1. Camera-, Meter- and Sensor-aided Field Measurement and Computational Technologies and Computer Modeling & Simulation to Approximate and Quantify Lighting Application Efficiency (LAE) and Human-Light Interaction (HLI)

Development of camera-, meter- and sensor-aided field measurement technologies and computational algorithms, as well as computer modeling & simulation to approximate and quantify real-time lighting application efficiency and human-light interactions through visual perception and non-visual circadian light exposure of space occupants in their daily luminous environments. Various types of visual and non-visual data are obtained from the perspective of the space occupants in light of their typical viewpoints and behaviors, with dynamic input from the scenario (e.g., visual tasks, background, environment, working area, traffic routes, work schedule, occupancy time).

2. Integrative Solid-State Lighting, Heating & Insulation Technologies of Next Generation

Research & development of hybrid solid-state lighting and heating technologies to harness both the light and the otherwise wasted heat generated by the same LED(s). Tiny LEDs can easily fit in small spaces for optimal integration with the building structure and enclosure. The heat generated by an LED remains on its back, thus, can be efficiently harvested without interruption of the light output in the forward direction.

3. Implementation in Professional Design and Engineering Practice

Research outcomes are implemented in professional design and engineering practice —including teaching —via continuing collaborations with the national and local lighting industry. 



Lighting Application Efficiency (LAE) of Solid-State Lighting Systems

Binocular Visual Field Model: conventional orthomode binocular visual field model (left) vs. new dynamic field of view (FOV) model (right)


Test rigs include an eye tracker (PupilLabs - Pupil Core) integrated with an additional Bluetooth inclinometer, and BLE-WIFI Gateway receivers (Minew G1-C) mounted at fixed position and Lanyard tags (Minew C6) worn on the space occupants

LAE is a family of six new metrics covering different aspects, including Lighting Delivery Efficiency η_delivery (%), Spectral Efficiency η_spectral (%), Intensity Effectiveness η_intensity (%), Whole Lighting System Efficacy Η_system (lm/W), Control Efficiency η_control (%), and Control Efficacy Η_control (lm/W).

MATLAB code, preliminary, for calculating intensity effectiveness

MATLAB code, preliminary, for calculating spectral efficiency spectrum_intersect.rar

Retrieve illuminance from Radiance HDR image with region of interest (ROI) lux selection


Computer modeling & simulation of LAE


Self-De-Icing LED signals





(As principal investigator (PI) unless noted otherwise)

“Building A New Goniophotometer in the Lighting Research Laboratory”, Henderson Engineers, Inc..

"Self De-Icing LED signals,” Transportation Pooled Fund Program, 2016-2020, Co-PI: Steven. D. Schrock, Co-PI: Eric. J. Fitzsimmons. Participating partners: Kansas, California, Michigan, New Jersey, Wisconsin, and Pennsylvania. (This project was launched in Aug 2016. Additional funding contributions are expected later from New Jersey (in Years 2 and 3), Pennsylvania (in Year 3), Wisconsin (in Years 2 and 3), and Maryland (in Years 1-3) with an Addendum.)

“Self De-Icing LED signals,” University of Kansas Innovation & Collaboration Proof of Concept Fund, 2016-2017, Co-PI: Steven. D. Schrock.

“Self De-Icing LED Signals for Railroad and Highway Operations and Safety,” Transportation Research Board (TRB) – IDEA program (joint-funded by the Federal Railroad Administration and National Cooperative Highway Research Program, 2016-2018, Co-PI: Steven. D. Schrock, Co-PI: Eric. J. Fitzsimmons.

“Harvesting the Otherwise Wasted Heat of LED Lights in Green Buildings – Phase I,” Environmental Protection Agency (EPA) – P3 Award at Phase I, 2015-2016, Student Team: Seyedeh F. Mahlab, Jeehwan Lee, Mohammed J. Alshayeb, and Haider I. Mohamed.

“Consolidating Lighting Education at the University of Kansas among Architectural Engineering, Architecture, and Theatrical Lighting Design,” Illuminating Engineering Society, 2014-2015, Co-PI: Jae D. Chang, Co-PI: Mark Reaney.

“A Highway LED Illumination Manual to Guide the Use of LED Replacement Lighting Systems in Kansas,” Kansas Department of Transportation. 2014-2015.

“Field Monitoring of MSE Walls to Investigate Secondary Reinforcement Effects,” Kansas Department of Transportation, 2013-2015, Co-PI with PI: Jie Han, Co-PI: Robert L. Parsons.

“Development of a Camera-Aided LED Testing Method for Chromaticity Binning,” University of Kansas Research & Graduate Studies, the Competition General Research Fund, 2013-2015.

“Development of a Working Prototype for a New LED Traffic Signal Lighting System for Melting Snow and Ice,” Federal Highway Administration through the University of Kansas Transportation Research Institute, 2013-2014, Co-PI: Steven D. Schrock, Co-PI: Eric Fitzsimmons.

“Methods for Field Identification of Fouled Railroad Ballast,” Mid-America Transportation Center, 2013-2014, Co-PI with PI: Robert L. Parsons, Co-PI: Jie Han, Co-PI: Tom Glavinich.

“Establishing an LED Workshop,” Department of Civil, Environmental and Architectural Engineering Differential Fund, 2013.

“Impact of New Lighting Technologies on Office Ergonomics,” Office Ergonomics Research Committee, 2012-2013.

“Development of High Dynamic Range Photogrammetric Techniques for Measuring Light and Geometry across an Entire Scene,” University of Kansas Research & Graduate Studies, the New Faculty General Research Fund, 2011-2013.

"Light Pollution in Lawrence and Solutions," University of Kansas Honors Program, Research Assistant: Andrew Leicht, 2011.



“Integrated Light and Heat Arrangement of Low Profile Light-Emitting Diode Fixture”. (Patent No. US 10,215,441 B2). Issued on Feb 26, 2019. Inventor: Hongyi Cai.

“Heated Lens Lighting Arrangement” (Patent No. US 10,253,965 B2). Issued on Apr 9, 2019. Inventors: Hongyi Cai (40%), Steven D. Schrock (30%), Eric J. Fitzsimmons (30%).

“Heated Lens Lighting Arrangement” (Patent No. US 9,851,086 B2). Issued on Dec 26, 2017. Inventors: Hongyi Cai (40%), Steven D. Schrock (30%), Eric J. Fitzsimmons (30%).

TECHNOLOGY DEVELOPMENT & INSTALLATION (self designed and custom made)

2016 - Present    

“KU Daylight Measurement Station” on the roof of Learned Hall, consists of climate-protected research-grade cameras in an array and meters (pyranometer, pyrheliometer, etc.) for measurement of daylight and solar energy and nighttime light pollution, wired to a computer station for data collection and treatment 24/7 continuously for years. (Under development)

2017 - 2019              

“Goniophotometer” for photometry measurement in the dark room.

2016 - 2017              

“A Portable Calorimeter Chamber” for accurate heat transfer measurement of LED products in a well-controlled environment (e.g., in the Warm Room and Cold Room in the M2SEC building in the School of Engineering), new facility for testing LED lighting and heating technologies of next generation and for class teaching.

2013 - 2014 

A third generation of “Heliodon Sunlight Simulator” with 3D angular movements of the scale model around a single fixed point (e.g., the center of the scale model) at a precision of 0.1°. Prototype installed in the dark room (1152 Learned Hall) of the University of Kansas lighting research lab. Used for class teaching and real project simulation studies.

2012 - 2013

A portable research instrument — “Sky Measurement Tripod Head”, equipped with multiple (1-4) cameras mounted in an array on the horizontal plane. Used for camera-array-based luminance mapping of the celestial hemisphere (both the sun and the sky) in daylighting research and practice. Prototype stored in the University of Kansas lighting research lab.

2012 - 2013

A portable research instrument — “Three-Dimensional Angular Measurement Tripod Head”, used for measurement of the camera’s 3D angular movement around its optical center, including yaw, pitch and roll angles, with a precision of 0.1°. Key instrument for high dynamic range photography and photogrammetry. Prototype stored in the University of Kansas lighting research lab.

2012 - 2013

“An Adjustable Chin Rest” for studies in human factor and ergonomics, to replace conventional vertical chinrests to prevent forward head and neck that leads to neck shoulder and upper back pain. Prototype stored in the University of Kansas lighting research lab.



2017 “Henderson Engineers Illumination Laboratory” dedicated by Henderson Engineers, Inc.

2016 University of Kansas Innovation and Collaboration (KUIC) Proof of Concept Fund Award. Co-PI: Steve Schrock.

2015 Environmental Protection Agency (EPA) – P3 Award at Phase I.

2014 Miller Scholar Award, by the School of Engineering at the University of Kansas, June 2014.


EPA-P3 PROJECT - PHASE I: Harvesting the Otherwise Wasted Heat of LED Lights in Green Buildings

Most of the electricity (70-80%) consumed by light-emitting diodes (LED) is converted to heat rather than light. We are developing new LED technologies to harvest both the light and the heat generated by the same LEDs for effective lighting and heating uses in the conditioned interior spaces. Our goal is to increase the LED luminaire system efficiency to at least 75% and reduce the annual overall building Energy Use Intensity (EUI) by 6-15% in retrofit projects and new constructions.

We presented our ideas in the National Sustainable Design Expo in the Washington DC Convention Center, April 15th-17th.