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Privacy preserving recognition of object-based activities using near-infrared reflective markers


This paper presents a low-cost privacy preserving method for recognizing object-based activities through the use of near-infrared (NIR) reflective markers. The NIR markers are thin pieces of durable reflective material that can be attached to objects, with their movement captured using a webcam that has been modified to capture NIR images. The camera is modified to replace its standard IR-blocking filter with an IR-passing visible-light-blocking filter to allow us to preserve the privacy of users during recognition. Using this equipment, we attempt to achieve accurate recognition of several object-based activities by differentiating between markers based on their stripe or grid designs, as well as by capturing the usage of the objects based on their unique movement patterns. We evaluate our method by identifying kitchen activities using markers attached to common kitchen utensils.

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This study is partially supported by JST CREST.

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Correspondence to Joseph Korpela.

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Korpela, J., Maekawa, T. Privacy preserving recognition of object-based activities using near-infrared reflective markers. Pers Ubiquit Comput 22, 365–377 (2018).

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