Rule-based continuous line classification using shape and positional relationships between objects in piping and instrumentation diagram

Abstract

Recently, the digitization of piping and instrumentation diagrams (P&IDs) has become increasingly necessary in the plant industry. In previous studies on line recognition in P&IDs, lines were classified according to line signs after line detection. However, detailed studies on the classification of continuous lines are limited. Herein, a rule-based method for classifying continuous lines in a P&ID is proposed. This method uses the shape and positional relationships between objects in the P&ID to classify continuous lines into eight types: drain, annotation, spec break, dimension, extension, leader, thick continuous, and continuous line. A prototype system was developed to validate the proposed method, and line classification experiments were conducted on actual high-density industrial P&ID systems. The experimental results indicated that the average precision, recall, and F1 score for the five P&IDs were 96.300%, 97.945%, and 96.415%, respectively. These results indicate the excellent performance of the proposed method in classifying continuous lines for various P&IDs.