Article: Lowering the Barrier to Entry Does Not Eliminate the Requirement for Professionals

We’re not a one-trick pony, and we’re not terrestrially-bound.  Unmanned Aerial Systems (UAS) represent the newest, low-cost acquisition platform – but low-cost doesn’t give license for lack of professional responsibility.   Continuing our contributions to your reading pleasure, check out another recent article authored by our own Eric Andelin that was published in the May edition of LiDAR News Magazine. 

Cheers!
Stephen

Article: LiDAR Fusion for Impervious Surface Mapping

With the deployment of our 2 brand new Lynx SG1 systems, the past month has been admittedly hectic.  Although we haven’t had much time lately to post new material to the Blog, our team continues to contribute to the profession through other media outlets.

Check out a recent article published in the May edition of LiDAR News Magazine that was authored by our own Dr. Srinivasan Dharmapuri and Aaron Morris.

Cheers!

Stephen

Mobile LiDAR and Flood Impact Studies

The Mobile LiDAR vehicle trajectories (shown in red) are
displayed with the 1979 Easter Flood boundary (in blue).

I arrived this morning to the latest issue of LiDAR News magazine sitting on my desk.  I am proud to have been a contributing writer for more than three years now - although lately my commitments do not afford me as much time to write as I once did for both the magazine and this blog.  However, Gene Roe, managing editor and co-founder of LiDAR News, does wrestle an article from me from time to time.

My latest article, Mobile LiDAR and Flood Impact Studies, details work we performed in the Jackson, MS metropolitan area to extract approximately 12,000 first floor elevations and other data to support the work of several partner organizations and stakeholders.  The project, completed over a period of approximately four months, required collection of over 700 miles of Mobile LiDAR data, survey ground control and aerial LiDAR validation.

Entire subdivisions are quickly captured with Mobile LiDAR data alleviating the need for entry onto private property to gain information.  Outreach was performed via news and print media prior to collections.

Several of our staff live within the boundary of the project.  Therefore, we had a more personal connection with the project and its successful completion than is experienced with a typical roadway design type application.  We were working with information pertaining to our homes and property.

Cheers!
Stephen

Processing and Internal Communication

After a brief hiatus from writing for LiDAR News, I made time after the holidays to prepare an article. One of the most crucial elements to project performance is communication.  Often when working across professional disciplines, markets and office locations, the communication can become increasingly difficult.  Couple that difficulty with the perceived complexity of Mobile LiDAR (often a new technology to many of our consumers) and you are bound to need additional tools to facilitate understanding.  Therefore, I've prepared an article on Processing and Communicating - Internally to discuss some methods for collaborating within a team/project environment.

Should you have recommendations for future articles or blog postings, please leave a comment.

Cheers!
Stephen

Mobile LiDAR Point Density - Part 2

I've had a brief hiatus from the blogosphere while working on a project that kept me out of town for a few weeks.  I usually do not travel with the system since our collection team is quite capable of anything I throw at them quite honestly.  However, the most recent mobilization was truly unique as you'll come to find out in future posts - can't share too much, yet.

Gene Roe, Managing Editor of LiDAR News, was successful in getting another article from me for the regular newsletter.  My latest contribution is a continuation of a previous topic and is titled:  Mobile LiDAR Point Density - Part 2.  I discuss how the following variables influence density:

• Vehicle speed, measurement frequency, and scanner rates;
• Angle of incidence and the impact of flat surfaces;
• Distance to target and effect of rotated sensors; and
• Collection paths and moving obstructions.

The images from the article are provided for a little more clarity. 

The image represents 3 passes along the same stretch of a 2 lane residential road. The data was collected at 25 mph with a scanner rate of 120 Hz. The three images show results of collecting at laser frequencies of 75 kHz, 100 kHz and 200 kHz – from left to right.

Using the vehicle speed and scanner rate, we can calculate the line spacing - the distance between lines of LiDAR points laid down on the surface.

The image above shows the data captured from one sensor along the centerline of a runway.  The data tapers off rapidly due to the limited backscatter caused by the flat surface. The point density on the pavement stripes at the extents is increased to to the material.

I will have one last article in the series next month.  It will focus on the resolution required to identify objects and tools that are available for feature extraction which utilize photography.

Feel free to leave a comment if there's a topic you would like to read about.

Cheers!

Stephen

LiDAR Point Density

Recently, I prepared an article for LiDAR News.  The purpose of the article, Mobile LiDAR Point Density, is to serve as an introduction to LiDAR point densities.  Whether from a static, mobile or aerial system there are various influences to point density or nominal point spacing.

A portrait of our founder Michael Baker Jr. hangs in our conference room. Here, a static scan with a horizontal and vertical resolution of 0.005’ at 30’ is shown. The image represents approximately 1,375,000 points and was collected using a Leica ScanStation 2.

The above image represents a colorized point cloud of an Aerial LiDAR capture - utilized collected orthophotography to perform the colorization. The collection was planned and executed to achieve a point density greater than 20 ppsm. 

There will be additional parts to the topic of point density.  The next will focus on the influences related to Mobile LiDAR densities.  While following articles will examine tools that assist in feature identification and exploitation of the point cloud and imagery.

Cheers!
Stephen

Point Classification

Baker's latest article for LiDAR News was published last week.  The article, Mobile LiDAR Point Classification, discusses the advantages to classifying features of similar type into groups. The grouping of features into classes provides the ability to isolate, remove or exploit smaller sets of information.  Due to the extensive detail and volume of data provided by Mobile LiDAR, point classification is incredibly useful for downstream applications.

The image above, presented in the article, shows classified features in an urban environment.  Street signs, vegetation, buildings, roads and other information are isolated into user defined classes.

Extents of tree canopies, outlines of building footprints, curbing and overhead wires are clearly depicted in the image above.  Ground points have been removed for clarity.

An elevation of a parking garage with DTM surface shows the undulating terrain.

If you have a recommendation for a future article, please leave a comment. 

Cheers,

Stephen

Thank you to William for helping with content and images for this and past articles.  And, as always, thanks to Aaron for continued support, proofing and guidance.

Identifying the Need for Mobile LiDAR

In my latest LiDAR News article, I take a stab at how we Identify the Need for Mobile LiDAR for a given project.  I briefly discuss 5 key characteristics to evaluate the use of the technology:

• Level of Detail
• Schedule
• Safety
• Access
• Security

Although there are other circumstances which influence a decision, these key elements are the primary drivers in the process.

Cheers!

Stephen

Data Fusion: Mobile and Aerial LiDAR

Over the weekend, Baker's latest article on LiDAR News was published.  The topic is "Data Fusion" - Mobile and Aerial LiDAR as well as traditional surveying.  In an earlier posting on the blog, I wrote about Knowing your Limitations - whether they're environmental, scale or technological.  Often, one tool or technology does not completely solve a problem.  By fusing data from multiple sources, we're able to complete the picture. 

Below are the images from the article in more detail:

The image above presents the fusion of Aerial LiDAR (red) and Mobile LiDAR (white). The tops of structures, including poles and push braces, are completely saturated with LiDAR points while the rail corridor (immediately adjacent to the buildings) contains dense information.

The image above depicts the fusion of Mobile LiDAR and Traditional Surveying (Aerial LiDAR points removed for clarity). The LiDAR data was supplemented outside of the Mobile LiDAR corridor to locate utilities, property boundaries and other features not captured by Aerial means within the larger corridor.

As the closing states, the information represented in surveying/engineering drawings can be captured in a number of ways.  Having an array of tools at your disposal can dramatically impact how you approach an assignment.  The integration of outputs from various technologies can provide a different perspective.

Cheers!
Stephen

Mobile LiDAR: Positioning Systems

In my most recent article for LiDAR News, I provide an overview of Positioning Systems for Mobile LiDAR.  It is a little more in depth than a blog posting I prepared back in 2009 titled Measuring Systems Part 1 - Positioning.

Mobile LiDAR is a system comprised of various components that are connected to provide a solution.

My belief is that the Position and Orientation System (POS) used to develop the Smoothed Best Estimate of Trajectory (SBET) is the distinguishing factor between available Mobile LiDAR systems. The ability to accurately position the vehicle has downstream advantages for the initial LiDAR processing and subsequent control adjustment.

Cheers!
Stephen