Gradient Direction Calculation Device Integer Arithmetic

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Solution Overview

Problem

Conventional gradient direction calculation devices face challenges with increased circuit scale and operation cycle due to the need for floating-point transcendental functions and successive magnitude comparisons.

Innovation Solution

A gradient direction calculation device is configured with an element gradient vector calculation unit, quadrant determination unit, ratio comparison unit, and gradient direction determination unit, which calculates element brightness gradient vectors, determines quadrants, and compares magnitudes to determine gradient directions without requiring floating-point operations, using a lookup table to determine the gradient direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If floating-point transcendental functions and successive magnitude comparisons are used for gradient direction calculation, then calculation accuracy is improved, but circuit scale and operation cycle increase

Engineering Contradiction:

Improvegradient direction calculation accuracyVSAvoidcircuit scale

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex floating-point transcendental function calculations with integer arithmetic operations. Specifically, it uses integer-based gradient magnitude calculations and comparison operations instead of floating-point arctangent computations, thereby reducing circuit complexity while maintaining adequate calculation accuracy for gradient direction determination

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the computational parameters from floating-point values to integer values. By representing gradient magnitudes and directions using integer arithmetic and predefined threshold comparisons, the system achieves the same functional outcome with simpler hardware requirements and reduced operational complexity

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If floating-point transcendental functions and successive magnitude comparisons are used for gradient direction calculation, then calculation accuracy is improved, but operation cycle increases

Engineering Contradiction:

Improvegradient direction calculation accuracyVSAvoidoperation cycle

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent substitutes time-consuming floating-point transcendental function operations with faster integer arithmetic operations. The use of integer-based gradient calculations and direct magnitude comparisons eliminates the computational overhead of floating-point arithmetic, significantly reducing the operation cycle while preserving the essential accuracy needed for gradient direction calculation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary classification of gradient directions into discrete categories (e.g., horizontal, vertical, diagonal) before detailed calculation. By pre-defining threshold ranges and using comparison-based decision logic, the system avoids performing full transcendental function calculations for every pixel, thereby reducing the overall operation cycle

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If conventional gradient direction calculation methods are used, then calculation precision is maintained, but device complexity increases

Engineering Contradiction:

Improvegradient direction precisionVSAvoidcalculation efficiency

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces complex conventional gradient direction calculation methods (using floating-point arctangent functions) with simplified integer arithmetic operations. This substitution maintains sufficient precision for practical gradient direction determination while dramatically improving calculation efficiency and reducing hardware resource requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11074712B2Gradient direction calculation device

Publication Date: 2021.07.27 DENSO CORP

AI summary

In a gradient direction calculation device, an element gradient vector calculation unit calculates two mutually perpendicular element gradient vectors with respect to a pixel of interest by using a difference in pixel values in the vicinity of the pixel of interest. A quadrant determination unit determines, based on a combination of positive/negative signs of each of the two element gradient vectors, a quadrant among the four quadrants defined by the two element gradient vectors that contains a gradient direction of the pixel of interest. A ratio comparison unit determines comparison results by comparing each of the ratios of magnitudes of the two element gradient vectors with a predetermined threshold. A gradient direction determination unit determines a gradient direction corresponding to a combination of the positive/negative signs and the comparison results.