Wisconsin Alumni Research Foundation

Chi Zhang

Xinyu Zhang

Jialiang Zhang

Shilin Zhu

Suman Banerjee

Joshua Tabor

A visual privacy system unilaterally blocks rolling shutter cameras by providing a periodically interrupted ambient light source imposing bright and dark bands on the image yet at a frequency imperceptible to human observers in the environment. Communication of the modulation pattern to authorized cameras allows unaffected imaging in these regions by authorized individuals. The system also contemplates operation in a barcoding mode with a light modulation providing embedded barcodes that can be extracted from images taken in the region to indicate that the images were improperly acquired and to block the images in certain applications.

Visual privacy protection system

A system for identifying the location of the mobile device uses standard fluorescent light fixtures commonly found in indoor environments and detects minor variations in the light output of those fixtures caused by normal manufacturing variation. These variations are catalogued as identifying fingerprints together with location of the light fixtures to provide for navigation.

Spatial location indoors using standard fluorescent fixtures

A system for identifying the location of a mobile device uses signatures of standard room lighting derived from the frequency spectrum of light fluctuations associated with driver circuitry of that lighting. Improved sensitivity (frequency and dynamic range) are provided by using a pair of dedicated photodetectors which may deduce a one-dimensional angular location of a light source by comparing the signals developed by two photodetectors having different angular sensitivities.

Navigation system tracking high-efficiency indoor lighting fixtures

A virtual touchscreen for mobile devices provides a touchscreen area displaced to a side of the display to eliminate problems of a finger blocking the display during normal touchscreen operation. The virtual touchscreen may be monitored by a sensor system looking edgewise from a housing of the mobile device employing as few as two displaced photodetectors and a correspondingly oriented light source constrained to sensitivity within a narrow fan-shaped light-sensing plane. Extraction of the spatial location of a finger touch within this touchscreen area may be performed by a model of reflected light signals of a finger in different locations calibrated to environmental parameters of finger reflectivity and background reflectivity by a simple calibration process.

Touch surface for mobile devices using near field light sensing

A visible light communication system identifies the location of a mobile device using light intensities corrected by mobile device orientation. This location can be used to generate a dynamic cluster of visible light transmitters about the mobile device providing improved 'handoff' between transmitters and reduced shadowing.

Growing community of inventors

Madison, WI, United States of America

Chi Zhang