Vector Line Drawing Network for Rough Raster Images

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vectorization software require clean line drawings on a white background, making it tedious to convert rough raster images directly into vector line drawings, often necessitating a two-step process of cleaning and then vectorizing, which is inefficient and difficult to automate.

Innovation Solution

A machine learning-based model using a recurrent neural network (RNN) trained end-to-end to convert rough raster images directly into vector line drawings, generating strokes stroke by stroke with a dynamic drawing window that moves and scales across the image, allowing for direct conversion without prior cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If existing vectorization software is used to convert raster images to vector line drawings, then the conversion can be performed, but the input raster images must be clean line drawings on a white background, requiring a two-step process of cleaning and then vectorizing

Engineering Contradiction:
Improveease of conversionVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the image cleaning function and vectorization function into a single integrated system. The neural network simultaneously performs denoising, background removal, and vector line drawing generation in one end-to-end process, eliminating the need for separate cleaning and vectorizing steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The vectorization system is designed to handle multiple types of input images (clean line drawings, rough sketches, photographs) and performs multiple functions (cleaning, vectorization) within a single model, making it universally applicable without requiring preprocessing for different input types.

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

2Manufacturing precision

If a two-step process of cleaning and then vectorizing is used, then accurate vector line drawings can be obtained, but the process becomes tedious and difficult to automate

Engineering Contradiction:
Improveaccuracy of vector line drawingVSAvoidoperational simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system performs preliminary cleaning actions automatically as part of the vectorization process. The neural network inherently handles denoising and background removal during training and inference, so no separate preliminary cleaning step is needed by the user.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The vectorization system is self-sufficient and automatically handles all preprocessing and conversion tasks without requiring user intervention for image cleaning. The model autonomously processes rough sketches and photographs directly into vector line drawings.

Inventive Principle:
Principle #25Self-service

3Productivity

If rough raster images are converted directly to vector line drawings without cleaning, then computational efficiency is improved, but the accuracy and quality of the vector output may deteriorate

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidquality of vector output
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces traditional mechanical image processing methods (filtering, thresholding, manual cleaning) with a neural network-based system. The deep learning model automatically learns to clean and vectorize images through end-to-end training, achieving both efficiency and quality without manual preprocessing.

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

Solution Approach 2:

The system changes the approach from sequential processing (cleaning then vectorizing) to simultaneous processing through end-to-end training. The loss function combines both cleaning accuracy and vectorization quality metrics, allowing the model to optimize both objectives together during training.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11928759B2Methods and devices for vector line drawing
Publication Date: 2024.03.12 HUAWEI TECH CO LTD
  • US11928759B2 patent drawing
  • US11928759B2 patent drawing
  • US11928759B2 patent drawing

AI summary

The present disclosure describes methods and devices for generating a vector line drawing. A vector line drawing network may include a machine learning-based model that is trained to convert a raster image to a vector line drawing directly. The vector line drawing network may be trained end-to-end, using supervised learning, where only raster images are used as training data. A vector line drawing is generated stroke by stroke, over a series of time steps. In each time step, a dynamic drawing window is moved and scaled across the input raster image to sample a patch of the raster image, and a drawing stroke is predicted to draw a stroke in a corresponding patch in the canvas for the vector line drawing. The image patches are pasted in the canvas to assemble a final vector line drawing that corresponds to the input raster image.