Augmenting video files with GPS data

This post describes in detail how to add GPS data to video file using `visual correlation' (see also: Video geocoding with gpsbabel).

Crossing at Osowa

There is an easy way to augment video files with GPS data using GPSbabel. Since version 1.4 of GPSBabel is able to create a subtitle file from a GPS tracklog. The subtitle contains latitude/longitude/altitude as well as the time. With a simple Perl scripts I have added current speed (not particularly accurate however).

To convert GPX file to subtitles one have to execute:

gpsbabel -i gpx -f FILE.gpx -o subrip,video_time=hhmmss,gps_time=hhmmss,gps_date=YYYYMMDD -F FILE.srt

Where: video_time -- video position (relative to beginning of video) for which exact corresponding GPS timestamp is known. gps_time -- the time part of the GPS timestamp which corresponds to a known position in the video. gps_date -- the date part of the GPS timestamp which corresponds to a known position in the video.

On a video (see below) you can see that in 34 second I passed the zebra crossing. The zebra's crossing coordinates can be easily identified at Google Maps (cf. picture Crossing at Osowa). Now one have to search the GPX track for the point which is nearest to 54.429591/18.477973. I developed a simple Perl script for that purpose:

$ perl My_GPX_nearest_timestamp.pl -c 54.429591:18.477973 20130420.gpx
*** USAGE: My_GPX_nearest_timestamp.pl -c latitude:longitude GPX-file
*** Looking for 20 points near: 54.429591:18.477973 (lat/lon) ***
> 15.3758195746663 2013-04-20T10:27:09Z  54.429509640:18.477780819
> 22.0617273294607 2013-04-20T09:05:15Z  54.429701502:18.478256240
> 32.6458959467509 2013-04-20T10:27:15Z  54.429787332:18.478348190
> 43.3771684316959 2013-04-20T09:05:24Z  54.429531014:18.477310427
> 47.7727043140018 2013-04-20T09:05:11Z  54.429905936:18.478475260
> 63.903936892351 2013-04-20T10:27:00Z  54.429627573:18.476987137
> 70.171200323179 2013-04-20T09:05:28Z  54.429655485:18.476893930

One can stipulate from the above output that I passed a point 15,4 meters away from 54.429591/18.477973 at 10:27:09 GMT as well as I passed another point which is 22 meters away from 54.429591/18.477973 at 09:05:15. As I cycled back and forth along the same route the second point is valid, the first is accidentally closer but as the time is almost one and half hours later it is clear that I was there on returning home. So gpsbabel should be executed as follows (20130420.gpx contains GPX track):

gpsbabel -i gpx -f 20130420.gpx -o subrip,video_time=000034,gps_time=090515,gps_date=20130420 -F 20130420_1.srt

Speed is added with another very simple Perl script:

perl add_speed_2_srt.pl 20130420_1.srt > 20130420_1_S.srt

Just to remind: internally all GPS units record time/date using Coordinated Universal Time aka Greenwich Mean Time vel Zulu time (for army enthusiasts). What the unit displays is another matter (usually it displays local time).

Pierwszy film poklatkowy

Ustaliłem empirycznie w jaki sposób podłączyć aparat do Raspberry Pi (do SheevaPlug zresztą też) żeby nic się nie zacinało. W skrócie:

1. Używam kompakta Nikon S3000 (Canon A620 się zacinał/odłączał--sprzedałem go na Allegro).

2. Podłączam aparat poprzez aktywny USB hub (kupiłem w tym celu cztero-portowy HUB firmy Vivanco).

3. Po każdym zdjęciu wykonuję reset stosownego portu USB za pomocą programiku pn. usb_reset (zobacz tutaj oraz tutaj).

Kilka aparatów

Używam dwóch aparatów Nikon S3000 (kupionych na Allegro oczywiście), więc jest problem z ustaleniem który jest który:

$gphoto2 --auto-detect
Model                          Port                                            
----------------------------------------------------------
Nikon Coolpix S3000 (PTP mode) usb:001,022     
Nikon Coolpix S3000 (PTP mode) usb:001,021  

Można użyć opcji --port usb:001,022 aby wykonać coś z ,,pierwszym'' aparatem oraz --port usb:001,021, aby dostać się do drugiego. Oczywiście umieszczenie numerów portów na-zicher w skryptach byłoby kiepskim pomysłem ponieważ nie są one ustalone, ale się zmienią jeżeli urządzenie zostanie odłączone/przyłączone ponownie. Lepszym sposobem zidentyfikowania aparatów jest wykorzystanie numeru seryjnego:

## $gphoto2  --get-config serialnumber --port PORT
## example
$gphoto2  --get-config serialnumber --port usb:001,022
Label: Serial Number                                                           
Type: TEXT
Current: 000047514512

Mam czarnego Nikona o numerze 000041076602 oraz różowego o numerze 000047514512. Używam następującego skryptu do wykonania zdjęcia określonym aparatem:

#!/bin/bash
PINK_CAM_ID='000047514512'
BLACK_CAM_ID='000041076602'

while test $# -gt 0; do
  case "$1" in
    -b|--black)   REQ_CAM="$BLACK_CAM_ID";;
    -p|--pink)    REQ_CAM="$PINK_CAM_ID";;
  esac
  shift
done

## Nazwa pliku ze zdjęciem:
FILENAME="NIK`date +"%Y%m%d%H%M"`.jpg"

## Przejrzyj wszystkie podłączone aparaty:
while read PORT_ID 
do 
        ##echo $PORT_ID 
        ## -n means string is non-empty
        if [ -n "$PORT_ID" ] ; then
                CAM_ID=`gphoto2 --get-config serialnumber --port $PORT_ID | awk '/Current:/ { print $2 }' `
                if [ $CAM_ID = "$REQ_CAM" ] ; then
                        REQ_CAM_PORT="$PORT_ID"
                        ##echo "*** Req Camera ID: #$CAM_ID."
                fi
        fi
        
done <<< "`gphoto2 --auto-detect | grep usb | awk '{ print $6}'`"

# Na wypadek błędu wyślij alarmowego SMSa
if [ -z "$REQ_CAM_PORT" ] ; then
      echo "*** Error: Camera $REQ_CAM not found ***"
      ## sent a SMS cf http://pinkaccordions.homelinux.org/wblog/sms_alerts_with_google_calendar.html
      sms_reminder.sh
      exit 1   
fi

## reset USB 
REQ_CAM_PORT_DEVNAME=`echo $REQ_CAM_PORT | sed 's/^.*://' | sed 's/,/\//'`
usb_reset /dev/bus/usb/${REQ_CAM_PORT_DEVNAME}

LANG=C gphoto2 --port "$REQ_CAM_PORT" --force-overwrite --set-config flashmode=1 \
   --set-config d002=4 \
   --capture-image-and-download --filename "$FILENAME"

## reset USB (powtórny) 
usb_reset /dev/bus/usb/${REQ_CAM_PORT_DEVNAME}

Właściwość d002 ustawia rozdzielczość zdjęcia (4 oznacza 2592x1944).

Wartość 1 właściwościflashmode wyłącza flash.

Z moich eksperymentów wynika, że bez wykonania usb_reset bateria aparatu nie jest doładowywana (czemu?) i po pewnym czasie z powodu braku zasilania aparat odłącza się.

Film

Po czterech tygodniach mam wystarczająco dużo zdjęć aby spróbować zrobić pierwszy film.

Najpierw konwertuję wszystkie zdjęcia do rozdzielczości 1920x1080 za pomocą programu convert (z zestawu ImageMagick) uruchamianego z ,,wewnątrz'' prostego skryptu Perla. Ponieważ nazwy plików wejściowych są konstruowane wg schematu NIKYYYYMMDDHHMM.jpg (gdzie YYY to rok, MM oznacza miesiąc, itd.) sortowanie alfabetyczne oznacza ustawienie ich także we właściwym porządku chronologicznym. Nazwy plików wynikowych są zaś konstruowane jako: hd1920_00001.jpg, hd1920_00002.jpg, itd.

#!/usr/bin/perl

opendir (DIR, ".");
my  @files = sort { $a cmp $b } readdir(DIR);

while (my $file = shift @files ) {
   if ($file =~ /.jpg$/) {  $fileNo++;
      $file_out = sprintf "hd1920_%05d.jpg", $fileNo;
      print "$file -> $file_out\n";
      system ("convert", $file, "-geometry", "1920x1080", "$file_out");
   }
}

Okazało się, że jest dokładnie 1784 zdjęć:

$ls -l hd1920_0* | wc -l
1784

Konwersja trwała około 30 min na moim przeciętnym zupełnie PC-cie. Każdy plik wynikowy miał około 0,5Mb; wszystkie razem zajmowały około 0,85Gb:

$ls -l hd1920_0* | awk '{t+=$5}; END{print t}'
853332231

Film został wykonany za pomocą programu ffmpeg:

ffmpeg -r 12 -qscale 2 -i hd1920_%05d.jpg Tomato_12.mp4

Gdzie -r 12 oznacza liczbę klatek na sekundę (12 fps) a -qscale określa jakość (1 oznacza najlepszą, 32 najgorszą jakość).

Film ma około 450 Mb. Konwersja zajmuje około 3min (on my decent PC) a długość filmu to 2min i 29 sekundy.

Film przedstawia sadzonkę pomidora (Pinkaccordion oczywiście :-). Zdjęcia były robione co 20 minut od 16 marca do 11 kwietnia.

Są także wersje na 25 fps oraz 6 fps.

Ponura historia sprzed lat

Jak byłem dawno temu w Anglii, to akurat w BBC puszczono film dokumentalny nt. następujących zdarzeń: Aidan Starrs, Gregory Burns i John Dignam -- agenci FRU oraz członkowie IRA mordują 30 czerwca 1992 r. Margaret Perry z obawy, że ta ostatnia może ich wydać. Morderstwo M. Perry pozostaje niewyjaśnione przez ponad rok -- do czasu aż mordercy Perry zostają porwani i zabici przez ISU, czyli kontrwywiad Armii Republikańskiej. Na dokładkę okazało się po latach, że w ISU latami działał inny agent FRU Freddie Scappaticci. Tak mi się to przypomniało a szczegóły wyguglałem, bo przecież po latach tych wszystkich detali i nazwisk nie pamiętałem.

Notka w BBC na temat.

Time lapse: first production

After almost 4 weeks I have enough pictures to create my first video production. (How to capture images with a still camera attached to Raspberry Pi is described here and here.)

I started from converting all pictures to 1920x1080 resolution with convert run from a simple Perl script. As the input file names are constructed as NIKYYYYMMDDHHMM.jpg (where YYY denotes year, MM denotes month etc) alphabetic sorting is OK. The resulting files are named as hd1920_00001.jpg, hd1920_00002.jpg, etc.

#!/usr/bin/perl

opendir (DIR, ".");
my  @files = sort { $a cmp $b } readdir(DIR);

while (my $file = shift @files ) {
   if ($file =~ /.jpg$/) {  $fileNo++;
      $file_out = sprintf "hd1920_%05d.jpg", $fileNo;
      print "$file -> $file_out\n";
      system ("convert", $file, "-geometry", "1920x1080", "$file_out");
   }
}

There are exactly 1784 pictures:

$ls -l hd1920_0* | wc -l
1784

Conversion of all images lasted circa half an hour on my decent PC. Each picture size is about 0,5Mb, while the total size is 0,85Gb:

$ls -l hd1920_0* | awk '{t+=$5}; END{print t}'
853332231

To create a video from the images I run ffmpeg now:

ffmpeg -r 12 -qscale 2 -i hd1920_%05d.jpg Tomato_12.mp4

Where -r 12 means frames ratio (12 fps) and -qscale determines video quality (1 denotes best quality and 32 is the lowest one).

The video size is about 450 Mb. The conversion takes circa 3min (on my decent PC) and the video length is 2min 29 seconds.

The movie's subject is a growing tomato (Pinkaccordion variety of course:-). The photographs were taken every 20 minutes from March 16th to April 11th.

There are versions at 25 fps and 6 fps as well.

Raspberry Pi: some progress with time-lapse photography

I have made some progress in accessing still camera with gphoto2 (cf. here). The detailed description of my set-up will be disclosed within a few weeks (as I am still not sure if it is 100% success:-). In short:

I changed camera from Canon A620 to Nikon S3000.

I connected camera with active USB hub.

On every capture USB port is reset with usb_reset utility (cf here and here)

Multiple cameras

I use two Nikon S3000 compact cameras so there is a problem how to identify which is which.

$gphoto2 --auto-detect
Model                          Port                                            
----------------------------------------------------------
Nikon Coolpix S3000 (PTP mode) usb:001,022     
Nikon Coolpix S3000 (PTP mode) usb:001,021  

So one can use --port usb:001,022 option to access first attached camera and --port usb:001,021 to access the second one. Of course hard-coded port numbers are troublesome as they are not fixed and change if the device is disconnected/connected again. Better way to identify the camera is to use it's serial number:

## $gphoto2  --get-config serialnumber --port PORT
## example
$gphoto2  --get-config serialnumber --port usb:001,022
Label: Serial Number                                                           
Type: TEXT
Current: 000047514512

I have black Nikon with 000041076602 serial number and pink one with 000047514512 serial number. I use the following bash script to access the cameras:

#!/bin/bash
PINK_CAM_ID='000047514512'
BLACK_CAM_ID='000041076602'

while test $# -gt 0; do
  case "$1" in
    -b|--black)   REQ_CAM="$BLACK_CAM_ID";;
    -p|--pink)    REQ_CAM="$PINK_CAM_ID";;
  esac
  shift
done

## Picture filename:
FILENAME="NIK`date +"%Y%m%d%H%M"`.jpg"

## Scan all attached cameras:
while read PORT_ID 
do 
        ##echo $PORT_ID 
        ## -n means string is non-empty
        if [ -n "$PORT_ID" ] ; then
                CAM_ID=`gphoto2 --get-config serialnumber --port $PORT_ID | awk '/Current:/ { print $2 }' `
                if [ $CAM_ID = "$REQ_CAM" ] ; then
                        REQ_CAM_PORT="$PORT_ID"
                        ##echo "*** Req Camera ID: #$CAM_ID."
                fi
        fi
        
done <<< "`gphoto2 --auto-detect | grep usb | awk '{ print $6}'`"


if [ -z "$REQ_CAM_PORT" ] ; then
      echo "*** Error: Camera $REQ_CAM not found ***"
      ## sent a SMS cf http://pinkaccordions.blogspot.com/2013/03/automatic-sms-alerts-using-google.html
      sms_reminder.sh
      exit 1   
fi

## reset the USB device
REQ_CAM_PORT_DEVNAME=`echo $REQ_CAM_PORT | sed 's/^.*://' | sed 's/,/\//'`
usb_reset /dev/bus/usb/${REQ_CAM_PORT_DEVNAME}

LANG=C gphoto2 --port "$REQ_CAM_PORT" --force-overwrite --set-config flashmode=1 \
   --set-config d002=4 \
   --capture-image-and-download --filename "$FILENAME"

## reset the USB device again
usb_reset /dev/bus/usb/${REQ_CAM_PORT_DEVNAME}

Property d002 sets picture resolution (4 means 2592x1944).

Value 1 of flashmode turns-off flash.

It seems that without usb_reset there are problems with battery charging (why?)

LaTeX: example of a complex titlepage design

Let's start from example preamble:

\documentclass[twoside]{article}
\usepackage{fancyhdr}

\pagestyle{fancy}
\renewcommand{\headrulewidth}{0.4pt}
\renewcommand{\footrulewidth}{0.4pt}

\makeatletter
%% headlines (\@shorttitle/\@shortauthorlist see below):
\fancyhead[RO]{\@shorttitle}
\fancyhead[LE]{\@shortauthorlist}

 ...
\makeatother

% Title (in Polish) and alternate title (in english):
\title{Hemofiltracja i~rewaskularyzacja u~pacjenta 
  z~zespołem sercowo-nerkowym typu 2}
\alttitle{Hemofiltration in patient with cardio-renal syndrome type 2}

% Authors list:
\author{WLUJ}{Janina Kowalska }
\author{CIL}{Zofia Dyrman}
\author{KCW}{Andrzej Jarzyna}
\author{CIL}{Wacław Jarząbek}
\author{CIL}{Krzysztof Chrostowicz}
% Undefined affiliation raises an error:
% \author{DoPX}{Zdzisław Dyrman}

% Affliations list:
\affiliation{WLUJ}{Wydział Lekarski Uniwersytetu Jagiellońskiego 
 -- Collegium Medicum, ul.~św.~Anny 12, 31--008 Kraków}
\affiliation{CIL}{Centrum Interwencyjnego Leczenia Chorób Serca 
 i~Naczyń, KSzS im.~Jana Pawła II, ul. Prądnicka 80, 31--202 Kraków}
\affiliation{KCW}{Klinika Choroby Wieńcowej UJ, Collegium Medicum,
 KSzS im. Jana Pawła II, ul. Prądnicka 80, 31--202 Kraków}
% Extra affiliation raises an error:
% \affiliation{DRS}{Druskienniki, Pendological Department}

% Short versions of title/authors list (defined if title/authors list
% is too long to fit the headlines:
% \shortauthor{Tratata}
% \shorttitle{Fififif}
%
\begin{document}
\maketitle

\end{document}

The titlepage

The main problem is long lists of authors and affiliations. There are more authors than affiliations so affiliations are labelled with consecutive numbers and each author is marked with appropriate label indicating his/her affiliation. It can be done manually of course but with the help of a few clever macros the numbers can be computed by LaTeX. This feature can be particularly helpful when for instance just before the (printing house) deadline a very important author (probably professor) insists his affiliation should be 1 not 4 (for example). All is needed to achieve this is to reorder \affiliation declarations.

The resulting document looks like shown in the picture.

The macros used:

%++Authors and affiliations
\newcount \authornumber
\newcount \affiliationnumber
\authornumber=0
\affiliationnumber = 0
%
\def\alttitle#1{\gdef\@alttitle{#1}}%
\def\shortalttitle#1{\gdef\@shortalttitle{#1}}

\def\author#1#2{%
  \global\advance\authornumber\@ne
  \authorAffiliationId{#1}% -- label --
  \authorName{#2}% -- author's name --
}
%
\def\authorAffiliationId#1{%
  \expandafter\def\csname theauthorid\number%
    \authornumber\endcsname {#1}% --author's id--
  %% label defined to check if affiliation exists:--
  \expandafter\def\csname theaffid:#1\endcsname {#1}%
}
%
\def\authorName#1{%
  \expandafter\def\csname theauthor\number%
    \authornumber\endcsname{\ignorespaces#1\unskip}%
  \expandafter\let\csname theauthoraffiliation\number%
    \authornumber\endcsname\relax
}
%
\def\affiliation#1#2{%
  \global\advance\affiliationnumber\@ne
  \expandafter\def\csname theaffiliation \number%
    \affiliationnumber \endcsname {\ignorespaces#2\unskip}%
  \expandafter\edef\csname affid:#1\endcsname {\number\affiliationnumber}%
  %% if defined in class CLS add error mesage:
  %%\@ifundefined{theaffid:#1}{\ClassError{CLS}{**Affiliation undefined: `#1'}\@ehc}{}%
}
%
\def\@author{\@defaultauthorlist}
\def\@affiliation{\@defaultaffiliationlist}
%
\newcount\count@@
%
% Authors/affiliations lists
\def\@defaultauthorlist{%
   \count@=\authornumber
   \count@@=0
   \begingroup
   \loop
   \ifnum\count@>0
      \advance\count@@ by 1
      \ignorespaces\csname theauthor\number%%
         \count@@\endcsname %-- autor's name --
      \edef\@TmP@Aff@Etykieta{\csname theauthorid\number\count@@ \endcsname}%
      % --check if \@TmP@Aff@Etykieta  exists: --
      \@ifundefined{affid:\@TmP@Aff@Etykieta}%
      %% if defined in class CLS add error mesage:
      %%{\ClassError{CLS}{**Brak afiliacji dla \csname theauthor\number%
      %%\count@@\endcsname}\@ehc}%
      %% print out affiliation label (number):
      {$^{\csname affid:\@TmP@Aff@Etykieta\endcsname}$}%
      %--Every author but last is separated by a comma--:
      \ifnum\count@=1\relax\else,\space\fi
      \advance\count@ by -1
   \repeat
   \endgroup
  }
% Short list of authors (w/o affiliations labels) for headlines.
% Simplified version of @defaultauthorlist:
\def\@defaultshortauthorlist{%
   \count@=\authornumber
   \count@@=0
   \begingroup
   \loop
   \ifnum\count@>0
      \advance\count@@ by 1
      \ignorespaces\csname theauthor\number\count@@\endcsname
      \ifnum\count@=1\relax\else,\space\fi
      \advance\count@ by -1
   \repeat
   \endgroup
  }
%
% Affilitions list:
\def\@defaultaffiliationlist{%
   \count@=\affiliationnumber
   \count@@=0
   \begingroup
   \loop
   \ifnum\count@>0
      \advance\count@@ by 1
      $^{\the\count@@}$ %-- affiliation number
      %-- print out the affiliation:
      \ignorespaces\csname theaffiliation \number\count@@\endcsname
      % ++Every affiliation but last is separated by a comma ++ :
      \ifnum\count@=1\relax\else,\space\fi
      % każda afiliacja od nowego wiersza:
      \par
      \advance\count@ by -1
   \repeat
   \endgroup
  }
% ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
% ++SIMPLIFIED titlepage (just to demonstrate macros defined):++
\renewcommand\maketitle{%
  \begin{titlepage}%
    \let\footnotesize\small
    \let\footnoterule\relax
    \let \footnote \thanks
    % ++Title: ++
    \parindent0pt
    \rightskip0pt plus 4em \pretolerance10001
    \leavevmode \noindent
    {\Large \sffamily \bfseries
    \@title\par
    % ++ Optional alternative title:
    \@ifundefined{@alttitle}{}{\vskip9pt%
    \large \sffamily \bfseries \@alttitle \par} }
    \vspace{5mm}
    % ++Authors list:
    {\rightskip 0pt plus6em%
     \@author\par}
    %
    \vspace{30pt}
    % ++Affiliations list
    {\rightskip 0pt plus6em \@affiliation\par}
    %
    % ++Define content for running headers/footers:
    \@ifundefined{@shortauthorlist}{\gdef\@shortauthorlist{\@defaultshortauthorlist}}{}%
    \@ifundefined{@shorttitle}{\gdef\@shorttitle{\@title}}{}%
    \@ifundefined{@shortalttitle}{\gdef\@shortalttitle{\@alttitle}}{}%
    % 
    \thispagestyle{empty}
  \end{titlepage}%
  %
  \setcounter{footnote}{0}%
  \global\let\thanks\relax
  \global\let\maketitle\relax
  \global\let\@thanks\@empty
  \global\let\title\relax
  \global\let\author\relax
  \global\let\date\relax
  \global\let\and\relax
}%%//maketitle//

\def\shorttitle#1{\gdef\@shorttitle{#1}}
\def\shortauthorlist#1{\gdef\@shortauthorlist{#1}}
\let\shortauthor\shortauthorlist

LaTeX: how to highlight some bibliography entries by adding an asterisk before the entry?

Author-year citation style is assumed.

If a bibliography is prepared manually it is as easy as to precede each entry with say \bibAst command. Example:

\newcommand\bibAst{\leavevmode\hbox to0pt{\hss$^\ast$}}

\harvarditem[Bagozzi and Dholakia]{Bagozzi and
  Dholakia}{2006}{bagozzidholakia06}
\bibAst\textsc{Bagozzi, R.~P.,  {\small and} U.~M. Dholakia}  (2006): ``Open
  Source Software User Communities: A Study Of Participation In {L}inux {U}ser
  {G}roups,'' \emph{Management Science}, 52(7), 1099--1115.

If one insists on using BiBTeX one has to mark records which are to be highlighted. It can be done with an extra field (named highlight in the example below):

@Article{bagozzidholakia06,
  title	= "Open Source Software User Communities: A Study Of
   Participation In {L}inux {U}ser {G}roups",
  author	= "Bagozzi, Richard P. and Dholakia, Utpal M.",
  journal	= j-msci,
  pages		= "1099--1115",
  number	= "7",
  volume	= "52",
  year		= "2006",
  highlight     = "Y"
}

Fields unknown to BiBTeX's particular style are omitted, so highlight cause no harm when processed with standard BiBTeX style.

One need to modify BiBTeX style now. This is a two-step procedure. First one has to add highlight to the body of ENTRY function:

ENTRY
 {
  ...
  highlight
 }

Next one has to modify format.authors function. Exact form of a format.authors function is style-dependent. In case of apalike the code looks like:

%FUNCTION {format.authors}
%{ author empty$
%    { "" }
%    { author format.names }
%  if$
%}
% change to:
FUNCTION {format.authors}
{ author empty$
    { "" }
    { highlight empty$
       { author format.names }
       { "{\bibAst}" author format.names * }
       if$
    }
  if$
}

BTW: the meaning of some BiBTeX expressions are as follows: S1 S2 * denotes S1 S2 strings concatenation; L F1 F2 if$ denotes logical if (execute F1 if L is true otherwise execute F2).

The contents of highlight is irrelevant. Sole existence of highlight denotes that the record is highlighted.

NOTE: the style should be more elaborate if some BiBTeX entries starts with something other than authors names.

Automatic SMS Alerts Using Google Calendar

The idea is to add an event to Google calendar with some short start time from now (say 15 minutes) and SMS reminder feature.

#!/bin/bash
# reminder via google with 15 minutes from now start time
#
MESSAGE="Neptune ALARM: something nasty has happened!"

# In case of service failure try 3 times:
for i in 1 2 3; do

# Compute 15min from now time with date:
NOW=`date "+%s"`
TIME_SHF1=$(($NOW + 900 ))
FWD_TIME1=`date +"%d/%m/%Y %H:%M" -d"@$TIME_SHF1"`; 

# Check for optional script argument 
if [ -n "$1" ] ; then MESSAGE="Neptune ALARM: $1" ; fi 

# use GoogleCL to add to calendar with 15m from now/1m reminder
google calendar add "$MESSAGE $FWD_TIME1" --reminder="1m"

RC=$?

if [ $RC -ne 0 ] ; then
   sleep 30;
else
   break ;
fi

done

The script uses GoogleCL (a python-based command-line utility for accessing Google). Installing GoogleCL is easy:

sudo apt-get  install googlecl
# or (in case there is no ready-to install package):
wget http://googlecl.googlecode.com/files/googlecl-0.9.13.tar.gz
tar -zxvf googlecl-0.9.13.tar.gz
cd googlecl-0.9.13
sudo python setup.py install

Note: googleCL is launched via google not googleCL command.

The first time one uses googleCL, ie:

google calendar add "test from neptune 22/03/2013 10:30:22"

it will prompt for one's Google username. One has to type it in and hit enter. Next the user is asked to grant access permissions.

On non-gui systems (text-based) w3m browser usually will be launched. When connected to google one has to press q y and the text silimlar to the following will be displayed:

Please log in and/or grant access via your browser 
at https://www.google.com/accounts/OAuthAuthorizeToken?oauth_token=\
    4%xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx&hd=default then hit enter.

One has to copy the above link to another machine (with gui browser). Next one has to grant access and then go back to the terminal and hit enter to complete the authorization.

BTW the access token is stored in:

~/.local/share/googlecl/access_tok_USERNAME

If access is granted from some machine it will probably suffice to copy the access token file to another machine to grant access for it as well (not tested).

The configuration file for googleCL is in:

~/.config/googlecl

If access is grated successfully the message similar to the following will be displayed:

Event created: http://www.google.com/calendar/event?eid=\
anFsdGFucXFwdmZnbW1sMmcwc2t1NDI3cm8gbG9vc2VoZWFkcHJvcDFAbQ

LaTeX: znaki cięcia/pasery, pakiety crop i fancyhdr

Kol. WP dba żebym nie wyszedł z wprawy w temacie znajomości LaTeXa.

Jakiś czas temu zażyczył sobie znaków cięcia (zwanych także paserami). Znaki cięcia mają określać wielkość kartki papieru jako 290x205mm (prawie A4). Mają być umieszczone na stronie o nietypowych wymiarach 330x250mm.

Używając pakietu crop można powyższe zalecenie zrealizować następująco:

\documentclass{article}

%% Inne pakiety dołączyć tutaj ...

\setlength\paperheight {290mm}\setlength\paperwidth{205mm}
\usepackage[cam,center,width=250truemm,height=330truemm,pdftex]{crop}
%%
%% Kolumna ma być wyśrodkowana na kartce (zalecenie drukarni)
%% Margines wynosi ( \paperwidth -\textwidth )/2
\oddsidemargin 18.5truemm %% dla \textwidth =  168mm
\evensidemargin\oddsidemargin

\begin{document}

...

\end{document}

No i działa. Dokument jest składany XeTeXem; używa w związku z tym pakietów polyglossia, fontspec, xunicode oraz xltxtra. Powyższe pakiety korzystają z kolei ze stada pakietów z l3kernel/l3packages bundles (fragment przyszłej, ciągle tworzonej od 20 bodajże lat, trzeciej wersji LaTeXa -- LaTeX3 project).

Po jakimś czasie okazało się, że nie działa w MikTeX 2.09. Pierwsza (tytułowa) strona jest podniesiona (względem znaków cięcia) o ok 4mm w porównaniu do wszystkich następnych.

Po dłuższym badaniu stwierdzono, że winna jest dwuwierszowa pagina górna znajdująca się na stronie tytułowej. Wydawała się niegroźna i co więcej, dokument był poprawnie kompilowany, ale tylko w dystrybucji TL 2011. Coś zmieniono w zestawie pakietów l3* (których jest dużo jak wiemy) i to te pakiety odpowiadają za błąd.

Żeby obejść problem postanowiłem składać dwuwierszową paginę w pudełko pionowe (\vbox) o wysokości równej wysokości wiersza tekstu:

\setbox0\hbox{\PM@HeaderFont\strut} %% 
\newdimen\PM@HeaderHt \PM@HeaderHt=\ht0
\def\PM@vboxToOneLine#1{\vbox to\PM@HeaderHt{#1\vss}}
%% ^^^^^^^ pudełko o wysokości wiersza tekstu ^^
%% %% ...
\fancypagestyle{plain}{%% zawartość paginy na stronie tytułowej:
\fancyhf{} % 
 %% ...
\fancyhead[L]{\leavevmode 
  \hbox{\PM@vboxToOneLine{\PM@HeaderFont pierwszy-wiersz ... \\
         ... drugi wiersz ...}}} %
\fancyhead[R]{\leavevmode 
   \hbox{\PM@vboxToOneLine{\PM@HeaderFont pierwszy-wiersz ... \\
         ... drugi wiersz ...}}}
%% ...
}

Teraz działa lepiej.

Nawiasem mówiąc dwuwierszowe paginy to kiepski pomysł. W szczególności fancyhdr wyrównuje górne wiersze pagin, co oznacza, że np. kreska pod paginą będzie nie wyrównana jeżeli (przykładowo) lewa pagina jest dwuwierszowa a prawa jednowierszowa. W omawianym przypadku nie ma kreski pod paginą, dwuwierszowa pagina jest zdefiniowana wyłącznie na stronie tytułowej (której układ jest znakomicie różny od pozostałych stron) a i tak skończyło się problemem.

Raspberry Pi: first steps with time-lapse photography

A620 powered with CA-PS500

A620 (side view)

I would like to remote control a still camera via gphoto2. After consulting a  list of supported cameras I bought (used) Canon A620 from Allegro (local Internet auction site, sort of E-bay).

This camera has many great features (I suspect even too great as Canon stop producing cheap cameras of this sort): viewfinder, retractable LCD and can be powered with Compact Power Adapter CA-PS500 instead of batteries (an important feature in my project). The plan was simple: connect camera via USB cable to computer and power it with PSU. Capture photos periodically with gphoto2:

 gphoto2 --auto-detect
     
 pi@raspberrystar ~/bin $ gphoto2 --auto-detect
 Model                          Port                                            
 ----------------------------------------------------------
 Canon PowerShot A620 (PTP mode) usb:001,006    

So far, so good.

Now, I tried to capture a photo:

# one shot without flash, download the file and store in a file named as: GPHyyyymmddhhmm.jpg
LANG=C gphoto2 --set-config flashmode=0 --capture-image-and-download --filename "GPH%Y%m%d%H%M.jpg"

As the creation time is wrong (due to camera wrong clock) I modified the above as follows (note that touch is used to adjust file's timestamp):

#!/bin/bash
FILENAME="GPH`date +"%Y%m%d%H%M"`.jpg"

LANG=C gphoto2 --set-config flashmode=0 --capture-image-and-download --filename "$FILENAME"
touch "$FILENAME"

Unfortunately there are problems: I am able to remotely capture only one photo. Next remote capture try results in an error and the camera has to be hard reset (with power on/off button). The problem is reported by others too.

BTW: when I connected the camera to my PC the reliability is much better (but seems not perfect---I experienced camera disconnection too.)

My first try to resolve the problems was to update gphoto2 (raspbian contains version 2.4.14 of gphoto2).

Compiling newest (march 2013) version of gphoto2 on Raspberry Pi

## optionally remove old version (there are no dependencies)
apt-get remove gphoto2

There is no need to remove gphoto2 as compiled one will be installed in another directory (/usr/local/ vs /usr/).

First install/compile the necessary packages:

apt-get install -y libltdl-dev libusb-dev libexif-dev libpopt-dev

## Download and install newer version of libusb 1.0.11
wget http://ftp.de.debian.org/debian/pool/main/libu/libusbx/libusbx_1.0.11.orig.tar.bz2
tar xjvf libusbx_1.0.11.orig.tar.bz2
cd libusbx-1.0.11/

./configure &&  make && sudo make install

## Download and install newer version of libgphoto
wget http://garr.dl.sourceforge.net/project/gphoto/libgphoto/2.5.1.1/libgphoto2-2.5.1.1.tar.bz2
tar xjf libgphoto2-2.5.1.1.tar.bz2
cd libgphoto2-2.5.1.1

./configure &&  make && sudo make install

Download and install newer version of gphoto2

wget http://downloads.sourceforge.net/project/gphoto/gphoto/2.5.1/gphoto2-2.5.1.tar.gz
tar xzvf gphoto2-2.5.1.tar.gz
cd gphoto2-2.5.1

./configure &&  make && sudo make install

## run ldconfig
sudo ldconfig
gphoto2 --version
gphoto2 2.5.1

Copyright (c) 2000-2013 Lutz Mueller i inni

BTW compiling gphoto2 on my fedora 14 box requires to install libtool-ltdl-devel popt-devel first:

#configure: error: cannot compile and link against libltdl
#libgphoto2 requires libltdl (the libtool dl* library),
#but cannot compile and link against it.

yum -y install libtool-ltdl-devel popt-devel

Upon installing above two packages, the compilation of libusb, libgphoto and gphoto2 proceeds smoothly.

Unfortunately installing new version of gphoto2 did not help.

The problem will be further examined...

Video geocoding with gpsbabel

Contour camera

NOTE: This post is (partially) obsolete as I prefer `visual correlation' method now (see my newer post.)

Some time ago I bought a Contour HD camera on Ebay and the seller claimed he was selling it as he want to upgrade to GPS enabled model. That inspired me to investigate how I can do the same with the camera lacking build-in GPS receiver. For example to geotag photos one can use GPS enabled still cameras, but usually it is a costly luxury and it suffice to synchronize GPS log with a photo timestamp. Using this approach I have developed a simple bash scripts which works neatly with all my cameras. So I can geotag my photographs without wasting a lot of time.

In case of video images the approach is similar: one has to synchronize video and GPS data. The best approach is to film the display of the GPS unit showing the GPS time. In case when the camera is unable to get a good quality image (because the digits are too small for example as in case of my Garmin Legend) a simple trick can be used: just one has to write down time on a sheet of paper (using 15-30 seconds time-ahead) and in a appropriate moment film it. Or one can says out loudly the time displayed if the microphone is able to record it. Looks silly and old fashioned but works. Instead of the above two methods one have to establish initial video geolocation with `visual correlation' method (described in the next paragraph).

The camera Pause button should not be used as it breaks out the GPS-camera synchronization. Namely after every pause one has to establish correct initial geolocation which can be difficult but not impossible (`visual correlation' can be used ie. inspecting video for distinguishable objects which geo-position can be established). I think the advantage of GPS-equipped camcorder boils down to that aspect (one can use Pause w/o worrying that his/her video will be out of sync.) but I suspect to take this extra advantage some extra software is needed which almost for sure runs on MS Windows. For a Linux users it can be usless or at least troublesome.

The only method I tried to augment video files with GPS data is to convert them to video subtitles. Since version 1.4 of GPSBabel is able to create a subtitle file from a GPS tracklog. The subtitle contains latitude/longitude/altitude as well as the time and current speed.

To convert GPX file to subtitles one have to execute:

gpsbabel -i gpx -f FILE.gpx -o subrip,video_time=hhmmss,gps_time=hhmmss,gps_date=YYYYMMDD -F FILE.srt

Where: video_time -- video position (relative to beginning of video) for which exact corresponding GPS timestamp is known. gps_time -- the time part of the GPS timestamp which corresponds to a known position in the video. gps_date -- the date part of the GPS timestamp which corresponds to a known position in the video.

Let's assume that the recorded image of GPS display appears in 15 second of the captured image. One has to look for (inside GPX file) the timestamp containing the exact time displayed (element <time> inside element <trkpt>). Let's assume this timestamp is <time>2013-02-07T09:58:29Z</time>. To convert GPX to subtitles one has to run:

gpsbabel -i gpx -f FILE.gpx -o subrip,video_time=000015,gps_time=095829,gps_date=20130207 -F FILE.srt

Just to remind: internally all GPS units record time/date using Coordinated Universal Time aka Greenwich Mean Time vel Zulu time (for army enthusiasts). What the unit displays is another matter (usually it displays local time).

My first geotagged video obtained using method described above can be seen here.