Shooting lens having vibration reducing function and camera system for same

• US 20110169973A1
• Filed: 03/18/2011
• Published: 07/14/2011
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Tomita, Hiroyuki, Matsumoto, Tsuyoshi, Usui, Kazutoshi
• Granted Patent: US 8,259,183 B2
• Time in Patent Office: Days
• US Class Current: 348/208.7
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position

Abstract

The invention includes a vibration reduction mechanism, a vibration detecting part, a reference signal generating part, a target drive position calculating part, and a driving part. The vibration reduction mechanism reduces a vibration of a subject image. The vibration detecting part outputs a vibration detection signal. The reference signal generating part estimates a reference signal of the vibration detection part. The target drive position calculating part obtains a vibration component from a difference between the vibration detection signal and the estimated reference signal to obtain a target position to which the vibration reduction mechanism is driven. The driving part controls the vibration reduction mechanism to follow the target position. Particularly, the reference signal generating part corrects the reference signal according to a motion signal obtained from a captured image. An accurate reference signal can be obtained by the correction, thereby improving the performance of the vibration reduction.

Claims

1. A shooting lens for forming an image of a subject on an imaging plane of a camera, the shooting lens comprising:

a vibration reduction mechanism for reducing a vibration of the image of the subject;

a vibration detecting part which detects a vibration of the camera and outputs a vibration detection signal;

an information obtaining part which acquires information on a motion signal obtained by analyzing an image shot with the camera; and

a controlling part which controls, using the vibration detection signal, the vibration reduction mechanism to perform feedforward operation and controls, using the motion signal, the vibration reduction mechanism to perform feedback operation, thereby reducing the image vibration; and

a center bias part which biases the vibration reduction mechanism to a center position by feeding back displacement of the vibration reduction mechanism from the center position to the control over the vibration reduction mechanism; and

wherein

the controlling part decreases a feedback gain of the motion signal as a feedback gain of the center bias part increases, and increases the feedback gain of the motion signal as the feedback gain of the center bias part decreases.

2. The shooting lens as set forth in claim 1, further comprising:

a sensor which senses information on at least one of states of the camera which are a state that the camera is fixed by a tripod and a state that the vibration reduction mechanism has moved to its limit, wherein;

the center bias part increases the feedback gain of the center bias part in accordance with the sensed information on the state of the camera; and

the controlling part decreases the feedback gain of the motion signal in accordance with the sensed information on the state of the camera.

5. The shooting lens as set forth in claim 1, wherein the controlling part comprises:

a reference signal estimating part which estimates a reference signal of the vibration detection signal in accordance with the vibration detection signal, the reference signal representing an output of the vibration detecting part while the camera is in a stationary state and free of a vibration;

a reference signal correcting part which corrects the reference signal by feeding back the motion signal to the reference signal estimated by the reference signal estimating part;

a target drive position calculating part which obtains a vibration component from a difference between the vibration detection signal and the corrected reference signal, and obtains, in accordance with the vibration component, a target position to which the vibration reduction mechanism is driven, the vibration component causing the vibration of the image, the vibration mechanism reducing the image vibration according to the vibration component; and

a driving part which controls the vibration reduction mechanism to follow the target position.

3. A shooting lens for forming an image of a subject on an imaging plane of a camera, the shooting lens comprising:

a vibration reduction mechanism for reducing a vibration of the image of the subject;

a vibration detecting part which detects a vibration of the camera and outputs a vibration detection signal;

an information obtaining part which acquires information on a motion signal obtained by analyzing an image shot with the camera; and

a controlling part which controls, using the vibration detection signal, the vibration reduction mechanism to perform feedforward operation and controls, using the motion signal, the vibration reduction mechanism to perform feedback operation, thereby reducing the image vibration, wherein

for stopping the vibration reduction by the vibration reduction mechanism, the controlling part controls the vibration reduction mechanism to stop the feedback operation before stopping the feedforward operation.

4. The shooting lens as set forth in claim 3, further comprising:

a sensor which senses information on at least one of states of the camera which are a state that the camera is fixed by a tripod, a state that the camera is panning, and a state that the vibration reduction mechanism has moved to its limit, wherein

the controlling part stops the feedback operation first according to the sensed information on the state of the camera and then stops the feedforward operation.

6. The shooting lens as set forth in claim 3, wherein the controlling part comprises:

a reference signal estimating part which estimates a reference signal of the vibration detection signal in accordance with the vibration detection signal, the reference signal representing an output of the vibration detecting part while the camera is in a stationary state and free of a vibration;

a reference signal correcting part which corrects the reference signal by feeding back the motion signal to the reference signal estimated by the reference signal estimating part;

a target drive position calculating part which obtains a vibration component from a difference between the vibration detection signal and the corrected reference signal, and obtains, in accordance with the vibration component, a target position to which the vibration reduction mechanism is driven, the vibration component causing the vibration of the image, the vibration mechanism reducing the image vibration according to the vibration component; and

a driving part which controls the vibration reduction mechanism to follow the target position.