Here are several surveys I created by taking photographs from my drone in various grid patterns. These photographs were then processed using OpenDroneMap. The process took a lot of computing power, with some taking 48 hours on a 24-core processor.
Measurements can be taken for heights, widths, distances and volume accurate to around an inch.
Please be patient as they are large files and may load slowly:
Using an ESP-32 board with an embedded E‑Paper display, I created a gadget that shows status information from my web server.
E‑Paper, also known as E‑Ink, only needs power when being updated, and uses no power between updates. This means that the gadget can be powered for weeks from a rechargeable battery.
The purpose of this gadget is to put on my wall or desk, and show regularly updated important information on my web server, to keep informed of web site problems and statistics. The information displayed can be easily changed, for example to the latest weather, news, currency prices or anything that can be accessed via the internet. E‑Paper means it uses a very small amount of power and heat, compared to a computer display or television.
Many people in the UK may be familiar with seeing groups of people, or sometimes a parked vechicle, clearly displaying a sign saying ‘Traffic Survey.’ These people are employed to keep a tally of the number of vehicles using a road, and the types of vehicles. This information is important for planning infrastructure, helping more efficient provision of transport capacity for cars, trucks/lorries and buses.
Many will also have seen temporary pressure sensors across roads, linked to a data collection box attached to a street lamp. This system also provides useful data on the number of vehicles using a road.
By using two pressure sensors, its possible to fairly accurately record the numbers of vehicles passing in two directions. However, there may be some inaccuracies when vehicles pass simultaneously or almost simultaneously. A 15-minute time period may have an inaccuracy of 10% (http://www.windmill.co.uk/vehicle-sensing.html). For roads with more than two lanes, accuracy would be even less and the system probably wouldn’t be feasible.
I’ve noticed what seems like a new technology recently, with a video camera mounted on a street light, and a data collection box attached to it. After researching it, these are video cameras that record conventional HD video for a period of 3 to 7 days. The model I saw in use also has advanced features like remote management and event alerts sent via mobile cellular networks (LTE), allowing settings to be changed and notifications of problems without having to travel back to where the unit is deployed.
Computer Vision (CV)
I expect computer vision techniques (e.g. OpenCV) are later used to analyse the numbers and types of vehicles passing:
Anonymity and Privacy
I expect there are strict rules in place to prevent ANPR (Automatic Number Plate Recognition) being used, as this may violate the privacy of drivers. However, if there are not, I expect travel time surveys could be made by calculating how long a commute takes for individual drivers, and how they change over time. Perhaps if this was calculated anonymously, it would be a usable technique.
While there have been companies that have monitored cellphones with Bluetooth and Wi-Fi serial numbers, often the general public have expressed concerns over privacy. An example hardware provider for this is http://www.libelium.com.
In conclusion, I found it interesting to research what these cameras and other equipment I see are used for, and expect it is an interesting field analysing queues of videos for traffic data.
My Sony smartphone has an unusual TRRRS (Tip-Ring-Ring-Ring-Seal) connector, allowing it to use very reasonably priced noise cancelling headphones (Sony MDR-NC31EM) that have an extra microphone in each earphone.
I found that the Sony app Sound Recorder allows selecting recording directly from these two microphones, and are great for binaural recording, and I gave it a go walking along a few busy streets. You can listen on YouTube and Soundcloud: