JPH04186325A - Camera blurring detecting device - Google Patents

Abstract

PURPOSE:To detect the blurring having low frequency and simplify processing and system at low cost by receiving the light which is projected from a light projecting means and reflected from a face and detecting blurring on the basis of the variation of the photoelectric current of a light receiving means. CONSTITUTION:An ultrared LED 13 for light projection and a photodiode 14 for light receiving are installed in proximity, keeping a prescribed interval, on the rear cover 12 of a camera body 11, at the position and direction permitting the light projected from the ultrared LED 13 to be reflected on the face 15 of a person as projection object, e.g., on a cheek 16 and to be receives by the photodiode 14. The ultrared LED 13 for light projection and the photodiode 14 for light receiving are arranged at the position where the reflection light radiated to the part having little unevenness on the face of the person can be received. Accordingly, when blurring is generated on the camera, the light receiving quantity varies, and the blurring of the camera can be detected easily.

Description

[Detailed description of the invention] do.

Since the human head is a part of the human body that is difficult to touch, the present invention detects camera shake by optically detecting the relative position of the head and the camera.

FIG. 1 shows a camera to which the camera shake detection device of the present invention is applied and the face of a photographer.

In the figure, an infrared LED 13 for projecting light and a photodiode 14 for receiving light are attached to the rear cover 12 of a camera body 11 at predetermined intervals. These infrared L E
D 13 and photodiode 14 are infrared LED
The photodiodes 14 are mounted in positions and directions such that the light emitted from the photodiode 14 is reflected by the photographer's face 15, such as the cheek 16, and is received by the photodiode 14, for example, close to each other. Infrared LED 13 and photodiode 14
The reason why the cheek 16 is provided in a position opposite to the cheek 16 is that this is a part of the face 15 that has relatively few irregularities. Further, a pressure plate 18 for directing the film 17 is provided inside the rear lid 12. Note that 19 is a finder that guides light from the subject to be captured by the photographer's eyes 20.

Next, detection of blur by the camera blur detection device shown in FIG. 1 will be described.

Generally, the amount of movement of the subject due to blur on the film plane is expressed as βx+fθ. Here, β is the lateral magnification of the photographic optical system, X is the amount of shift in the direction parallel to the film plane due to camera shake, f is the focal length of the photographic optical system, and θ is the tilt due to the shake of the photographic optical axis. Here, unless the subject is at a short distance, fθ is closer to β or θ, so fθ becomes more dominant than βX.

FIG. 2 shows the state of the test 8 of this inclination θ. 2nd at the beginning
As shown in Figure (a), it is assumed that the camera body 11 is held at a distance g from the photographer's cheek 1B. Here, for convenience of explanation, the infrared LED 13 and the photodiode 14 are shown at the same position. For example, as shown in FIG. 2(b), when the camera body 11 rotates due to shaking relative to FIG. 2(a), the positions of the infrared LED 13 and photodiode 14 and the cheek 16
The distance from this point is g2. That is, in the state shown in FIG. 2(a) and the state shown in FIG. 2(b), the distance of the light emitting/receiving system (infrared LED 13, photodiode 14) to the cheek 16 changes from g to p2, and then The angle between the face I5 and the light emitting/receiving system is different. Therefore, it can be seen that a change occurs in the reflected light incident on the photodiode 14, which is a light receiving element.

In this way, the camera body 11
By arranging the light emitting element and the light receiving element at a location where the output of the photodiode 14 changes according to the inclination θ,
It becomes possible to generate pressure in response to camera shake.

For this reason, the light emitting element and the light receiving element are located on the back of the camera, and there is little change in infrared reflectance depending on their position.
It is also desirable to place it in an area that is not very uneven.

3(a) and (b) show an example of the arrangement of these light projecting elements and light receiving elements (infrared LED 13, photodiode 14). cheek 1
An infrared LED 13 and a photodiode 14 are arranged at a position where light is irradiated onto the portion 6. Also, the same figure (b)
is the upper part of the camera body 11 and the forehead 2 of the photographer's face 15.
An infrared LED 13 and a photodiode 14 are arranged at a position where light is irradiated onto the portion 1.

FIG. 4 shows the processing circuit of this detection device.

Generally, the highest frequency of vibration is about 208'z,
It is assumed that the circuit shown in the figure is designed to amplify signals of 20 Hz or less. In the same figure, light emitting circuit 2
The light emitted from the infrared LED+3 by the infrared LED+3 is received by the photodiode 14. The photocurrent from the photodiode 14 flows into the resistor R, and the buffer amplifier 23 receives the generated voltage change. The output of the second buffer amplifier 23 is input to a bypass filter 24 composed of a capacitor C1 and a resistor R2. This bypass filter 2
4 is intended to cut direct current, and since the direct current component is cut and then input to the amplifier 25, the cutoff frequency should be as low as possible.

What is needed here is the change in the amount of light received by the photodiode 14, so the steady state light component is cut off by the bypass filter 24.

The signal is then amplified by an amplifier 25 with resistors R3 and R4, and then input to a low-pass filter 2B. This low-pass filter 26 passes frequencies of 20 Hz or less, and can remove, for example, noise from fluorescent lights.

The output of the low-pass filter 26 is then input to an A/D conversion terminal of a CPU (central processing unit) 27, where it is subjected to subsequent processing. Furthermore, this CPU27
Regarding the processing of
Since the details are described in No. 88, the explanation will be omitted here.

In FIG. 4, the infrared LED 13 emits light by continuous lighting, but the invention is not limited to this.

FIG. 5 shows an example in which this infrared LED is modulated. That is, in the circuit shown in FIG. 4, the infrared LED 13 emits modulated light, and the detection circuit 28 is inserted between the amplifier 25 and the low-pass filter 26. According to this, even if noise light having fluctuations of 20 Hz or less is incident, the influence of this noise light can be removed.

In this way, a light-emitting element and a light-receiving element are provided in the camera body, and these elements are placed in a position where they can receive the light irradiated onto the less uneven part of the photographer's face, and the changes in the amount of light are calculated. This allows camera shake to be easily detected.

[Effects of the Invention] As described above, the present invention provides a camera shake detection device that is capable of detecting low-frequency shake regardless of shutter speed or contrast, is inexpensive, and has no complicated processing or system. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a camera to which the camera shake detection device of the present invention is applied and the face of the photographer, and FIGS. 2(a) and (
b) is a diagram showing how the camera shakes due to the pre-detection device of the camera shown in Fig. 1; This figure is a schematic circuit diagram showing a processing circuit of the detection device, and FIG. 5 is a schematic circuit diagram showing another processing circuit of the detection device. 11... Camera body, 12... Back cover, 13... Infrared LED, 14... Photodiode, 15... Face, 16... Cheek, 21... Forehead, 22...・Light projection circuit, 23...Buffer amplifier, 24...Bypass filter, 25...Amplifier, 26...Low pass filter, 27...CPU (Central processing unit II, 28...
・Detection circuit. Applicant's representative Patent attorney Atsushi Tsuboi Figure 1 Section 2 Figure Procedural amendment dated March 3, 1998 - June 1998 Director General of the Patent Office Satoshi Uematsu 1, Indication of the case Patent application No. 2-318417 2, Title of the invention Camera shake detection device 3, relationship with the case of the person who makes the correction Patent applicant (037) Olympus Optical Industry Co., Ltd. 4, Agent 3-7-2 Kasumigaseki, Chiyoda-ku, Tokyo 100 Telephone 03 (3502) 3181 ( 7. Contents of amendment (1) In the first line of page 6 of the specification '1s, the phrase "β becomes θ" is amended to "β becomes 0."

Claims (1)

[Scope of Claims] Light projecting means arranged on the camera body so as to project light toward a part of the face, and light receiving means for receiving reflected light from the face projected by the light projecting means. What is claimed is: 1. A shake detection device for a camera, comprising: detecting shake based on a change in photocurrent of the light receiving means.