from apprentice to master

When I grew up on the western edge of Lugano, life in the old country was not very mobile and people tended to spend their life at audible distance from the church bells they heard at birth. The most exotic person you could come across was that wiry old man in a tattered white suit hiking in the woods of Collina d'Oro that was Hermann Hesse, often carrying a drafting book and a box of water colors, totally absorbed in his thoughts.

With this, when Ravi Shankar came to town for a concert sponsored by Migros, it was like a little prince coming from an other planet. Indeed, he and his daughter were wearing traditional Indian clothing, something that had never been seen before on the streets of Lugano. I had the chance to spend a full day and an evening chatting with him, while conducting an interview for the youth radio and helping setting up the recording equipment for the concert.

I was amazed by the difference in personality between him and his daughter. The latter was distant and exotic, but Ravi Shankar was immediate and approachable. It was easy to talk casually with him. I had never seen a sitar before and started to talk with him about the complexity of the instrument. Since he was classically educated, I asked him how long it had taken him to become a master, compared to the piano or the violin. He countered he was not a master at all. When I noted his total command of the sitar and how he appeared to be one with it—even citing Jimi Hendrix and his electric guitar—he rebutted that he was just an apprentice. He continued that the sitar is an instrument that takes a whole life to learn to play, and it is only after reincarnation that one can play it as a master. He pointed out, that when performing on a complex instrument, total mental concentration was necessary and mastery of the sitar takes two lifetimes.

During the concert, I was at the left side of the first row and soon noticed that he was not only in constant musical contact with the other players, but he was also conversing with me through his eyes. Indeed, his protocol was to fixate a member in the audience he thought had an interesting posture, then fixate me, return to the first person to guide my gaze, and when I followed his gaze and looked at that person, he acknowledged with the hint of a smile. While Herman Hesse was totally absorbed in his thoughts, Ravi Shakar was involved concomitantly in three conversations—with the sitar, the orchestra, and the audience—meaning he had full awareness of his surrounding while he was also fully absorbed in the music.

Yesterday Ravi Shankar reached the end of his apprenticeship and today—12/12/12—he is a master sitar player.

Extending the printer gamut upwards

Full color printing started with cyan, magenta, and yellow. Then black was added to extend the gamut down in the shadows. Later spot colors were added to make the gamut wider (Hexachrome, Indichrome, etc.). Now Romain Rossier & Roger David Hersch are adding light fluorescent magenta and yellow to extend the gamut up in the light colors. They are presenting their work at the CIC 20^th Conference in Hollywood in the Friday afternoon session on Printing chaired by Jan Allebach. Of course, the slides are limited by the projector's gamut, so you need to be there and look at the actual prints.

GPU-accelerated Path Rendering

Last May I wrote about a major breakthrough in path rendering on the GPU by Mark Kilgard. I am happy to report that Mark—together with Jeff Bolz—has been hard at work on the rest necessary for a complete raster image processor (RIP). They have invented a new "Stencil, then Cover" (StC) algorithm in which the stencil step is explicitly decoupled from the subsequent cover step.

In the stencil step, a path's filled or stroked coverage is determined. In the cover step, the conservative geometry intended to test and reset the coverage determinations of the stencil step is rasterized, while shading color samples within the path. They have not only achieved fantastic acceleration, but also full completeness and correctness. Usually, the performance killer is the bottleneck between CPU and GPU, like when transparency is computed in the CPU. Kilgard and Bolz solve their revalidation bottleneck by using a configurable front-end processor in the GPU to transition quickly between the stencil step and the cover step.

For more information, see their paper at SIGGRAPH Asia, a pre-print of which is available at this link: http://developer.nvidia.com/game/gpu-accelerated-path-rendering.

Binarization

This year I have been working on document information retrieval, which is as far from color as you can imagine. Indeed, business documents are pretty dry binary black and white items, so that the first step—before even doing optical character recognition—is to binarize the document images so we can efficiently work with bitmaps. In the old days binarization was relatively easy, because almost any scanner illumination can easily be compensated when it is not uniform (see US patent 5,901,243).

Today binarization is much harder, because an increased number of documents is imaged with digital cameras, most often of the kind in smart phones. Much work went into extending existing binarization algorithms to text in pictorial images, alas with little success. It turns out that a completely different algorithmic approach is required, as was recently published in the paper

Yan Wang and Chuanjiang He, Binarization method based on evolution equation for document images produced by cameras, Journal of Electronic Imaging 21 (2012), no. 2, 023030

Here is the abstract:

We present an evolution equation-based binarization method for document images produced by cameras. Unlike the existing thresholding techniques, the idea behind our method is that a family of gradually binarized images is obtained by the solution of an evolution partial differential equation, starting with an original image. In our formulation, the evolution is controlled by a global force and a local force, both of which have opposite sign inside and outside the object of interests in the original image. A simple finite difference scheme with a significantly larger time step is used to solve the evolution equation numerically; the desired binarization is typically obtained after only one or two iterations. Experimental results on 122 camera document images show that our method yields good visual quality and OCR performance.

Blue nights

I usually sleep with open curtains. Fireflies aside, growing up, when I woke up in the middle of the night and looked up, I saw the Milky Way. It was quite a change when as a student I moved into a room in Zürich's Predigergasse that had a gaslight on the corner of the house, just outside my windows. When I woke up in the middle of the night, instead of a black firmament with the twinkling Milky Way, I experienced being bathed in a flickering red light. My insomniac nights changed from black to red.

Our house in Palo Alto features a street light smack in front. At night, monochromatic yellow sodium light shines through the large picture window and paints the house in a warm light, emphasizing the polenta-yellow walls and the golden white oak hardwood floors.

Until yesterday.

The City replaced the sodium lamp with an LED lamp and the floors are now patterned by cold blue reflections, which in turn create eerie light plays on the walls. Instead of averaging and blurring the material structures, the new light analyzes and emphasizes them.

It will take some time getting used to it.

By the way, in 1980 low pressure sodium street lighting became common in the Silicon Valley in support of the Lick Observatory on Mount Hamilton, to reduce light pollution. The Barron Park neighborhood in Palo is dark at night, because the inhabitants keep their porch lights off. Their neighborhood park is named after Cornelis Bol, a Stanford physicist and the inventor of the high-intensity mercury vapor lamp.

Avoidance of plagiarism

As the center of gravity for scientific research is moving from old locales with longstanding traditions to new geographies with forgotten traditions or which never had them, plagiarism has become a major issue. At times it feels like being in the Wild West.

Sometimes papers are pure copies of previous work. More often, authors have not yet developed a proper hygiene for citing related work. I am always surprised how often authors cite secondary references instead of primary references, a fact I tend to take as laziness and punish with a negative review.

In Volume 6, Issue 1 of the SPIE Journal of Nanophotonics, Editor-in-Chief Akhlesh Lakhtakia has written a very useful editorial on this topic. Follow this link: http://dx.doi.org/10.1117/1.JNP.6.069901.

Firefly

The firefly plays a special role in Japanese culture. It is called hotaru (蛍, ほたる) and we researchers know it from the expression 蛍雪 (けいせつ), or firefly-writing, which refers to diligence in studying (i.e., continue to study even in such poor light as offered by a firefly). For more wordly people, the firefly is the symbol of passionate love.

At least from the 24 April 1185 battle of Dan-no-ura, where the Genji under Minamoto no Yoshitsune, defeated the Heike (Taira), if not from earlier, it is believed that when soldiers are killed in battle, their souls are transformed into fireflies. Therefore, in Japan the view of hotaru is very sentimental and patriotic.

Today the life of scientists is more peaceful, as researchers are no longer killed like Goethe's Faustus when his grant was up or Giordano Bruno when he came up with the mathematical concept of infinity (see glad not to be on the stake), so we can be cheerful when we see fireflies.

I remember when we moved to Lugano, at the city's border, consisting mostly of untended fields. The place did not even have a name yet, it was just the far end of Besso, or Lugano 3, as the postal system prosaically called it with the introduction of zip codes. As kids we only had to run away from the apartment buildings for a few minutes to be in a completely dark environment devoid of any light pollution. The black sky was dotted with infinite stars, but in summer, towards Cortivallo and the lake of Muzzano, we were immersed in a cloud of fireflies. It was a magic experience.

Of course, today as color scientists we are more interested in the spectrum of the firefly. Entomology teaches us that males and females are anatomically different, with the latter having two lateral light sources and the former three adjacent light sources. This means that we have to measure the sexes independently. How can we achieve that?

In his recent paper in Atti della Fondazione Giorgio Ronchi, volume LXVII (2012), number 3, pages 455–458, Paolo Stefanini reports how he accomplished it.

The males normally cruise above the fields, while the females are hidden in the grass. When the females want to mate, the crawl to the apex of the grass leaves and wait. A males ready to mate flashes his light and a female flashes back, then they go at it. Therefore, Stafanini first measured the males, then he built a male decoy using LEDs. The decoy allowed him to beat the females out of the bushes, so he could measure them too.

La tienda de las curiosidades sobre el color

Gladstone famously asserted Homer—and in fact all Ancient Greeks—were color blind because Homer's works never mentioned a color. I do not know what Gladstone was reading in school, but I remember reading Homer's vivid descriptions of sunrises and sunsets, not to mention the descriptions of light at sea, for example when Odysseus tried to withstand the song of the sirens.

This demonstrates the need to teach the perception of color: if we cannot express it, it does not exist. Today, the world is much more colorful, so it has become an easier task. I remember when I was a kid and the world was much more monochromatic: cars were either black or white, and most clothes were grey. In elementary school, we boys had to wear a black smock, while the girls wore a white smock. Next door from our apartment building, Pasticceria Ceroni had the first TV in Bellinzona, and it was black and white. Later, when color TV came on the market, it was so expensive, that kids used to brag by exclaiming: "my dad makes more money than yours, we have a color TV." Meanwhile my family was so poor that even our rainbows were just in black and white…

Despite all the color stimulation everybody can enjoy today, it still must be sorted out and explained, otherwise kids cannot enjoy the rainbows in color. April 27, Mark Fairchild and Manuel Melgosa Latorre presented a new book edited by the Editorial Universidad de Granada (eug), in collaboration with the Parque de las Ciencias that makes a wonderful contribution toward this task: “La tienda de las curiosidades sobre el color.”

El libro “La tienda de las curiosidades sobre el color” da respuesta a 64 preguntas didácticas sobre el color: ¿Cuántos colores hay en el mundo?, ¿qué es el color?, ¿cuál es el mejor color para unas gafas de sol?, ¿por qué el cielo es azul?, ¿puede un perro ver el color lo mismo que yo?, ¿por qué tienen las flores distintos colores?, ¿por qué no podemos ver los colores de noche?, ¿por qué mis fotos no tienen los mismos colores que las escenas originales?

Estos son algunos de los interrogantes que el libro desvela. Las preguntas están ordenadas en 8 módulos (luz, objetos, ojos, etc.), y dentro de cada módulo hay 8 niveles de creciente complejidad, ya que el libro va dirigido tanto a estudiantes de primaria como a estudiantes universitarios, y también a cualquier persona interesada en la ciencia.

The book is also available in English: Explore Mysteries of Color — Discover Why is Color.

Colorful Language: The Results

It has been almost a year since we mentioned Eleanor Maclure's survey on Colorful Language. First of all, congratulations to Eleanor for a successful graduation! In fact, she has since completed the course and produced an illustrated report of the results of the survey.

The report is easier to look through on Eleanor's issuu profile, but she also has the PDF available to download from her blog. There are other parts to the project which are more visual explorations of color and language as well, she did a number different things for her MA because it is such a big area to study.

Enjoy!

war of currents

Power distribution is a key technology for increasing the efficiency of work, thus increasing life quality and improving the human condition. Early factories had extensive belt systems to transmit the mechanical force of a water wheel to the workstations in a plant. In the industrial revolution the water wheel was replaced with the more predictable and powerful steam machine, but the inefficient and inconvenient mechanical distribution through belts remained.