Image pickup apparatus capable of shooting at high frame rate, control method therefor, and storage medium

• US 9,087,257 B2
• Filed: 08/20/2013
• Issued: 07/21/2015
• Est. Priority Date: 08/20/2012
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kimura, Masafumi
• Primary Examiner(s): Wu, Jingge
• Application Number:
  US13/971,002
• Publication Number:
  US 20140050420A1
• Time in Patent Office: 700 Days
• US Class Current: 1/1
• CPC Class Codes: H04N 23/6845 by combination of a plurality of images sequentially taken
• CPC Class Codes: H04N 23/951 by using two or more images to influence resolution, frame rate or aspect ratio

Abstract

An image pickup apparatus which is capable of obtaining a high-quality image at high speed even when frame rate is high. A frame rate control unit controls frame rate for the shooting. An image decimation unit samples a plurality of images at predetermined time intervals and selects at least two images among the plurality of images as decimation images. A moving vector detection unit detects a moving vector indicative of a moving direction and a moving amount of a subject between the decimation images. A decimation control unit changes decimation conditions according to an absolute value of the moving vector output from the moving vector detection unit. A synthesizing unit aligns the plurality of images based on the output from the moving vector detection unit and then synthesizes the aligned plurality of images to obtain the composite image.

Claims

1. An image processing apparatus that aligns a plurality of images, which are obtained by continuously shooting a subject, and then synthesizes the plurality of images to obtain a composite image, comprising:

an image decimation unit configured to sample the plurality of images at predetermined time intervals and select at least two images among the plurality of images as decimation images;

a moving vector detection unit configured to detect a moving vector, which is indicative of a moving direction and a moving amount of the subject, between the decimation images;

a decimation control unit configured to change decimation conditions, on which said image decimation unit performs the sampling, according to an absolute value of the moving vector which is an output from said moving vector detection unit; and

a synthesizing unit configured to align the plurality of images based on the output from said moving vector detection unit and then synthesize the aligned plurality of images to obtain the composite image.

2. The image processing apparatus according to claim 1, further comprising a pixel decimation unit configured to, when said image decimation unit performs the sampling, decimate a predetermined number of pixel data pieces from the sampled images to reduce the sampled images in size.

3. The image processing apparatus according to claim 1, wherein said decimation control unit changes the decimation conditions when the absolute value of the moving vector is greater than a prescribed value prescribed in advance.

4. The image processing apparatus according to claim 3, wherein said decimation control unit changes the decimation conditions when a time interval in the sampling is greater than a setting value set in advance.

5. The image processing apparatus according to claim 4, wherein said moving vector detection unit discontinues detection of the moving vector for the decimation images when the time interval in the sampling is equal to or smaller than the setting value, and the absolute value of the moving vector is equal to or smaller than the prescribed value.

6. The image processing apparatus according to claim 1, further comprising a buffer unit configured to hold the plurality of images taken by performing shooting for a longer time than an exposure time set in advance.

7. The image processing apparatus according to claim 6, said buffer unit holds images corresponding in number to a power of 2.

8. A control method for an image processing apparatus that aligns a plurality of images, which are obtained by continuously shooting a subject, and then synthesizes the plurality of images to obtain a composite image, comprising:

an image decimation step of sampling the plurality of images at predetermined time intervals and selecting at least two images among the plurality of images as decimation images;

a moving vector detection step of detecting a moving vector, which is indicative of a moving direction and a moving amount of the subject, between the decimation images;

a decimation control step of changing decimation conditions, on which the sampling is performed in said image decimation step, according to an absolute value of the moving vector obtained in said moving vector detection step; and

a synthesizing step of aligning the plurality of images based on the moving vector obtained in said moving vector detection step and then synthesizing the aligned plurality of images to obtain the composite image.

9. A non-transitory computer-readable storage medium storing a control program for use in an image processing apparatus that aligns a plurality of images, which are obtained by continuously shooting a subject, and then synthesizes the plurality of images to obtain a composite image, the control method comprising:

a frame rate control step of controlling frame rate for the shooting;

an image decimation step of sampling the plurality of images at predetermined time intervals and selecting at least two images among the plurality of images as decimation images;

a moving vector detection step of detecting a moving vector, which is indicative of a moving direction and a moving amount of the subject, between the decimation images;

a decimation control step of changing decimation conditions, on which the sampling is performed in the decimation step, according to an absolute value of the moving vector obtained in the moving vector detection step; and

a synthesizing step of aligning the plurality of images based on the moving vector obtained in the moving vector detection step and then synthesizing the aligned plurality of images to obtain the composite image.