Visible Light Sensor Glare Detection for Window Treatment Control
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Solution Overview
Problem
Existing load control systems inaccurately control motorized window treatments due to detecting small, high-intensity glare conditions outside the building, which do not cause glare inside, leading to unnecessary adjustments.
Innovation Solution
A visible light sensor processes images to determine the position of glare sources by comparing pixel luminance to a threshold, adjusting resolution and grouping pixels, and controlling motorized window treatments to prevent glare from affecting occupants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If window sensors detect high light conditions outside the building, then the system controller controls motorized window treatments to prevent glare, but small high-intensity glare conditions outside that do not cause glare inside are incorrectly detected, leading to unnecessary adjustments
Solution Approach 1:
The patent segments the detection task by using multiple sensors positioned at different locations and orientations. The first sensor detects glare conditions from one direction while the second sensor detects from another direction, allowing the system to distinguish between actual glare sources that affect occupants and external high-light conditions that do not penetrate into the building.
Solution Approach 2:
The patent introduces an intermediary processing layer that analyzes sensor data in context of building geometry, window locations, and occupancy patterns. This intermediary layer filters out false positives by determining whether detected high-light conditions actually represent glare sources that will affect occupants inside the building, rather than simply reacting to all high-light detections.
2Extent of automation
If the system uses predicted sun location and building orientation to control window treatments, then automatic control throughout the day is achieved, but the system requires complicated configuration procedures and advanced system controllers
Solution Approach 1:
The patent enables the system to automatically determine building orientation, window locations, and glare patterns through the sensor network without requiring manual configuration. The sensors self-calibrate by detecting actual glare conditions and learning the relationship between external light sources and internal occupancy areas, eliminating the need for complicated setup procedures.
Solution Approach 2:
The patent changes the control parameters from requiring detailed building geometry inputs to using raw sensor data from multiple positions. By controlling window treatments based on actual detected glare conditions rather than predicted sun paths, the system simplifies the control parameters while maintaining or improving automation effectiveness.
3Reliability
If the sensor detects all high-intensity light sources outside, then comprehensive glare coverage is achieved, but unnecessary adjustments are made for small high-intensity sources like reflections or rain drops that do not cause actual glare inside
Solution Approach 1:
The patent applies local quality by having different sensors positioned at specific locations with specific detection directions. Each sensor monitors a particular zone or aspect of the building, and the system integrates these localized detections to determine overall glare conditions. This allows the system to ignore localized high-intensity sources like rain drops on windows that do not represent actual glare problems for occupants.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurately prevents glare by identifying and addressing small, high-intensity glare conditions, reducing unnecessary system adjustments and improving control precision.
Implementation Method 1
A sensor (e.g., a visible light sensor) and/or a system controller may process an image to determine the position of a glare source and control motorized window treatments to prevent the glare source from affecting an occupant of a room. The sensor (e.g., a visible light sensor) and/or system controller may process the pixels of the image to determine whether a glare condition exists. The sensor and/or system controller may compare the luminance of the pixels in the image to a glare condition threshold to determine whether a glare condition exists.
Data Source
AI summary
A sensor and/or system controller may process an image multiple times at multiple resolutions to detect glare conditions. A glare condition threshold used to determine whether a glare condition exists may be based on the resolution of the image. When the resolution of the image is higher, the glare condition threshold may be higher. The sensor and/or system controller may organize one or more adjacent pixels having similar intensities into pixel groups. The pixel groups may vary in size and/or shape. The sensor and/or system controller may determine a representative group luminance for the pixel group (e.g., an average luminance of the pixels in the group). The sensor and/or system controller may determine a group glare condition threshold, which may be used to determine whether a glare condition exists for the group of pixels and/or may be based on the size of the group.