Hand-Drawn Sketch Vectorization Using Deep Learning

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Solution Overview

Problem

Traditional vectorization techniques struggle to distinguish between intentionally drawn lines and noise in hand-drawn sketches, resulting in excessive geometry and unwanted features in digital representations, making the conversion process cumbersome and inefficient.

Innovation Solution

A deep learning-based system that uses a generator-discriminator structure with a residual block architecture and generative adversarial network to transform hand-drawn sketches into clean vector images by removing auxiliary features, preserving only the salient lines and intent of the artist.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional vectorization techniques are used to convert hand-drawn sketches to digital images, then all lines including noise and artefacts are captured, but the resulting vector image contains excessive and unwanted geometry with thousands of Bézier segments

Engineering Contradiction:
Improveline detection accuracyVSAvoidvector image complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the salient features (intentional lines) from the hand-drawn sketch by removing auxiliary features (noise, artefacts, background). The system identifies and isolates the essential geometric information while discarding unnecessary details, resulting in a simplified vector representation that captures the artist's intent without the clutter of drawing imperfections.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the vectorization process into distinct stages: first identifying salient lines versus auxiliary features, then separately processing each category. This segmentation allows the system to apply different treatment to intentional drawing elements versus noise, enabling precise control over which features are preserved and which are eliminated in the final vector image.

Inventive Principle:
Principle #1Segmentation

2Loss of information

If traditional vectorization techniques are used to convert hand-drawn sketches, then complete geometric detail is preserved, but the conversion process becomes cumbersome and inefficient

Engineering Contradiction:
Improvesketch detail preservationVSAvoidconversion efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The system extracts only the essential information (salient lines representing artist intent) while removing redundant information (auxiliary features like noise and artefacts). This extraction approach maintains the critical geometric details needed for accurate representation while eliminating unnecessary data that would otherwise require extensive processing and cleanup.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameters of the vectorization process by introducing intelligence that distinguishes between salient and auxiliary features. Rather than treating all lines equally, the system dynamically adjusts which features are vectorized based on their significance, transforming the conversion from a brute-force capture of all elements to a selective process that prioritizes quality and efficiency.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If traditional vectorization attempts to capture all sketch features, then no information is lost, but the output contains excessive geometry that cannot be simplified

Engineering Contradiction:
Improvesketch feature completenessVSAvoidvector image quality
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The system extracts and preserves only the salient features that constitute the essential artistic intent, while removing auxiliary features that degrade quality. This selective extraction ensures that the most important geometric information is retained while eliminating elements that would otherwise create excessive complexity and reduce overall image quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different quality standards to different parts of the sketch based on their significance. Salient lines receive high-fidelity vectorization with precise geometric representation, while auxiliary features are either removed or simplified. This local differentiation of quality ensures that critical elements maintain manufacturing precision while non-critical elements do not consume excessive resources.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11532173B2Transformation of hand-drawn sketches to digital images
Publication Date: 2022.12.20 ADOBE INC
  • US11532173B2 patent drawing
  • US11532173B2 patent drawing
  • US11532173B2 patent drawing

AI summary

Techniques are disclosed for generating a vector image from a raster image, where the raster image is, for instance, a photographed or scanned version of a hand-drawn sketch. While drawing a sketch, an artist may perform multiple strokes to draw a line, and the resultant raster image may have adjacent or partially overlapping salient and non-salient lines, where the salient lines are representative of the artist's intent, and the non-salient (or auxiliary) lines are formed due to the redundant strokes or otherwise as artefacts of the creation process. The raster image may also include other auxiliary features, such as blemishes, non-white background (e.g., reflecting the canvas on which the hand-sketch was made), and/or uneven lighting. In an example, the vector image is generated to include the salient lines, but not the non-salient lines or other auxiliary features. Thus, the generated vector image is a cleaner version of the raster image.