In tetracam tutorial (https://support.pix4d.com/hc/en-us/articles/202560219-How-to-create-and-process-a-Tetracam-dataset#gsc.tab=0) the camera band definitions are said to be taken by MCA file of the camera. However pix4d does not ask for the MCA file after adding images. Also I cannot set the band information by editing the camera model. The drop down menu only shows RGB. Can you help me in defininig the 6 bands of the images correctly. I attach some screenshots of the menus.
We were able to reproduce this issue: the images are recognized as 3 bands instead of 6. We have opened a bug report for our developers. Thanks for bringing up the problem.
The problem has been identified by the developers and the way the information from the bands is read should be improved. Updates will be posted here if it gets fixed.
We would need a *.mca image file from the Tetracam RGB+3 camera to continue fixing the issue.
This will help us understand how Tetracam saves the RGB information in the .mca, so that we can correctly read it.
Could an owner of that camera send us such files through a support request? Please mention that it is related to this Forum post.
A few improvements were made already for Tetracam cameras to improve the reading of the images and the camera model, these will be released in the next 3.3 Preview. However, to continue improving the compatibility, we would need the file above. Thanks for your help.
I have just uploaded a sample image as requested - that is 7 individual images (6 bands plus the ILS) and one multi-page TIF of the 6 bands processed using PixelWrench and your suggested workflow for processing Tetracam data.
Here is also an extract from some correspondence from Tetracam on the image format I had in the past:
"When you open a 10 bit RAW or DCM image in PW2 it is presented on screen as a 24 bit image (due to limitations of the Microsoft GDI+ display environment). 24 bits = 3 bitplanes of 8 bits each. To preserve 1024 levels of data we encode into 24 bit space;
1. Modulo division of input pixel value by 4, keep the remainder. 2. Write the quotient to the green and red bitplanes. 3. Write (quotient – remainder) to the blue bitplane.
This displays the image as monochrome with a maximum difference on the blue bitplane of –3.
To extract the original 10 bit input from this scheme;
1. Read green value. 2. Read blue value and subtract from green (results in 0 to 3) 3. Multiply green x 4 and add the difference (from above).
The pixel ordering of an RGB image is b-g-r so you need to tell your output programhow to interpret what it’s reading. If you are able to get RGB samples directly then just perform the math above to reconstruct to 10 bit."
In the past, I have separately processed the imagery an additional step (as above) to a 10-bit monochrome TIF across the 6 bands (actually saved as 16-bit) bit format to process in the SfM software we were using at that time…but I am hoping you can solve this to allow direct import of the imagery and allow us to utilise the full colour depth of 10-bit data.
The way the camera model for Tetracam cameras is read should be improved in the next Preview version that will be released here: https://cloud.pix4d.com/download/
We would need an *.mca file of a TetracamRGB+3 project to further improve the compatibility of this camera.
This new revision has not fixed the problem. The program now asks for the .mca file, but does not bring up multiple cameras as shown in your documentation. I still get an Tetracam RGB sensor that can’t be edited to add four bands. How can I send you my .mca?
Here’s a few screen shots. Loading images, reading EXIF files. Next screen asking for .mca file. Next screen after .mca was loaded showing Tatracam RGB+3 sensor loaded. I can edit the camera model, but won’t let me add the right sensor(s) with the proper four bands.
Ina, any progress on this issue? I sent you my .MCA file along with with one of the projects we are trying to modell? It seems you do not have download any of the file from We Transfer?
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