Image Processing Apparatus for Stationary Subject Detection

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Solution Overview

Problem

Conventional subject detection methods, such as the background difference method, face challenges in accurately and efficiently detecting subjects, especially when the subject remains stationary for a period, leading to false detection of background changes and widened search ranges, which hampers rapid detection.

Innovation Solution

An image processing apparatus that calculates differences between input video data and a background model, updates the model based on appearance information, and selectively updates the standard model to maintain accurate background representation, thereby reducing false positives and narrowing the detection search range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the background difference method is used to detect moving objects, then the detection can be performed based on feature quantity differences, but when a subject remains stationary for a predetermined time, the background features are forgotten from the standard model, causing false detection of background changes and widened search ranges

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies local quality by differentiating between foreground and background regions based on spatial location and temporal characteristics. The determination device analyzes local feature quantities in specific regions (detection windows) and compares them with standard models for both foreground and background, allowing accurate identification of stationary subjects without false detection of background changes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the standard model adaptive and updateable. The update device dynamically adjusts the standard model based on detected subject movements and background changes, allowing the system to respond to temporal variations in the scene while maintaining accurate detection of stationary objects.

Inventive Principle:
Principle #15Dynamics

2Reliability

If subject detection is performed by scanning detection windows in the entire image, then comprehensive coverage is achieved, but processing costs become very expensive

Engineering Contradiction:
Improvedetection completenessVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the image into multiple detection windows and systematically processing only the relevant portions. The determination device scans detection windows in a structured manner, and the update device selectively updates only the standard model regions affected by detected subjects, reducing overall processing requirements while maintaining detection completeness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by performing subject detection only in regions where background differences indicate potential subjects. The determination device identifies candidate regions based on feature quantity comparisons, and subsequent processing is concentrated only on these partial regions rather than the entire image, significantly reducing processing costs.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the search range for subject detection is narrowed based on background difference, then processing efficiency improves, but when a subject is stationary, the background difference causes the search range to be inappropriately widened

Engineering Contradiction:
Improvedetection speedVSAvoidsearch range accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies feedback by continuously monitoring detected subject positions and using this information to refine the standard model. The update device receives feedback from the detection device about stationary subjects and adjusts the standard model accordingly, preventing future false detection of background changes and ensuring accurate search range narrowing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements preliminary action by pre-processing the image to identify potential subject regions before performing detailed subject detection. The determination device preliminarily compares feature quantities and identifies candidate areas, allowing the subsequent subject detection to focus only on these pre-identified regions with appropriate search range control.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS8818096B2Apparatus and method for detecting subject from image
Publication Date: 2014.08.26 CANON KK
  • US8818096B2 patent drawing
  • US8818096B2 patent drawing
  • US8818096B2 patent drawing

AI summary

An image processing apparatus includes a calculation unit configured to calculate a difference between a feature quantity of input video data and a feature quantity of a model representing a background, a determination unit configured to determine whether a partial area in the input video data is a foreground or a background based on the difference, a detection unit configured to detect a subject area from an area determined to be a foreground, a first update unit configured to update appearance information that represents an appearance state of a background relating to the subject area, and a second update unit configured to update the model based on the appearance information.