Image sensing apparatus and its control method

• US 20050046738A1
• Filed: 08/24/2004
• Published: 03/03/2005
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sato, Keiji
• Granted Patent: US 7,436,451 B2
• Time in Patent Office: Days
• US Class Current: 348/362
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation

Abstract

An image sensing apparatus in which time required before the apparatus becomes in an image-sensing possible status is reduced. The image sensing apparatus has a constituent element comprising a first image sensing unit as a main unit and a constituent element comprising a second image sensing unit as a sub unit, having a structure more simple than that of the first image sensing device. An aperture amount in an initial stage of an aperture unit when the first image sensing unit is enabled to perform image sensing is determined based on a light amount detected by a light amount detector in the second image sensing unit and an F value of the first image sensing unit.

Claims

1. An image sensing apparatus having first image sensing unit as a main unit and a second image sensing unit as a sub unit, comprising:

a light amount detection unit, provided in said second image sensing unit, to detect a light amount; and

an initial light amount determination unit to determine an aperture amount to control light amount in an initial stage of an image sensing mode by said first image sensing unit, based on information on the light amount detected by said light amount detection unit,

wherein said first image sensing unit is set with the aperture amount determined by said initial light amount determination unit, thereby said apparatus enters an image-sensing possible status.

2. The image sensing apparatus according to claim 1, wherein said second image sensing unit is provided in a direction different from an image sensing direction of said first image sensing unit.

3. The image sensing apparatus according to claim 2, wherein said second image sensing unit is provided in a display panel of said image sensing apparatus.

4. The image sensing apparatus according to claim 1, further comprising a display panel to display an image obtained by said first image sensing unit and an image obtained by said second image sensing unit.

5. The image sensing apparatus according to claim 4, wherein the image obtained by said second image sensing unit is combined in the image obtained by said first image sensing unit.

6. The image sensing apparatus according to claim 1, wherein if said light amount detection unit of said second image sensing unit does not function, said first image sensing unit determines an automatic exposure (AE) initial aperture amount based on a light amount obtained by an image sensing device of said first image sensing unit.

7. The image sensing apparatus according to claim 1, wherein said initial light amount determination unit determines the aperture amount in the initial stage of the image sensing mode by said first image sensing unit while detection of defective pixel is performed in said first image sensing unit.

8. The image sensing apparatus according to claim 1, wherein the timing of transition from an image-sensing impossible status to the image-sensing possible status in said second image sensing unit is earlier than that in said first image sensing unit.

9. The image sensing apparatus according to claim 1, further comprising a first aperture unit to control the amount of light outputted from said first image sensing unit and a second aperture unit to control the amount of light outputted from said second image sensing unit.

10. A control method for an image sensing apparatus having first image sensing unit as a main unit and a second image sensing unit as a sub unit, comprising:

a detection step of detecting a light amount of light incident from said second image sensing unit by using light amount detection unit provided in said second image sensing unit; and

an initial light amount determination step of determining an aperture amount to control light amount. in an initial stage of image sensing mode by said first image sensing unit, based on information on the light amount detected at said detection step,

wherein said first image sensing unit is set with the aperture amount determined at said initial light amount determination step, thereby said apparatus enters an image-sensing possible status.

11. An image sensing apparatus having image sensing unit, a display panel to display an image signal obtained by said image sensing unit as a video signal, and recording unit to record said video signal on a predetermined recording medium, comprising:

a light amount detection unit, provided independently of said image sensing unit, to detect a light amount and

an initial light amount determination unit to determine an aperture amount to control light amount in an initial stage of image sensing mode by said image sensing unit, based on information on the light amount detected by said light amount detection unit,

wherein said first image sensing unit is set with the aperture amount determined by said initial light amount determination unit, thereby said apparatus enters an image-sensing possible status.

12. A control method for an image sensing apparatus having image sensing unit, a display panel to display an image signal obtained by said image sensing unit as a video signal, and recording unit to record said video signal on a predetermined recording medium, comprising:

a detection step of detecting brightness of an environment where said apparatus exists by a light amount detection unit provided independently of said image sensing unit; and

an initial light amount determination step of determining an aperture amount to control light amount in an initial stage of an image sensing mode by said image sensing unit, based on information on the brightness detected at said detection step,

wherein said image sensing unit is set with the aperture amount determined at said initial light amount determination step, thereby said apparatus enters an image-sensing possible status.