Recently I flew a DJI Phantom 4 Pro v2 head to head with an in-house (U of MN AEM UAS Lab) developed fixed wing UAS. This comparison isn’t entirely apples to apples, but maybe someone will find it useful.

phantom4

DJI is the king of the hill for small UAS aerial surveys. Once you figure out the apps and a few basic things, operating one of these is pretty much click and fly and makes aerial survey work about as easy as it can be. Some quick details of our system:

P1030025

Our in-house fixed wing survey platform is a full size X-UAV Talon (with the 15 cm wing extensions.) The camera is a Sony A6000 with a 30mm prime lens.

Recently we flew both of these systems over the same area for a head to head match up. We flew both systems at an altitude of 200′ AGL. If you look at the respective camera specs you will already know what to expect, but I wanted to share the head to head imagery.

The Sony A6000 yields approximately double the pixel resolution at the same altitude (4x the pixels for any area.) In addition, the Sony imaging sensor has about 3x the area compared to the DJI imaging sensor. You can see much better pixel detail in the Sony images as well as more subtle color variations, less washout (saturation), richer colors, and fewer compression artifacts when you zoom way in. So with all that said, here are the image snippets for direct comparison.

Side by side comparison

Hint: For best image pair viewing results: right-click on each image and select “open in new window”. Then drag the windows so you can see the images side by side. You may be able to click in each new window to expand the size to full resolution. If you are reading this on your phone, then I’m sorry!

Van: look for subtle things like the windshield washer nozzles, the wheel rim pattern, gravel pattern.

van-dji

van-talon

Stumps: notice the overall details, you can see bark patterns in the sony image.

stumps-dji

stumps-talon

Evergreens and snow patch: see how the subtle details are preserved in the snow patch better with the Sony camera and individual pine needles are clearly visible.

evergreen-dji

evergreen-talon

Spring buds: notice the details in the fine branching structures and the new buds on all the branches. This is a pair of images that also show the extra jpg compression artifacts in the DJI images.

buds-dji

buds-talon

Gravel road: notice the richer colors in the Sony image, notice the subtle details in the snow patch (the DJI image gets totally washed out in the snow area) and notice the overall sharper detail in the gravel. And again you can see where the extra jpg compression on the DJI image limits how much you can usefully zoom in.

gravel-dji

gravel-talon

Pile of branches: look for the detail in the bark pattern, the shading detail in the snow patches, the detail vs. compression artifacts in the tiny branches.

pile-dji

pile-talon

Conclusion

This is a comparison of two systems (the Phantom 4 is popular commercial system vs. our U of MN UAS Lab in-house built fixed wing system) both flying at 200′ AGL. This is not a perfect apples to apples comparison and it may not be representative of your own typical use cases. What I have shown here is that a higher quality camera produces better pictures (duh!) For some types of missions the details and the image quality do matter!

Thanks for reading!

2019-04-12 16:40:14 -0500 - Written by curt