I’ve recently learned that newer Sony cameras than the two I’ve used (a5100 and a6000) have the ability to save jpegs in “super fine” compression.
I’m curious to know how much if any this benefits Pix4D in building models, orthomosaics or DSM’s.
The new cameras also have a newer processor that support an improved “color science” - that might make a difference.
I’d appreciate knowing if benefits exist that justify buying a newer camera.
Thank you!
Hi Joe,
If we are talking about the image quality and the resolution here, the Extra Fine or Super Fine could benefit the model with its higher resolution. I looked at the difference between the Standard and the Extra Fine images in the references below, Extra Fine images seem to store and record using a higher quality. This also comes with a larger image size.
References:
What is the difference between Fine and Standard picture modes?
Sony Help Guide: Quality (still image)
However, with the Color Science feature, one thing to keep in mind is that the images in a dataset should have a similar to the same color scheme for photogrammetry software to find key points. Since the Color Science feature seems to rely on the sensor reproducing the color, I am unsure if this can cause images to show differences in the color scheme.
Nevertheless, feel free to give it a try and share the result with us!
Best,
Rosana (she/her)
Thank you Rosanna Lin for your kind reply.
Since I posted my message, I have purchased a Sony a6100, and have created Pix4D projects using images saved in “Super Fine” mode.
So far, these images seem to work fine - but there isn’t a noticeable difference in the resulting orthos, meshes, or DEMs.
I recently learned (from using WebODM) about how images are “scaled” when processed. It’s made me think about how much camera resolution is really necessary - or where the benefits exist for higher resolution images.
Interestingly, when choosing “half-scale” in Pix4D, the quality report does not show a resulting reduction in GSD. WebODM on the other hand, reports a reduction of GSD when the images are scaled to a smaller size.
It’s hard to know what’s right - is the Pix4D quality report misreporting the impact to GSD when scaling the images?
I appreciate your help. I’ll report back if I make further findings on this topic.
Best regards - Joe
Hi Joe,
I believe your question regarding how much camera resolution is really necessary is, perhaps, the least understood in the drone industry. The push by most users is to always go bigger. But this poses a lot of problems that are not understood very well. One issue is that the demands on your system resources become significant. If you are at or above 45mp, then you better have some decent RAM installed on your machine.
Another issue that is not understood well is when trying to map areas with vegetation. The large-resolution images see too much detail and it can cause calibration issues. Vegetation has a complex geometry that can move in the wind. As a result, it is best to process at a lower image scale to reduce the noise.
Drones with high-resolution cameras should be flown high. Unfortunately, the 400ft (120m) ceiling imposed by the FAA limits their true usefulness.
Thank you Mike - I appreciate your kind response.
I am familiar with the principles you mention - but it’s nice to hear them confirmed.
Vegetation and water are both challenging. And I’m familiar with the effects scaling and multi-scaling can have with them.
It wasn’t until I learned WebODM that I understood how scaling is typically used.
GSD’s below 1cm don’t have much value in most cases. But higher pixel count sensors allow flying faster and higher - which for a multi-copter is more efficient.
As it happens - the Sony image compression setting from “Standard” to “Fine” to “Super Fine” doesn’t change the number of pixels in the image. It changes the level of compression. So things like dynamic range are different. So my assumption is that the photogrammetry algorithms produce better results with better input data.
Hi Joe,
“higher pixel count sensors allow flying faster and higher - which for a multi-copter is more efficient” - Yes, this is absolutely the case. It is unfortunate that regulations limit altitudes to 400’ AGL. If you could fly at double the altitude with a 60mp sensor, then you could cover a lot of ground very efficiently and effectively.
Unfortunately, I am not familiar with Sony’s compression settings. A higher compression might produce a better result, but I would not assume anything. It could be quite the opposite.