JP4328491B2 - Optical device and camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical apparatus having a metering means having a range photometric area detection are several possible luminance corresponding to a plurality of distance measurement areas of the screen, a camera equipped with a optical device, and a still image capturing function of the video It relates to the improvement of the camera .
[0002]
[Prior art]
Conventionally, in a camera equipped with a distance measuring device having a plurality of distance measuring points, the main subject is located at the distance measuring point from which the distance measuring information indicating the shortest distance is obtained among the distance measuring points from which the distance measuring information is obtained. It is known that it is considered to be positioned and a focusing operation is performed based on this distance measurement information.
[0003]
Further, in a camera including a photometry device having a photometry area corresponding to each distance measurement point in addition to the distance measurement device, luminance information relating to the main subject is obtained from the photometry area corresponding to the distance measurement point used for focusing. By doing so, it is also known to be able to perform evaluation photometry with a focus on the main subject.
[0004]
In Japanese Patent Laid-Open No. 2000-171446, luminance information is obtained using a sensor at a distance measuring point from which information used for focusing is obtained, and luminance information from the sensor and a plurality of photometric areas are obtained. There has been proposed a method in which backlight determination for a main subject is performed based on luminance information from a photometric sensor having a light source.
[0005]
[Problems to be solved by the invention]
However, when the distance measuring device is a passive method (phase difference detection method) that detects a phase difference based on image information from a pair of image sensors and obtains distance information, there is generally no contrast in the main subject. Cannot measure distance. For example, if the main subject is a person, etc., if there is only a part of the face such as the forehead or a non-contrast part such as clothing that has a single color at the position of the distance measuring point in the screen, the corresponding distance measuring point It will not be possible to measure the distance.
[0006]
In addition, when the main subject covers a plurality of distance measuring points, distance information cannot be obtained from the distance measuring point that is the center of the main subject, and the distance measuring point that is located next to the distance measuring point does not support the main subject. In some cases, distance measurement is performed by detecting a phase difference based on contrast due to a contour or an edge. In such a case, the area from which the distance information is obtained is an area that is off the center of the main subject. If the luminance information of the photometry area corresponding to the distance measurement area is used as the luminance information of the main subject, incorrect luminance information is obtained. It will be controlled using.
[0007]
FIG. 6 is a diagram showing an example of this, and is a diagram simultaneously showing a plurality of distance measuring areas and photometric areas in a shooting screen of a certain camera and a person I as a main subject.
[0008]
In the figure, F10 to F14 represent five distance measuring areas in the photographing screen of this camera. In the figure, E1 to E14 denote 14 divided photometric sensors in the photographing screen of the camera. Each area is shown. E10 to E14 are used for photometry in the screen corresponding to the distance measurement areas F10 to F14.
[0009]
FIG. 3 shows only the distance measuring area on the shooting screen, and FIG. 4 shows the metering area on the shooting screen.
[0010]
As shown in FIG. 6, the person I who is the main subject is located at the center of the screen, and the central portion of the main subject is all around the distance measuring area F12 at the center of the screen, and the main subject is at the distance measuring areas F11 and F13. When a part of the subject is covered, the distance measurement area F12 cannot measure the distance because a part of the face such as a forehead with no contrast is measured, and the distance measurement areas F11 and F13 are the edges of the main subject. The distance can be measured.
[0011]
Also, luminance information is obtained from the photometric areas E11, E12, E13 corresponding to the distance measuring areas F11, F12, F13. However, in the photometric area E12 at the center of the screen, since the person I is in contact with all the photometric areas F12, accurate luminance information about the person I is obtained, but only half of the person I is obtained for the photometric areas E11 and E13. Therefore, the accurate luminance information of the person I is not obtained from this area.
[0012]
When the relationship between the distance measurement area and the photometry area on the shooting screen is as described above, information from the photometry area corresponding to the distance measurement area from which the distance information is obtained is disclosed in Japanese Patent Laid-Open No. 2000-17184. If the backlight is detected, the backlight is detected based on the metering area that is off the center of the main subject, and the main subject is only on a part of the one metering area. Accurate backlight detection for the subject could not be performed.
[0013]
(Object of invention)
An object of the present invention is to provide an optical device, a camera, and a camera capable of performing suitable backlight detection for a scene including a main subject even when the main subject exists in a distance measurement area where a distance measurement result is not obtained. It intends to provide a video camera with a still image shooting function.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a distance measurement area distance information set in the center portion of the photographing screen, the peripheral portion adjacent to the central portion of the photographing screen, and the peripheral portion outside the adjacent peripheral portion. The distance means and the photographing screen are divided into a plurality of photometric areas including a photometric area corresponding to the distance measuring area set in the central portion of the photographing screen, the adjacent peripheral portion, and the outer peripheral portion, respectively. In an optical device having a photometric means for obtaining a photometric value of the photometric area and a backlight detecting means for performing backlight detection based on the photometric value of the photometric area , the distance measuring means at the center of the photographing screen is measured by the distance measuring means. When it is not possible to obtain distance information in the area, it has determination means for determining whether distance information can be obtained in the distance measuring area of the adjacent peripheral part, and the determination means Shooting When it is determined that distance information cannot be obtained in the distance measuring area in the center of the surface and it is determined that distance information can be obtained in the distance measuring area in the adjacent peripheral part, the backlight detection means The optical device performs backlight detection based on a photometric value of a photometric area corresponding to the distance measuring area at the center of the photographing screen .
[0017]
Similarly, in order to achieve the above object, the present invention provides a camera equipped with the above optical device of the present invention .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on illustrated embodiments.
[0019]
FIG. 1 is a block diagram showing a circuit configuration of main parts of a camera according to an embodiment of the present invention.
[0020]
In Figure 1, 1 is a microcomputer where a control means for controlling various operations of the camera, not shown CPU (central processing unit), ROM, RAM, distance measurement and built-in A / D circuit, described later The A / D conversion is performed on the outputs from the unit 2, the photometry unit 3 and the like, and each calculation for obtaining distance measurement and photometry information and each control of other peripheral circuits are also performed.
[0021]
Reference numeral 2 denotes a distance measuring unit (which may be a focus detecting unit, but a distance measuring unit is a representative example) including a pair of light receiving lenses 13 and 14 and a pair of sensor arrays 15 and 16 having a plurality of areas. The light beam from the subject is guided onto the sensor array 15 by the light receiving lens 13 and onto the sensor array 16 by the light receiving lens 14, and after photoelectric conversion is performed according to the light intensity distribution of the subject image, the signal accumulation and The signal amplified by the signal amplification circuit 17 is output as a subject image signal. A photometric unit 3 obtains luminance information using a sensor having a plurality of areas (not shown), and has a photometric area corresponding to the distance measuring area.
[0022]
4 is a shutter control unit that controls opening and closing of the shutter, 5 is a switch SW1 that is turned on by a first stroke of a release switch (not shown) for starting a shooting preparation operation and a shooting operation, and a release switch SW2 that is turned on by a second stroke. The SW input unit includes a switch for setting each shooting mode and the like. Reference numeral 6 denotes a DC / DC unit that converts a power supply voltage into a predetermined voltage and supplies power to each circuit. A strobe unit 7 is a known circuit that charges a main capacitor (not shown) and emits light. Reference numeral 8 denotes an oscillation unit for supplying a clock to the microcomputer 1. Reference numeral 9 denotes a display unit composed of a liquid crystal display for displaying a battery remaining amount display, various types of shooting information, a warning, and the like. A motor control unit 10 controls a feeding motor and a lens barrel driving motor for winding and rewinding a film (not shown).
[0023]
Next, the operation of the microcomputer 1 during the photographing operation in the camera having the above configuration will be described with reference to the flowchart of FIG.
[0024]
First, in step S101, the microcomputer 1 detects the state of the switch SW1 included in the SW input unit 5. As a result, if the switch SW1 is turned on, the process proceeds to step S102 to start the photographing preparation operation, and the distance measuring unit 2 and the photometric unit 3 perform the distance measuring and the photometric operation. If the switch SW1 is OFF in step S101, step S101 is repeated. The distance measurement and photometry operations will be described later, and detailed description thereof will be omitted here. In the next step S103, the flash unit 7 is started to charge the main capacitor that stores energy for causing the flash to emit light.
[0025]
In the next steps S104 and S105, the states of the switch SW1 and the release switch SW2 are detected. If both the switches SW1 and SW2 are turned on, the process proceeds to step S106 to start the photographing operation. If at least one of the switches SW1 and SW2 is OFF, the process returns to step S101.
[0026]
In step S106, focusing of the photographic lens (not shown) is performed by controlling the lens barrel motor (not shown) by the motor control unit 10 based on the distance information obtained in step S102, and the focus is set on the subject. To match. In the next step S107, in order to expose the film, the shutter controller 4 that performs shutter energization control is operated to open the shutter. At this time, in order to measure the shutter opening time, the timer circuit (not shown) starts measuring a predetermined time. The shutter opening time at this time is set based on exposure information including backlight information obtained in step S102, strobe light emission information, and the like.
[0027]
In the subsequent step S108, the flash unit 7 is caused to emit flash light if the light emission conditions are satisfied with reference to the flash light emission information based on the photometric information and backlight information obtained in step S102. In the next step S109, after a predetermined time is measured by a timer circuit (not shown), the shutter control unit 4 is caused to perform the shutter closing operation. Finally, in step S110, in order to wind the film, the feeding operation is performed by starting energization to a feeding motor (not shown) via the motor control unit 9. After the feeding operation, the process returns to step S101 and waits until the switch SW1 is turned on.
[0028]
Next, distance measurement and photometry operation in the camera having the above-described configuration will be described with reference to the flowchart shown in FIG.
[0029]
FIG. 3 shows a distance measuring area in the shooting screen of the camera that can be measured by the distance measuring unit 2 in FIG. 1. In FIG. 3, F10 to F14 indicate five distance measuring areas. Yes. FIG. 4 shows a photometric area in the photographing screen of the camera that can be measured by the photometric unit 3 in FIG. 1, and E1 to E14 are each divided into 14 by the photometric sensor. For the photometry areas E10 to E14, photometry is performed in the areas corresponding to the distance measurement areas F10 to F14 in FIG.
[0030]
FIG. 5 shows the distance measurement area and the photometry area in the camera photographing screen by superimposing FIGS. 3 and 4 described above.
[0031]
As a distance measuring method in the present embodiment, a known external light passive method is used, and the microcomputer 1 in FIG. 1 detects a phase difference from a pair of image information output from the distance measuring unit 2 in FIG. Thus, the distance information is obtained, and the focusing data for focusing is obtained. Further, by performing this phase difference detection for each distance measuring area F10 to F14, distance information for each area is obtained.
[0032]
FIG. 7 is a flowchart showing the distance measurement and photometry operation of the camera in the configuration described with reference to FIGS.
[0033]
In this embodiment, the distance measurement area is 5 points (F10 to F14), F12 is the central portion of the photographing screen, F11 and F13 are peripheral portions adjacent to the central portion, and F10 and F14 are further peripheral portions on the outside thereof. Are arranged so that each can be measured.
[0034]
Further, as a role of each distance measuring area, F12 is for distance measurement in the central portion of the photographing screen, and F10 and F14 are for distance measurement in the peripheral portion of the photographing screen. F11 and F13 are used as an area at the center of the screen when distance measurement is impossible for some reason at the center F12, and the distance measurement results obtained here are those at the center of the shooting screen. It is handled in the same way as the result.
[0035]
In FIG. 7, first, in step S201, the signal accumulation and signal amplification circuit 17 performs accumulation control for all areas F10 to F14. Then, when the accumulation is completed, the process proceeds to step S202, and the signals from F12 in the central part and F10 and F14 located at the most peripheral part (end part) are sequentially amplified by the signal accumulation and signal amplification circuit 17 and the output is outputted. Capture and A / D conversion in the microcomputer 1.
[0036]
In the next step S203, calculation for detecting a known phase difference is performed for each distance measurement area based on the signal A / D converted in step S202, and measurement corresponding to F10, F12, and F14 is performed. Get distance information in the distance area. Here, when the phase difference cannot be detected and the distance cannot be measured, the image signal from the area has a low contrast, or the pair of image signals are determined to be unreliable due to a difference. Etc. are considered. For an area where phase difference cannot be detected and distance information cannot be obtained, infinity is set as a predetermined distance as distance information of the area.
[0037]
In the next step S204, it is determined whether or not distance measurement is possible in any or all of the distance measurement areas F10, F12, and F14. As a result, if distance measurement cannot be performed in any of the distance measurement areas F10, F12, and F14 (NG), the process proceeds to step S211 and the distance measurement operation by F11 and F13 is started as a central area as described later. Let Otherwise, since the distance is measured in any area, the process proceeds from step S204 to step S205.
[0038]
In step S205, it is determined whether or not distance measurement is possible in the distance measurement area F12 located in the center. As a result, when it is determined that distance measurement is possible in the distance measurement area F12, since distance measurement is performed with respect to the central portion of the shooting screen, information in the distance measurement area F12 is used as distance measurement information in the central portion. The process proceeds to S206. On the other hand, if ranging is not possible in the ranging area F12, the process proceeds to step S218 described later.
[0039]
In step S206, the distance measurement area indicating the shortest distance is selected from the distance measurement information of the distance measurement areas F10, F14 and the distance measurement area F12 in the center of the shooting screen. The distance information from the distance measuring area is selected as the distance information of the main subject, that is, the focusing data. In the next step S207, a photometry area corresponding to the distance measurement area selected in step S206 is selected, and setting is made so that luminance information can be obtained as an area for detecting backlight against the main subject. Proceed to S208. Here, when the selected distance measuring area is F12, E12 is selected as the photometric area, when it is F10, E10 is selected as the photometric area, and when it is F14, E14 is selected as the photometric area. Will do.
[0040]
In the next step S208, a photometric operation is performed. The photometric value is calculated for each of the 14 photometric areas (E1 to E14), and the photometric value selected for backlight detection in any of the above step S207 and steps S215, S217, S222, and S224 described later. The photometric value (luminance information) of the area is obtained as SPOT, and the average photometric value of the photometric area excluding the photometric area for detecting the backlight is calculated as AEave.
[0041]
In the subsequent step S209, the average photometric value AEave calculated in step S208 is compared with the photometric value SPOT of the area where the main subject selected as the backlight detection photometric area is located, and the difference is a predetermined value ( In this embodiment, if 2EV is set as a predetermined luminance value), it is considered that the backlight is in the backlight state, and the process proceeds to step S210. If it is equal to or smaller than the predetermined value, it is determined that the backlight is not in the backlit state, and the distance measurement and photometry operations are finished as they are.
[0042]
Further, when the process proceeds from step S209 to step S210 assuming that the backlight is in the backlit state, here, a flag for performing exposure correction at the time of backlighting, etc. is set, and depending on each shooting mode and the subject distance, strobe light emission and exposure plus Setting is made to perform correction and the like, and the distance measurement and photometry operations are finished.
[0043]
If it is determined in step S204 that the distance measurement results in the distance measurement area F12 in the central portion and the distance measurement areas F10 and F14 in the peripheral portions (edge portions) are all distance measurement NG, the steps are performed as described above. The process proceeds to S211, where F11 and F13 arranged adjacent to both sides of the F12 are used instead of the normally used F12 as the distance measuring area in the center of the screen, and the distance measurement in the center is started. Here, among the ranging areas accumulated in step S201, the signals from F11 and F13 are sequentially amplified by the signal accumulation and signal amplification circuit 7, and the output is taken in, and A / D converted in the microcomputer 1. The process proceeds to step S212.
[0044]
In step S212, the A / D converted signal is subjected to known phase difference detection for each distance measurement area, thereby obtaining distance information of the distance measurement area corresponding to F11 and F13. Then, in the next step S213, it is determined whether or not the phase difference detection could not be performed (NG) in any of the ranging areas F11 and F13. If the distance cannot be detected, the process proceeds to step S216. On the other hand, if the phase difference can be detected in one or both of the distance measurement areas F11, F13, the process proceeds to step S214.
[0045]
In step S216, since all the ranging areas are NG, infinity is set as the focusing data, and in the next step S217, the lowest value among the photometric areas corresponding to the ranging area is shown. The area is selected for backlight detection, and the process proceeds to the processing after step S208 described above. In the present embodiment, the area showing the lowest value is selected as the backlight detection area. However, the present invention is not limited to this, and the reliability data is the highest among the ranging areas. A photometry area corresponding to the distance measurement area indicating the value may be selected, or may be selected by a predetermined algorithm.
[0046]
Further, when proceeding from step S213 to step S214, here, the distance measurement area indicating the short distance is selected from F11 and F13, and the distance measurement information from the distance measurement area is selected as the focusing data. In the next step S215, the photometric area E12 located in the center of the screen is set as the photometric area for detecting the backlight in this case, and the process proceeds to the processing after step S208 described above.
[0047]
In step S215, the photometry area E12 located in the center of the screen is set. The reason for proceeding to step S215 is that the distance measurement in the center is performed by both or one of the distance measurement areas F11 and F13. This is also the case, and since the distance measurement areas F11 and F13 can be measured as the distance measurement area located in the center, a subject as shown in FIG. 6 is assumed, and there is a possibility that the subject exists in the center. As the photometric area, E12 at the center between F11 and F13 is selected.
[0048]
If the central distance measuring area F12 is the distance measuring NG in step S205, the process proceeds to step S218 as described above. Here, as in step S211, the signal amplification of the distance measuring areas F11 and F13 is performed. And capturing the output and A / D conversion. In the next step S219, phase difference detection is performed in the same manner as in step S212, and distance information in each distance measurement area is obtained. Then, in the next step S220, it is determined whether or not the phase difference could not be detected in each of the distance measurement areas F11 and F13. Here, if no phase difference is detected from any of the distance measurement areas at the center, all the distance measurement areas are NG, and therefore the focusing data is selected from the distance measurement area F10 or F14 at the peripheral part (edge). In step S223, a distance measurement area indicating a short distance is selected, distance information from the distance measurement area is selected as focusing data, and in step S224, photometry corresponding to the selected area is selected. The area is set as a photometric area for backlight detection, and the process proceeds to the above-described steps after step S208.
[0049]
On the other hand, if the phase difference is detected in one or both of the distance measurement areas F11 and F13 in step S220, the process proceeds to step S221, where focus data is selected, but F12 is already the distance measurement NG. Since it is known, a distance measuring area indicating a short distance is selected from distance measuring areas other than F12 and distance information from the distance measuring area is selected as focus data. To do. The range-finding areas that may be selected here are F10, F11, F13, and F14. Then, in the next step S222, a photometry area used for backlight detection is selected from the distance measurement area selected in step S221. If the selected distance measurement area is F10, the photometry area is selected. If E10 is F14, E14 is used as the photometry area, and if the selected distance measurement area is F11 or F13, an object as shown in FIG. 6 is assumed. Select as photometry area for backlight detection.
[0050]
In the present embodiment, the backlight detection is performed by using the photometric value and the average photometric value of the area selected as the photometric area for detecting the backlight, but it goes without saying that the average photometric value is not limited. It may be compared with a predetermined photometric area located in the vicinity, or it is compared with an average photometric value in a photometric area that does not correspond to a distance measuring area, and it is in a backlight state when there is a predetermined luminance difference. Needless to say, it may be determined.
[0051]
According to the above embodiment, when a distance measurement result cannot be obtained in the central distance measurement area F12, the adjacent distance measurement areas F11 and F13 (when the distance measurement area F12 is distance measurement NG, A distance measurement area arranged to be used as a distance measurement area) to determine whether or not a distance measurement result as a central portion can be obtained from at least one, and measure at least one of the adjacent distance measurement areas. If the distance was sufficient, the photometry area used for backlight detection could not be obtained. However, the photometry area corresponding to the photometry area F12 at the center of the shooting screen where the main subject is assumed to be located E12 (Steps S204 → S205 → S218 → S219 → S220 → S221 → S222 in FIG. 7 or Steps S204 → S211 → S212 → S213 → S214 → S215) It is possible to improve the detection accuracy of the backlight detection with respect to the subject.
[0052]
Therefore, for example, accurate backlight detection is possible even during the shooting screen shown in FIG.
[0053]
Further, the distance measurement area for obtaining the focusing data is selected based on the distance measurement information from the distance measurement area from which the distance measurement information can be obtained from the plurality of distance measurement areas (the above-described implementation). In this mode, the focus adjustment is performed using the distance measurement information from the distance measurement area as focusing data, so that the focus adjustment is suitable for the main subject. Focus adjustment can be performed.
[0054]
In the above embodiment, the example applied to the camera is described. However, the present invention is not limited to this, and any optical device having distance measuring and photometric functions can be applied in the same manner. Furthermore, if it is only intended to perform accurate backlight detection, it can be applied to an apparatus having only a photometric function.
[0055]
【The invention's effect】
As described above, according to the present invention, it is possible to perform suitable backlight detection for a scene including a main subject even when the main subject exists in a distance measurement area where a distance measurement result is not obtained. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a circuit configuration of main parts of a camera according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a photographing operation of a camera according to an embodiment of the present invention.
FIG. 3 is a diagram showing a distance measuring area in a shooting screen of a camera according to an embodiment of the present invention and a conventional camera.
FIG. 4 is a diagram showing a photometric area in a shooting screen of a camera according to an embodiment of the present invention and a conventional camera.
5 is a diagram showing distance measurement and photometry areas in the photographing screen shown in FIGS. 3 and 4. FIG.
FIG. 6 is a diagram illustrating an example of a relationship between a subject, a distance measurement, and a photometry area in a shooting screen of a camera according to an embodiment of the present invention and a conventional camera.
FIG. 7 is a flowchart showing ranging and photometry operations of the camera according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Distance measurement part 3 Photometry part 4 Shutter control part 5 SW part 6 DC / DC part 7 Strobe part 8 Oscillation part 9 Display part 10 Motor control part 13, 14 Photosensitive lens 15, 16 Sensor array 17 Signal accumulation and signal amplification circuit

Claims (5)

Ranging means for obtaining distance information of a ranging area set in each of a peripheral portion adjacent to the central portion of the photographing screen, a peripheral portion adjacent to the central portion of the photographing screen, and a peripheral portion outside the adjacent peripheral portion;
The shooting screen is divided into a plurality of metering areas each including a metering area corresponding to the distance measuring area set in the central part of the shooting screen, the adjacent peripheral part, and the outer peripheral part. A photometric means for obtaining a photometric value;
In an optical device having a backlight detection means for performing backlight detection based on a photometric value of the photometric area,
Determination of whether distance information can be obtained in the distance measuring area in the adjacent peripheral portion when distance information cannot be obtained in the distance measuring area in the center of the photographing screen by the distance measuring means. A determination means for performing
When it is determined by the determination means that distance information cannot be obtained in the distance measuring area in the central portion of the shooting screen, distance information can be obtained in the distance measuring area in the adjacent peripheral portion, The optical apparatus according to claim 1, wherein the backlight detection unit performs backlight detection based on a photometric value of a photometric area corresponding to a distance measuring area at a central portion of the photographing screen.   The backlight detection means is in a backlight state when the difference between the photometric value of the photometric area corresponding to the distance measuring area at the center of the shooting screen and the average photometric value of the other photometric areas exceeds a predetermined value. The optical device according to claim 1, wherein: When it is determined by the determination means that distance information can be obtained in the distance measurement area of the adjacent peripheral part, the shortest distance among the distance information obtained in the distance measurement area of the adjacent peripheral part The optical apparatus according to claim 1, wherein distance information indicating ??? is selected as focusing data. When the distance measurement means cannot obtain distance information in the distance measurement area at the center of the shooting screen, the determination means obtains distance information in the distance measurement area of the adjacent peripheral part. If it is determined that the distance information can be obtained in the outer peripheral distance measurement area, the distance information of the outer peripheral distance measurement area is focused. The optical device according to claim 1, wherein the optical device is selected as data for use.   A camera comprising the optical device according to claim 1.

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