I understand that it's tempting to look at an equation such as NA = n sin θ, and wonder what meaning can be inferred if n or θ were negative.

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Helios environmental intelligence platform from NV5 Geospatial provides essential information about hyperlocal weather that traditional weather sources typically struggle to discern. Helios uses Artificial Intelligence (AI) to detect the occurrence and impacts of weather in specific locations on critical ground infrastructure through its large terrestrial camera network. This timely weather analytics is important for weather-dependent decision making.

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With access to the full Helios API, you can also perform powerful searches and save imagery using recordings or collections, all from your desktop or mobile device.

Helios Transition Analytic identifies transitioning and trending ground conditions that are predictive of major incidents (e.g. knowing exactly when snow begins to accumulate can help ensure safer travel and efficient deployment of resources).

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Helios Road Snow Analytic provides visual confirmation of snow impacting road or pavement conditions, identifying three specific road snow conditions: no snow, partially covered, and totally covered.

Helios ground weather analytics uses AI to detect and classify ground conditions and impacts day and night. The AI has been trained using millions of global, seasonal, regional and historical images for high detection rates.

Helios Visibility Analytic alerts users of real-time fog formation, dissipation, and overall poor visibility conditions caused by fast-moving, localized fog, heavy rain, heavy snow (white-out condition), or even smoke.

Helios Road Ice Analytic provides warning for road icing conditions by combining weather data information about precipitation on the ground, falling precipitation, fog, and road temperature.

Helios is integrated with tens of thousands of publicly available terrestrial cameras in different locations around the world. These cameras are primarily located on critical roadway infrastructure and can be easily enhanced.

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A scalable cloud AI processing platform is the foundation for imagery management and provides an open API and web application for content delivery. The hyperlocal weather technology platform brings large existing disparate camera networks together. This removes the need/cost to source and maintain these camera networks.

Helios applies more than 50 years of NV5’s remote sensing and AI expertise and patented analytics to terrestrial cameras. Helios provides tip and cue alerts for changing ground weather and its impacts to support weather forecasting, traffic management, emergency response and vehicle safety in each location. Helios analyzes imagery from tens of thousands of existing public and private video cameras using a combination of machine learning and traditional image science to instantaneously identify and classify the type of condition and any changes.

There is no need to spend valuable time monitoring hundreds of cameras; let Helios® real-time ground weather analytics do it for you. A browser-based interface allows users to have an interactive mapping application that integrates multiple hyperlocal weather observations and weather data layers such as clouds or radar to get the most complete picture of weather events in a particular spot.

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* Helios is adding traffic congestion detection to its suite of analytics to allow users to correlate mobility with road weather conditions.

No, there's really not such a thing as a negative numerical aperture. Understand that NA is about an image forming lens, bringing the incoming light (in the case you mentioned, collimated) to a single focus point. Meaning, a net-convex system.

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The Helios Explore web app provides on-screen visualization capabilities to get the complete weather picture. Our interactive map interface allows you to browse live imagery from the vast camera network, view real-time weather alerts from the National Weather Service and view traditional weather sources such as radar and cloud cover.

Helios Road Wetness Analytic provides confirmation of precipitation affecting road or pavement conditions and notifies users of wet or dry pavement and potentially dangerous locations during a storm event.

Helios Precipitation Analytic detects moderate-to-heavy rain conditions that require reduced speed and could result in hydroplaning and localized flooding.