JPH03276140A - Image blur detector - Google Patents

Abstract

PURPOSE:To calculate the extent of blur of an image during exposure by detecting the image projected on a film surface by an area sensor and calculating the extent of blur of the image on the film surface based on the output of the area sensor. CONSTITUTION:At the time of exposure, the luminous flux passing a lens group 7 forms the image of an object on a film 5. An image blur detecting optical system 9 forms the object image, which is projected on the rear face of the film 5, on the light reception face of an image blur detecting sensor 8 again. An image blur arithmetic unit calculates the extent of blur of the image on the surface of the film 5 based on the output of the sensor 8 in accordance with the control signal from a camera control arithmetic part 11. Thus, the extent of blur of the object image due to shake of a camera during exposure is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pre-detection device that detects the amount of pre-presence of a subject image caused by vibration of a camera.

Today, the technology of auto 7 focusing (hereinafter abbreviated as AF) has advanced, and it has become possible to accurately and quickly focus on the subject, eliminating the need for out-of-focus photos. The second thing that is attracting attention is the flow of images due to the vibration of the camera at the time of release.Such photos are often mistaken for out-of-focus photos, but they are also known as blurry images. The difference is that all the subjects appear to be moving in the direction of the camera's vibration.This image blur is generally referred to as hand blur.

If the image is distorted due to this camera shake, the entire photo will look blurry even if it is in focus. Therefore, when taking measures to prevent image blur caused by this camera shake, first of all,
It is necessary to detect the amount of play due to camera shake. Such devices are conventionally disclosed in Japanese Patent Laid-Open No. 62-47013 and Japanese Patent Laid-Open No. 62-182728.

The device disclosed in the former publication has an acceleration sensor installed inside the lens to detect acceleration in each of the up, down, left, and right directions.
The amount of lens displacement is determined from the output and converted to the amount of hand movement.

Further, the device disclosed in the latter publication utilizes an optical system for AF to detect dynamic blur in an image caused by camera shake.

However, these conventional devices have the following problems.

First, the former device requires as many as four acceleration sensors, is expensive, and requires a large amount of storage space. Further, when determining the amount of camera movement from the output of the acceleration sensor, it is necessary to perform the integration process twice, which makes the process complicated.

On the other hand, with the latter device, the light is not guided to the AF detection optical system during exposure, so it is not possible to measure the actual amount of deflection that occurs during exposure.If the exposure time is short, it can be predicted to some extent, but , as the exposure time becomes longer, the error between the predicted amount and the actual amount becomes larger, making it impossible to perform accurate pre-correction and warning) 6 Therefore, the present invention has developed an optical image preform that solves these conventional problems. The purpose is to provide a detection device.

In order to solve the above problems, the present invention 1 includes an area sensor for inspecting the image reflected on the film surface, and an area sensor that detects the amount of shake of the image on the film surface based on the output of the area sensor. The present invention is characterized in that it has a calculation means for calculating .

For production The area sensor detects the image on the film surface.

Then, the calculation means calculates the amount of image on the film surface based on the detected image.

111-Shoichi An embodiment of the present invention will be explained with reference to FIG.

(1) is the camera body, (2) is the pentaprism, (3)
is Faing-, (6) is the lens body and has the lens group (7), ν・ru, (4) l is the lens group (7)
It is a mirror that guides the subject light passing through it to the 7th wing (3), and during exposure (this mirror is retracted to the 4th position to guide the subject light to the film (5)).
). Moreover, (15) is a shank group. Reference numeral (16) is a photometric element for exposure control, which measures the brightness of the film surface during exposure.

(17) is an image pre-detection unit, which is placed inside the back cover of the camera. Note that the back cover of this camera is replaceable, so if image preview detection is not required, a normal back cover can be attached.

An optical system for image pre-detection (9) and a sensor (8) are arranged at a position facing the back surface of the film in the image pre-detection secondary (17).

During exposure, the light flux passing through the lens group (7) is transferred to the film (
5) The image of the subject is focused above. The image blur detection optical system (9) re-images the subject image captured on the back surface of the film (5) onto the light receiving surface of the image blur detection sensor (8). The sensor (8) is attached to this optical string for image blur inspection (
9) The luminance distribution of the subject image on the film (5) that has passed through the film (5) is converted into an electrical signal and output.
D, P, S.

A photoelectric conversion element such as D is used. The output of the sensor (8) is supplied to the image pre-production IL device (10) by two people.

The image pre-calculation device (1) is a camera!Ij control calculation unit (1
According to the control signal from 1), the output of the sensor (8) is captured at predetermined time intervals, and the two images captured at different times are compared to represent the forward direction and amount of the image within that time. This is a device that outputs a signal. This signal is input to a camera control calculation unit (11) that performs overall control, where the play direction and amount are calculated.

On the other hand, one part of the photographic lens has an image pre-correction system @ section (12).
, correction lens (13) and correction actuator (1
4) is built in. The image blur correction control unit receives signals representing the direction and amount of image blur from the camera control unit, and adjusts the correction lens (13) according to the direction and amount of image blur.
A signal is output to the correction actuator (14) to drive the correction actuator (14). The correction lens (13) is driven by the correction actuator (14) to be centered on the optical axis in the vertical and horizontal directions, so that even if the camera is blurred due to camera shake, the image formed on the film surface will remain unchanged. It is driven so that it does not play against the film.

Since this drive must be performed in real time during exposure, a pulse motor, an electromagnetic filter, a piezoelectric element, a bimorph, or the like, which can control the position at high speed and with high precision, is used as the drive actuator.

In addition, the correction lens includes the inside of the lens of the lens group (7),
It is best to select a lens that causes the least reduction in aberration and the largest change in image position when moved and decentered relative to the optical axis.X,'r.

FIG. 2 is a block circuit diagram of the camera of this embodiment. Components that are the same as those shown in FIG. 1 are given the same numbers.

The camera control calculation section (11) receives signals from a lens ROM (LEC), a light metering circuit (LMC), and a film sensitivity reading circuit (ISO) in addition to the above-mentioned image pre-calculation device (10). A lens ROM (LEC) is provided in the conversion lens and stores information specific to the lens, such as focus, focus, open F-number, etc., and this information is read out by the camera control calculation unit (11). Ru. The light metering circuit (LMC) is a circuit that receives the light that has passed through the lens with a light receiving element (not shown) and detects the brightness of the subject based on the output of the light receiving element, and it detects the brightness of the subject based on the output of the light receiving element. Output (B). The film sensitivity reading circuit (ISO) reads the DX code of the film and outputs an Avec-based digital signal (S
).

The camera control calculation unit (11) also outputs the image pre-direction and amount to the image pre-correction control unit (12) as described above, and also outputs subject brightness data (B) from the photometry circuit (LMC). The exposure value is calculated from the film sensitivity data (S) from the V74 lumen sensitivity reading circuit (ISO), the shutter speed and the fringe value are determined, and these values are displayed on the display circuit (DISP). The operation of camera control calculation 11FlI (11) is as follows:
It is determined according to the state of (S2). In addition, the switch (
S) is a /in switch, switch (S) is a metering start switch, and switch (S2) is a release switch. Switches (S,) and (S,) are operated by the same push button, and when pressed halfway, switch (Sl) turns ONL,
When pressed further, the switch (S2) is turned on.

Below, with reference to FIG.
) operation is described in detail.

First, when you turn on the switch (S), Stella 7'(#3
-0). Here, it is determined whether the switch (Sl) is ON or not, and if it is not ON, step (#3-1
Proceeding to step 2), it is determined whether the switch (S) is still on. If it is, the process returns to step (#3-0); if it is not, the operation ends. Step (#3-0
), if the switch (Sl) is ON, it means the start of photometry, and steps 70- from step (#3-1) onwards are executed. First, in step (#3-1), lens information is input from the lens ROM (LEC), and in step (#3-2), film sensitivity data (S
). Then, in step (#3-3), input the subject brightness data (B) from the photometry circuit (L (C)) and move on to step (#3-5).Step (#3-5
), step (#3-1)(#3-2)($
The exposure value is calculated based on the data obtained in step t3-3), and the shutter speed and aperture value are determined. next,
Determine whether the switch (S2) is ON in step (#3-6), and if it is ON, proceed to step (#3-7)
Move to. If it is not ON, it is determined in step (#3-8) whether the switch (Sl) is still ON. If it is ON, the process moves to step (#3-1) and again.
Photometry is performed, and if it is OFE', the process returns to step (#3-0).

Switch (S2) is ON, step (#3-7)
Moving on, it is determined here whether or not release is possible. This determination is made, for example, when the subject brightness is too low and is outside the exposure control range, or in a camera with an auto7 focus function, when focusing is not completed, etc., it is determined that the release is not possible. If the release is not possible, move to step 7 (#3-8), and if release is possible, move to step / step ($3-9). In this step, exposure control is performed according to the shutter speed and frit value determined by the Ste/Knob (#3-5), and the above-mentioned image pre-correction is performed. Note that details will be described later. When the exposure is completed, move on to step (#3-10) and wind the film. Then, wait until step (Sl) turns OFF at step ($3-11), and when it turns off, move on to step (#3-0). ) Return to

Next, with reference to FIG. 4, the operation in the aforementioned step (#3-9) will be described in detail.

First, in step (#4-0), mirror up is started. Then, in step ($4-1>(#4-2), the pattern is embossed. At this time, in the step ($3-5
) The amount of embossment ECNT is determined from the embossment value determined in step 2, and this value is set in a subtraction counter, and is subtracted according to the amount of embossment. When this value ECNT reaches O, the desired emboss is achieved. The loading is completed and the process moves to step (#4-3).

In Kute/Bu ($4-3), wait until time t1 has elapsed from the start of the mirror knob. This time t is set to a sufficient time (for example, 70 m5) to complete the mirror application. Thereafter, in step (#4-4), the shutter is made to run for one hour and exposure is started.

Exposure is then carried out until step (#4-11), during which time the pre-image of the subject is detected,
Pre-correction is performed by driving the correction lens r (13).9 This starts with step (#4).
-5) sends a signal to the image pre-arithmetic unit (10) to capture the first image.

Next, step (#4-6)! Send a signal to capture the image of @2. Then, the image pre-performance device (10)
The first image and the second image are compared, and a pre-signal representing the pre-direction and pre-amount as a result of the comparison is output. The camera control calculation unit (11) inputs this pre-signal in step (#4-7). Then, in step (#4-8), the pre direction and pre amount are calculated from this pre signal, and step (#4
-9) to output to the image pre-correction control unit (]2). The image blur correction control unit (2) drives the correction lens (13) based on this value.
-10), it is determined whether the exposure time has reached the set value, and if the exposure time has reached the set value, step l$4-1.1
) to complete the exposure. If the set value is not reached, the process returns to step (#4-6) and a signal is again sent to the image pre-calculation device (10) to capture the third image. Then, the image pre-arithmetic device (10) compares the second image captured last time with this third image, and outputs a pre-signal in the same manner as the previous time. Then, the camera control calculation unit (11) performs image blur correction control to drive the correction lens (13) again based on this pre-signal! The play direction and play amount are output to ff (12). In this way, during exposure, step (#4
Loop from -6) to (#4-10) and perform image pre-correction!
It is supposed to be returned.

As described above, according to this embodiment, the pre-correction is performed by looking at the subject image formed on the film (5), so the pre-correction is performed during exposure. That is,
Unlike conventional technology, the play direction and amount are not predicted and corrected, but the actual play is detected and corrected, so even if an unpredictable play occurs, it can be corrected accurately.

FIG. 5 is a diagram showing a second embodiment, in which parts having the same functions as those in FIG. 1 are given the same numbers.

In this embodiment, the optical path of the light from the object image reflected on the back surface of the film is bent by a mirror (18), and an optical system for detecting an image pre-detection (9) and a sensor (8) are arranged in the extension thereof. By doing so, the thickness of the photographic lens in the optical axis direction can be reduced.

FIG. 6 is a diagram showing a third embodiment. In the second embodiment, the image reflected on the back surface of the film is detected from the tilt direction. In this case, a long optical path can be obtained without using a mirror, and image pre-detection (22) (17)
can be made thinner.

Alternatively, multiple sensors may be used to detect images at different positions. For example, the center * part and the peripheral part of the screen may be detected separately, and it may be determined which output is to be used for pre-correction. Make it possible to switch. Since the image at the center of the screen is often the main subject, and the images at the periphery of the screen are often Tt, it becomes possible to switch which of the main subject or the background to perform pre-correction on.

In addition, in a camera that has the function of measuring distance at multiple points on the screen, the distance measurement area and the image detection area are matched,
It may also be possible to control which images are subjected to pre-correction based on the measured distance values.

According to the present invention, since the subject image on the film surface is monitored to detect image shake, it is possible to calculate the amount of image shake during exposure.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a camera according to an embodiment of the present invention, FIG. 2 is a block diagram of the camera, FIGS. 3 and 4 are 70-charts showing the operation of the camera, and FIG. FIG. 6 is an explanatory diagram of a camera according to the third embodiment of the present invention. 5...Film 8...Area sensor 10.11...Calculating means Minolta Camera Co., Ltd. 12 Figure 4

Claims (1)

[Claims] 1. An area sensor for detecting an image reflected on a film surface, and a calculation means for calculating the amount of shake of the image on the film surface based on the output of the area sensor. Image shake detection device. 2. The image blur detection device according to claim 1, wherein the area sensor is arranged on the back side of the film and detects an image reflected on the back side of the film.