Halftone Frequency Detection via Statistical Thresholding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional methods for halftone frequency detection are computationally complex and require hardware acceleration, leading to increased device size, cost, and power consumption, while failing to efficiently address the needs of different frequency halftones.

Innovation Solution

A threshold-based halftone frequency detection system that uses predefined windows to determine statistical parameters and assign active values to pixels, estimating frequency based on pixel neighborhoods, allowing for software-based implementation without hardware acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional complex techniques (pattern training, image segmentation, gradient estimation, wavelet-based decomposition, MAP probability estimation) are used for higher frequency halftone detection, then detection accuracy is improved, but computational complexity increases and hardware acceleration is required

Engineering Contradiction:
Improvehalftone frequency detection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the approach from complex computational methods to a simpler parameter-based method using pixel intensity statistics (mean, standard deviation, skewness, kurtosis) and threshold comparison. This transforms the detection problem into comparing whether pixel intensities fall above or below calculated thresholds, dramatically reducing computational requirements while maintaining detection accuracy for both low and high frequency halftones

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical/computational processing systems (pattern training, wavelet decomposition, gradient estimation) with a statistical analysis system that uses predefined windows and threshold comparisons. This substitution eliminates the need for hardware acceleration while achieving the same detection goals through software-based statistical methods

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If multiple processors are used to implement conventional halftone detection techniques, then processing capability is improved, but device package size, cost, and power requirements increase

Engineering Contradiction:
Improveprocessing capabilityVSAvoidpower requirements
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent creates a universal detection system that handles both low frequency (below 130 cpi) and high frequency (above 130 cpi) halftones using the same statistical thresholding methodology. This single unified approach eliminates the need for multiple specialized processors that would be required by conventional methods, reducing power consumption, device size, and cost while maintaining high processing capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the essential detection requirement from complex methods and reduces it to a core statistical comparison operation. By taking out only the necessary statistical parameters (mean, standard deviation, skewness, kurtosis) and threshold comparisons, the system achieves high processing capability with minimal computational resources, eliminating the need for multiple processors and their associated power and size requirements

Inventive Principle:
Principle #2Taking out (Extraction)

3Speed

If hardware acceleration is used to meet divergent processing needs of different frequency halftones, then processing speed is improved, but device cost and package size increase

Engineering Contradiction:
Improveprocessing speedVSAvoidhardware requirements
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent performs preliminary calculations of statistical parameters (mean, standard deviation, skewness, kurtosis) and thresholds before the actual detection process. By pre-computing these values using simple formulas based on pixel intensity distributions within predefined windows, the system enables fast real-time detection without requiring hardware acceleration, achieving high speed processing through efficient software-based preliminary analysis

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent substitutes hardware acceleration with a software-based statistical processing system. By replacing the need for specialized hardware processors with efficient software algorithms that compute statistical parameters and perform threshold comparisons, the system achieves high processing speed while eliminating hardware complexity, reducing device cost and package size

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9628635B1Systems and methods for halftone frequency detection
Publication Date: 2017.04.18 XEROX CORP
  • US9628635B1 patent drawing
  • US9628635B1 patent drawing
  • US9628635B1 patent drawing

AI summary

Embodiments of the present disclosure disclose methods and systems for halftone frequency detection in a halftone image. The method includes receiving a first window, a second window, and the halftone image having a predetermined resolution; assigning an active value to a max variable and a min variable associated with each pixel within a first pixel neighborhood defined by the first window based on a pixel intensity value being compared with a three-way threshold set determined based on values a plurality of predetermined statistical parameters; estimating a first frequency estimate and the second frequency estimate based on a number of pixels having active values in the max variable and the min variable respectively within a second pixel neighborhood defined by the second window; and determining the halftone frequency based on the first frequency estimate value, the second frequency estimate value, and the predetermined resolution.