Hawthorne, Los Angeles, will introduce a drone enforcement program by the end of this year. When a 911 call is made, the first responder to arrive on the scene will be a drone. If there are no injuries or potential dangers, police officers will not be dispatched.

It is reported that Hawthorne is collaborating with BRINC, a Seattle-based company, to establish a drone emergency response system integrated with the city’s 911 operations.

These drones are no longer operated by the police but are deployed from “nests” set up by BRINC in various locations, arriving at the scene before the police.

Blake Resnick, founder and CEO of BRINC, stated that the drone response system aims to reach the scene within 70 seconds and can use its camera to provide responders with a better understanding of the situation. “This is the world’s first drone specifically designed for 911 responses. They will use it to respond to all 911 calls: police, fire, emergency, and more.”

Resnick mentioned that an early version of the system was used in Chula Vista, near San Diego, which was able to identify non-emergency situations or resolve issues before the police arrived, thus canceling 25% of 911 calls and allowing police to be dispatched to more critical incidents.

“For example, if there is a report of a suspicious person near my home, the drone arrives at the scene and finds that the suspect has already left or there is no suspicious activity, the police will not dispatch officers,” Resnick explained. “Or if there is a report of an obstruction on the road, the drone arrives and finds that the obstruction has been removed, no police will be dispatched either. These situations occur in about one-fourth of the drone system’s responses.”

The cost of the drone system ranges from tens of thousands to millions of dollars, depending on the number of drones and the size and geographical location of the surrounding area. Dispatchers can also use drones to deliver life-saving medications or tools to patients in danger, and fire departments can use them to scout burning buildings.

“Providing naloxone, defibrillators (AED), EpiPens, life rings… it is crucial for firefighters to have thermal imaging of fire scenes,” Resnick said. “Thermal imaging can also easily identify people who may be lost in forest environments.”

Authors: Wang Yuzhu, Kong Juan, Meng Qiang
Source: Journal of Geomatics and Spatial Information Technology, Volume 47, Issue 5, May 2024
Remarks: Original in Chinese. Translated and Edited by SkyeyeUAV

Abstract:

This paper briefly introduces the basic principles of oblique photogrammetry and discusses its application in the surveying and mapping of rural real estate. Through practical application, quality inspection, and data analysis, the reliability of this technology in rural real estate surveying and mapping is established, providing a reference for its wide application in various industries in the future.

Keywords: UAV, oblique photogrammetry, rural housing, real estate survey, title survey

Introduction

To fully implement the Opinions on Improving the Property Rights Protection System and Legally Protect Property Rights, and to follow the work plan of the Henan Provincial Government to increase rural reform efforts and activate endogenous development power, the Real Estate Registration Bureau of Henan Province has conducted rural house real estate registration and title surveys. This initiative aligns with various governmental directives and technical guidelines, focusing on surveying, title information integration, database construction, and real estate registration.

Traditionally, the cadastral surveying of rural houses relied heavily on GPS-RTK and total stations for comprehensive outdoor digital surveying. While this method is highly accurate, it demands significant human resources, has high labor intensity, is time-consuming, costly, and has a long work cycle. The advent of oblique photogrammetry, a new surveying technology, addresses issues like scattered rural house distributions and tight project timelines. This technology can capture high-resolution images from multiple angles, generate three-dimensional models, and produce various types of maps, meeting the needs of rural house real estate surveying.

Overview of Oblique Photogrammetry

Principle

UAV oblique photogrammetry, developed in recent years, integrates UAV technology with oblique photogrammetry. UAVs serve as the platform, carrying photogrammetry equipment to perform the surveying. Unlike traditional vertical photogrammetry that only captures orthographic images, oblique photogrammetry captures images from five different angles (vertical, left, right, front, and back), allowing for detailed three-dimensional reconstruction of the surveyed objects. This method creates realistic 3D models, accurately reflecting the size, shape, planar position, elevation, and terrain of the objects.

Advantages

Compared to traditional photogrammetry, oblique photogrammetry offers several benefits:

1. 3D Model Realism: It captures multi-angle image data, generating realistic 3D models that provide a comprehensive view of the surveyed scene. Traditional methods only offer top-down images without 3D information.
2. Versatility: It allows for the measurement of length, area, angle, slope, and height on the 3D model. Traditional methods are limited to planar measurements.
3. Flexibility: UAVs, being less restricted than manned aircraft, can fly at lower altitudes and are subject to fewer airspace regulations. They are cost-effective and do not require a crew.
4. Efficiency and Cost-effectiveness: UAVs require fewer personnel, reducing costs and increasing efficiency. Automated 3D modeling significantly shortens project timelines compared to manual methods.

Application in Rural Real Estate Surveying

Overview

Following the technical guidelines, the survey team verifies the original land use survey data and conducts supplementary rural house real estate registration and cadastral surveys. This includes surveying buildings and structures, and integrating cadastral information for database construction. Traditional methods involve manual surveying, requiring professional technical skills and resulting in low efficiency and tight project schedules.

UAV oblique photogrammetry can quickly capture image data from different angles with minimal manual intervention, reducing the impact of weather conditions. The efficient 3D modeling process significantly improves work efficiency and reduces costs.

Workflow

The basic workflow of UAV oblique photogrammetry includes preparation, control point layout, 3D modeling, and stereoscopic mapping.

1. Preparation
   • The DJI Matrice 300 RTK UAV, equipped with a Rebo D2PSDK five-lens camera and POS system, is used. The ground resolution is less than 0.02 meters, with a flight altitude of 80-100 meters and a flight overlap of no less than 70%.
   • Flight routes are designed based on the survey area, typically rectangular, with flight parameters set according to on-site conditions.
2. Control Point Layout
   • Control points are set up according to flight routes, often marked with paint on the ground. These points should be clear, unobstructed, and easy to recognize.
   • Network RTK is used to measure control points, ensuring their accuracy for the overall positioning of the 3D model.
3. 3D Modeling
   • Image data undergo quality checks, with additional flights if necessary. All photo data are imported into modeling software.
   • The process involves importing control point coordinates, matching coordinate systems, aerial triangulation, and model creation using the Smart3D system.
4. Stereoscopic Mapping
   • The 3D model created by Smart3D is imported into the EPS platform for stereoscopic mapping, producing cadastral maps, house plans, survey tables, and other related documents.

Quality Check and Accuracy Assessment

To verify the reliability of UAV oblique photogrammetry results, a Topcon GTS-102N total station (with an angular accuracy of 2″ and distance accuracy of ±2mm+2ppm) was used to measure corner points of different areas. The results showed that the largest point error was 0.091 meters, with a mean error of ±4.27 cm, meeting the technical guidelines’ accuracy requirements.

Coordinate Accuracy Verification Table (unit: m)

Conclusion

This study demonstrates the application of UAV oblique photogrammetry in real estate surveying within a specific jurisdiction. The results, verified by total station measurements, confirm the reliability of this method for rural house real estate surveying. It significantly improves efficiency, reduces costs, and shortens project timelines compared to traditional methods. However, issues such as image matching inaccuracies and geometric distortions caused by obstructions like trees need further optimization. Future research should focus on improving image registration methods, adjusting flight parameters for better resolution and model accuracy, and enhancing overall surveying efficiency.

References

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