Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Image-based recognition of surgical instruments by means of convolutional neural networks
    ( 2023)
    Lehr, Jan
    ;
    Kelterborn, Kathrin
    ;
    Briese, Clemens
    ;
    Schlueter, Marian
    ;
    Kroeger, Ole
    ;
    Krüger, Jörg
    Purpose: This work presents a novel camera-based approach for the visual recognition of surgical instruments. In contrast to the state of the art, the presented approach works without any additional markers. The recognition is the first step for the implementation of tracking and tracing of instruments wherever they are visible and could be seen by camera systems. Recognition takes place at item number level. Surgical instruments that share the same article number also share the same functions. A distinction at this level of detail is sufficient for most clinical applications. Methods: In this work, an image-based data set with over 6500 images is generated from 156 different surgical instruments. Forty-two images were acquired from each surgical instrument. The largest part is used to train convolutional neural networks (CNNs). The CNN is used as a classifier, where each class corresponds to an article number of the surgical instruments used. Only one surgical instrument exists per article number in the data set. Results: With a suitable amount of validation and test data, different CNN approaches are evaluated. The results show a recognition accuracy of up to 99.9% for the test data. To achieve these accuracies, an EfficientNet-B7 was used. It was also pre-trained on the ImageNet data set and then fine-tuned on the given data. This means that no weights were frozen during the training, but all layers were trained. Conclusion: With recognition accuracies of up to 99.9% on a highly meaningful test data set, recognition of surgical instruments is suitable for many track and trace applications in the hospital. But the system has limitations: A homogeneous background and controlled lighting conditions are required. The detection of multiple instruments in one image in front of various backgrounds is part of future work.
  • Publication
    Transition to a Circular Economy in Europe through New Business Models: Barriers, Drivers, and Policy Making
    ( 2023)
    Försterling, Gabi
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    Orth, Ronald
    ;
    Gellert, Benjamin
    In recent years, because of global challenges resulting from increased resource shortages and the climate crisis, interest in and the commitment to transition to a more sustainable economic system, especially a circular economy, has increased among scientists, politicians, and practitioners in Europe. To create a system that maintains the value of products as long as possible and minimizes waste, new business models, so-called circular business models (CBMs), are required. So far, as a result of far-reaching barriers, no breakthrough regarding CBMs has been observed and there are a lack of comprehensive analyses on the barriers and drivers of CBMs. Using a systematic literature analysis, this gap was filled and 637 barriers and 394 drivers were extracted from 76 publications, which were categorized into eight areas and synthesized in a comprehensive framework. The results show that an undifferentiated analysis of CBMs could result in incorrect assumptions, as the barriers between them differ. Overall, however, the most significant effect on all CBMs is from external barriers at a macro level. In this paper, drivers, in the form of success factors and political measures, were assigned to concrete barriers, indicating that policy interventions are needed in Europe in order to overcome these barriers and accelerate systematic change. The article provides research, policy, and practice with a theoretically grounded basis for analyzing these barriers and overcoming them.
  • Publication
    Systematic Literature Review of System Models for Technical System Development
    ( 2021)
    Manoury, Marvin Michael
    ;
    Zimmermann, Thomas
    ;
    Stark, Rainer
    In Model-Based Systems Engineering (MBSE) there is yet no converged terminology. The term 'system model' is used in different contexts in literature. In this study we elaborated the definitions and usages of the term 'system model', to find a common definition. We analyzed 104 publications in depth for their usage and definition as well as their meta-data e.g., the publication year and publication background to find some common patterns. While the term is gaining more interest in recent years, it is used in a broad range of contexts for both analytical and synthetic use cases. Based on this, three categories of system models have been defined and integrated into a more precise definition.