converting Agisoft Metashape lens calibration files to the ASP .tsai

[Michael Studinger]

Hi everyone,

before I ask my question let me first thank the ASP team (Oleg!) for the amazing support on this channel and a superb user manual that comes with ASP. Great job!

A colleague and I am working on converting Agisoft Metashape lens calibration files to the ASP .tsai PINHOLE/TSAI format. The Agisoft lens calibration files contain three radial distortion parameters (k1,k2,k3) and the ASP manual lists the AdjustableTSAI format for using Agisoft Metashape lens calibration parameters:

AdjustableTSAI
Radial Coeff: Vector3(1.31024e-04, 1.31024e-07, 1.31024e-08)
Tangential Coeff: Vector2(-2.05354e-07, 1.05354e-07)
Alpha: 0.4

I have copy/pasted the above into a .tsai file in the second part of the .tsai file but ASP can't ingest the format. Any pointers what I am doing wrong?

ASP does not seem to mind an additional k3 parameter in a TSAI format file, but I am guessing k3 is not being used to calculate the lens distortion. This file, including k3, ingests without issues:

VERSION_4
PINHOLE
fu = 5227.633227844355
fv = 5227.633227844355
cu = 2459.238704269580
cv = 1622.801130607475
u_direction = 1  0  0
v_direction = 0  1  0
w_direction = 0  0  1
C = 0 0 0
R = 1 0 0 0 1 0 0 0 1
pitch = 1.0
TSAI
k1 =   -0.094196634563
k2 =    0.115036424262
k3 =   -0.032238313341
p1 =   -0.000256622541
p2 =   -0.000353613460

Does anyone have an example .tsai file in AdjustableTSAI format that I can use as a template?
Thanks for any help,

Michael

[Alexandrov, Oleg (ARC-TI)[KBR Wyle Services, LLC]]

Michael,

I don't know how easy is to convert Metashape lens calibration files to ASP's ones. Could be possible, but I never tried. Can try to talk about that in more detail offline. 

To address you immediate issue, here's an adjustable tsai file that works for me:

VERSION_3

fu = 2.7972434018886133

fv = 2.7972434018886133

cu = 2.0804211742736006

cv = 1.040347088449553

u_direction = 1 0 0

v_direction = 0 1 0

w_direction = 0 0 1

C = -1935200.2981592226 -1247482.848182166 6115499.7869778136

R = -0.93368489757983908 -0.2046650229694324 0.29384475561807771 -0.15162826435410026 0.96934084312936153 0.19335769777855261 -0.32440928081713255 0.13597999196271743 -0.93609190804403952

pitch = 0.001

AdjustableTSAI

Radial Coeff: Vector3(1.31024e-04, 1.31024e-05, 1.31024e-05)

Tangential Coeff: Vector2(-2.05354e-05, 1.05354e-05)

Alpha: 0.4

What you have is fine though, but maybe something is different in the first part.

> ASP does not seem to mind an additional k3 parameter in a TSAI format file, but I am guessing k3 is not being used to calculate the lens distortion. This file, including k3, ingests without issues:

In the very latest builds I made some changes. k3 is used if provided, and not used if not. Before that, likely k3 was ignored or it would have thrown an error, not sure.

Oleg

---

From: ames-stereo-pi...@googlegroups.com <ames-stereo-pi...@googlegroups.com> on behalf of Michael Studinger <michael....@gmail.com>
Sent: Sunday, April 7, 2024 7:00 PM
To: Ames Stereo Pipeline Support <ames-stereo-pi...@googlegroups.com>
Subject: [EXTERNAL] [BULK] converting Agisoft Metashape lens calibration files to the ASP .tsai

 

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