Digital image processing method for evaluation of discoloration on fair-faced concrete surfaces

摘要

In the case of fair-faced concrete surfaces the architect is responsible for defining the aesthetical requirements, the applicable examination methods and the conformity criterias. The surface quality can be defined by using the national or international standards and guidelines or by setting up specific evaluation aspects and methods. However, regarding the variety of these surfaces, the assessment can be very subjective in some cases and depends on the culture of the given country, especially when considering the discoloration. This paper presents an evaluation method for discoloration of the fair-faced concrete surfaces using digital image processing techniques. The program was written in Python, as a part of a more extensive project including further evaluation aspects of these surfaces. The method was tested on 24 concrete surfaces. Results show, that the changes in concrete composition or in the dimensions of the sample can be observed in the colour tone of the surface, however the automatic method should be supported by subjective evaluation to get the right classification.