JPH09318865A - Focusing device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately search the moving destination of an object image in efficient order by searching the moving destination thereof along stored past selection order. SOLUTION: A focus detection means 1 individually detects focus detection information corresponding to a focusing state concerning plural focus detection areas. A storage means 2a stores the selection order of the focus detection area used for focus control. A focus predicting means 3 denotes the tendensy of the focus detection information concerning the focus detection area used for the focus control and calculates the predicted value of the focus detection information. A searching means 4a searches the focus detection area coincident with the predicted value calculated by the means 3 along 'the selection order in the case of the focus control in past' stored in the storage means 2a. A focus control means 5 performs the focus control concerning the searched focus detection area. Thus, the time taken until the moving destination is found out is efficiently shortened concerning the subject image with high reproducibility of a moving course.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention searches for a moving destination of a subject from a plurality of focus detection areas arranged in a photographing screen of a camera and continues focus control for the searched focus detection areas. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus, and more particularly, to a focus adjustment apparatus that searches for focus detection areas in an efficient order.

[0002]

2. Description of the Related Art In recent years, it is known that a camera automatically adjusts the focus by following a subject image moving on a shooting screen. Such a camera is equipped with a focus adjustment device that searches for a destination of a subject image from a plurality of focus detection areas and continuously executes focus control with respect to the searched focus detection areas. 1-288816).

The operation of this type of focus adjusting device will be outlined below. First, the focus adjustment device initially sets a focus detection area located at the center of the shooting screen as an area used for focus control (hereinafter referred to as “selection area”). Next, the focus adjustment device, for the plurality of focus detection areas,
The defocus amount, which is the distance between the image plane of the subject image and the imaging plane, is individually measured. Then, the lens position of the photographing lens is added to each of these defocus amounts to obtain the image plane position for each focus detection area.

The focus adjustment device determines the continuity between the previous image plane position and the current image plane position for a series of selected areas. If there is continuity in the image plane position, the focus adjustment device
It is determined that the subject image located in the selected area is still located in the selected area. Therefore, the focus adjustment device predicts the variation of the image plane position for this selected area and performs focus prediction control.

On the other hand, when there is no continuity in the image plane position, the focus adjusting device determines that the subject image located in the selected area is
It is determined that it has moved out of the selected area. Therefore, the focus adjustment device fetches the latest image plane position from all focus detection areas, obtains the difference from the previous image plane position in the selected area, and calculates the image plane velocity. The image plane velocity calculated in this way is the image plane velocity when it is assumed that the subject image previously positioned in the selected area has moved to another focus detection area.

The focus adjusting device selects, from all these image plane velocities, the one closest to the previous image plane velocity of the selected area. The area thus selected can be determined as the destination of the subject image located in the selected area, and is set as the selected area after this time. The focus adjustment device continues focus control for the selected area thus changed.

By repeating such an operation, the focus control can be continued while automatically switching the focus detection areas by following the subject image moving on the photographing screen. Further, Japanese Patent Application Laid-Open No. 5-45576 discloses a device that preferentially searches for a moving destination of a subject from a focus detection area in which detection of a defocus amount has been completed earlier.

In this type of apparatus, the search for the destination of the subject image can be started quickly without waiting for the completion of detection of all defocus amounts.

[0009]

SUMMARY OF THE INVENTION Incidentally, Japanese Patent Application Laid-Open No. Hei.
In the focus adjustment device as described in Japanese Patent No. 288816, the optimum area for focus control is selected from the defocus amounts of all focus detection areas. Therefore, there is a problem that the destination of the subject image cannot be specified unless the detection is completed for all defocus amounts, and the time required for the search is long.

Further, in the apparatus as disclosed in Japanese Patent Laid-Open No. 5-45576, the moving destination of the subject image is searched for in the order of defocus amount detection, without waiting for the completion of detection of all defocus amounts. However, the detection order of the defocus amount is an order that depends on the illuminance of the focus detection area, and has no correlation with the moving direction of the subject image. Therefore, although it is guaranteed that the search will be started promptly, the destination is not always found quickly.

Furthermore, since there is no correlation between the detection order of the defocus amount and the moving direction of the object, there is a high possibility that another object searched for by chance will be erroneously determined as the object, and the search result will be reliable. There was a problem that it was poor.
Therefore, in order to solve such a problem, the inventions according to claims 1 to 4 provide a focus adjustment device capable of accurately searching for a destination of a subject image in an efficient order. With the goal.

According to the fifth aspect of the invention, particularly when it is difficult to specify the search order, the possibility that the search time becomes long is stochastically distributed, and the moving destination of the subject image is efficiently searched. An object is to provide a focus adjustment device. In the invention described in claims 6 and 7, any one of claims 1 to 4
In addition to the purpose of the item, it is an object of the present invention to provide a focus adjustment device that can accurately determine the search order by appropriately responding to changes in the camera position.

[0013]

FIG. 1 is a block diagram showing the principle corresponding to the first aspect of the present invention. The invention according to claim 1 is a focus detection means 1 for individually detecting focus detection information corresponding to a focus state for a plurality of focus detection areas.
And a storage unit 2a that stores the selection order of the focus detection areas used for focus control, and a focus detection information trend for the focus detection areas used for focus control, and the predicted value of the focus detection information is calculated. The focus prediction unit 3 and the search unit 4a that searches the focus detection area that matches the predicted value calculated by the focus prediction unit 3 according to the "selection order in the past focus control" stored in the storage unit 2a. And search means 4
and a focus control unit 5 for performing focus control on the focus detection area searched by a.

FIG. 2 is a principle block diagram corresponding to the second aspect of the present invention. According to a second aspect of the present invention, a focus detection unit 1 that individually detects focus detection information corresponding to a focus state for a plurality of focus detection areas, and a memory that stores the appearance frequency of the focus detection areas used for focus control. The means 2b, the focus predicting means 3 that extends the trend of the focus detection information and calculates the predicted value of the focus detection information for the focus detection area used for the focus control, and the appearance frequency order stored in the storage means 2b. And a focus control unit 5 for performing focus control on the focus detection area searched by the search unit 4b. To do.

FIG. 3 is a principle block diagram corresponding to the third aspect of the present invention. According to a third aspect of the present invention, a focus detection unit 1 that individually detects focus detection information corresponding to a focus state for a plurality of focus detection areas, and a memory that stores a transition frequency of the focus detection areas used for focus control. The means 2c, the focus predicting means 3 for extending the trend of the focus detection information and calculating the predicted value of the focus detection information for the focus detection area used for the focus control, and the transition frequency stored in the storage means 2c. And a focus control means 5 for performing focus control on the focus detection area searched by the search means 4c. To do.

FIG. 4 is a principle block diagram corresponding to the invention described in claim 4. In FIG. In the invention according to claim 4, the focus detection means 1 for individually detecting the focus detection information corresponding to the focus state for a plurality of focus detection areas, and the “focus detection area setting order” set or selected by manual operation.
Is stored in the storage unit 2d, the focus prediction unit 3 that extends the trend of the focus detection information and calculates the predicted value of the focus detection information for the focus detection area used for the focus control, and the storage unit 2d. Focus prediction means 3 in the order of setting
The search unit 4d that searches for a focus detection area that matches the predicted value calculated by, and the focus control unit 5 that performs focus control on the focus detection area searched by the search unit 4d.
And is configured.

FIG. 5 is a principle block diagram corresponding to the invention described in claim 5. In the invention according to claim 5, the trend of the focus detection information about the focus detection means 1 for individually detecting the focus detection information corresponding to the focus state for the plurality of focus detection areas and the focus detection information used for the focus control. And a focus predicting means 3 for calculating a predicted value of focus detection information, and a search means 4e for searching a focus detection area that matches the predicted value calculated by the focus predicting means 3 in a randomly selected search order. And a focus control means 5 for performing focus control on the focus detection area searched by the search means 4e.

FIG. 6 is a principle block diagram corresponding to the invention described in claims 6 and 7. The invention according to claim 6 is
The focus adjustment device according to any one of claims 1 to 4, further comprising a camera position detection unit 6 that detects whether the camera position is a horizontal position or a vertical position, and the storage area of the storage unit 2 is for each camera position. Is provided exclusively for the camera position detecting means 6
It is characterized by being switched according to the camera position detected by.

The invention according to claim 7 is the invention according to any one of claims 1 to 4.
The focus adjustment device according to any one of the items 1 to 3, further comprising a camera position detection unit 6 that detects whether the camera position is a horizontal position or a vertical position, and the storage unit 2 stores the camera position detected by the camera position detection unit 6. The arrangement of the focus detection area on the storage area is rotated in accordance with the above.

(Operation) In the focus adjusting device according to the first aspect, the storage means 2a stores the selection order of the focus detection areas. The search means 4a searches for the moving destination of the subject image in the order of the past selection.

Generally, when photographing a car or a pedestrian moving on the road, individual subject images pass through the same course on the photographing screen in succession. As for the subject image having a high reproducibility of the moving course, the time until the destination is found is efficiently shortened by searching the destination of the subject image in the order of selection in the past as described above. .

Therefore, the first search requires the same search time as the conventional one, but the search time for the second and subsequent searches can be drastically shortened. Further, by preferentially performing the search from the focus detection area having a high probability, the possibility that an object other than the subject is erroneously discriminated from the subject is low, and the reliability of the search result is significantly high.

In the focus adjusting device according to the second aspect, the storage means 2b stores the appearance frequency (appearance probability) of the focus detection area. The search means 4b searches for the moving destination of the subject image in the order of the past appearance frequency. In general, when macro shooting a flower swaying in the wind or shooting a child on a swing, the subject image periodically passes through the same course on the shooting screen.

For such a subject image, the time for which it is located at both ends of a simple vibration is longest, and the frequency of appearance of focus detection areas corresponding to both ends is high. Therefore, by searching for the moving destination of the subject image in the order of the appearance frequency in the past as described above, the time until the moving destination is found is efficiently shortened. Therefore, the initial search requires the same search time as the conventional one, but it is possible to accurately grasp the appearance frequency and dramatically reduce the search time as time goes by.

Further, by preferentially performing the search from the focus detection area having a high probability, it is less likely that an object other than the subject is erroneously discriminated from the subject, and the reliability of the search result is significantly increased. In the focus adjusting device according to the third aspect, the storage unit 2c stores the frequency of the focus detection area to be moved next from the current focus detection area (hereinafter referred to as "transition frequency"). The searching means 4c searches for the moving destination of the subject image in the order of the past transfer frequency.

Generally, when photographing an automobile or a pedestrian moving on the road, individual subject images pass through the same course on the photographing screen in succession. For a subject image with a high reproducibility of the moving course, the time to find the destination is efficiently shortened by searching for the destination of the subject image in the order of the transfer frequency as described above. .

Therefore, the initial search requires the same search time as the conventional one, but with the passage of time, it becomes possible to accurately grasp the transition frequency and to drastically reduce the search time. In addition, by preferentially searching from the focus detection area with a high probability, objects other than the subject can be detected.
The possibility of misidentifying the subject is low, and the reliability of the search result is much higher.

In the focus adjusting device according to the fourth aspect, the searching means 4d searches for the moving destination of the subject image in the order of the manual setting (manual selection). Generally, when photographing an automobile or a pedestrian moving on a road, a subject image passes through an expected moving course. In this way, for a subject image for which the moving course can be predicted to some extent, the photographer determines the setting order, whereby the time required for the search can be effectively shortened.

Further, since the search is performed in the order of the photographer's setting, there is little possibility that an object unexpected for the photographer will be mistakenly identified as the subject, and the reliability of the search result can be significantly improved. is there. In the focus adjusting device according to the fifth aspect, the searching means 4e searches for the moving destination of the subject image in a random order.

Generally, when photographing a child running around in a plaza or when photographing a fluttering butterfly,
It is difficult to specify the moving course of the subject image. When the moving course cannot be specified in this way, if the conventional search order is uniformly set, the search time is likely to be uniformly long. Therefore, as described above, if the search order is randomly changed every time, the possibility that the search time becomes long can be stochastically distributed.

Therefore, when it is difficult to specify the search order, it becomes possible to search the moving destination of the subject image at an average speed. In the focus adjusting device according to the sixth aspect, whether the camera position is the horizontal position or the vertical position is detected via the camera position detecting means 6. The storage unit 2 switches the dedicated storage area according to the camera position.

In this case, a plurality of storage means 2 may be provided for each camera position, or the storage area of the storage means 2 may be divided for each camera position. In general, the moving course of the subject image is often different between the horizontal position and the vertical position. Therefore, by providing a dedicated storage area for each camera position, it is possible to accurately reflect the change in the moving course due to the difference in the camera position in the history result of the storage unit 2.

Therefore, it is possible to more accurately determine the search order of the subject images in consideration of the state of the camera position. In the focus adjusting device according to the seventh aspect, whether the camera position is the horizontal position or the vertical position is detected via the camera position detecting means 6. The storage unit 2 stores, according to the camera position,
The position of the focus detection area on the storage area is rotated.

In general, the moving course of the subject image is often rotated by about 90 ° between the horizontal position and the vertical position.
Therefore, by rotating the stored contents of the storage means 2 according to the camera position, it is possible to absorb the difference in the moving course depending on the camera position. Therefore, it is possible to accurately determine the search order of the subject images regardless of the state of the camera position.

Further, since the history of the moving course can be centrally collected for the horizontal position and the vertical position, the number of samples stored in the storage means 2 increases. Therefore, it is possible to more accurately determine the search order of the subject images.

[0036]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 7 is a diagram showing a first embodiment (corresponding to claims 1 and 6). In FIG. 7, a lens barrel 12 is attached to the front surface of a camera body 11, and a photographing optical system 13 is arranged inside the lens barrel 12. Shooting optical system 13
The mirror 14 and the sub-mirror 15 are sequentially arranged on the optical axis of the sub-mirror 15, and the focus detection unit 1 is provided in the reflection direction of the sub-mirror 15.
6 are arranged. The image signal output from the focus detection unit 16 is output to the microprocessor 18 via the A / D conversion unit 17.
Connected to.

The PWM (pulse width modulation) output of the microprocessor 18 is connected to the motor 19 via a drive circuit, and the driving force of the motor 19 is transmitted to the lens driving mechanism 20 in the lens barrel 12. This lens drive mechanism 20
The focus adjustment lens group of the photographing optical system 13 is moved forward and backward. An encoder 21 that detects the number of revolutions is installed on the drive shaft of the motor 19, and the pulse output of the encoder 21 is
It is connected to the microprocessor 18.

Further, the microprocessor 18 is connected with a release button 22 for horizontal position shooting, a vertical position release button 23 for vertical position shooting, and a subject course selection button 11a. FIG. 8 is an exploded perspective view showing the internal configuration of the focus detection unit 16. In FIG. 8, a lens holder portion 51 is provided on the upper surface of the focus detection portion 16, and a condenser lens 52 is fitted in the lens holder portion 51.

A light shielding plate 53 is arranged on the upper surface of the condenser lens 52, and visual field masks 53a to 53e are punched in the light shielding plate 53 in accordance with the arrangement of the focus detection areas.
An infrared cut filter 54 that blocks infrared light is disposed on the upper surface of the light shielding plate 53. Also, the condenser lens 52
A mirror 55 is disposed obliquely under the mirror 55, and an aperture plate 57, a lens plate 58, and an image sensor 59 are sequentially disposed along the reflection axis of the mirror 55. Image sensor 59
The output of is connected to the microprocessor 18 via the A / D converter 17.

Further, the diaphragm plate 57 is perforated with diaphragm masks 57a to 57e each having a pair of openings in accordance with the arrangement of the focus detection area, and the lens plate 58 is also provided.
, Separator lenses 58a to 58e formed of a pair of imaging lenses are integrally formed in accordance with the arrangement of the focus detection area. On the light receiving surface of the image sensor 59, light receiving portions 59a to 59e each including a pair of light receiving element rows are formed in accordance with the arrangement of the focus detection area.

Regarding the correspondence relationship between the invention according to claim 1 and the first embodiment, the focus detecting means 1 corresponds to the focus detecting portion 16, and the storing means 2a stores "in the order of selection" of the microprocessor 18. Corresponding to "memory function", focus prediction means 3
Corresponds to the "image plane position predicting function" of the microprocessor 18, the searching means 4a corresponds to the "object moving destination searching function" of the microprocessor 18, and the focus control means 5 includes the motor 19 and the lens driving mechanism 20. , Corresponding to the “focus control function” of the encoder 21 and the microprocessor 18.

Regarding the correspondence between the invention according to claim 6 and the first embodiment, the camera position detecting means 6 includes a release button 22, a vertical position release button 23 and a "camera position determination function" of the microprocessor 18. ". FIG. 9 is a flowchart illustrating the operation of the first embodiment.

The operation of the first embodiment will be described below with reference to these figures. First, the transmitted light of the photographing optical system 13 passes through the transmitting portion of the mirror 14, and then the sub-mirror 15
And is focused on the light shielding plate 53 in the focus detection unit 16 to form an image. The light shielding plate 53 selectively shields light other than the focus detection area via the field masks 53a to 53e. The light beam that has passed through the light shielding plate 53 in this way reaches the diaphragm plate 57 via the condenser lens 52 and the mirror 55.

In the diaphragm plate 57, the light beams are individually divided through the diaphragm masks 57a to 57e. These split beams are
Individually tilted through the separator lenses 58a to 58e to form a plurality of pairs of light images on the light receiving surface of the image sensor 59. In this state, when the release button is pressed halfway (FIG. 9S1), the microprocessor 18 determines which of the vertical position button and the horizontal position button is pressed, and opens the storage areas in the selection order described later. Switch (S2 in FIG. 9).

Next, the microprocessor 18 controls the image sensor 59 to carry out the accumulation of photocharges. During this charge accumulation period, the microprocessor 18 detects the lens position based on the pulse output of the encoder 21 (S3 in FIG. 9). The light receiving units 59a to 59e transfer the photocharges in the order in which the accumulation of the photocharges is completed, and output the photocharges to the microprocessor 18 as image signals.

Here, the microprocessor 18 determines the search order P (i) of the focus detection area as follows. First, the microprocessor 18 reads out the selection order of the focus detection areas at the time of the previous focus control from the selection order storage area (S4 in FIG. 9). The microprocessor 18
Following this selection order, the search order P (i) starting from the currently selected area (the initially set area at the time of the first focus detection) is determined (FIG. 9S5) For example, as shown in FIG. , The previous subject image has passed through the focus detection area in the order of “a → c → d”, and the current selection area is “a”, the search order P (i) is P (1) = a P (2) = c P (3) = d.

The rest of the search order may be determined randomly, or P (4) = b P (5) = e by parallelly moving the moving course of the subject as shown in FIG. May be

After the search order P (i) is set in this way, the microprocessor 18 initializes the variable i to 1 (S6 in FIG. 9) and starts the search for the focus detection area. First, the microprocessor 18 performs a known correlation calculation on the focus detection area corresponding to the search order P (i),
The defocus amount is detected (S7 in FIG. 9). The image plane position is calculated by adding the defocus amount thus detected and the lens position (FIG. 9S8).

The image plane position thus calculated is the image distance from the photographing optical system 13 to the subject image (Image Distance).
And is a value that directly indicates the motion of the subject in the front-back direction. The microprocessor 18 obtains the image plane velocity Vim based on the past image plane velocity in the selected area, and as shown in FIG. 11, the current image plane velocity is "0.5 times to 1.5 times the image plane velocity Vim". It is determined whether or not it falls within the allowable range of "double" (S9 in FIG. 9).

If the current image plane position does not fall within the allowable range, it is possible to determine that the subject image being tracked does not exist in the focus detection area because the image plane position is not continuous. Therefore, the microprocessor 18 increments the variable i and then returns to step S7 (FIG. 9S10) and repeats the above determination for the focus detection area indicated by the next search order P (i).

Despite such a search, if the corresponding focus detection area is not found (S11 in FIG. 9),
It can be determined that the subject being tracked is out of the shooting screen. Therefore, the microprocessor 18 initializes the selection area and shifts to the next focus control (FIG. 9).
S12). On the other hand, when the image plane position is within the allowable range (S9 in FIG. 9), the continuity of the image plane position is maintained,
It is highly possible that the subject image being tracked is located within the focus detection area. Therefore, the microprocessor 18
The focus detection area indicated by the current P (i) is set as the selection area, and the selection order in the storage area is updated (S1 in FIG. 9).
3, S14).

Next, the microprocessor 18 performs regression analysis on "a predetermined number of image plane positions and accumulation center time" in a series of selected areas to calculate the latest prediction function Qr (t) (S15 in FIG. 9). ). If the number of data is less than the predetermined number of samples, the microprocessor 18
Performs regression analysis on the range of the current number of data. The microprocessor 18 drives the motor 19 according to the latest prediction function Qr (t) to execute focus adjustment (FIG. 9S).
16).

By the operation described above, in the first embodiment, the moving destination of the subject image is searched in the order of selection in the past, so that for a subject having a high reproducibility of the moving course,
It is possible to efficiently reduce the time required for the search.
Further, since the focus detection area having a high probability is preferentially searched, there is less possibility that an object other than the object is erroneously discriminated as the object, and the moving destination of the object can be accurately searched.

Further, since a dedicated storage area is provided for each camera position, it is possible to optimally determine the search order of subject images in consideration of the difference in camera position. next,
Another embodiment will be described. FIG. 12 is a diagram for explaining the operation of the second embodiment (corresponding to claims 2 and 7).

The configuration of the second embodiment is the same as the configuration of the first embodiment (FIGS. 7 and 8) except for the internal function of the microprocessor 18, and therefore the description thereof is omitted here. Regarding the correspondence relationship between the invention according to claim 2 and the second embodiment, the focus detection unit 1 is the focus detection unit 1
6, the storage means 2b corresponds to the "frequency of appearance storage function" of the microprocessor 18, the focus prediction means 3 corresponds to the "image plane position prediction function" of the microprocessor 18, and the search means 4b corresponds to the micro. The focus control unit 5 corresponds to the "object moving destination search function" of the processor 18, and the motor 19, the lens drive mechanism 20, the encoder 21 and the microprocessor 18 "focus control function".

Regarding the correspondence between the invention according to claim 7 and the second embodiment, the camera position detecting means 6 includes a release button 22, a vertical position release button 23 and a "camera position determination function" of the microprocessor 18. ". The operation of the second embodiment will be described below with reference to FIGS. 7, 8 and 12. When the release of the camera is half-pressed (FIG. 12S1), the microprocessor 18 determines which of the vertical position and the horizontal position of the release button is pressed, and swaps the storage area allocation (FIG. 12S2).

That is, as shown in FIG. 13A, when the camera body 11 which has been in the lateral position until the last time is rotated counterclockwise by 90 °, the microprocessor 18 allocates the storage area. The positions of the focus detection areas are interchanged and rotated by 90 ° counterclockwise. FIG.
FIG. 4 is a diagram showing the allocation of storage areas that changes according to such camera positions.

As for the vertical position, as shown in FIG. 13 (B), there is also a state in which it is rotated clockwise by 90 ° from the horizontal position. Therefore, one horizontal position and two vertical positions may be distinguished by using an attitude sensor or the like, and the storage areas may be exchanged according to these three camera positions. Here, the microprocessor 18 controls the image sensor 59 to execute the accumulation of photocharges. During this charge accumulation period, the microprocessor 18 counts the number of pulses of the encoder 21 to detect the lens position (FIG. 12).
S3).

Next, the microprocessor 18 reads the appearance frequency of the focus detection area from the storage area inside the processor (S4 in FIG. 12). The microprocessor 18
The appearance order is followed in descending order to determine the search order P (i) starting from the current selected area (the initially set area at the time of the first focus detection) (FIG. 12S5). The moving destination of the subject is sequentially searched along the order P (i) (FIGS. 12S6 to 12).

The microprocessor 18 sets the focus detection area thus searched as a selection area and updates the appearance frequency in the storage area (FIGS. 12 S13 and S1).
4). Focus adjustment is performed on the selected area set in this way (FIGS. 12S15 and S16). By the operation described above, in the second embodiment, the moving destination of the subject image is searched in the order of appearance frequency of the focus detection area, so that the time required for the search can be shortened efficiently.

Further, since the focus detection area having a high probability is preferentially searched, the possibility that an object other than the object is mistakenly determined as the object is reduced, and the moving destination of the object can be accurately searched. Becomes Further, since the contents of the storage area are rotated according to the camera position, it is possible to absorb the difference in the moving course due to the change in the camera position and to integrally store the history of the moving course.

Next, another embodiment will be described. FIG. 15 is a diagram for explaining the operation of the third embodiment (corresponding to claim 3). The configuration of the third embodiment is
Except for the internal function of the microprocessor 18, the configuration is the same as that of the first embodiment (FIGS. 7 and 8), and thus the description thereof is omitted here. Regarding the correspondence relationship between the invention according to claim 3 and the third embodiment, the focus detection means 1 corresponds to the focus detection part 16, and the storage means 2c is the "transition frequency storage function" of the microprocessor 18. The focus predicting means 3 corresponds to the "image plane position predicting function" of the microprocessor 18, and the searching means 4c corresponds to the microprocessor 18.
The focus control means 5 corresponds to the "search function of the moving destination of the subject" of the motor 19, the lens driving mechanism 20, the encoder 2
1 and "Function of focus control" of microprocessor 18
Corresponding to.

A characteristic feature of the operation in the third embodiment is that the search order P (i) is set in the descending order of transition frequency (S3 and S4 in FIG. 15). For example, in the state of transition frequency as shown in FIG. 16, if the current selection area is “a”, the search order P (i) is the focus detection area a.
In order of increasing frequency of transfer from P, P (1) = a P (2) = c P (3) = d P (4) = b P (5) = e.

By adopting such a search order P (i), the time required for the search can be efficiently shortened in the third embodiment. Further, since the focus detection area having a high probability is preferentially searched, there is a low possibility that an object other than the object will be erroneously discriminated as the object, and the reliability of the search result is significantly improved.

Next, another embodiment will be described. FIG. 17 is a diagram for explaining the operation of the fourth embodiment (corresponding to claim 4). The configuration of the fourth embodiment is
Except for the internal function of the microprocessor 18, the configuration is the same as that of the first embodiment (FIGS. 7 and 8), and thus the description thereof is omitted here. Regarding the correspondence relationship between the invention according to claim 4 and the fourth embodiment, the focus detection means 1 corresponds to the focus detection part 16, and the storage means 2d is the subject course selection button 11a and the microprocessor 18 ". The focus predicting means 3 corresponds to the “image plane position predicting function” of the microprocessor 18, and the searching means 4
d corresponds to the “object moving destination search function” of the microprocessor 18, and the focus control means 5 corresponds to the “focus control function” of the motor 19, the lens drive mechanism 20, the encoder 21 and the microprocessor 18.

A feature of the operation in the fourth embodiment is that the search order P (i) is set in the order manually selected through the subject course selection button 11a (S3 and S4 in FIG. 17). ). For example, the manually set order is "a
→ c → d → e ”and the current selection area is“ c ”, the search order P (i) is set to P (1) = c P (2) = d P (3) = e To be done. The rest of the search order is set randomly, for example.

With such an operation, in the fourth embodiment, for the subject whose movement course can be predicted to some extent, the photographer appropriately determines the setting order, thereby effectively shortening the time required for the search. be able to. In addition, since the search is performed in the order of the photographer's setting, there is little possibility that an unexpected object for the photographer will be mistakenly determined as the subject, and the reliability of the search result can be significantly improved.

Next, another embodiment will be described. FIG. 18 is a diagram for explaining the operation of the fifth embodiment (corresponding to claim 5). The configuration of the fifth embodiment is
Except for the internal function of the microprocessor 18, the configuration is the same as that of the first embodiment (FIGS. 7 and 8), and thus the description thereof is omitted here. Regarding the correspondence relationship between the invention according to claim 5 and the fifth embodiment, the focus detection unit 1 corresponds to the focus detection unit 16, and the focus prediction unit 3 performs “prediction of image plane position” of the microprocessor 18. Function, the search means 4e corresponds to the "object moving destination search function" of the microprocessor 18, and the focus control means 5 includes the motor 19, the lens drive mechanism 20, the encoder 21, and the "focus control of the microprocessor 18." Function.

A characteristic feature of the operation of the fifth embodiment is that the search order P (i) is set in a random order (S3 and S4 in FIG. 18). By adopting such a search order, in the fifth embodiment, it is possible to stochastically spread the possibility that the search time will be uniformly long for the subject whose moving course cannot be specified.

Although the defocus amount is used as the focus detection information in the above-described embodiment, the present invention is not limited to this configuration, and if the detected value or the calculated value indicating the focus state is used, focus detection is performed. It can be used as information. For example, the distance measurement value to the subject, the position of the image plane of the subject, the external light passive image interval, the target drive position of the photographing optical system, the external light active light receiving angle or the light receiving position, etc. are used as focus detection information. Good.

Further, in the above-described embodiment, the predicted value of the focus detection information is obtained based on the statistical prediction, but the structure of the focus prediction means 3 is not limited to this. The predicted value of the focus detection information may be obtained based on linear hold or other linear prediction.

Furthermore, in the first and second embodiments,
Although the vertical position is determined by pressing the vertical position release button 23, the configuration of the camera position detecting means 6 is not limited to this. For example, an attitude sensor may be provided in the camera to detect the camera position. Further, although the appearance frequency is stored in the second embodiment, the present invention is not limited to that configuration, and a value corresponding to the appearance frequency may be stored. For example, the appearance probability may be stored.

Furthermore, in the third embodiment, the metastasis frequency is stored, but the present invention is not limited to this configuration,
A value corresponding to the transfer frequency may be stored. For example, the transfer probability may be stored.

[0075]

As described above, according to the first aspect of the invention, the moving destination of the subject image is searched for in the order of past selection.

For example, an object moving along a certain trajectory such as an automobile or a pedestrian moving on the road has a high reproducibility of the moving course. When such a subject is photographed, the time required for the search can be efficiently shortened by searching for the moving destination of the subject image in the order of past selection. Therefore, even when the subject moves at a high speed, it is possible to quickly search and continue to focus without losing the moving destination.

Further, since the search is preferentially performed from the focus detection area having a high probability, there is little possibility that an object other than the object is mistakenly determined as the object, and the reliability of the search result is significantly improved. is there. According to the second aspect of the present invention, the moving destination of the subject image is searched for in the descending order of appearance frequency.

For example, a subject image that periodically moves along a certain trajectory, such as a flower swaying in the wind or a child riding on a swing, has the longest time at both ends of the periodic trajectory, and focus detection corresponding to both ends is performed. Areas appear more frequently. In this way, when a subject frequently appearing in a specific place is photographed, the time required for the search can be efficiently shortened by searching the moving destination of the subject image in the order of the past appearance frequencies.

Therefore, even when the above-mentioned subject moves at a high speed, it is possible to quickly search and continue to focus without losing the moving destination. Further, since the focus detection area having a high probability is preferentially searched, there is a low possibility that an object other than the object will be erroneously discriminated as the object, and the reliability of the search result is significantly improved.

According to the third aspect of the present invention, the moving destination of the subject image is searched for in the descending order of the transition frequency. For example, an object moving along a certain trajectory, such as an automobile or a pedestrian moving on the road, has high reproducibility of the moving course. When such a subject is photographed, the time required for the search can be efficiently shortened by searching the moving destination of the subject image in the order of the past transfer frequency.

Therefore, even when the above-mentioned subject moves at high speed, it is possible to quickly search and continue to focus without losing sight of the moving destination. Further, since the focus detection area having a high probability is preferentially searched, there is a low possibility that an object other than the object will be erroneously discriminated as the object, and the reliability of the search result is significantly improved.

According to the fourth aspect of the invention, the destination of the subject image is searched in the manually set (selected) search order. Generally, when photographing an automobile or a pedestrian moving on a road, a subject image passes through an expected moving course. Therefore, for the subject image whose moving course can be predicted in this way, the time required for the search can be efficiently shortened by determining the search order according to the order set by the photographer.

Therefore, the search time is drastically shortened,
It is possible to quickly search for a subject image that moves at high speed and continue to focus. In addition, since the search is performed in the order of the photographer's setting, there is little possibility that an unexpected object for the photographer will be mistakenly determined as the subject, and the reliability of the search result can be significantly improved.

Further, it is possible to flexibly deal with a complicated search order that cannot be dealt with by automatic setting by manual setting (selection). Therefore, the focus adjustment can be systematically executed in accordance with the photographer's careful shooting intention. According to the fifth aspect of the invention, the moving destination of the subject image is searched in a random order. In general, it is difficult to specify a moving course of a subject image when photographing a child running around a plaza or when photographing a fluttering butterfly.

As described above, if the conventional search order is uniformly set for a subject whose movement course is complicated and cannot be specified, the search time may be uniformly lengthened. However, as described above, if the search order is randomly changed every time, it is possible to stochastically disperse the possibility that the search time becomes long. Therefore, when it is difficult to specify the search order, it is possible to search the moving destination of the subject image at an average speed.

According to the sixth aspect of the invention, the storage area of the storage means is exclusively switched according to the camera position. By such an operation, the change of the moving course due to the difference in the camera position can be accurately reflected in the history result of the storage means.

Therefore, it is possible to more accurately determine the search order of subject images in consideration of the difference in camera position. In the invention according to claim 7, the stored contents of the storage means are rotated according to the camera position. Therefore, it is possible to absorb the difference in the moving course due to the change in the camera position and to integrally store the history of the moving course.

Therefore, it is possible to accurately determine the search order of subject images regardless of changes in the camera position. In addition, since the history of the moving course can be centrally collected for the horizontal position and the vertical position, the number of samples stored in the storage means increases. Therefore, it is possible to more reliably determine the search order of subject images.

As described above, in the focus adjusting device that selectively or independently employs the inventions described in the claims, the subject image can be flexibly adapted to quickly and accurately track the subject image. It is possible to continue to focus steadily. Therefore, the responsiveness of the focus adjustment device is effectively improved, and the performance of the focus adjustment operation can be significantly improved.

[Brief description of drawings]

FIG. 1 is a principle block diagram corresponding to the invention described in claim 1;

FIG. 2 is a principle block diagram corresponding to the invention described in claim 2;

FIG. 3 is a principle block diagram corresponding to the invention described in claim 3.

FIG. 4 is a principle block diagram corresponding to the invention described in claim 4.

FIG. 5 is a principle block diagram corresponding to the invention described in claim 5;

FIG. 6 is a principle block diagram corresponding to the invention described in claims 6 and 7.

FIG. 7 is a diagram showing a first embodiment (corresponding to claims 1 and 6).

8 is an exploded perspective view showing the internal configuration of the focus detection unit 16. FIG.

FIG. 9 is a flowchart illustrating the operation of the first embodiment.

FIG. 10 is a diagram illustrating movement of a subject on a shooting screen.

FIG. 11 is a diagram illustrating a search for a focus detection area.

FIG. 12 is a second embodiment (corresponding to claims 2 and 7).
It is a figure explaining operation of.

FIG. 13 is a diagram illustrating a change in camera position.

FIG. 14 is a diagram showing a change in storage area allocation due to a change in camera position.

FIG. 15 is a diagram illustrating an operation of the third embodiment (corresponding to claim 3).

FIG. 16 is a diagram showing an example of an area transfer frequency.

FIG. 17 is a diagram illustrating an operation of the fourth embodiment (corresponding to claim 4).

FIG. 18 is a diagram for explaining the operation of the fifth embodiment (corresponding to claim 5).

[Explanation of symbols]

 1 Focus Detection Means 2 Storage Means 2a to d Storage Means 3 Focus Prediction Means 4a to e Search Means 5 Focus Control Means 6 Camera Position Detecting Means 11 Camera Body 11a Subject Course Selection Buttons 12 Lens Tube 13 Photographic Optical System 14 Mirror 15 Sub Mirror 16 Focus detection unit 17 A / D conversion unit 18 Microprocessor 19 Motor 20 Lens drive mechanism 21 Encoder 22 Release button 23 Vertical position release button 51 Lens holder unit 52 Condenser lens 53 Light-shielding plate 53a-e Field mask 54 Infrared cut filter 55 Mirror 57 Aperture plate 57a-e Aperture mask 58 Lens plate 58a-e Separator lens 59 Image sensor 59a-e Light receiving part

Claims (7)

[Claims] 1. A focus adjusting device for searching a moving destination of an object from a plurality of focus detecting areas arranged in a photographing screen of a camera and continuing focus control for the searched focus detecting areas, For a plurality of focus detection areas, focus detection means for individually detecting focus detection information corresponding to the focus state, storage means for storing the selection order of the focus detection areas used for the focus control, and used for the focus control With respect to the focus detection area, the trend of focus detection information is extended and the focus prediction means for calculating the predicted value of the focus detection information, and along the “past selection order at the time of focus control” stored in the storage means. A search unit that searches for a focus detection area that matches the predicted value calculated by the focus prediction unit; and a focus that performs focus control for the focus detection area searched by the search unit. Focusing device being characterized in that a control means. 2. A focus adjusting device for searching a moving destination of a subject from a plurality of focus detecting areas arranged in a photographing screen of a camera and continuing focus control for the searched focus detecting areas, For a plurality of focus detection areas, focus detection means for individually detecting focus detection information corresponding to the focus state, storage means for storing the frequency of appearance of the focus detection areas used for the focus control, and used for the focus control For the focus detection area, the focus prediction unit that extends the trend of the focus detection information and calculates the predicted value of the focus detection information, and the order of appearance frequency stored in the storage unit is calculated by the focus prediction unit. Search means for searching a focus detection area that matches the predicted value obtained, and focus control means for performing focus control on the focus detection area searched by the searching means. Focusing device, characterized in that was e. 3. A focus adjusting device for searching a moving destination of a subject from a plurality of focus detecting areas arranged in a photographing screen of a camera and continuing focus control for the searched focus detecting areas, For a plurality of focus detection areas, focus detection means for individually detecting focus detection information corresponding to the focus state, storage means for storing the transition frequency of the focus detection areas used for the focus control, and used for the focus control The focus detection area, the focus prediction means for extending the trend of the focus detection information and calculating the predicted value of the focus detection information, and the focus prediction means along the order of the transition frequency stored in the storage means. Search means for searching a focus detection area that matches the predicted value obtained, and focus control means for performing focus control on the focus detection area searched by the searching means. Focusing device, characterized in that was e. 4. A focus adjustment device that searches for a moving destination of a subject from a plurality of focus detection areas arranged in a photographing screen of a camera and continues focus control for the searched focus detection areas, For a plurality of focus detection areas, focus detection means for individually detecting focus detection information corresponding to the focus state, storage means for storing the “setting order of focus detection areas” set or selected by manual operation, and the focus For the focus detection area used for control, the trend of focus detection information is extended, and focus prediction means for calculating the predicted value of focus detection information, along with the setting order stored in the storage means, by the focus prediction means. Search means for searching a focus detection area that matches the calculated predicted value, and focus control for performing focus control on the focus detection area searched by the searching means. Focusing device being characterized in that a stage. 5. A focus adjusting device that searches for a moving destination of a subject from a plurality of focus detection areas arranged in a photographing screen of a camera and continues focus control for the searched focus detection areas, For a plurality of focus detection areas, focus detection means for individually detecting the focus detection information corresponding to the focus state, and for the focus detection area used for the focus control, the trend of the focus detection information is extended, A focus prediction unit that calculates a predicted value, a search unit that searches for a focus detection area that matches the predicted value calculated by the focus prediction unit, in a randomly selected search order, and a focus searched by the search unit. A focus adjustment device comprising: a focus control unit that performs focus control for a detection area. 6. The focus adjustment device according to claim 1, further comprising a camera position detection unit that detects whether the camera position is a horizontal position or a vertical position, and the storage area of the storage unit is The focus adjusting device is provided for each of the camera positions and is switched according to the camera position detected by the camera position detecting means. 7. The focus adjustment device according to claim 1, further comprising a camera position detection unit that detects whether the camera position is a horizontal position or a vertical position, and the storage unit includes the camera. A focus adjustment device characterized in that the arrangement of focus detection areas on a storage area is rotated according to the camera position detected by the position detection means.