  The industry 4.0 is leveraging digital technologies and machine learning
techniques to connect and optimize manufacturing processes. Central to this
idea is the ability to transform raw data into human understandable knowledge
for reliable data-driven decision-making. Convolutional Neural Networks (CNNs)
have been instrumental in processing image data, yet, their ``black box''
nature complicates the understanding of their prediction process. In this
context, recent advances in the field of eXplainable Artificial Intelligence
(XAI) have proposed the extraction and localization of concepts, or which
visual cues intervene on the prediction process of CNNs. This paper tackles the
application of concept extraction (CE) methods to industry 4.0 scenarios. To
this end, we modify a recently developed technique, ``Extracting Concepts with
Local Aggregated Descriptors'' (ECLAD), improving its scalability.
Specifically, we propose a novel procedure for calculating concept importance,
utilizing a wrapper function designed for CNNs. This process is aimed at
decreasing the number of times each image needs to be evaluated. Subsequently,
we demonstrate the potential of CE methods, by applying them in three
industrial use cases. We selected three representative use cases in the context
of quality control for material design (tailored textiles), manufacturing
(carbon fiber reinforcement), and maintenance (photovoltaic module inspection).
In these examples, CE was able to successfully extract and locate concepts
directly related to each task. This is, the visual cues related to each
concept, coincided with what human experts would use to perform the task
themselves, even when the visual cues were entangled between multiple classes.
Through empirical results, we show that CE can be applied for understanding
CNNs in an industrial context, giving useful insights that can relate to domain
knowledge.
