Wednesday, September 30, 2009


Hi to everyone from AIC09 Sydney (as you can see from the picture),
happy to be part of the colored group
stay tuned ...

Bright and early

In a large metropolis the best light is in the morning, when the air is still pristine. Life in Coogee Bay starts bright and early. Many of the coffee shops open at six o'clock and immediately fill up with customers,
but the action is along the beach. Joggers and walkers occupy the promenade, and while the sand is being cleaned, swimmers emerge from the ocean and pools.

On the beach, coaches and personal trainers work out their clients.

Boxing appears to be a favorite with girls.

On the other side of the promenade, on the lawn, many group exercise classes are peaced through the daily training circuits by decisive coaches.

Drinking a Reward

In a mere 20 weeks previously color blind monkeys appear to have become trichromats through a subretinal injection of a virus containing L-opsin (1).

Tuesday, September 29, 2009

Nominal Scaling of Print Substrates

Towards the end of Giordano's AIC presentation is a preview of our next paper "Nominal Scaling of Print Substrates".

This paper has recently issued as a technical report.

One way to look at this paper is what to do when you have 100 different types of commercial print media on the floor of your cube. They vary by color, thickness, surface texture, opacity and more. They come from multiple vendors. They have multiple branded names and descriptors.

How can this pile be put into some kind of order?

Monday, September 28, 2009

Towards robust categorical colour perception

We presented our paper Towards robust categorical colour perceptionand it was very well received. Here are the slides:

Why are animals colourful? Sex and violence, seeing and signals

Yesterday's problems of finding the venue, the missing proceedings, and the absence of Internet connectivity were made up for at the opening ceremony earlier today. The following invited papers were excellent. I cannot give a minute-to-minute account, so I will report on just one of the lectures: Justin Marshall from the University of Queensland in Brisbane lectured on Why are animals colourful? Sex and violence, seeing and signals.

The human visual system is much less colourful than that of many animals, so our world is much poorer. Justin Marshall studies how animals see the world, which comprises 3 main subject areas

  1. Visual ecology
  2. Camouflage
  3. Display — sex and violence

The function of colour is to add contrast. At least two channels are required to see colour. Why do mantis shrimp have 12 channels then?

Most cephalopods have only one channel and are therefore achromats. They use colour only for camouflage, not for display. However, some cephalopods use colour to display their toxicity.

Lungfish and birds have oil droplets in their retinas to tune their spectral sensitivities. They are tetrachromats. We do not understand the variability of the visual system in the various reef fish species.

The only way to enhance display is to use fluorescence.

To other fish, yellow fish are the same colour as the reef, because fish do not see in the red part of the spectrum (however, they see much farther in the UV domain than us humans), which is where the reef spectrum looks different from yellow fish. They do not need to match for camouflage in the reds. Stripes are disruptive and are meant for camouflage.

Stomatopods like mantis shrimp are the masters of colour vision. Four channels are in the UV portion of the spectrum and 6 channels have circular or linear polarisation vision through a kind of nanotube. To manage the architectural complexity of so many channels, the stomatopods are live-scanners.

Remote sensing is very interested in the eye structure of the mantis shrimp, because the current vision models are so much poorer compared to that of mantis shrimp.

The coral reefs are dying due to global warming and ocean acidification, as assessed among other with the Coral Health Chart. The current aspirational goals for CO2 are unrealistically high and will lead to the disappearance of all coral reefs in a few decades. Just in the Coral Reef Triangle alone live 500 million people who depend on the reef fish for survival and will have to mass-migrate to other parts of the world.

Justin Marshall and colleagues have given up trying to educate adults and are now focusing on educating children. Their new book for children will be available shortly though the web site

Now let us hope the UNSW IT department can figure out how to run a wireless LAN so I can upload this post. The DSL modem in my hotel room had been vandalized, so I am living in a pre-digital world. So much for Nathan's dream of attending the congress remotely through a blog. For now we still have to squeeze in a sardine box flung across the oceans to attend meetings.

Sunday, September 27, 2009

Where is the AIC?

The closest HP approved hotel to NSW University in Sydney is in Coogee Bay, not at walking distance and not near a bus line, but it is a very nice hotel.

Medina Hotel, Coogee Bay

The area is very diverse and multicultural.

Shops along Coogee Bay Road

The block down from the hotel is a row of coffee shops, and their coffee is excellent.

Cooffe shops along Coogee Bay Road

Before leaving Palo Alto I was very busy thinking about the code I am wrangling for my day job, so I forgot to read and print out the information of how to reach the venue. I did print and take the advance program, but it had only the auditorium names, and none of the students and staff ambulating on the campus had ever heard these names. I ended up systematically scanning the campus in a zigzag pattern and entering each building with crowds of people, until in the middle of the campus I found a building with the familiar faces of the AIC delegates.

It turns out, other people in the registration line had similar experiences, with up of two hours of random walks in the campus being reported. When I asked the registration lady why the venue is not marked, she explained my mistake was that walking up from Coogee Bay I entered through the rear gate instead from the front gate, which is on the opposite end. Since the Internet subnet for the congress is not yet up, I decide to make the formal entrance from Anzac Parade. Here is what you see standing on Anzac Parade and look towards the conference building:

view from Anzac Parade

Do you see the white poster in the window with AIC written in the upper right corner?

Let me zoom in then:

zoomed in

Do you see it now? Well, let us walk up:

do you see it now?

How about now?

do you see it now?

Well, this is as close as you can get:

do you see it now?

Tuesday, September 22, 2009

Ripping efficiency

The tool for deciding informatics infrastructure investments is benchmarking. In the past, the game was to invent a new performance metric, create mind-share for its superiority, and then optimize one's offerings to become the best platform according to the new metric.

Today the game is much more complex. Integrated circuits have hit the wall and it is no longer possible to simply increase the clock speed. Also, there is the new requirement of both upwards and downwards scalability: an architecture must be applicable also to cluster computing (or cloud computing) and mobile devices. One of the hot themes in benchmarking is the comparison of CPUs to GPUs, as we are now exeriencing a return of array co-processors in the form of programmable GPUs.

Recently David Kanter wrote the interesting article Computational Efficiency in Modern Processors in Real World Technologies. He uses double precision (DP) GFLOPS/s per W and DP GFLOPS/s per mm2 as the metrics. Since all integrated circuits are based on the same physics, not surprisingly these metrics do not give new insights for classical designs but show that radically different paradigms like WLIW in AMD's approach give the edge to a handful of circuits in terms of computational efficiency: ATI's RV670 and RV770, IBM's PowerXCell 8i and Intel's Atom.

For color image processing, and more specifically ripping, it is more interesting to look at the overall efficiency of a RIP (raster image processor) system, also known as DFE (digital front end) in the trade. Currently our colleague I-Jong Lin is Louisville, Kentucky for IS&T's 25th Non-Impact Printing conference, also known as NIP. There he is presenting a first paper on Proposal for Next Generation Print Infrastructure: Gutenberg-Landa TCP/IP, where he discusses GPU-based RIPs.

He explains, Graphics Processing Units (GPU) are special purpose coprocessors originally targeted at the PC gaming market. The enormous size and volume of the gaming market have driven GPU capabilities up and costs down, making GPUs into a viable and well-supported parallel computing architecture. Today, the cost of a GPU is so low that even handheld devices have a GPU.

Besides the cost reduction from using commodity hardware instead of high-performance components, an array of simple CPUs uses less power than an array of full-fledged CPUs ripping for the same high-speed printer. Let us compare an HP SmartStream Production Pro Print Server to the GPU-RIP system proposed. Since the volume of the two systems is almost the same, we do not need a full exergy destruction analysis and can just compare the CO2 footprint of the two systems.

We use the HP Power Calculator Utility and the HP workstation quick specs to compile the energy usage data. The total amount of power a device requires from the facility AC feed is known as apparent power and is measured in volt-amperes (VA). The British Thermal Unit (BTU) is the standard for measuring the capacity of cooling systems. The amount of power (Watts) consumed by equipment determines the number of BTUs/hr required for component cooling.

speed [GHz]
PCI cards
VA rating

The table above lists the data for the conventional Digital Front-End (DFE) RIP. Multiplying the ratings for each system component with the number of units of that component and adding up yields a total BTU/h of 14,380 and VA rating of 4,420.4. The table below lists the data for our experimental GPU-RIP. Multiplying the ratings for each system component with the number of units of that component and adding up yields a total BTU/h of 4,200.96 and VA rating of 1233.36.

speed [GHz]
PCI cards
VA rating

Assuming the RIP will be operated in a factory building, it will probably not need special cooling. Therefore, we can limit our calculations to the total system VA rating. Assuming a continuous full-capacity workload for an entire year, the DFE-RIP will consume 38,723 KWh and generate 23,234 Kg of CO2. For the GPU-RIP the corresponding numbers are 10,804 KWh and 6,483 Kg, i.e., the GPU-RIP in a year will generate 16,751 Kg less CO2. To put this number in context, we used an online CO2 footprint calculator and entered the largest car owned by the authors and the miles it was driven over the last year. The calculator determined his car generated 1.52 tonnes of CO2. Thus, with the CO2 saved by the GPU-RIP in a year, he can drive for 12 years, or if just two of you esteemed readers deploy a GPU-RIP instead of a DEF-RIP, in one year you will have offset his total lifetime CO2 footprint so far.

These are the numbers we have so far. In vero, the assumption of a continuous full-capacity workload for an entire year is not realistic. In a second paper with title Numerical Simulation and Analysis of Commercial Print Production Systems, I-Jong Lin presents a new simulation system, that will allow us to make realistic predictions of ripping efficiency in terms of the CO2 footprint as a performance metric.

Monday, September 21, 2009

Oh Sonorous Imaging Devices

An HP ScanJet 5P performs the Ode to Joy:

While another ScanJet performs a Vivaldi piece:

And a printer plays Mary Had a Little Lamb:

Clearly DPI is only part of the picture.

Sunday, September 20, 2009

That Unthinkable Future

In 2005 John Updike wrote a poem about his birthday. It included the lines:

A life poured into words -
apparent waste
intended to preserve the thing
For who, in that unthinkable
when I am dead, will read? The
printed page
was just a half-millennium's brief

Unthinkable future indeed.

Shortly after reading this I had yet another discussion with Giordano about tags (and/or labels) not really being about serendipity but for structure. He had previously emphasized discipline with the mostlycolor tags to the point of giving me a small figurine of a Pueblo storyteller for my desk.

The mother figure is shown surrounded with children listening to her stories. But the figurine is just a metaphor for tagging. Each child is a thread that emerges over time with thoughtful and consistent tagging.

Fine I will not add a John Updike, poetry or half-millennium labels to this post.

But have we reached the unthinkable future?

Late last week, a partnership between Google and OnDemand was announced which would allow allow books digitized by Google Books to be printed (and finished) by OnDemand's Espresso Book Machine. If you haven't seen an Espresso Book Machine yet it looks something like this:

OK so once Updike's poems pass into the public domain (you do the math) then you might be able to get a copy printed on demand via this partnership. Sounds good. John may be remembered even after my glass is long empty. I for one think it was great that "he was still asleep when we went to school, and was often home already when we got back".

Then I hear Neil Postman whispering: "We might even say that the printing of the Bible in vernacular languages introduced the impression that God was an Englishman or a German or a Frenchman--that is to say, printing reduced God to the dimensions of a local potentate." And I'm left struggling with another deconstructed medium projecting a disproportionate sense of scale to the participants of that deconstructed medium.

Kind of like blogging (the first medium born deconstructed?).

And in in that same Postman essay is an aside to Solomon's proverbial wisdom. A whopping 3000 proverbs. An oral tradition in which presumably every spoken word was in the public domain. The competitive advantage was then the way in which those words were spoken, remembered, expressed and maybe lived.

What an unthinkable past.

Friday, September 18, 2009

CUDA and OpenCL

Parallel computing on a GPUs is undergoing two paradigm shifts: in the early days of GPU computing, GPUs where hard-wired for graphic rendering and the programming paradigm was to express generic operations in terms of rendering and texture mapping operations. In a first paradigm shift (since NVIDIA's G80), the hardware architecture has been changed to allow general parallel computations, embodied in CUDA. The upcoming paradigm shift is a new software architecture to allow scalability and portability, embodied in the OpenCL technology. These two disruptive changes will require different algorithms to achieve the aspirational goal of a performance improvement of two orders of magnitude over current implementations.

Tuesday, September 15, 2009

Color Calculator from 1994

Found in the desk drawer while looking for something else.

A nice souvenir from the 1994 meeting of the DCC/ISCC.