IMAGE CAPTURING APPARATUS, LIGHT METERING METHOD, LUMINANCE CALCULATION METHOD, AND PROGRAM

• US 20080231728A1
• Filed: 03/05/2008
• Published: 09/25/2008
• Est. Priority Date: 03/19/2007
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: ASOMA, Akira
• Granted Patent: US 7,916,209 B2
• Time in Patent Office: Days
• US Class Current: 348/229.1
• CPC Class Codes: G03B 7/093 for control of exposure time
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors

Abstract

An image capturing apparatus includes: an image capturing processing unit capable of selectively performing a normal image capturing process in a normal image capturing mode and a combined image capturing process in a combined image capturing mode, the normal image capturing process being a process of obtaining a single exposure image signal in a unit period and generating captured image data by performing signal processing upon the obtained signal, and the combined image capturing process being a process of obtaining a long-exposure image signal and a short-exposure image signal and generating captured image data by performing signal processing including signal combination upon these obtained signals; a detection unit for performing light metering upon the captured image data; and a control unit for controlling switching between light metering methods used in the detection unit in accordance with an image capturing mode used.

Claims

1. An image capturing apparatus comprising:

an image capturing processing unit capable of selectively performing a normal image capturing process in a normal image capturing mode and a combined image capturing process in a combined image capturing mode, the normal image capturing process being a process of obtaining a single exposure image signal in a unit period and generating captured image data by performing signal processing upon the exposure image signal, and the combined image capturing process being a process of obtaining a long-exposure image signal by exposure for a relatively long period and a short-exposure image signal by exposure for a relatively short period and generating captured image data by performing signal processing including signal combination processing upon the long-exposure image signal and the short-exposure image signal;

a detection unit configured to perform light metering upon the captured image data generated by the image capturing processing unit; and

a control unit configured to control switching between light metering methods used in the detection unit in accordance with an image capturing mode used, the normal image capturing mode or the combined image capturing mode.

2. The image capturing apparatus according to claim 1, wherein the control unit performs exposure control for the image capturing processing unit on the basis of a result of the light metering performed by the detection unit.

3. The image capturing apparatus according to claim 1, wherein, when the normal image capturing process is performed in the normal image capturing mode, the control unit causes the detection unit to use any one of a center-weighted metering method and an evaluative metering method as a light metering method.

4. The image capturing apparatus according to claim 1, wherein, when the combined image capturing process is performed in the combined image capturing mode, the control unit causes the detection unit to use an averaging metering method as a light metering method.

5. The image capturing apparatus according to claim 1, wherein, when it is determined that an instruction for the use of a partial area metering method has been input during performance of the normal image capturing process in the normal image capturing mode or performance of the combined image capturing process in the combined image capturing mode, the control unit causes the detection unit to use the partial area metering method as a light metering method.

6. The image capturing apparatus according to claim 1, wherein, when it is determined that an abnormal condition has been detected during performance of the normal image capturing process in the normal image capturing mode or performance of the combined image capturing process in the combined image capturing mode, the control unit causes the detection unit to use the partial area metering method as a light metering method.

7. A light metering method for an image capturing apparatus capable of selectively performing a normal image capturing process in a normal image capturing mode and a combined image capturing process in a combined image capturing mode, the normal image capturing process being a process of obtaining a single exposure image signal in a unit period and generating captured image data by performing signal processing upon the exposure image signal, and the combined image capturing process being a process of obtaining a long-exposure image signal by exposure for a relatively long period and a short-exposure image signal by exposure for a relatively short period and generating captured image data by performing signal processing including signal combination processing upon the long-exposure image signal and the short-exposure image signal, the light metering method comprising the steps of:

performing light metering upon the captured image data generated by the image capturing processing unit using any one of a center-weighted metering method and an evaluative metering method when the normal image capturing process is performed in the normal image capturing mode; and

performing light metering upon the captured image data generated by the image capturing processing unit using an averaging metering method when the combined image capturing process is performed in the combined image capturing mode.

8. A luminance calculation method for an image capturing apparatus that includes,

an image capturing processing unit capable of selectively performing a normal image capturing process in a normal image capturing mode and a combined image capturing process in a combined image capturing mode, the normal image capturing process being a process of obtaining a single exposure image signal in a unit period and generating captured image data by performing signal processing upon the exposure image signal, and the combined image capturing process being a process of obtaining a long-exposure image signal by exposure for a relatively long period and a short-exposure image signal by exposure for a relatively short period and generating captured image data by performing signal processing including signal combination processing upon the long-exposure image signal and the short-exposure image signal, and

a detection unit configured to perform light metering upon the captured image data generated by the image capturing processing unit, the luminance calculation method comprising the steps of:

controlling switching between light metering methods used in the detection unit in accordance with a image capturing mode used, the normal image capturing mode or the combined image capturing mode; and

receiving a value obtained by light metering performed by the detection unit, and performing computation using the received value on the basis of a light metering method performed in the detection unit to calculate a luminance value per unit area.

9. A program causing a computer to perform a luminance calculation method for an image capturing apparatus that includes,

an image capturing processing unit capable of selectively performing a normal image capturing process in a normal image capturing mode and a combined image capturing process in a combined image capturing mode, the normal image capturing process being a process of obtaining a single exposure image signal in a unit period and generating captured image data by performing signal processing upon the exposure image signal, and the combined image capturing process being a process of obtaining a long-exposure image signal by exposure for a relatively long period and a short-exposure image signal by exposure for a relatively short period and generating captured image data by performing signal processing including signal combination processing upon the long-exposure image signal and the short-exposure image signal, and

a detection unit configured to perform light metering upon the captured image data generated by the image capturing processing unit, the luminance calculation method comprising the steps of:

controlling switching between light metering methods used in the detection unit in accordance with a image capturing mode used, the normal image capturing mode or the combined image capturing mode; and

receiving a value obtained by light metering performed by the detection unit, and performing computation using the received value on the basis of a light metering method performed in the detection unit to calculate a luminance value per unit area.