which the change changes gently contributes little. That is, it depends on the size of the contrast of each part. Therefore, if the degree of the above contribution (hereinafter referred to as the degree of contribution) for each place x of the data strings A1 ... AN, B1 ... BN is obtained, and the correction amount is obtained from the contribution correction data S (x) corresponding to this place Good. The contribution W _m can be obtained, for example, from the difference between adjacent data in the data string. [Procedure Amendment 11] [Name of Document to Amend] Specification [Name of Item to Amend] 0030 [Correction Method] Change [Details of Amendment] That is, W _m = | A _m −A _{m + 1} | or | B _m
-B _{m + 1} |. This value W _m is shown in FIG. Of course, it is also possible to use | A _m −A _{m + 1} | + | B _m −B _{m + 1} | as W _m . The correction amount ST is [procedure correction 12] [correction target document name] specification [correction target item name] 0031 [correction method] change [correction content] [0031] [Equation 2] [Procedure amendment 13] [Document name for amendment] Specification [Item name for amendment] [Correction method] Change [Correction content] Here, S _m is s when x = m
(X). Therefore, the corrected image shift amount ZT is obtained from the following equation. ZT = L _m −ST In addition, a positional shift corresponding to a position between the relative position between the first photoelectric element array and the optical image on it and the relative position between the second photoelectric element array and the optical image on it. If the amount is extremely large, it may be difficult to correct the image shift amount with high accuracy using the correction data S (x). Therefore, the positional deviation amount is corrected in advance to some extent by changing the pitch of the photoelectric elements of the first and second photoelectric element arrays according to the location, and the remaining positional deviation amount is stored as correction data. It is desirable to do. [Procedure Amendment 14] [Name of Document to Amend] Specification [Name of Item to Amend] [Correction Method] Change [Details of Amendment] [Effect of the Invention] As described above, according to the present invention, a plurality of subjects Focus detection is performed on the part of the image, and in consideration of the depth of the subject from the obtained detection results of multiple image shift amounts, the one closest to the photographer or the one occupying a wide range is selected, and Since the detection result is displayed or the photographing lens is driven, it is possible to focus on the subject that is considered to reflect the intention of the photographer. [Procedure Amendment 15] [Document Name for Amendment] Description [Item Name for Amendment] Brief Description of Drawing [Correction Method] Change [Details of Amendment] [Simple Description of Drawing] [Fig. 1] (a) is general FIG. 6 is an optical diagram showing the relationship between a focus detection optical system and a photoelectric element array. FIG. 3B is a front view showing the position of an optical image on the photoelectric element. FIG. 2 is a block diagram showing an embodiment of the present invention. FIG. 3 is a graph showing an example of a relative positional deviation amount. 4A and 4B are circuit diagrams showing a specific configuration example of a correction data storage unit. FIG. 5 is a graph showing another example of the relative positional deviation amount. FIG. 6A is a graph showing an example of image output.
FIGS. 9B and 9C are diagrams showing how the image output is divided into a plurality of areas. FIG. 7 is a flowchart showing a specific operation of the first embodiment. FIG. 8A is a graph showing another example of image output.
(B) is a graph showing the intensity of change in image output. [Description of Signs of Main Parts] 105, 106 ... Photoelectric element array 205 ... Image shift calculation means 206 ... Correction calculation means 207 ... Correction data storage means

Claims (1)

What is claimed is: (1) A focus detection optical system that forms two images having parallaxes in a plurality of different regions of the object field, and a plurality of images of the plurality of regions from photoelectric output of the two images. A focus detection device, characterized in that a calculation means for calculating a shift amount and an image shift amount indicating the shortest distance among the plurality of image shift amounts are used as focus detection outputs. (2) A focus detection optical system that forms two images having parallaxes in a plurality of different regions of the object field, and a calculation that calculates a plurality of image shift amounts of the plurality of regions from photoelectric outputs of the two images. And a focus detection device that outputs an image shift amount corresponding to a subject occupying the widest area among the plurality of image shift amounts as focus detection output. (3) The focus detection optical system forms two images having a parallax with respect to a substantially continuous predetermined region of the object field, and the computing means divides the photoelectric output of the two images into a plurality of parts to obtain the two images. The focus detection device according to claim 1 or 2, wherein a plurality of image shift amounts regarding the area are calculated.