Free Stitching | FieldAgent Platform by Sentera | Free Orthomosaics

What can I do with FieldAgent’s free stitching capability?

Update on Free Stitching:

After a lot of development and testing, we have officially launched our integration of FieldAgent with OpenDroneMap to bring free stitching and, soon afterward, 3D modeling to the FieldAgent platform.

Thank you to all of our customers who participated in our limited beta from November through February.


OpenDroneMap is an awesome open source project that integrates some other great open source projects and related past efforts into a usable and robust point cloud and orthophoto generation product. Sentera supports this project and the related WebODM project, and if you’d like to contribute in any way, you can, too!

Orthomosaics in plain English

If you’ve used stitching platforms, you know that orthomosaics are built from collections of individual photos of the same area, usually taken at about the same time. Where images overlap with other images, the software finds the areas that they have in common and combines them together.

The result is a single big image that presents the area covered by all of the many images used as an input.

The nitty gritty of orthomosaics

The above is a huge oversimplification. What’s actually going on is a lot more complicated. The software is really estimating a lot other information to build the model, such as:

  • How the camera and lens distort an image
  • Where each point in an image probably sits in a 3D space, and
  • Where the camera was located when the photo was taken

These are topics for another day.

For our purposes: pictures go in, the mosaic is built and it exists, and it’s a more efficient way to look at large areas that extend beyond what an individual photo can capture.

The nature of the processing also makes the spatial registration more accurate. This means that we can localize each pixel of the mosaic on the ground more accurately than we can localize a pixel in an individual image from the camera. In this first release, Sentera supports RGB (regular color photo) mosaics, as well as NDVI and Red Edge (NDRE) mosaics.

The right stitching solution for your needs

Sentera’s FieldAgent platform is compatible with a lot of commercial stitching and modeling tools, and sometimes these are still the best solution. Many of our enterprise customers use our multispectral sensors, or process large image sets in our cloud environment. Commercial tools are best in these scenarios.

But, we also noticed that many of our customers collect smaller datasets. We know (because they told us over and over) that it’s frustrating to wait to upload these smaller datasets to the cloud for stitching, or to pay a lot of money to buy commercial stitching solutions just to stitch visual, NDVI, and Red Edge products. Enter FieldAgent.

FieldAgent: free, automatic image stitching

So, here’s our solution.

When a dataset that meets certain criteria (mostly based on number of images) is added to the FieldAgent Windows client, it will be stitched automatically by OpenDroneMap and added to the user’s account, right on the local machine. You don’t even have to be connected to the internet.

That’s the good part. There are some caveats. Stitching is not for the computationally challenged. Your PC must have at least 32GB of RAM. Even with a fast machine, it can take a while — sometimes hours — to stitch a large image set.

But (did we mention this?) — it’s free, and requires no connectivity. And compare the cost of 32GB of RAM to the cost of a commercial stitching package.

Some things to consider

The OpenDroneMap team has spent a lot of time creating a performant and robust free stitching capability. Sentera has spent a lot of time making it work smoothly with FieldAgent.

We’re all here to help and we want you to use this capability and benefit from it. As is the case with any technology in its infancy, there are bound to be some hiccups. In that vein, we would like to ask users to keep a few things in mind:

  • Sentera isn’t actually in the image-stitching technology creation business. We build awesome sensors, analytics, and a data management platform. If OpenDroneMap doesn’t meet your needs, we’d like to know about it. We’re going to keep building out the capability with the OpenDroneMap team, but we might suggest that you look to one of the commercial solutions that we support in the short term and ask that you not get upset with us in the process. We’re trying to do something to move the ball forward.
  • We focused on making this work with Sentera sensors and with the integrated products that we sell, which are primarily DJI-based. These get first priority for our support. We’re not going to do anything evil or annoying to limit the ability to use FieldAgent with any imaging hardware, but we have a commitment to those who buy our products. They get our attention first, followed by the sensors that fly alongside Sentera sensors, followed by everything else. That being said, a high-quality sensor will probably work.
  • We are limiting the size of the image sets that can be processed in our integration of OpenDroneMap. Again, we’re not being sinister. We’re using a set of constraints that A LOT of testing suggests will yield a good outcome for our users. Too many images requires too many resources from our users’ hardware. We struck a balance. If these limits are too low, check out our commercial options, or download a copy of OpenDroneMap directly and configure it to meet your needs.
  • It’s always been possible to use Sentera’s mobile app to collect data using settings outside those recommended, or to use other mobile apps to collect data. The FieldAgent Windows client will cooperate and import and use whatever data it’s given. But if imagery isn’t collected the way we recommend, be advised that stitching might not work reliably. Or it might.
  • As always, if there are safety concerns or high-value economic decisions that result from these data products, validate the results independently and develop criteria for trust. Everybody’s terms of service, including Sentera’s, say this. It’s a good idea.

Enough caveats.

For tons of our users, this is an incredibly useful new capability. We’ll be releasing tutorials and how-to documents around the free stitching capability over the coming weeks.

Your feedback, good and bad, will play a big part in what happens next with this capability. We already have a list, and yes, RTK support is on it, and yes, ground control point support is on it.

FieldAgent Subscription Download Stitching Module


Written by Eric Taipale, Chief Executive Officer and Co-Founder of Sentera

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