Match File

Match file is used to import directly a list of pictures with their associated time stamps. This match file is used by the photogrammetry module and more specifically the dedicated JPEG export plugin.

The export plugin, needs a list of pictures files with associated time stamps to update EXIF/XMP pictures information with accurate position and orientation.

ASCII Match Format

This is the easiest way to import pictures match file is using a CSV like text file format.

The file format is composed of an optional header followed by pictures matches stored line by line. If Qinertia doesn't find the header, the default configuration values are used. The file can use either Windows, Unix or Linux line ending conventions and should use UTF-8 encoding.

ASCII header

The header is used to configure how Qinertia should parse and import the file. The header always starts with the  $qmatch magic keyword to identify it. Then each parameter can be set using a succession of  <param>:<value>  pairs stored line by line.

If there is no header or the parameter is not present in the file, Qinertia will use the default value that is indicated in bold.

Param	Optional	Description
$version		Match ASCII file format version, should be set to 1
$timeSource		Events time stamp format: gps: Seconds from 6 January 1980 (no leap second) gpsTow: GPS time of week in seconds utcIso: ISO 6801 (e.g. 2020-06-19T11:50:04.535Z) unix: Seconds from 1 January 1970 (UTC time) Default value is gps
$gpsWeekNumber		GPS week number to use in case $timeSource is gpsTow If gpsTow is selected this parameter is mandatory and has no default value.

ASCII data

The ASCII match data part is just a succession of time/picture match stored line per line. Each column field is separated by a tabulation '\t' or semicolon ';' character.

Field	Type	Unit	Optional	Description
timesamp	-	-		The picture time stamp expressed in the format specified by the $timeSource header field.
picture	string	-		The picture file path, can be absolute or relative and can contains spaces.
offsetN	float	m		North offset to add to the relocate the GNSS only solution from the antenna APC to the camera CMOS.
offsetE	float	m		East offset to add to the relocate the GNSS only solution from the antenna APC to the camera CMOS.
offsetD	float	m		Down offset to add to the relocate the GNSS only solution from the antenna APC to the camera CMOS.

APC to CMOS offset

This offset is only applied for GNSS only computations and is expressed directly in North East Down navigation frame. For INS computations, you can however provide a IMU to camera lever arm expressed in body frame in the dedicated Photogrammetry configuration panel.

Example

The example below shows a few matched pictures with the file header:

$qmatch
$version:1
$timeSource:gpsTow
$gpsWeekNumber:2000
490735.000;pictures/DSC08100.JPG;0.043;0.008;0.123
490736.150;pictures/DSC08101.JPG;0.003;-0.006;0.186
490737.015;pictures/DSC08102.JPG;0.023;-0.016;0.171
490737.515;pictures/DSC08103.JPG;-0.053;0.001;0.123
490738.320;pictures/DSC08104.JPG;0.032;0.036;0.165
490738.456;pictures/DSC08105.JPG;0.083;-0.022;0.194
490739.101;pictures/DSC08106.JPG;0.039;-0.011;0.174
490739.532;pictures/DSC08107.JPG;0.033;0.059;0.168
490740.000;pictures/DSC08108.JPG;0.008;-0.012;0.197
490741.000;pictures/DSC08109.JPG;0.044;0.007;0.189
490742.000;pictures/DSC08110.JPG;0.048;0.006;0.186
490743.000;pictures/DSC08111.JPG;-0.004;-0.008;0.196

Relative Path

You can use relative pictures paths. In this case, the path is relative to the input ASCII match file.