MOTION DETECTION APPARATUS

• US 20090244297A1
• Filed: 03/26/2009
• Published: 10/01/2009
• Est. Priority Date: 03/26/2008
• Status: Active Grant

• Current Assignee: Xacti Corporation (Office Support KK)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Toba, Akira
• Granted Patent: US 8,125,527 B2
• Time in Patent Office: Days
• US Class Current: 348/208.100
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal

Abstract

A motion detection apparatus includes a CPU. The CPU detects partial motion vectors of an object scene corresponding to motion detection blocks based on raw image data. The CPU also reduces a weighted amount allocated to a motion detection block which captures a partial object scene having a contrast below a reference out of the motion detection blocks. Furthermore, the CPU performs a weighted average process referring to the weighted amount on the partial motion vectors so as to detect a motion of the entire object scene. The CPU obtains a minimum correlation value of a luminance difference between frames of the raw image data corresponding to each of the motion detection blocks, and executes a process for increasing the reference according to an increase of the obtained minimum correlation value corresponding to the motion detection block which captures the partial object scene having a contrast below the reference.

Claims

1. A motion detection apparatus, comprising:

a first detector for detecting a motion of a partial object scene captured in each of a plurality of blocks allocated to an object scene based on image data repeatedly outputted from an imager;

a reducer for reducing a weighted amount allocated to a block in which a partial object scene having a contrast below a reference is captured, out of a plurality of weighted amounts respectively allocated to the plurality of blocks;

a second detector for detecting a motion of the entire object scene by performing a weighted average process in which the plurality of weighted amounts are referenced on the motion detected by said first detector;

a fist obtainer for repeatedly obtaining a minimum correlation value of a luminance difference between screens of the image data outputted from said imager, corresponding to each of the plurality of blocks; and

an increaser for executing a process for increasing the reference according to an increase of the minimum correlation value obtained by said first obtainer, corresponding to the block in which the partial object scene having the contrast below the reference is captured.

2. A motion detection apparatus according to claim 1, further comprising a second obtainer for repeatedly obtaining an average correlation value of a luminance difference between screens of image data outputted from said imager, corresponding to each of the plurality of blocks, wherein said reducer includes a comparator for comparing the average correlation value obtained by said second obtainer with the reference so as to determine the contrast.

3. A motion detection apparatus according to claim 1, further comprising an extractor for extracting one portion of the image data outputted from said imager so that a motion detected by said second detector is compensated.

4. A motion detection apparatus according to claim 3, wherein said extractor includes:

a writer for writing the image data outputted from said imager into a memory;

a reader for reading out one portion of image data belonging to an extraction area, out of the image data accommodated in said memory by writer; and

a changer for changing a position of the extraction area so that the motion detected by said second detector is compensated.

5. A motion detection apparatus according to claim 1, further comprising a starter for starting said increaser corresponding to the block in which an object having a motion amount below a threshold value is captured.

6. A motion detection apparatus according to claim 1, further comprising an initializer for initializing the reference increased by said increaser after an elapse of a designated period.

7. A motion detection apparatus according to claim 1, wherein each of the plurality of blocks includes a plurality of minute blocks, said motion detection apparatus further comprising a difference calculator for calculating, as a correlation value, a difference between a representative pixel value in image data of a previous screen and each of a plurality of pixel values in image data of a current screen, for each minute block.

8. A motion detection program product executed by a processor of a motion detection apparatus, comprising:

a first detecting step of detecting a motion of a partial object scene captured in each of a plurality of blocks allocated to an object scene based on image data repeatedly outputted from an imager;

a reducing step of reducing a weighted amount allocated to a block in which a partial object scene having a contrast below a reference is captured, out of a plurality of weighted amounts respectively allocated to the plurality of blocks;

a second detecting step of detecting a motion of the entire object scene by performing a weighted average process in which the plurality of weighted amounts are referenced on the motion detected in said first detecting step;

an acquiring step of repeatedly acquiring a minimum correlation value of a luminance difference between screens of image data outputted from said imager, corresponding to each of the plurality of blocks; and

an increasing step of executing a process for increasing the reference according to an increase of the minimum correlation value obtained in said acquiring step, corresponding to the block in which the partial object scene having the contrast below the reference is captured.

9. A motion detection method executed by a motion detection apparatus, comprising:

a first detecting step of detecting a motion of a partial object scene captured in each of a plurality of blocks allocated to an object scene based on image data repeatedly outputted from an imager;

a reducing step of reducing a weighted amount allocated to the block in which a partial object scene having a contrast below a reference is captured, out of a plurality of weighted amounts respectively allocated to the plurality of blocks;

a second detecting step of detecting a motion of the entire object scene by performing a weighted average process in which the plurality of weighted amounts are referenced on the motion detected in said first detecting step;

an acquiring step of repeatedly acquiring a minimum correlation value of a luminance difference between screens of image data outputted from said imager, corresponding to each of the plurality of blocks; and

an increasing step of executing a process for increasing the reference according to an increase of the minimum correlation value obtained in said acquiring step, corresponding to the block in which the partial object scene having the contrast below the reference is captured.