Topics

1

General / Agisoft and Micasense RedEdge Processing

« on: July 13, 2016, 12:52:04 PM »

Is Agisoft Photoscan Pro able to accurately corregister the individual channels of fixed-frame multi-lens cameras such as the micasense rededge or parrot sequioa? If so, any specific settings or workflow to follow for such cameras?

It is important for vegetation índex Calculations, for example, that the resulting multi-channel mosaic has all bands properly aligned in space. Even a few pixels displacement may produce incorrect índices.

I have found a number of posts on the forum where users have had problems processing missions, but none reporting success...

Dvoralai

2

General / Multispectral mosaic blending

« on: June 15, 2016, 02:15:42 AM »

Hullo

Very interested in hearting about experiences and obtaining advice on best method to use to  blend mosaics (blending, average, disabled) for "accurate" NDVI map creation rfom Agisoft mosaics.
For
(1) modified consumer-grade cameras (e.g. maxmax products) - JPEG vs RAW images
(2) multispectral cameras such as the micasense rededge, parrot sequioa
(3) tetracam ADC cameras

We are using the maxmax Canon SX230 HS and SX260 HS (always in manual mode with infinite focus, fixed f-stop value, fixed ISO, fixed exposure time) and in general getting NDVI maps that groundtruthing indicates provide correct patterns of relative NDVI (after reflectance calibration of channels) from Orthos created using Mosaic blending - but occasionally the maps show variations in NDVI that may just arise from flightline directions.

One can expect that blending mode will still be important when using "true" multispectral cameras to capture images.

3

Feature Requests / Reflectance calibration

« on: June 15, 2016, 02:06:17 AM »

Excellent that Photoscan Professional nowe permits vegetation index calculation using raster caluclator. It would be extremely valuable to add a Reflectance Calibration module, for mosaics creayed using images that have not been radiometrically corrected at the time of image capture.
Common procedure is to identify areas in mosaic with known reflectance (such as scenes with one or more reflectance targets) to generate a correction equation for each channel so that pixel intensity (DN) is mapped to the approximate reflectance value.
Then allow "automatic" application of correction factor to each channel for the raster calculator.
Such a feature is important for generating more accurate NDVI (ore relative NDVI) and other veg index maps.

4

General / Tetracam adc multispectral camera processing AGAIN

« on: May 05, 2015, 09:48:50 PM »

Hi

It would be most helpful if detailed instructions for processing Tetracam ADC aerial images (latest Photoscan Pro version) could be posted.

I have the same problems reported by others on this forum (images not aligning, and the plane of the model built from those that do is oriented about 90 degrees from where it should be) and I have tried following instructions posted in several places on this forum as well as other methods.

None of these work:

(1) Batch export RAWs to TIFs using PixelWrench2 and using these in Photoscan
(2) Batch export RAWs to multi-page TIFs using PixelWrench2  (setting NIR channel 1 as master channel in Photoscan Pro).
(3) PixelWrench2/TifExport the above created multipage TIFs as per instructions in this forum -- PixelWrench2 creates 16 bit images (images have one channel only, makes no difference if use default or channel 1 as master).

Like others have lamented, (3) is not working, and similarly wondering 'what am i doing wrong?´

Note: locations are available for all images and there should well be sufficient overlap (about 65% lateral, 80% longitudinal).

p.s. I have been looking to purchase Agisoft Photoscan Pro as an alternative to a rival orthomosaicing software that we have been using to date but where we are unsatisfied with the quality of mosaics for NDVI calculations (as verified by field scouting) - but that depends on being able to use Photoscan to process TTC images (which the other product can do). Photoscan os doing a good job with images from digital cameras (including modified ones), but TTC processing is proving a bummer.