, "Large-field-of-view optical elastography using digital image correlation for biological soft tissue investigation," J. Med. Imag. 4(1), 014505 (2017), doi: 10.1117/1.JMI.4.1.014505. Abstract. In minimally invasive surgery the haptic feedback, which represents an important tool for the localization of abnormalities, is no longer available. Elastography is an imaging technique that results in quantitative elastic parameters. It can hence be used to replace the lost sense of touch, as to enable tissue localization and discrimination. Digital image correlation is the chosen elastographic imaging technique. The implementation discussed here is clinically sound, based on a spectrally engineered illumination source that enables imaging of biological surface markers (blood vessels) with high contrast. Mechanical loading and deformation of the sample is performed using a rolling indenter, which enables the investigation of large organs (size of kidney) with reduced measurement time compared to a scanning approach. Furthermore, the rolling indentation results in strain contrast improvement and an increase in detection accuracy. The successful application of digital image correlation is first demonstrated on a silicone phantom and later on biological samples. Elasticity parameters and their corresponding four-dimensional distribution are generated via solving the inverse problem (only two-dimensional displacement field and strain map experimentally available) using a well-matched hyperelastic finite element model. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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This paper presents a method for dynamic adjustment of cable preloads based on the actuation redundancy of cable-driven parallel robots (CDPRs), which allows increasing or decreasing the platform stiffness depending on task requirements. This is achieved by computing preload parameters with an extended nullspace formulation of the kinematics. The method facilitates the operator's ability to specify a defined preload within the operation space. The algorithms are implemented in a real-time environment, allowing for the use of optimization in hybrid position-force control. To validate the effectiveness of this approach, a simulation study is performed, and the obtained results are compared to existing methods. Furthermore, the method is investigated experimentally and compared with the conventional position-controlled operation of a cable robot. The results demonstrate the feasibility of adaptively adjusting cable preloads during platform motion and manipulation of additional objects.

, "Large-field-of-view optical elastography using digital image correlation for biological soft tissue investigation (erratum)," J.

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