JP2012255896A5

JP2012255896A5 -

Info

Publication number: JP2012255896A5
Application number: JP2011128551A
Authority: JP
Filing date: 2011-06-08
Publication date: 2014-07-17
Anticipated expiration: 2031-06-08

Description

本発明は、被写体を撮像することによって撮像部により取得される撮像信号に基づいてフォーカスレンズの位置を制御する撮像装置であって、前記撮像信号より特定の周波数成分を抽出して焦点信号を生成する焦点信号生成手段と、前記撮像信号の異なる周波数成分からそれぞれ生成された複数の前記焦点信号を用いて、合焦の程度を示す合焦度を算出する合焦度算出手段と、前記焦点信号の所定期間毎の変化量を用いて、合焦位置に対する前記フォーカスレンズの位置の近傍度合いを判定する判定手段と、前記合焦度算出手段により算出される合焦度および前記判定手段による判定結果に基づいて、前記フォーカスレンズの駆動速度を設定するフォーカス速度設定手段と、を有することを特徴とする。 The present invention is an imaging device that controls the position of a focus lens based on an imaging signal acquired by an imaging unit by imaging a subject, and generates a focus signal by extracting a specific frequency component from the imaging signal A focus signal generation unit that calculates a focus degree indicating a degree of focus using the plurality of focus signals respectively generated from different frequency components of the imaging signal, and the focus signal. Determining means for determining the degree of proximity of the position of the focus lens with respect to the in-focus position using the change amount for each predetermined period, the degree of focus calculated by the focus degree calculating means, and the determination result by the determining means based on, and having a focus speed setting means for setting the driving speed of the focus lens.

Claims

An imaging device that controls the position of a focus lens based on an imaging signal acquired by an imaging unit by imaging a subject,
Focus signal generating means for generating a focus signal by extracting a specific frequency component from the imaging signal;
A degree-of-focus calculation means for calculating a degree of focus indicating a degree of focus using a plurality of the focus signals respectively generated from different frequency components of the imaging signal ;
Determination means for determining the degree of proximity of the position of the focus lens with respect to the in-focus position using a change amount of the focus signal for each predetermined period;
The focus degree based on a determination result by the focus degree and the determination means is calculated by the calculation means, imaging apparatus characterized by having a focus speed setting means for setting the driving speed of the focus lens.

Having an exposure condition detection means for detecting an exposure condition when imaging a subject;
The focus speed setting means, in accordance with the exposure conditions detected by the exposure condition detection means, and the criteria used for setting the driving speed of the focus lens of the determination result by said determining means and said focusing degree The imaging apparatus according to claim 1, wherein the priority order is changed .

Having an exposure condition detection means for detecting an exposure condition when imaging a subject;
The focus speed setting means determines whether or not to use the degree of focus for setting the driving speed of the focus lens according to the exposure condition detected by the exposure condition detection means. The imaging apparatus according to 1.

When the exposure condition detected by the exposure condition detection unit is the first exposure condition, the focus speed setting unit uses the focus degree to drive the focus lens according to the determination result by the determination unit. Set
4. The focus speed setting means sets the drive speed of the focus lens without using the degree of focus in the case of a second exposure condition with lower illuminance than the first exposure condition. The imaging device described in 1.

In the first exposure condition,
When it is determined by the determination means that the focus lens is in the first region near the in-focus state, the focus speed setting means sets the drive speed of the focus lens to the first speed,
When it is determined by the determination means that the focus lens is in a second area farther from the focus position than the first area, the focus speed setting means drives the focus lens according to the degree of focus. The imaging apparatus according to claim 4, wherein a speed is set.

The focus speed setting means sets the drive speed of the focus lens so that the higher the focus degree, the lower the speed of the focus lens when setting the drive speed of the focus lens according to the focus degree. The imaging device according to claim 5.

In the first exposure condition, when the determination unit determines that the focus lens is in a third region farther from the in-focus position than the second region, the focus speed setting unit includes: The imaging apparatus according to claim 5, wherein the driving speed is set to a second speed that is lower than the first speed.

In the second exposure condition, the focus speed setting unit is a region farther from the focus position than the predetermined region when the determination unit determines that the focus lens is in a predetermined region near the focus. 8. The imaging apparatus according to claim 4, wherein the driving speed of the focus lens is set so as to be lower than that in the case where it is determined to be in the range.

9. The exposure condition detection unit according to claim 3, wherein the exposure condition detection unit detects an exposure condition in accordance with a gain amount for controlling a level of the imaging signal or a luminance of a subject. Imaging device.

The focus degree calculating means normalizes a first focus signal based on a first frequency component of the imaging signal using a second focus signal based on a second frequency component lower than the first frequency . by imaging apparatus according to any one of claims 1 to 9, and calculates the focus level.

The imaging device according to claim 10, wherein the determination unit determines a proximity degree of the position of the focus lens with respect to a focus position using a change amount of the second focus signal for each predetermined period. .

The determination means obtains a first derivative output and a second derivative output of the focus signal , and determines a degree of proximity of the position of the focus lens with respect to a focus position based on a change in each derivative output. The imaging device according to any one of claims 1 to 11.

In the first control for controlling the focus lens to drive in a direction in which the focus signal increases, the focus speed setting unit drives the focus lens based on the degree of focus and the determination result by the determination unit. The imaging apparatus according to any one of claims 1 to 12, wherein a speed is set.

In the first control, when the drive speed is set to 0 by the focus speed setting means , a second control for determining the in-focus direction based on the focus signal obtained by intermittently moving the focus lens. The imaging apparatus according to claim 13 , further comprising a switching unit that switches between the two.

A focus adjustment method for an imaging apparatus that controls the position of a focus lens based on an imaging signal acquired by an imaging unit by imaging a subject,
A focus signal generation step of generating a focus signal by extracting a specific frequency component from the imaging signal;
A focus degree calculating step of calculating a focus degree indicating a degree of focus using a plurality of the focus signals respectively generated from different frequency components of the imaging signal ;
A determination step of determining the degree of proximity of the position of the focus lens with respect to the in-focus position using a change amount of the focus signal for each predetermined period;
The focusing degree calculated based on the determination result by the focus degree and the determination step is calculated in step, the focus adjustment method characterized by having a focus speed setting step of setting the driving speed of the focus lens.

A program for focus adjustment of an imaging device that controls the position of a focus lens based on an imaging signal acquired by an imaging unit by imaging a subject,
A focus signal generation step of generating a focus signal by extracting a specific frequency component from the imaging signal;
A focus degree calculating step of calculating a focus degree indicating a degree of focus using a plurality of the focus signals respectively generated from different frequency components of the imaging signal ;
A determination step of determining the degree of proximity of the position of the focus lens with respect to the in-focus position using a change amount of the focus signal for each predetermined period;
On the basis of the determination result obtained by the focus degree and the determination step is calculated by the focus level calculation step, a program for executing the focus speed setting step for setting the driving speed of the focus lens, to the computer.