Confused Life - Reloaded

Medieval Fair 2013 - Making rings for chainmail

2013-05-16T05:13:00.001-07:00

I have dressed up as Robin Hood and gone to the Medieval fair in Gumeracha sporting a bow. This year I decided to sport my camera with the classic 20mm pancake instead. The first thing I walked into was a sword holding competition. The challenge was to hold a 15 kilo sword with the arm extended horizontally for as long as possible. Plenty of fitness instructors and heavy lifters had a go at it, the record while I watched was around 3 minutes. I think I am going to practice with a cricket bat for next year.

Being a builder builds muscles

There were also jugglers and irish dancers, and to my dismay people with huge amounts of camera gear shadowing them. I felt really unprofessional with my dinky m43, then again this is the age of mobile photography and the battle between processing vs gear is on. It is now even being used as a marketing point by those Sony NEX ads. Granted a micro-four thirds sensor is smaller than the APS-C, still the weight advantages and flexibility bonuses do apply.

Juggler practicing

There were a few knights in chainmain and I walked into a conversation involving effort and time that goes into making the armor. Eventually the talk drifted to cheap Indian labour working for $1 a day so that people can have fun the fair, at that point people glanced at me and stopped talking. I should start tinkering with fencing wire to keep the stereotype going. Some things cannot be mechanised yet, clothing be it out of fibres or metals is one of them. The economics of hobbies is also interesting.

Riveted chainmail

The melee of kids with pugil sticks reminded me of a Schlock Mercenary episode. It will be good to get some excercise done while in costume.

Pugilists not boxing

There were also Middle eastern belly dancers and scribes doing calligraphy while complaining that the Belly dancers are not Medieval. Though the ululation accompanying the dancing is fairly universal.

Belly dancer and musician

Finally I managed to put the 850mm IR filter to good use and capture a panorama including the little lake at the Viking encampment. Without special IR modifications to the camera I had to use a pretty high ISO (1600) and a 2 second exposure. The processing through RawTherapee worked fine using some IR profiles I found floating around in Github, Hugin did a fair job of stitching as well.

850mm IR filter with unmodified camera panorama

NASA SpaceApps Adelaide 2013

2013-05-13T17:26:00.001-07:00

A few weeks ago NASA hosted its second annual space apps challenge. I did not manage to participate on the first day and only managed to struggle in on the second day to witness the finale. The Adelaide Hackerspace provided the venue this year and Simon has very nice write-up on their blog.

There were a few more entries from around Australia including a slinky based greenhouse suitable for use on the moon and a meteor tracker integrated with Google sky. It was a couple of days of pizza and coffee, ending with beers by the time we finished.

Everybody went home pretty tired, but happy. I will definitely try to put in a couple of days of participation next year. Meanwhile feel free to use Mearth and look up all those cold place in Russia, Scandanavia and Hokkaido which have Mars like temperatures. Whoever is considering applying for Mars-One should visit one of these places and film on location.

Accurate positioning with UBlox Neo-6P and STM32

2013-05-11T06:52:00.000-07:00

The Ublox Neo-6P provides raw clock phases and ephemeris suitable for use in post-processing based accurate positioning, or even RTK solutions using RTKLib.

STM32 with Eclipse was fairly messy to set up and depending on which version of GCC and CoreSupport libraries you use their are a few bugs to iron out. Used Code-Sourcery Lite toolchain, but compiled version did not behave as original firmware did. There are Eclipse based STM32 development commercial support from Atollic, and there were hacks to get the debugger Atollic packages working for ST-Link using the free options, but in the recent incarnation they have locked it down to TrueStudio only. I had to resort to OpenOCD for my debugging needs, it works like a charm with standard Eclipse settings, but I managed to nuke my STLink driver in the process and had to work hard to get it back.

Importing to GrafNav is fairly straight forward via the UBX converter, but it gives no indication on how it converts events, and you need sufficiently long logs to pick up any ephemeris. UBlox Receiver protocol is a must read for configuring the NEO-6P properly and monitoring the logs to ensure GPS lock. I am looking into the STM32 demonstration samples to add some more functionality to the project, including external interrupts from a camera for event marking and a GPS lock acquired status LED.

Adelaide Mini Maker Faire, Zoo and Indian Mela

2013-05-09T06:51:00.000-07:00

I have been involved with the Adelaide Hackerspace on and off. Lately my attendance has dropped a lot due to work commitments and a casual addiction to photography. A few photography related hacks are stewing in my brain, so I might go back there. Anyway a few weeks back I went to the Adelaide Mini Makerfaire and it was great opportunity to see all the different things going on in Adelaide, from Dalek making, Metal working to 3D printing and Electric cars. I had a great time catching up with people and learning about new groups. The airstream guys had some hacked wireless AP's on display, including the Minitar on which I cut my teeth in cross-compiling and writing kernel modules to interact with the wifi-stack. There are a lot more photos.

I had planned a busy day, so I headed off to the zoo to attend the local photography group session and check out some pandas. It was my first time at the Adelaide zoo, so it took a while to get oriented. We covered a fair bit of ground in the hour and a half before closing. Managed a few shots of hippos, birds, otters and mountain goats. Lots of other animals which hardly stood still enough to compensate for my nascent photography skills.

We were trudging and hobbling back to the car when we noticed the bright lights and steady stream of people heading to Elder park. The local indian community was throwing their annual mela. So we headed there for a meal and to feed our cameras with some colour. The movement and low light made photography pretty difficult from the back of the crowd. It was a great day overall.

Building Liblas for Win x64 with GDAL and Geotiff

2013-04-04T18:21:00.002-07:00

Some things are obvious to even the most oblivious, how to get liblas from OSGeo4W is one of them. However you quickly run into trouble as images, dem files and las files get bigger and the 32 bit osgeo builds start causing issues. There have been some discussions regarding a 64 bit version of Osgeo4W but getting builders for all the packages probably hasn't been achieved yet. I will see if I can step in and fill my drive with source trees and wield my MSVC 2010 license for good rather than evil. It is now up on the OSGeo GSOC ideas page, may be someone will take it up and make GIS toolchain deployment easier.

Liblas install for OSGeo4W set-up

Anyway here is how to built Liblas, assuming you are reasonably familiar with downloading sources and clicking a few buttons in CMake GUI. Grab LibLAS 1.7.0 sources. Since we want to add image support, grab GDAL 64 bit builds with headers from GISInternals. Build Geotiff 64 bit by hand using the handy CMake system, pointing it to proj and tiff obtained from the GDAL build above. Grab Boost from the handy distribution in PCL, you can get it somewhere else but PCL was my last port of call for boost. The final Liblas config page in CMake should look something like below.

CMake Liblas config

Change CMakeLists.txt for LibLAS to include the boost chrono library, there are linker errors otherwise.

find_package(Boost 1.38 COMPONENTS program_options thread chrono REQUIRED)

MSVC 2010 Liblas project

Configure and build away. I use MSVC 2010 Professional, running the bigfile_test after building has finished creates a 4GB+ dummy .las file and is nice for checking the x64 version. Put all the dependency DLL's in place after the build has finished using the handy Dependency walker.

Dependency walker check for libraries

Most windows users do not have a compiler installed and the inability to get a GIS toolchain on windows which can handle large datasets beyond 32bit restrictions is a major stumbling block in the wider adoption of the OSGeo toolchain. You can grab my Liblas binaries here and if you are interested student looking to package for 64bit let OSGeo know.

Where am I .... all the time

2013-02-28T04:33:00.001-08:00

Okay lets start by clearly stating the futility of position, every defintion of position requires a reference frame. It would be pretty messy to define where I am relative to the centre of our galaxy at all times, the super-massive blackhole makes measuring time there pretty messy as well. I could define my position better in ECEF or ENU or in most cases Platte Carre. I set out to build a project which could define where I am at all times for the posterity and essentially keep a track of my spime. My spime is the only thing I have absolute natural rights to, everything else can be taken away and be subject to argument with sufficient legal juggling. Come to think of it even the personal spime is not inviolate, meh reading to much Hannu Rajaniemi. Android My Tracks is pretty good, but a phone sometimes feels like too many eggs in one basket, I don't want to leave it lying around in the car dash gathering sunlight.

The project is mainly based on a Seeeduino stalker board with a convenient Bee socket. I plugged the UBlox Neo-6M based GPS Bee there. Data logs go to a 2GB SD card and Lipo power is backed by a 1w solar cell. The GPS constantly spits out NMEA strings which get logged to the SD card as long as power and space is available. A log with 2 days worth of data took up 45Mb, so I can hold about 3 months of data. Unfortunately the 2000mAh battery died after 2 days of continous use, with some solar recharge while in use. Since the battery death, in order to prevent melt down in harsh sunlight and continuous use, I have added a USB charger option as a stop gap. This should hold the fort till I plug in the quartz/heat powered charger for use while hiking and the mini windmill for use while wind surfing. Eventually the SD card will blow off into star dust after I have had my fun and extracted and time and location of said fun, but hey SD cards are more expensive per-ounce than gold.

Baby food and Poker machines - Snapping stuff in MongKok

2013-02-18T02:09:00.003-08:00

The biggest story making headlines while I killed time between city walks in HongKong was one featuring "Baby Formula", including an event just a few steps from me at the MongKok East station. Someone taking lights over was cornered and searched for baby food by citizens and angry mothers.

Australia is one of the wealthiest nations in the world in per-capita terms and most of our wealth is locked up in the Australian dream - house. In contrast it is quite difficult for young people to own a house in HongKong, so the consumption tends to be high in other areas. People eat out more often, since the living areas are small and can be a hassle cooking.

People invest more in personal appearance, buying jewellery, clothes and watches. Admittedly I am very poor at brand recognition, but the greek links to Doxa made me remember that particular brand. Personal investment is also apparent in all the rush for cosmetics and offers for private tuition. Image and wealth you can carry about on you is everything here. Just like the pokie joints pretending to be video game parlours.

There is a tension between pro and anti-Falun gung groups. The posters for both factions are displayed side-by-side near the star ferry terminal, right next to the anti-communist party booth. The Harbour city mall with its clientele of mostly mainland buyers is nearby. The rebelliousness may be filtering back along with the baby food.

Living and dying in the Sunderbans

2013-02-10T22:31:00.001-08:00

This is a well established wikipedia fact the the Sunderbans are the world's largest single block of Mangrove forests. It is difficult to grasp the scale and density of it unless you are drifting around in the countless rivers cris-crossing it for an entire day. A couple of days ago, I did just that. Nothing as dangerous as what the locals do - strolling into the deep forest with a pass bought for AUD50 or so and spending days at end collecting fish and honey. Occasionally falling prey to tigers or crocodiles. At least they get to see the elusive tiger briefly. They keep doing it since profit margins are huge, some AUD4000 per month, better than sitting exams and waiting for a government job.

On the same day we saw human footprints heading into the jungle and after drifting around a bit more tiger footprints crossing the river. Crocodiles were everywhere, sunning themselves. We even saw a juvenile croc, looked rather harmless. One of the anecdotes we picked up was about a tiger losing his back legs to a croc while crossing the rivers.

Those who don't earn their living from the forest have taken to clearing it and planting rice. The conservation efforts are ongoing to protect the forest and reduce land clearing. The big cyclone in 2009 - Aila, caused stormsurges and deposited salt on most of the rice fields. This has sent people back to the forests, until the salt tolerant rice comes along. The other noticeable thing was the profusion of solar panels, since most of this area is off the grid. Often there were separate panels supplying separate rooms and one clearly identified for the TV, attached to a satellite dish.

The television is a rarity only afforded by the rich. The local live music and theatre scene seems to be pretty active. You can often spot musicians on the ferry heading to a gig on a pushbike with a dhol strapped to their back. Tourism is catching up to provide some more support and even more exposure for the area. It provides an alternative to "jungling", our cook lost her husband to a tiger. However local tourism can be quite destructive, since the locals tend to dump rubbish everywhere and get drunk and drown themselves in the river. Not much different from stories I read about Australians in Laos.

It is a beautiful place, but in the danger of disappearing under the pressure of people. The great economic importance the forests have in their non-destructive use is keeping them from destruction. Things may go slightly awry if urbanisation finally catches up, being off the grid is actually good for this place.

Two weddings and Tiger Footprints

2013-02-10T03:38:00.000-08:00

It is that time of the year when I visit my family in India and throw in a drive by tour of another place in Asia. This trip is almost round the world in its scope - Adelaide, Singapore, HongKong, Kunming, Kolkata, Dubai .... back. There are always memorable things at each spot. Singapore airport is just too familiar, but on 2 flights I sat next to Capgemini employees flying in and out of China (from Australia and to India). Something huge is brewing.

The highlight of HongKong was the busy life-style, crazy shopping and the hybrid cultural wedding. The lights make for great photography and testing out of my new 4/3 camera. Some serious lens shopping coming up. The wedding was a fun, great venue, good scale and +Rowan Fry looked understandly over the moon. The best part was the entrance in traditional chinese gear, he would have made a rather respectable official in imperial china. I wish them a happy life together.

Last week I attended another wedding in Bengal. The contrast was stark, the rush, the colours, the food. The only thing that was constant was the hot wire cut foam decorations, the flowers and the suit I wore to the other wedding. The wedding invitations extend to whoever bothers to come, I hardly knew anybody, not even bride and the groom. Felt a bit like a wedding crasher, till we went to see the bride's dad, he was laid up with all the stress from getting the feast organised for some 600 people.

The last few days we toured the Sunderbans with a Backpackers group aimed at foreigners, much more relaxed than trying to do it packed like sardines in local style. There seems to be zero-respect locally for the Sunderbans, since the majority have not been lucky enough to see the tigers, all believe no tigers exist. They should perform 3D photogrammetry on tiger footprints, lay out some tiger sized dolls and change the holiday season to coincide with tiger mating season. Only then will people believe tigers do exist. Saw plenty of crocs though and some crazy tourists to keep us company. I was both local and foreign, had fun teaching Bengali - managed to teach a Canadian to count to ten. Should start some word association based Bengali learning kit.

On map Augmented Reality with Vuforia + Unity

2012-12-18T01:58:00.001-08:00

I have been doing some more development with Android, using a different (and easier) renderer this time than the still nascent OpenSceneGraph port, with a bit of Augmented Reality thrown in via Vuforia.Which basically functions as an OpenCV port with image orientation recognition thrown in optimized for Qualcomm's Snapdragon SoC. The feature detection and texture packing is annoyingly performed at the Qualcomm site, I guess they want to keep track of images over which features are detected and prevent inappropriate use by script kiddies. From the looks of FastCV, the features are either MSER or Harris corners.

I already have Android dev kits going so the fun bit was in importing our nice models into Unity and sending the package over to the device. Textured models seem to import best into Unity via Blender, after a bit of copying around of textures and forcing association with the right materials.

Setting up the scene in Unity is fairly straight forward, the Vuforia SDK delegated to Unity for rendering and simply attaches a handler to the Camera. The visible object is automatically centred in the scene so the camera to target geometry is irrelevant in this case. However lighting is not, so a bit of tweaking in lights is necessary for a nice model render. Switch all the materials to diffuse/mobile to load the appropriate shaders in GLES2. Add an LODGroup node if the model is getting too big, though I was able to render some 100,000 triangle models.

When all is set the tracking can begin. I lined up the model to our orthoimagery, the screenshot does not do it justice. It is really cool watching a 3D object stick out of your screen. Everybody at work is very used to viewing things in stereo, but multi-perspective 3D still has a wow-factor.

Building OpenSceneGraph with Android NDK

2012-12-04T04:25:00.000-08:00

I have been rapidly picking up Android development for the last 2 days with Native coding in C++ thrown in. Cross compiling for embedded systems is nothing new for me having played with Beagleboards in various incarnations, the Hawkboard and Pandaboard. Neither is JNI, I did a fair bit of JNI work while at CSIRO trying to make NetCDF faster.

So to build OpenSceneGraph for Android (I am using my Nexus S running 4.2), do the obvious:

Get OSG source
Get ADK
Get NDK
Get ADT if you are Eclipse fan like me
Get Sequoyah, CDT and whatever else Eclipse wants to build native code.

Build OSG for Android with whatever hack you can imagine. I ended up getting CMake to generate with NMake build files, but built directly using ndk_build afterwards since the MSYS shell could not access DOS commands ndk-build seems to call. Install automation did not work either so I copied OSG headers over by hand into the build directory. It took a while to build, the NDK compilers are rather slow, in the future I will run with -j 12 to take advantage of all my cores.

The next bit was rather easy since the OSG Android sample is already configured for Eclipse. I had to fix up settings with MSYS for bash. Most tutorials refer to cygwin for Linuxy utilities, but I loathe cygwin and I already a have a bunch of MSYS installs floating around through OSGeo4W and Git-bash. The include files and compiler checks are rather strict in Eclipse and any errors in the IDE will prevent uploading the build, be naughty and just delete the errors due to ADT bugs. This is just a proof of concept after all. I had to change a few little things like false to JNI_FALSE to keep the compiler happy. After some toing and froing with gnustl_static, the whole thing built and ran fine.

I wanted to have jpeg textures embedded in the .ive and .osgb files displayed as well as load models with PagedLOD's over http. So I needed to link the little trivial application to curl and jpeg in their Android native incarnations. The hard work has been done already and you can get thirdparty bundles. The first attempt with 8192x8192 textures expectly blew up on the little platform, but atleast libjpeg seemed to be working, I squished textures down to something sane. Libcurl works to download a file hosted on our webserver just fine, but you can't wait for an eternity on this plaform, unless the basefile is a few kb and links to the rest via LOD's the GL context will be lost before the download finishes. Overall it was a fun experiment and I am glad i managed to load a Jesus statue to celebrate this festive season - though it represents death rather than birth.

Blender as a Python module, happy coding from Eclipse

2012-11-08T02:52:00.000-08:00

This post is going to be a reminder to self in-case I ever need to do this again, or I am cloned and the clone is wondering how the original spent his time.

Get Blender source
Set options as pointed by IdeasMan to build as Python module
Compile with Visual Studio
Set BLENDER_SYSTEM_SCRIPTS as an environment variable, small undocumented caveat where reading the source actually helps.

Import Bpy and Python 3.2 in Eclipse and use Blender algorithms in headless mode.

Trivial CMAKE for OpenSceneGraph

2012-10-30T03:23:00.002-07:00

It is often fun to get open source projects working with Visual Studio since a lot of build systems leave out a few Microsoft specific vagaries. With CMAKE life in the last few years has become much easier, though sometimes it requires a bit of digging to locate the right incantations to pull in the right dependencies for a trivial project.

CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
PROJECT(AeroViewer)

SET(TARGET_SRC aeroviewer.cpp )

find_package(OpenSceneGraph REQUIRED osgDB osgUtil osgGA osgViewer osgText)

ADD_EXECUTABLE(aeroviewer ${TARGET_SRC})

INCLUDE_DIRECTORIES(${OPENSCENEGRAPH_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(aeroviewer ${OPENSCENEGRAPH_LIBRARIES})

The aim of this quick dash is to add a screen overlay with the company logo to the default osgViewer. This requires adding a geometry node to the scene with some static geometry in camera space. Which ends up being equivalent to a HUD in osg parlance. After a bit of tweaking and rotations in texture space I got this, not too bad for a cold-start in OSG land. This bit of sample code is better for HUD's than the tutorial, the required projection and modelview matrices are encapsulated by the CameraNode.

Why is gold valuable anyway ? - Midas and Supernovas

2012-10-20T22:16:00.001-07:00

Growing up as a child in India in a family of goldsmiths it is hard to ignore the role gold plays in perception of wealth and daily conversation. My uncle would often refer to "stuff" or "maal", meaning gold. On my last visit the regular obsession was checking the current gold price from the wholesalers via SMS. According to a recent article - Man's addiction to gold - India holds pretty large stockpiles of the metal in the proverbial family jewels. It changes hand at marriages as gifts and dowry.

Gold has no intrinsic bio-chemical value which supports life as the cautionary tale of King Midas points our. Its inherent inertness however gives it great value in the burgeoning electronics industry and it is very rare to start with anyway due to the cosmic element forming processes making it harder and harder to produce heavier elements. The vagaries of nucleosynthesis are so universal that they have even made it to being a Hollywood plot device in "Cowboys and Aliens" where aliens set up a gold mine.

The ultimate statement on how we value things comes down to supply and demand - gold is in short supply due to its nuclear weight and on high demand due to its permanence once acquired. We now just need to find suitable biochemistries or bioelectronics to make it part of a living body. Gold abundance is a measure of the midas touch of supernovas.

Making Furniture from Banana

2012-10-17T03:31:00.000-07:00

I had a solid grounding in natural fibers and polymer chemistry thanks to my father. My mum still has a picture of him happily holding a sisal leaf. We took this picture in the plantations just outside Mombasa. Well the agave family is pretty notorious, apart from sisal it also gives us pineapples and tequila.

So I tend to talk about the wonders of polymer chemistry often. I kept rambling at the Augustiner Biergarten in Munich about natural fibers, hair and aramids, to slightly disbelieving stares. Ended up learning a bit about making violins out of Kevlar.

The whole chain of thought started on the plane from Adelaide to Kualalumpur. I sat next to Ed organising the overseas operations in Egypt for Papyrus inc and making veneer out of banana stems. He treated me to a nice time in KL on condition that I show the same consideration to any travelling PhD student I meet in the future, when I am a director or something. Otherwise it was a great conference featuring a visit to the EADS solar panel and rocket engine manufacturing facility - which used to serve as the tank manufacturing facility at its inception. As well as plenty of nice technical sessions and a strange conversation regarding compressed sensing and the difference between SAR and optical.

I finally did the IGARSS Conference review survey today, so getting the blog out is timely. May be I will present about point clouds at the next conference and take a break from the SAR stuff. Check this video for what I have been doing recently.

The sunset cermony at Arche de Triomphe

2012-08-18T18:39:00.000-07:00

There are many battles listed on the Arche de Triomphe, they were all fought, but not all of them ended in victory. We walked through Paris starting at Place de La Madeleine filled with red blooms and people sitting on the steps. Thinking this is Paris where building a church is considered a public service, useful in keeping people sane and full of hope. We walked a beeline to the obelisk and lined ourselves up with the Arche de Triomphe along Avenue des Champs-Élysées.

We slowly waded into the ocean of tourists, passed a man cutting out silouhettes in 2 minutes using just scissors, got pigeon poop on my bag, saw the citroen demo car with solar panels on the roof and had a burger at Q being served by a very tall girl. We got lost crossing the roundabout to get to the arch and went round in a cricle before we figured out the right underground tunnel to take. As usual there was a huge queue to climb the Arche, I am not really into queues so we went and sat under the arch. All these random events led us to sit next to a very small old lady (we later found out that she was 92), carrying a large flag.

I started doing my usual sketching thing, the old lady was a subject you just can't pass by. Some tourists noticed us and introduced us to the old lady. She spoke excellent English and had served with the Free French Forces under Charles de Gaulle during WWII, in intelligence. We came around to discussing the olympics and to our surprise she started reciting the venues of all the olympics since the 40's. I did some quick sketches of her and dutifully handed them over, she asked us to stay for the sunset ceremony alongside all the dignitaries in suits.

It was a rather odd half an hour as we struggled to be inconspicuous among all the military attire and the ambassadors. The tourists were all herded out and looked on from the outside. All the national anthems of allied countries were played - France, UK, Australia and some I did not recognize. Wreaths were laid on the memorial to the fallen soldiers. The logo on my t-shirt was mistaken for a regimental emblem and I was asked which one I belonged to. It was a rather strange end to our random walk through Paris. Thanks for letting us stay Paulette.

Redrawing Diagrams - Fun with Inkscape

2012-07-17T07:10:00.000-07:00

Hand drawn curves

Good diagrams in publications are hard to come by and sometimes already published ones get re-used exactly due to the lack of the know-how on reproducing them. One classic example is the Entropy-Alpha space diagram produced by Cloud-Pottier. Though the diagram is simple enough and the space limit curves can be computed from the equations, it is sufficiently complex given no full recipe to warrant copying as-is. Copying with attribution is standard practice in science, but gives no insight into how the diagram was originally produced without contact with the authors or forensic analysis of the lines. The tell-tale randomness of the curves in this particular one makes me of the opinion that it was hand drawn, I will have to as Shane Cloude when I meet him over a beer in Munich.

Entropy/Alpha diagram

So I decided to try out my Inkscape skills and redraw the diagram from scratch using some theory and some free-hand approximations. Without definitive parametric equations for the bounding curves it is rather like trying to work out how the pyramids at Giza were built.

Lots of images to lots of OBJ to lots of images

2012-07-13T22:52:00.000-07:00

Working with Structure from Motion and Dense matching can be a lot of fun. If the project get sufficiently big though, the reconstructed models is broken up into multiple Wavefrom Object files and can be difficult visualise and render. I like doing most of my rendering in Blender, and the handy Python API for loading OBJ files makes the job of getting all the files in easy.

To grab a bunch of obj files from a folder into Blender simply script this in the console:

import glob
objects = glob.glob("Filepath\*.obj")
for obj in objects:
    try:
        bpy.ops.import_scene.obj(filepath=obj, axis_forward='X', axis_up='Z')
    except:
        print("Failed "+obj)

Just like that you create a scene with 100's of object tiles. Make sure they are viewed in outline mode, so that the display is zippy while setting up lights, cameras and animation action. Start off the render and go get a beverage.

Rage against the machine - Pattern Matching

2012-07-06T04:41:00.001-07:00

One of the major strengths (and sometimes weakness) of the human brain is its ability to perform pattern matching - the classic is where people play more attention while playing games and digitising and gamifying the airport security leads to less false positives. We perform heuristics in everything we see and hear, often coming to conclusions based on partial information, based on extrapolation performed using past experience. This is why upper-case letters in English are so much easier to read since we have built up heuristics to infer the letter from the top-half, people who write in all capitals seem to be almost shouting as our visual heuristics take the cue.

Ambiguous painting

Machines are getting better at the heuristics as well as brute force, we have passed them on just the way we pass on preconceptions of right and wrong, beauty and religion to our children. Based on this system of thought and accumulated body of knowledge, machines can perform pattern matching tasks they are programmed for in vastly superior ways than humans. All they demand in return is energy, materials to build them and intelligent human beings to make some long intellectual marches in programming them.

Cat videos are the dominant species

In someways the rote jobs of pure pattern matching has made us mental Neanderthals with short neural loops focused on ambush hunting only the job at hand, rather than thinking long term strategy. The long chase where all the short easy pattern matching jobs have been mechanised is for the more creative, the artists. Yet there is still need for the engineer to keep the machines functioning. There are always predictions of race of against the machines. We still need to communicate our mental models imperfectly via whatever means.

Genies are just machines with Genius

May be with exposure to lots of cat videos and artwork, the machine will eventually learn to play with cats while painting, and we will keep building bigger machines since we can't be born biologically with bigger skulls or weild GeV's with our finger tips.

Searching point clouds - Hashes vs Trees

2012-06-22T05:28:00.001-07:00

About a year ago I was sitting in the lawn outside of the Google buildings in Mountain View, discussing the project I was working on at the time. I had the fun job of displaying very large (60GB +) NetCDF data sets in NASA WorldWind. We were approaching it from the classic game developer perspective and considering building an octree or hyper-octree (this data had temporal slices) index over the dataset to quickly locate subsections we wanted to display at the proper detail. As an aside we began to consider what the limits of the disk to screen transmission are. A 1920x1200 screen with RGB data will have about 6.6 MB of data uncompressed, with compression this will come down a bit. At 60 FPS this requires about 3 Gbit/s disk bandwidth, compare this to what is available via SATA 3. SATA 2 will definitely be too slow adding the times required to search the index, perform seeks and read the pre-computed chunk. It might look better with highly redundant data and good compression.

The idea here comes down to searching using 2 different methods - Hash Search vs Binary Search. Octree based rendering is essentially a binary search in 3 dimensions. The other way to render would be to hash the camera position and orientations or view frustrums, create indexes and blocks of the point cloud being rendered to load chunks as the camera is moved around and data block required is located on the disk using the index + hash. The gamers keep harping on about polygon counts without looking at how the facade of the very large word-count of the internet can be quickly acessed via hashing the query, similarly the first surface of a large object count scene can be quickly accessed via hashing the camera.

All this brings me to the point of the conversation. In the last few days a bit of a drama played out in the hard-core gamer community regarding a leak from Euclideon, who make engines not websites. Hash based searching will work quite well for static data and unlike trees will not require rebalancing for dynamic data. Finding a nice unique hash for frustrums can get quite tricky and storing and compressing the results in a nice data format will also be a challenge. Building a game engine from scratch without all the blocks the graphics world has put in place is a Radical Rewrite. May be it will work, then again we live in a universe where there are 4 dimensions and no one asks how to compute the volume of a hyper-sphere. Knowing e=mc^2 does not let you build an atom bomb or a nuclear reactor, even figure out how to avoid Fukushima. Engineering simply is not the same as Mathematics.

Power of appearances - Peacocks and Pandas

2012-06-16T06:54:00.000-07:00

Somebody once told me the only survival adaptations pandas have evolved is their cuteness. They eat hard to digest, scarce low nutrient food, move and breed slowly and are distinct and highly visible to predators. They have only survived because people find them cute.

Studying the appearance and optic manipulation performed to achieve the colours opens up a huge arena in the study of wave propagation. Peacocks achieve their iridiscent plumage through structural colouration. The quality of the colouration reveals a lot regarding the refinement of the genetic processes which create it.

Beauty is said to be in the eye of the beholder, it more like beauty is in the sensor and the heuristics attached to the sensor. With proper training you will find X-rays of ribcages and hyaenas beautiful (of course after you have spent a few years studying the subject for say a PhD). Beauty is often associated with a halo effect and positive attributes are lumped onto those who pass our physical beauty filter.

Rampant use of cosmetics has messed up our facial feature filters somewhat, soon we will be judging people by their bone structure (this happens a bit already among athletes), heat distribution or UV images. All the better for cyborg like optical implants or AR Goggles. I will keep performing full wave EM simulations in head and keep seeing things in Gigahertz range. With the anthropic principle in effect and metallic content of the known universe increasing due to fusion and the cosmic background being in this range, it might come in handy one day.

Go back to PvE - fighting each other vs conquering the universe

2012-06-09T23:33:00.000-07:00

In Hobart I used to hang out often at the Dr.Coffee. One Sunday I was sitting around drinking coffee and sketching, I met somebody preparing a lesson for a church gathering. We started talking about what each of us did and eventually I started describing, 3D modelling and game design. How a game has to have balance, PvE (player versus environment) and PvP (player versus player), how often at low levels the player is made struggle against the environment and some choose to keep doing it or on a game like Guild Wars with low level cap they choose to play PvP after having attained a certain level. Keeping on playing against the mind less monsters in the environment is considered grinding or farming, and generally looked down upon, unless you are a gold farmer who exchanges game gold for real world gold.

At the end of this conversation the believer in God left me a few words - "While you design and play games do not forget who designed you and which game you are living in.". This theme has been a common refrain since the advent of gaming. The overlap between virtual worlds and the real world is growing and is captured in a lot of cyber punk such as REAMDE. Currencies are changing hands by being sacrificed to gods in game world only to be converted to fiat in real world. Religions pose a similar dogma in real world, proposing to convert our material wealth, faith or in certain cases lives to real wealth for our players in some world beyond this one. The central premise being this is sort of a game world and we should indulge in PvP against players of the opposing team(religion, colour, nation, whatever label seems appropriate) to earn points, which will be converted to rewards in the world in which this simulation is running. The grand illusion of material world ideas have been around for a while, not as long as the 14billion year long illusion, but if you believe in such weirdness, time itself is an illusion anyway.

We seem to have reached a level cap for the time being in our evolutionary progression and become so heavily embroiled in PvP i.e. taking it out on each other that we have no time to engage in conquering our environment and making our society stronger. Widening our play ground, instead of squabbling over the invididual grains of sand in the sand pit. There is a favourite refrain among elite PvP players - "Go back to PvE". The politicians, financial magnets and all those playing to beat other humans in the game of life are PvP players looking down on those attempting to conquer the environment, be it in exploring new frontiers in medicine, space or fabrication.

If this does happen to be a game, why not figure out the mechanics first and become masters of the environment before going around shouting from roof tops about religion and judgement day, and why we should serve the games master i.e. a deity if we want to finish with a good score. We should just get along and keep playing the game of life, all eschatology aside. Our indulgence in gaming world seems to have helped in expanding the boundaries of real world through the likes of Elon Musk, we just need more people to stop playing against each other.

Content supply for Apple's venture into mapping

2012-05-27T04:59:00.001-07:00

This suspense is killing me. Hope it will last. - Oscar Wilde

Apple put up a big fight against the Big Blue to establish itself in the market of personal computers. Now it has to put up a similar brave face to the big blue, red, yellow and green.

Apple acquires C3, now needs oblique and ground based photography to populate the world. While keeping bandwidth usage low and discretional. Apple will be requiring lots of data to populate its more detailed world and there will be rush of data acquisition coming up to create a multiple view representation of the static world.

The most interesting aspect of 3D reconstruction I find is the temporal decorrelation. We can never know all aspects of an object from multiple perspectives simultaneously without violating relativity. A fun aspect of this is the modelling of clock-towers. The reconstructed view always has slightly different times in the clock faces.

Causality is much more absolute than simultaneity, in our frame of reference we might be experiencing events such as the launch of Apple mapping platform whose cause is hidden in some future outcome. Meanwhile the suspense of seeing the big launch from the big fruit in a post-Jobs era is killing me.

Portable Energy - from fire sticks to lithium

2012-05-20T08:26:00.000-07:00

Last night there was a knock on my door at 3am, the flatmate wanted a flame to light his cigarette. We seem to have forgotten how to make fire without help. I have been reading Triumph of the nomads by Geoffrey Blainey. It has some interesting cultural facts regarding knowledge of energy generation.
Aboriginal fire sticks , the methods of fire making.

Pulling stick over bark, fire plough or fire saw
The bow-drill
The percussion method with pyrites

From fire as source of energy and light we have moved on to more chemical mean, emphasizing on coal, potassium, phosphorus and sulphur. Energy currencies like adenosine tri-phosphate which our own cells prefer to use. I collected a lot of matchboxes while I was young and yesterday the TV was filled with imges of David Beckham and James Bond carrying the Olympic torch across the British Isle. We simply cannot afford to forget how fire is made or let all the fire in our immediate vicinity go out.

Then things switched over to fire steel - ferrocerium and butane, petroleum derivatives. It is still our highest energy density power source being used in most mobile power hungry equipment. Next came the more metallic solid state power sources, burning without visible flames, quietly without explosions unless overheated in certain laptops.

Battery technology has gone through several generations - lemon battery, copper-zinc, zinc-carbon, NiCad, NiMH, Fuel cells, Vanadium Pentoxide, Silver oxide, Lithium and CSIRO made some headway into ultra-batteries by coupling super-capacitors to conventional chemical reaction systems. All involve chemistry and pushing ions up and down electrical staircases to store up energy around the nucleus. With our highly connected life-styles we are plagued by nomophobia, recharge mania. Sometimes I remember the sky is the ultimate device and carry around solar cells to transfer energy from the sky device.

We are constantly pushing electrons downhill in an effort to climb out of this gravity well of a planet we call home. Our techniques to harvest energy so far are not good enough to give us a ticket out without destroying a fair amount of our civilisation in the process. We will have to come up with something rather drastic to get out of this bind, pseudoscience or not.

Producing Denser SiftGPU points - at the expense of time and RAM

2012-05-06T02:05:00.002-07:00

One of the old adages I learnt doing CS was that you can not optimise everything - there is always a trade-off between speed and RAM (and sometimes accuracy). If you solve a problem faster then there will be a bigger problem that cannot be solved by your faster method. GPU computing seems to suffer from this scalability problem a fair bit mainly due to limited GPU Memory. In some cases there can also be issues with numerical stability. There is a fine line between Amdahl's law and Gustafson's law.

The latter is actually more fun since large problems have a patently real world feel. While playing around with large collection of aerial and terrestrial photography we found that SiftGPU seemed to be producing similar amount of key points no matter how big an image we threw at it and asked it operate at lower octaves to take advantage of the higher resolution. A bit of code inspection later I found the usual collection of magic numbers designed to prevent memory overflows ( if you have 60+GB RAM and some Teslas the magic numbers are too small). For posteriry here are the hard limits you can unsafely raise if your hardware can take a thrashing.

//hardware parameter,   automatically retrieved
int GlobalParam::        _texMaxDim = 12800;    //Maximum working size for SiftGPU, 3200 for packed
int    GlobalParam::        _texMaxDimGL = 16384;        //GPU texture limit
int GlobalParam::       _texMinDim = 16; //
int    GlobalParam::        _MemCapGPU = 0;
int GlobalParam::        _FitMemoryCap = 0;
int    GlobalParam::        _IsNvidia = 0;                //GPU vendor

The large aerial frames were defaulting to octave 3 silently, running them at octave 0 produced 500k SIFT features per frame (yes that is ridiculously huge, but these cameras are ridiculously good). With greater number of features you can perform sparse bundle adjustment using more restrictive angle range constraints and more accuracy.

Bundle adjusment has also had a recent boost from the release of Google Ceres library. This has been suitably adapted to allow faster solution of general multi-camera problems. Asteroids seem to be on everyone's mind.

"... for it is now clearly shown that the orbit of a heavenly body may be determined quite nearly from good observations embracing only a few days; and this without any hypothetical assumption."

- Carl Friedrich Gauss