Imaging apparatus having selection unit to select focus detection areas

• US 8,712,101 B2
• Filed: 02/13/2013
• Issued: 04/29/2014
• Est. Priority Date: 07/04/2007
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Muramatsu, Keiko
• Primary Examiner(s): DRENNAN, BARRY T
• Application Number:
  US13/766,741
• Publication Number:
  US 20130155287A1
• Time in Patent Office: 440 Days
• Field of Search: None
• US Class Current: 382/103
• CPC Class Codes: G06F 18/214 Generating training patterns; Bootstrap methods, e.g. bagging or boosting
• CPC Class Codes: G06F 18/24323 Tree-organised classifiers
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 7/248 involving reference images or patches
• CPC Class Codes: G06V 10/764 using classification, e.g. of video objects
• CPC Class Codes: G06V 10/774 Generating sets of training patterns; Bootstrap methods, e.g. bagging or boosting
• CPC Class Codes: H04N 23/61 based on recognised objects
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body
• CPC Class Codes: H04N 23/675 comprising setting of focusing regions
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements

Abstract

An imaging apparatus includes a first imaging unit, a second imaging unit, a light measurement calculator, a holding unit, a detection unit, a recognition unit, a selection unit, and a focus adjustment controller. The second imaging unit is configured to acquire first image information, second image information, and third image information. The selection unit is configured to select the at least one of focus detection areas using a recognition result of the recognition unit. The focus adjustment controller is connected to the selection unit and is configured to perform a focus adjustment control using a focus adjustment state in a focus detection area selected by the selection unit. The changing unit is connected to the recognition unit and is configured to change the predetermined range based on the first determination and the second determination.

Claims

1. An imaging apparatus comprising:

a first imaging unit configured to acquire first image information to be stored;

a second imaging unit configured to repeatedly acquire second image information different from the first image information;

a light measurement calculator configured to perform a light measurement calculation using the second image information;

a holding unit configured to hold reference information that functions as a reference image;

a difference calculator configured to repeatedly calculate a difference between the second image information repeatedly output from the second imaging unit and the reference information held by the holding unit;

a first determining unit configured to repeatedly determine whether the difference calculated by the difference calculator is greater than or equal to a first threshold value;

a second determining unit configured to determine whether the first determining unit determines that the difference is greater than or equal to the first threshold value continuously at a number of times which is greater than or equal to a second threshold value;

a third determining unit configured to determine whether the first determining unit determines that the difference is neither greater than nor equal to the first threshold value continuously at a number of times which is greater than or equal to a third threshold value;

a threshold changing unit configured to increase the first threshold value if the second determining unit determines that the first determining unit determines that the difference is greater than or equal to the first threshold value continuously at a number of times which is greater than or equal to the second threshold value, the threshold changing unit being configured to decrease the first threshold value if the third determining unit determines that the first determining unit determines that the difference is neither greater than nor equal to the first threshold value continuously at a number of times which is greater than or equal to the third threshold value;

a recognition unit configured to recognize a position corresponding to the reference information in the second image information repeatedly output from the second imaging unit;

a selection unit configured to select at least one of focus detection areas using a recognition result of the recognition unit if the first determining unit determines that the difference is neither greater than nor equal to the first threshold value, the selection unit being configured to select at least one of the focus detection areas without using the recognition result of the recognition unit if the first determining unit determines that the difference is greater than or equal to the first threshold value; and

a reference-information updating unit configured to change a degree of change of the reference information in accordance with the difference.

2. The imaging apparatus according to claim 1,

wherein the reference-information updating unit updates the reference information if the first determining unit determines that the difference is neither greater than nor equal to the first threshold value, and

wherein the reference-information updating unit does not update the reference information if the first determining unit determines that the difference is greater than or equal to the first threshold value.

3. The imaging apparatus according to claim 2,

wherein the reference-information updating unit is configured to update the reference information using

at least part of the second image information acquired when the first determining unit determines that the difference is neither greater than nor equal to the first threshold value, and

a latest reference information prior to being updated.

4. The imaging apparatus according to claim 3,

wherein the reference-information updating unit is configured to assign greater weight to the latest reference information than to the at least part of the second image information acquired when the first determining unit determines that the difference is neither greater than nor equal to the first threshold value.

5. The imaging apparatus according to claim 1,

wherein the difference calculator is configured to calculate differential values between the reference information and respective areas defined in a searching range and is configured to set a smallest differential value among the differential values as the difference.

6. The imaging apparatus according to claim 1,

wherein the difference calculator is configured to calculate the difference using color information.

7. An imaging apparatus comprising:

a first imaging unit configured to acquire first image information to be stored;

a second imaging unit configured to repeatedly acquire second image information different from the first image information;

a light measurement calculator configured to perform a light measurement calculation using the second image information;

a holding unit configured to hold reference information that functions as a reference image;

a difference calculator configured to repeatedly calculate a difference between the second image information repeatedly output from the second imaging unit and the reference information held by the holding unit;

a first determining unit configured to repeatedly determine whether the difference calculated by the difference calculator is greater than or equal to a first threshold value;

a recognition unit configured to recognize a position corresponding to the reference information in the second image information repeatedly output from the second imaging unit;

a selection unit configured to select at least one of focus detection areas using a recognition result of the recognition unit if the first determining unit determines that the difference is neither greater than nor equal to the first threshold value, the selection unit being configured to select at least one of the focus detection areas without using the recognition result of the recognition unit if the first determining unit determines that the difference is greater than or equal to the first threshold value; and

a reference-information updating unit configured to change a degree of change of the reference information in accordance with the difference.