Dynamic Quantization Parameter Adjustment for Surveillance Image Bitrate Control

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Solution Overview

Problem

Surveillance camera systems face inefficiencies in resource utilization due to inadequate methods for determining quantization parameters, leading to inappropriate bitrate adjustments based on motion area and average bitrate values, resulting in suboptimal image quality and resource consumption.

Innovation Solution

An image capture apparatus determines a quantization parameter correction value based on the size of a motion area and average bitrate, adjusting its range dynamically to optimize bitrate management, ensuring precise adjustment by considering both motion area and bitrate values, thereby improving resource allocation and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a fixed quantization parameter correction value is used, then the device complexity is reduced, but the image quality and bitrate management become suboptimal when motion area changes rapidly

Engineering Contradiction:
Improveimage qualityVSAvoidquantization parameter determination complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment of the quantization parameter correction value based on motion area size. The controller continuously monitors the motion area in the input image and adjusts the correction value accordingly - increasing it when motion area is large and decreasing it when motion area is small. This dynamic approach resolves the contradiction by adapting the quantization parameter to changing scene conditions, thereby improving image quality without requiring overly complex fixed-parameter systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the quantization parameter correction value as a variable parameter based on motion area characteristics. By establishing a relationship between motion area size and the appropriate correction value range, the system optimizes bitrate management and image quality. This parameter change approach allows the system to handle varying scene complexity efficiently, resolving the trade-off between simplicity and performance.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the quantization parameter correction value is adjusted frequently, then the bitrate management precision is improved, but the loss of time for parameter adjustment increases

Engineering Contradiction:
Improvebitrate management precisionVSAvoidparameter adjustment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-defining adjustment ranges for the quantization parameter correction value based on motion area size categories. Instead of calculating optimal values in real-time, the system pre-establishes appropriate correction value ranges for different motion scenarios. This allows rapid selection of appropriate parameters without extensive computation, improving bitrate management precision while minimizing time loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the motion area size and adjusting the quantization parameter correction value based on this information. The controller receives feedback about scene changes and automatically adjusts parameters within pre-defined ranges. This feedback mechanism enables precise bitrate management responsive to actual scene conditions without requiring excessive adjustment time, as the system only modifies parameters when motion area changes are detected.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If a wide adjustment range of quantization parameter correction value is used, then the adaptability to different motion areas is improved, but the loss of information through quantization increases

Engineering Contradiction:
Improveadaptability to motion area sizeVSAvoidimage information loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies local quality by adjusting the quantization parameter correction value specifically for regions with motion based on the detected motion area size. Rather than uniformly applying a wide adjustment range across the entire image, the system tailors the correction value to the local characteristics of motion regions. This selective approach maintains adaptability to different motion scenarios while minimizing information loss in static regions where aggressive quantization is unnecessary.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3293974B1Quantization parameter determination method and image capture apparatus
Publication Date: 2021.07.21 HANWHA VISION CO LTD
  • EP3293974B1 patent drawingFigure 1~2
  • EP3293974B1 patent drawingFigure 3A~3B
  • EP3293974B1 patent drawingFigure 4

AI summary

A method of determining a quantization parameter includes determining an adjustment range of a quantization parameter correction value based on a size of a motion area of an input image, calculating an average bitrate value of the input image, and adjusting the quantization parameter correction value by decreasing the quantization parameter correction value within the adjustment range in response to determining that the average bitrate value is greater than an upper limit value, and by increasing the quantization parameter correction value within the adjustment range in response to determining that the average bitrate value is equal to or less than a lower limit value.