Camera with autofocus function

• US 20060204122A1
• Filed: 02/28/2006
• Published: 09/14/2006
• Est. Priority Date: 03/08/2005
• Status: Active Grant

• Current Assignee: Casio Computer Corporation (Casio Computer Company Limited)
• Original Assignee: Casio Computer Company Limited
• Inventors: Onozawa, Masaru
• Granted Patent: US 7,671,918 B2
• Time in Patent Office: Days
• US Class Current: 382/255
• CPC Class Codes: G02B 7/36 using image sharpness techniques , e.g. image processing techniques for generating autofocus signals image data processing per se G06T; in cameras having a solid state image sensor H04N23/67
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/05 Combinations of cameras with electronic flash units
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming

Abstract

A camera includes a first transfer unit which transfers, in a first transfer time, pixel data of a first pixel range of a plurality of pixel data, a second transfer unit which transfers, in a second transfer time that is shorter than the first transfer time, pixel data of a second pixel range of the plurality of pixel data, a number of pixels of the second pixel range being less than a number of pixels of the first pixel range, a first control unit which causes the first transfer unit to transfer the pixel data, updates a display screen on the basis of the pixel data, and controls the autofocus adjustment, and a second control unit which causes the second transfer unit to transfer the pixel data, interrupts the updating of the display screen while the pixel data is being transferred, and controls the autofocus adjustment.

Claims

1. A camera which executes autofocus adjustment using pixel data acquired from an image capturing device, comprising:

a first transfer unit which transfers, in a first transfer time, pixel data of a first pixel range of a plurality of pixel data that are acquired by exposure of the image capturing device;

a second transfer unit which transfers, in a second transfer time that is shorter than the first transfer time, pixel data of a second pixel range of the plurality of pixel data that are acquired by exposure of the image capturing device, a number of pixels of the second pixel range being less than a number of pixels of the first pixel range;

a first control unit which causes the first transfer unit to successively transfer the pixel data, successively updates a display screen for conformation of a subject on the basis of the pixel data that is successively transferred by the first transfer unit, and controls the autofocus adjustment on the basis of the pixel data that is successively transferred by the first transfer unit;

a second control unit which causes the second transfer unit to successively transfer the pixel data, interrupts the updating of the display screen for the conformation of the subject while the pixel data is being transferred by the second transfer unit, and controls the autofocus adjustment on the basis of the pixel data that is successively transferred by the second transfer unit; and

a control determination unit which determines whether the autofocus adjustment is to be controlled by the first control unit or the second control unit.

2. The camera according to claim 1, wherein the control determination unit comprises:

an exposure time adjusting unit which adjusts an exposure time of the image capturing device;

a determination unit which determines whether the exposure time, which is adjusted by the exposure time adjusting unit, is shorter than a first predetermined time; and

a third control unit which causes the second control unit to execute the operation of the second control unit if the determination unit determines that the exposure time is shorter than the first predetermined time, and causes the first control unit to execute the operation of the first control unit if the determination unit determines that the exposure time is not shorter than the first predetermined time.

3. The camera according to claim 1, further comprising a selection unit which selects one of an operation mode in which the operation by the first control unit is executed and an operation mode in which the operation by the second control unit is executed, in accordance with an instruction by a photographer,

wherein the control determination unit determines whether an operation is to be executed by the control of the first control unit or by the control of the second control unit, in accordance with the operation mode that is selected by the selection unit.

4. The camera according to claim 2, wherein the first predetermined time is set in accordance with one of a transfer time by the first transfer unit and a transfer time by the second transfer unit.

5. The camera according to claim 2, further comprising:

an input unit which inputs designation of the first predetermined time; and

a time setting unit which sets the first predetermined time in accordance with the designation that is input by the input unit.

6. The camera according to claim 1, wherein in the autofocus adjustment, a contrast value of the pixel data is detected when a focusing lens, which is moved, reaches a plurality of positions which are determined under a predetermined condition,

the control determination unit includes a time determination unit which determines whether a movement time of the focusing lens between the respective positions in the autofocus adjustment is shorter than a second predetermined time, which is set in accordance with the transfer time by the first transfer unit or the transfer time by the second transfer unit, and

the control determination unit causes the second control unit to execute the operation of the second control unit if the time determination unit determines that the movement time of the focusing lens is shorter than the second predetermined time, and causes the first control unit to execute the operation of the first control unit if the time determination unit determines that the movement time of the focusing lens is not shorter than the second predetermined time.

7. The camera according to claim 6, wherein the predetermined condition is a detection interval of a contrast value for obtaining a predetermined focus precision.

8. The camera according to claim 6, further comprising a zoom unit which adjusts a zoom magnification,

wherein the time determination unit determines whether the movement time of the focusing lens between the respective positions, which varies in accordance with the zoom magnification adjusted by the zoom unit, is shorter than the second predetermined time, which is set in accordance with the transfer time by the first transfer unit or the transfer time by the second transfer unit.

9. The camera according to claim 1, further comprising:

a third transfer unit which transfers, in a third transfer time that is longer than the first transfer time, pixel data of a third pixel range of the plurality of pixel data that are acquired by the exposure of the image capturing device, a number of pixels of the third pixel range being greater than the number of pixels of the first pixel range; and

a unit which causes, in a state in which the autofocus adjustment is not executed, the third transfer unit to successively transfer the pixel data, and successively updates the display screen for conformation of the subject on the basis of the pixel data that is successively transferred by the third transfer unit.

10. An autofocus control method for a camera which executes autofocus adjustment using pixel data acquired from an image capturing device, comprising:

first transferring pixel data of a first pixel range of a plurality of pixel data that are acquired by exposure of the image capturing device, in a first transfer time;

second transferring pixel data of a second pixel range of the plurality of pixel data that are acquired by exposure of the image capturing device, a number of pixels of the second pixel range being less than a number of pixels of the first pixel range, in a second transfer time that is shorter than the first transfer time;

first controlling to successively transfer the pixel data by the first transfer, to successively update a display screen for conformation of a subject on the basis of the pixel data that is successively transferred by the first transfer, and to perform an operation of the autofocus adjustment on the basis of the pixel data that is successively transferred by the first transfer;

second controlling to successively transfer the pixel data by the second transfer, to interrupt the updating of the display screen for the conformation of the subject while the pixel data is being transferred by the second transfer, and to perform the operation of the autofocus adjustment on the basis of the pixel data that is successively transferred by the second transfer; and

determining whether the operation of the autofocus adjustment is to be controlled by the first control or the second control.