Hi all,
I have not had all the time I wanted to dedicate to this, so it is
uncomplete. Herewith I share the current draft, hoping that somebody
will pick it up and continue from here.
Architecture: a mysql database with web based input / output. Export
format, relevant for the desktop tools using the db, XML.
Two type of inputs: deterministic (i.e. specific correction parameters
as determined by a volunteer who intended to calibrate the lens) and
stochastic (i.e. the parameters obtained while optimizing a hugin
project). Credit goes to Bruno Postle and JD Smith on the hugin-ptx list
for this second approach. In both approaches the critical settings are
proper physical lens set up. The deterministic approach relies on the
volunteer to set 100% perfectly, which is seldom the case. The
stochastic approach is based on mean-reversion and relies on the fact
that the set up errors of many users in many project will cancel each
other out.
In the output, the user is free to decide on which of the two processes
he prefers to rely. Can output the whole database, or lens/camera
specific XML.
The database is in the attachement, with a bit more analysis and a short
todo list.
License is http://creativecommons.org/licenses/by/3.0/ - though this
code could be released in the public domain as far as I am concerned.
The value here is not the code, but the data in the database which takes
a lot of effort to collect and refine.
Comments and critique welcome.
enjoy the summer!
Yuv
http://www.photopla.net/070606main.php
(C) 2007 Yuval Levy, released under http://creativecommons.org/licenses/by/3.0/
1. INPUT
This database will accept two types of lens calibration profiles:
deterministic and stochastic. The stochastic process was suggested by Bruno
Postle and JD Smith on the hugin-ptx mailing list.
1.1. DETERMINISTIC PROCESS
* volunteer logs in to the web based system
* volunteer fills out a web based form to populate ci_calinfo as well as
one instance of distorsion and vignetting parameters. One hit on the
form per each set of focal distance and aperture. Up to four files
(three images and one hugin project file) per hit will be stored.
* maintainer goes over new entries in ci_calinfo and assigns ambiguous
camera/lens definition to unique disambiguated id
* maintainer verifies calibration
1.2. STOCHASTIC PROCESS
* user create a login to the web based system
* user allows hugin to transfer relevant project information
(calibration parameters)
* each project generates a hit on the database and populates ci_calinfo as well
as one instance of distorsion and vignetting parameters.
* hugin might send in an evaluation of how good the parameters are
(Pablo d'Angelo)
* maintainer uses statistic tools and methods to weed out stray parameters and
come up with a calibration output that is then exported via XML.
The database is expandable: when new/different/better algorithms become known
(such as suggested by Alexandre Jenny on hugin-ptx), a new table can be added
for those parameters, like the vi_vignetting table if the parameters are
aperture-dependent or by expanding the dp_distorsion table if they are only
focal-length dependent.
2. OUTPUT
The PHP code will generate, based on selection parameters, an XML export for
selected camera/lens combos. Selection parameters are:
- type of profile (deterministic/stochastic)
- quality level
-- deterministic: level of approval by maintainer
-- stochastic: acceptable standard deviation range from which output parameters
are calculated
-- camera (or: all cameras)
-- lens (or: all lenses)
3. TO DO:
- clean up the data structure
- write PHP code / forms to populate it
- write PHP code to export XML
# could split into different tables so that additional algorythms
# would get new tables or additional algorythms just make the table
# larger
# xml export format does not really matter, since tags can be
# added/expanded
# so far, there is one table for focal-length only dependent
# corrections and one for the combination of focal-length and aperture
QUESTION:
Does it make sense to add mount information in cl_camera2lens?
or even in an extra table?
#--------------------------------------------------------
# Table: ur_user
# Date: 2007-may-11
# Description: user static data
#--------------------------------------------------------
CREATE TABLE ur_user (
# unique user identifier
ur_uid INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# first name
ur_pname CHAR(50),
# last name
ur_lname CHAR(50),
# email
ur_email CHAR(50),
# password
ur_password CHAR(50),
# status
ur_status SMALLINT(6) UNSIGNED DEFAULT 0 NOT NULL,
# keys
PRIMARY KEY uid(ur_uid)
);
#--------------------------------------------------------
# Table: ci_calinfo
# Date: 2007-may-11
# Description: calibration info settings
#--------------------------------------------------------
CREATE TABLE ci_calinfo (
# unique set of calibration information
ci_cid INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# disambiguation
ci_lid INT(11) UNSIGNED,
# project file
ci_pto CHAR(50),
# input image 1
ci_img1 CHAR(50),
# input image 2
ci_img2 CHAR(50),
# input image 3
ci_img3 CHAR(50),
# entered lens description
ci_lens CHAR(100),
# entered lens description detail
ci_detail TEXT,
# entered camera make
ci_camera CHAR(100),
# entered manufacturer
ci_manu CHAR(100),
# entered camera type
ci_type TINYINT(2),
# entered min focal length
ci_min_fl CHAR(10),
# entered max focal length
ci_max_fl CHAR(10),
# entered max aperture
ci_max_f CHAR(10),
# entered conversion factor
ci_conv CHAR(10),
# associated distorsion parameters
ci_did INT(11) UNSIGNED,
# associated vignetting parameters
ci_aid INT(11) UNSIGNED,
# management process: user who entered the calibration
ci_uid INT(11) UNSIGNED NOT NULL,
# management process: maintainer assigned to verify
ci_mid INT(11) UNSIGNED NOT NULL,
# management process: status of the data
ci_status TINYINT(2) UNSIGNED DEFAULT 0,
# add timestamps
# add keys
# add hugin version information
# add contributing software / version
)
#--------------------------------------------------------
# Table: cl_camera2lens
# Date: 2007-may-11
# Description: entry for camera in the lens
#--------------------------------------------------------
CREATE TABLE cl_camera2lens (
# identifier of camera
cl_cid int(11) UNSIGNED NOT NULL,
# identifier of lens
cl_lid int(11) UNSIGNED NOT NULL,
# keys
PRIMARY KEY (cl_cid, cl_lid)
);
#--------------------------------------------------------
# Table: ls_lens
# Date: 2007-may-11
# Description: static lens info
#--------------------------------------------------------
CREATE TABLE ls_lens (
# unique lens/camera identifier - also used
# for disambiguation in the XML output
ls_lid INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# lens description (can be ambiguous)
ls_lens CHAR(50),
# lens/camera details
ls_details TEXT,
# crop factor belongs theoretically to the camera
# but has an influence on the correction params
# and is used only for disambiguation
ls_crop DECIMAL(3,2),
# min focal length
ls_min_fl DECIMAL(5,0),
# max focal length
ls_max_fl DECIMAL(5,0),
# max aperture
ls_max_f DECIMAL(3,1),
# lens type
ls_type TINYINT(2) UNSIGNED NOT NULL,
# management process: maintainer responsible for this entry
ls_mid INT(11) UNSIGNED NOT NULL,
# management process: status of the data
ls_status TINYINT(2) UNSIGNED DEFAULT 0,
# keys
KEY t(ls_type),
PRIMARY KEY (ls_lid)
)
#--------------------------------------------------------
# Table: ca_camera
# Date: 2007-may-11
# Description: static camera info
#--------------------------------------------------------
CREATE TABLE ca_camera (
# unique camera identifier
ca_cid INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# manufacturer
ca_manu CHAR(50),
# camera text description
ca_camera CHAR(50),
# crop factor
ca_crop DECIMAL(3,2),
# camera type
ca_type TINYINT(2),
# keys
PRIMARY KEY (ca_cid),
KEY c(ca_camera),
KEY m(ca_manu),
KEY t(ca_type)
)
#--------------------------------------------------------
# Table: fl_focal
# Date: 2007-may-11
# Description: entry for a single focal length
#--------------------------------------------------------
CREATE TABLE fl_focal (
# unique focal length identifier
fl_fid INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# applicable focal length
fl_fl SMALLINT(5) UNSIGNED,
# management process: user responsible for this entry
fl_uid INT(11) UNSIGNED NOT NULL,
# management process: status of the data
fl_status TINYINT(2) UNSIGNED DEFAULT 0,
# keys
PRIMARY KEY (fl_fid),
KEY uid(fl_uid),
KEY status(fl_status)
)
#--------------------------------------------------------
# Table: dp_distorsion
# Date: 2007-may-11
# Description: perspective distorsion and chromatic
# aberration parameters that depends only
# on the focal length.
# multiple / ambiguous entries possible
#--------------------------------------------------------
CREATE TABLE dp_distorsion (
# unique identifier for this set of parameters
dp_did INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# unique focal length id to which this aperture belongs
dp_fid INT(11) UNSIGNED,
# radial distortion correction parameters, as in PTLens
dp_a DECIMAL(10,7),
dp_b DECIMAL(10,7),
dp_c DECIMAL(10,7),
# transverse chromatic aberration red
dp_tcar_a DECIMAL(10,7),
dp_tcar_b DECIMAL(10,7),
dp_tcar_c DECIMAL(10,7),
# transverse chromatic aberration blue
dp_tcab_a DECIMAL(10,7),
dp_tcab_b DECIMAL(10,7),
dp_tcab_c DECIMAL(10,7),
# management process: user that entered the data
dp_uid INT(11) UNSIGNED NOT NULL,
# management process: status of the data
dp_status TINYINT(2) UNSIGNED DEFAULT 0,
# keys
PRIMARY KEY (dp_did),
KEY fid(dp_fid),
KEY uid(dp_uid),
KEY status(dp_status)
)
#--------------------------------------------------------
# Table: vi_vignetting
# Date: 2007-may-11
# Description: parameters for a single aperture
#--------------------------------------------------------
CREATE TABLE vi_vignetting (
# unique aperture/vignetting identifier
vi_vid INT(11) UNSIGNED NOT NULL AUTO_INCREMENT,
# unique focal length id to which these aperture
# vignetting parameters belongs
vi_fid INT(11) UNSIGNED,
# applicable aperture
vi_ap DECIMAL(3,1) UNSIGNED,
# vignetting correction
vi_b DECIMAL(10,7),
vi_c DECIMAL(10,7),
vi_d DECIMAL(10,7),
# management process: user that entered the data
vi_uid INT(11) UNSIGNED NOT NULL,
# management process: status of the data
vi_status TINYINT(2) UNSIGNED DEFAULT 0,
# primary key
PRIMARY KEY (vi_aid),
KEY fid(vi_fid),
KEY uid(vi_uid),
KEY status(vi_status)
)
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