Part 1 : The Limitations of Traditional OCR in Processing Technical Drawings
Introduction
Technical drawings are the foundation of communication in the engineering world. However, extracting data from these drawings has always been a challenge. The machine building industry has long sought technology solutions to automate data extraction from Technical Drawings. The only option up to this point has been using OCR (Optical Character Recognition), such as Google Vision or Amazon Textract. These methods often fall short when faced with the complexity of technical drawings.
In this first part of our series, we’ll explore why OCR struggles with technical drawings and why a more advanced solution is needed to meet the demands of modern engineering.
Why OCR Fails with Technical Drawings
OCR has been widely used for extracting text from documents, but it was never designed to handle the unique challenges of technical drawings. Here are the key reasons why OCR falls short:
Fragmented Text and Complex Data Formats
The biggest challenge for machines while reading Technical Drawings is to understand the meaning of individual text elements and know when and how to group them into structured data format. OCR can only read the text but cannot understand the meaning of its own result.
Technical drawings often feature complex data formats and fragmented text, such as Measure and GD&T. Measure is often presented as a Nominal Size with the Upper and Lower Deviation stacked on top of each other. OCR reads text linearly so it can only extract text from left to right and is not capable of distinguishing which text is Nominal Size, Upper Deviation or Lower Deviation. It also makes numerous mistakes in grouping corresponding elements due to complex visual surroundings, thus, making it incapable of understanding these relationships.
Another Example is the Title Block, where captions (the small text describing what the content is about) such as “Designation”, “Drawing ID”, “Company” are commonly missing. This makes OCR results useless, because the computer does not understand if the text is Designation, Drawing ID or company details.
Multiple Ways of Expressing the Same Idea
Often, technical drawings have the same idea expressed in different ways. For example, SM1, CH45, and 1x45deg all mean the same: a Chamfer of length 1 and 45deg angle. On the other hand, the same word could refer to different things, such as CH45, which could mean a chamfer or a material. OCR would be unable to help in either of these situations.
Context Awareness
OCR can often fail in differentiating numbers or characters that look alike, such as “1”, “7”and “I”, “0” and “O” or “6” and “8”. This makes OCR an unreliable option in processing Technical Drawings in practice.
Special Symbols and Annotations
Symbols like "Ø" (diameter) or "±" (tolerance) are common in technical drawings but are often misinterpreted or ignored by OCR due to different font, leading to unreliable results. Similarly, GD&T (Geometric Dimensioning and Tolerancing) symbols are beyond OCR’s capabilities.
Multiple Orientations
Unlike standard documents, technical drawings contain text in various orientations—horizontal, vertical, or even tilted. OCR struggles to process these variations, leading to incomplete or inaccurate results.
Complex Graphics
Technical drawings are filled with intersecting lines, annotations, and other visual elements that confuse OCR systems, which require a dominant orientation from the document, resulting in errors or missed data.
The Need for a Smarter Solution
The limitations of OCR create inefficiencies, errors, and missed opportunities for businesses relying on technical drawings. To truly unlock the potential of technical drawings, a solution that understands the context, structure, and meaning of the data is essential.
Werk24’s AI-powered TechRead API is that solution. Werk24 stands at the frontier of this AI-driven data revolution in the manufacturing sector, allowing you to effortlessly extract essential manufacturing data from technical drawings.
What’s Next?
In the next part of this series, we’ll dive into how Werk24’s advanced AI technology goes beyond OCR to revolutionize data extraction from technical drawings. Stay tuned for Part 2. In the meantime, explore how Werk24 is already helping businesses streamline their processes with cutting-edge AI solutions.
Contact our experts now to find out how Werk24 can make a difference to your business!