Electronic blur correction device and electronic blur correction method

Abstract

A blur correction device is disclosed, which acquires a plurality of time-division images, each captured for a time-division exposure time having a period that is an integral multiple of an image reading cycle of an image pickup device, to generate a blur-corrected image from the plurality of time-division images. According to this blur correction device, since the exposure times for the plurality of time-division images are substantially continuous, an image in which the trajectory of a moving body is continuous can be obtained.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

FIG. 1 is a block diagram showing an electric system of a digital camera according to a preferred embodiment to which the present invention is applied;

FIG. 2 is a diagram showing the structure of an image pickup device 1 of the embodiment;

FIG. 3 is a block diagram showing the details of a gain control amplifier AMP of the embodiment;

FIG. 4 is a flowchart showing a time-division imaging operation of the digital camera of the embodiment;

FIG. 5 is a flowchart showing the operation of computation of time-division imaging control parameters in the digital camera of the embodiment;

FIG. 6 is a flowchart showing a blurred image correction and recording subroutine in the digital camera of the embodiment;

FIG. 7 is a flowchart showing the operation of a blurred image correction subroutine in the digital camera of the embodiment;

FIG. 8 is a timing chart showing a shooting operation of the digital camera of the embodiment;

FIG. 9 is a timing chart showing another shooting operation of the digital camera of the embodiment;

FIG. 10 is a timing chart showing still another shooting operation of the digital camera of the embodiment;

FIG. 11 is a block diagram showing an alternative example of the gain control amplifier AMP in the digital camera of the embodiment; and

FIG. 12 is a table showing the relationship among input signal, ISO sensitivity, and gain in the gain control amplifier AMP of the digital camera of the embodiment.

Claims

1. An electronic blur correction device for generating a combined image from a plurality of time-division images continuously acquired from an image pickup device by performing a time-division imaging where mutual blurring among the plurality of the time-division images is corrected in the combined image, the device comprising: an imaging part for converting subject light to an image signal;an image reading part for reading the time-division images, each captured for a predetermined time-division exposure time, from the imaging part;a time-division exposure time control part for controlling the time-division exposure time to be an integral multiple of the reading cycle of the image reading part;a blur compensation part for compensating for mutual blurring of the plurality of images captured by the imaging part; andan image synthesis part for combining the plurality of images compensated by the blur compensation part.

2. The electronic blur correction device according to claim 1 wherein the time-division exposure time is shorter than a blur tolerable limit exposure time.

3. The electronic blur correction device according to claim 1 further comprising: an exposure time computing part for computing an exposure time (Texp) necessary for obtaining a fixed amount of exposure; andan image amplification part for amplifying the images read by the image reading part,wherein when an amplification factor of the image amplification part is A and the time-division exposure time is ΔTexp, A=Texp/ΔTexp.

4. The electronic blur correction device according to claim 1 further comprising a comparison part for comparing the cycle of reading the time-division images from the image pickup device with a blur tolerable exposure time,wherein when the cycle of reading the time-division images is shorter than the blur tolerable exposure time as a result of comparison by the comparison part, the time-division exposure time control part sets the time-division exposure time to be an integral multiple of the reading cycle.

5. The electronic blur correction device according to claim 4 wherein when the reading cycle of each of the time-division images is Tf, the blur tolerable exposure time is TLimit, and a value obtained by either rounding down or rounding up the fractional part of a real number TLimit/Tf is k, an exposure time ΔTexp for the time-division imaging is set to k×Tf.

6. The electronic blur correction device according to claim 5 further comprising: an exposure time computing part for computing an exposure time (Texp) necessary for obtaining a preferable amount of exposure; andan image amplification part for amplifying the time-division images,wherein an amplification factor A of the image amplification part is set to Texp/ΔTexp.

7. The electronic blur correction device according to claim 6 wherein the time-division imaging is performed m times, where m is a value obtained by either rounding up or rounding down the fractional part of the real number Texp/ΔTexp.

8. An electronic blur correction method comprising: setting a time-division exposure time to be an integral multiple of a reading cycle of an image pickup device, the time-division exposure time being shorter than a blur tolerable limit exposure time;performing a time-division imaging for the time-division exposure time a plurality of times; andgenerating a blur-corrected image using a plurality of images acquired by performing the time-division imaging a plurality of times.