Saturday, November 28, 2009

Mantis Shrimp Gets Fifteen Seconds of Fame

PBS is currently running a series entitled "Human Senses" and the most recent episode featured none other than our previously blogged friend and polarizing figure, the ultra-percieving mantis shrimp. It's quite something to actually see its remarkable pair of multi-channel photon detectors in action.

Mantis shrimp eyes
[Click for video and scroll to 09:02]

This episode will be repeated in the San Francisco Area tonight at 11:00PM on KQEDW (Digital 9.3). Elsewhere, check your local listings.

Tuesday, November 24, 2009

Checker This Out

Are the squares A and B the same shade of gray?

The answer is, yes! Do you need your eyes check(er)ed?

Color naming follow-up

I received some interesting feedback on the color naming tech. report. A reader implied that in traditional psychophysics experiments the informants are first screened for color vision deficiencies (CVD), and our on-line experiment fails to do that. This was felt to be a grave omission especially in light of the two recent JOSA A papers by Kimberly Jameson and Natalia Komarova: and

Postdoctoral Fellowship in Computational Categorization

The Print Production Automation Laboratory of Hewlett-Packard Laboratories in Palo Alto, California is seeking candidates for an ASEE/NSF postdoctoral fellowship in computational categorization in the area of color imaging. A brief description of this opportunity has been posted to the ASEE/NSF web site.

The position will apply experience and interests in perceptual categorization, machine learning, statistical pattern recognition, and natural computation to a sizeable, diverse and growing collection of laboratory and web-derived ground truthing databases for color imaging. Join a team working on advanced optical feedback for commercial printing and provide knowledge of multi-variate clustering, to implement software to perform computational categorization.

Sunday, November 22, 2009

Color naming: color scientists do it between Munsell Sheets of Color

Last year at the IS&T/SPIE Electronic Imaging symposium in San Jose the conference Color Imaging: Displaying, Hardcopy, Processing, and Applications started a session on controversial topics called "The Dark Side of Color." These are papers that transcend the incremental research methodology of solving a problem, proving the solution's contribution in an experiment, and reporting the result in a conference. This session consists of papers were authors go out on a limb, not afraid of intuition and speculation, and propose new paradigms.

A preprint of our contribution is now available at this link:

Friday, November 20, 2009

Un nuovo libro

Studiose, storiche, giornaliste ed esperte del colore, Lia Luzzatto e Renata Pompas hanno maturato una lunga esperienza internazionale sul colore. Membre di network internazionali riconosciuti, tengono lezioni, conferenze, seminari in aziende, istituzioni e università. Oltre a centinaia di articoli e contributi in libri collettivi, hanno al loro attivo numerose pubblicazioni.

Thursday, November 19, 2009

Still Life with Sopapilla and Equations

Still digesting the technical content of CIC17. In the mean time here are some photos. Albuquerque, New Mexico has quite a few architectural gems. Here Steve is standing with one of them that has been clearly labeled.

Next is a still life with sopapilla and equations.

Mavericks are best for crowd-sourcing

Maverick is the antonym of conformist or a culturally competent person. Synonyms include: individualist, nonconformist, free spirit, unorthodox person, original, eccentric; rebel, dissenter, dissident, enfant terrible; informal cowboy, loose cannon.

When we do a psychophysics experiment the old fashioned way in a lab, we want informants that are culturally competent persons. In fact, we are very careful in writing clear instructions, make sure the informants understand them, and check they follow the rules. The experimental conditions are strictly controlled so all informants perform exactly the same experiment.

When we do a psychophysics experiment the new way on the Web using crowd-sourcing, we get all beaten up by our colleagues and our papers keep getting rejected. "You are getting all those disruptive loose cannons out there, your results are meaningless." Well, we could almost reply "consider this formula:"

mean correlation of the aggregated responses to a world standard

I have to write "almost" because James Shilts Boster started writing his paper The Value of Cognitive Diversity: The Correlation of Local Aggregates with World Standards on May 6, 2004, but then as far as I know never got around to publish it.

The formula is for the mean correlation of the aggregated responses to a world standard. rxy is the average individual informant's correlation with the world standard, rxx is the average correlation among informants on the similarity judgment task, and N is the number of informants in the pool of aggregated responses.

This formula teaches that when N is small, like in the case of the old fashioned experiment, then we get the best correlation when all informants are culturally competent. Check!

However, when N is large, like in crowd-sourcing, then each new conformist informant does not contribute much to the correlation. Instead, it is the maverick informants, or better, the disagreement among informants that allows their aggregation to closely approximate the world standard. Surprise!

With this we call all rebels, dissenters, and mavericks out there and beg them to contribute to our color naming experiment at the link of their language on this page:

Wednesday, November 18, 2009

A color never comes alone

This is a motto I was using 25 years ago. At that time I was working on VLSI design automation tools at Xerox PARC, more specifically on design rule checkers for full custom CMOS. The designers were doing so many layout errors that I could not understand how a top notch designer could do them. I had the suspicion that some of the designers could have a color vision deficiency — and 20 years later I discovered one of them is a dichromat — but that was not explaining the the type and volume of errors. I decided to investigate.

Saturday, November 14, 2009

New Image Search: No Training Required

Engineers at the UCSC have developed a new approach to computer recognition or categorization of images or videos. They claim to have overcome a major drawback of existing methods for computer recognition of objects in images—the need for an extensive training phase using a large number of samples. With a single photograph or video clip as a template, their software supposedly sifts through thousands of images or videos and presents the ones that look most like the template. Submitted to IEEE Trans. on Pattern Analysis and Machine Intelligence.

Thursday, November 12, 2009

CIC17 Presentations

The 17th IS&T/SID Color Imaging Conference in Albuquerque, New Mexico has been busy.

In addition to some twilight geocaching with the call of a rout of coyotes in the distance, was an opportunitity to give a last minute keynote. The first keynote speaker was unable to attend and so I gave an encore presentation of my 25th anniversary of the Munsell Color Science Laboratory keynote.

The presentation was well received and there were many follow-up questions, comments and discussions. This afternoon I will present the paper, Nominal Scaling of Print Substrates.

Color Sorting with a Bow-Tie

A Fractal antenna is more efficient than a conventional antenna, which is why most cell phones already have them embedded. This level of compactness is highly beneficial for long wavelength radiation such as: DTV, Wi-Fi, FM and AM radio. What about shorter wavelengths, like visible light?

optical bow tie antennaResearchers at the Lawrence Berkeley National Laboratory have engineered a new class of bowtie-shaped devices that capture, filter and steer light at the nanoscale. These "nano-colorsorter" devices act as antennae to focus and sort light in tiny spaces, a potentially useful technique for harvesting broadband light for color-sensitive filters and detectors.

The scanning electron image (at left) of a nano color sorter shows the vertical bow-tie antenna shifted 5 nm to the left of center. In Figure (a) the bowtie has been exited at 820 nm and in Figure (b) at 780 nm wavelength. The two modes are spectrally and spatially distinct while maintaining nanoscale mode volumes. [Source: LBNL]

Friday, November 6, 2009

Encyclopedia of Color Science and Technology

A quick announcement about a new color related project - the Encyclopedia of Color Science and Technology. This major reference work about color in color will be published by Springer and I will be busy as the editor-in-chief. The first sample entry has been completed and is available on the project web site. It's an entry on CIECAM02.

The effort thus far has given me a new appreciation for indexing. As Harman(1) states of indexing: "the second key decision for any indexing is the choice of what constitutes a word and, then, which of these words to index." Stay tuned.

(1) D. Harman, Challenges in Indexing Electronic Text and Images, ASIS Monograph, Medford NJ, p. 249 (1994).

Tuesday, November 3, 2009

Nature's almost perfect quarter-wave retarder

On September 28, I reported on the keynote lecture on Why are animals colourful? Sex and violence, seeing and signals Justin Marshall gave at the AIC in Sydney. Prof. Marshall gave a description the mantis shrimp's eye noting how it can see polarization with the help of a structure like a kind of nanotube.

The eye of a particular species of mantis shrimp is well-known to have the most complex vision system in nature

With his colleagues, Prof. Marshall has just published a letter in Nature Photonics 3, 641-644 (2009) with the title A biological quarter-wave retarder with excellent achromaticity in the visible wavelength region.

This paper explains in detail how the mantis shrimp detects polarization. The authors illustrate how a novel interplay of intrinsic and form birefringence results in a natural achromatic optic that significantly outperforms current man-made optical devices. Achromatic here means that polarization detection is independent from the wavelength (±2.7º), which is something we humans do not really know how to build.

a, A frontal view of the compound eye of Odontodactylus scyllarus with the midband rows 5 and 6 highlighted by the greyed out region. VH, ventral hemisphere; DH, dorsal hemisphere; MB, midband. The section A'–A'' is shown schematically in b. Scale bar, 800 m. b, Schematic of a transverse section (A'–A'' in a). This illustrates the arrangement of the 5th and 6th rows of the midband and the location of the 8th retinular cell (R8) quarter-wave retarder and the underlying R1–7 cells. The R8 cell is 150 m long.

A syntectic mantis shrimp eye could be a boon for remote sensing. However, with mother nature being and order of magnitude better than what physicists can build, this will not happen any time soon. It is interesting that this structure has not been repeated in any other animal, as far as we know.

Monday, November 2, 2009