picture of the moon

(click for larger image)

According to the EXIF data this picture of the moon was taken on 2011/11/6 at 20:10 hrs with a SONY NEX-5 and a Leitz Summicron 50mm f/2 lens. The exposure was 13 sec, with the gain set to +2EV at ISO 1600, equivalent to ISO 400. I don’t have a record of the aperture, but it was probably stopped down to prolong the (automatic) exposure. No tripod.

Here are some light paintings made with the same method, but aiming the camera along the horizon to catch photons from shops, cars, and street lamps.

(click for larger images)

Excercise: Why do the latter three ‘light paintings’ contain many segmented lines whereas the moon picture is made up of smooth continuous lines? What determines the length of these segments? Exposures for these three images were (6 sec, 3.2 sec, 3.2 sec) respectively.

Vimeo & YouTube HD Informal Comparison

I uploaded the same HD video file (1280×720 progressive) to YouTube and Vimeo. Watch these on full screen, with resolution set to 720p on YouTube and ‘HD Mode’ selected on Vimeo.

Simple P5 Sketch Circle Animation (720p) from Michael Lyons on Vimeo.

This is an unusual video in that it consists only of moving black lines on a pure white background, so compression artifacts are quite noticeable. The raw data (1800 png image files) is over 200MB but artefacts were barely visible in the ~100MB H.264-compressed mp4 file I uploaded to both Vimeo and YouTube. That noted, it seems clear that YouTube has the advantage in terms of quality. Since I’ve read otherwise in informal reports on the web, I’m not sure whether or not the quality might improve with Vimeo Plus, a paid upgrade currently available for the discounted price of US$60/year. Overall, Vimeo offers a calmer, more pleasant user experience than YouTube. The user interface is nicely designed and the online help files are easy to navigate and genuinely helpful. The content and the community are generally more edifying: no denying it there’s a lot of trash on YouTube. The advertising on YouTube is also more obtrusive and distracting. As for pure spec: time to upload and process a video is much quicker with YouTube. Upload is slower with Vimeo and they also make non-paying users wait for at least 30 minutes before the video goes online. Moreover there are weekly limits on total data and only one HD video may be uploaded per week. Third party advertising is less intrusive but lately Vimeo is pushing the paid-subscription fairly hard.

Addendum: Vimeo offers a slightly better experience when browsing from iOS devices in that it’s easier to directly open the 720p viewer. But compression artefacts are still more noticeable, with this file, than with YouTube. Note also that YouTube allows upload of higher resolution videos such as ‘Full HD’ (1080p).

NIME Zemi Basic Tools Part II: Max/MSP

While we are on the topic of basic tools for this seminar, I suspect everyone already knows about, or at least has heard of Max/MSP, a multi-media visual programming environment sold by the company Cycling ’74. If you have any intention to do work in the media arts, and I expect that everyone who joins my seminar has such an interest, then you should try to develop some knowledge of P5, mentioned in the previous post, and Max/MSP.

Our faculty does not presently offer any courses in either of these two tools, however there are plenty of ways you can learn about these through self-study. Just as with P5, there are many resources online for learning about Max/MSP, including the built in tutorials and help files. There are also introductory books, and a popular book written in Japanese is 2061: A Max Odyssey. This book dates from 2006, and there have been some changes to Max/MSP in the mean time, however the basic way of working with Max/MSP has not changed and this book is still very useful.

Max/MSP can be even more fun than P5 because it uses a visual programming paradigm: you create a program by connecting little boxes having a dedicated function. The programs are called patches because the links between the objects resemble the electronic patch cables of the old analog sound synthesizers. Here’s what a simple Max/MSP patch looks like:

Click for larger image.

This is a Max/MSP patch I created after a few hours experimenting with percussion sequences based on the Fibonacci numbers. I’ve titled it ‘Quasi-Periodic Drum Circle’ but it’s not really quasi-periodic because the patterns eventually do repeat and it’s not really a drum circle, because some of the presets use other MIDI instruments such as whistles, and a Cuíca. A more accurate name would be ‘Quasi-Quasi-Periodic Latin Percussion Circle’. This is what a few of the presets sound like:

One of the (many) nice things about the new version of Max/MSP, Max 6, is that it allows you to create standalone applications. If you’d like to try my Percussion Circle as a standalone application on Mac OS X, send me a quick email and I’ll reply with a download link. Because I’ve used several Fibonacci numbers to create the drum patterns, it will take a very long time before the pattern repeats (I’ll leave it as an exercise to calculate just how long it takes.) So this also functions as an ambient generative Latin Percussion app: you can run it as background music if you like that sort of thing.

Like P5, Max/MSP is multi-platform, there are versions for Windows and Mac. Unlike P5, Max/MSP is not free, however it is very reasonably priced and there is a good student discount. Moreover, Cycling ’74 allows you to download Max 6 and try the entire software package for free for one month. Cycling ’74 is an excellent small company to deal with. Members have also showed up at the annual NIME conference from time to time.

You might be wondering where the name Max/MSP comes from. MSP stands for ‘Max Signal Processing’ because MSP handles the audio signals. MSP also stands for the initials of Miller S. Puckette, who first developed Max. Max is named for Max Matthews, who is considered the father of computer music, known for, amongst other things, having programmed the song sung by HAL in the film 2001: A Space Odyssey. Unfortunately Dr. Matthews passed away last year. I have nice memories of meeting him at NIME and other conferences. Here is Max graciously acting as the MC during the first NIME conference concert in 2001.

Processingをはじめよう

As some of you may remember, at the beginning of last year’s zemi class, I handed out a number of a copies of Getting Started with Processing, a very short introduction to programming in the Processing environment by the founders of the project, Casey Reas and Ben Fry.

That short book is probably the best book for beginners to get started with Processing, or P5 as it is known for short. However, I suspect that some of you may have been put off by the fact that the book is written in English. Since a few months ago, the same book, with some additional helpful sections, has been translated into Japanese and is available from Amazon. The book seems to be selling fast, so if you plan to buy a copy, it might be a good idea to do so soon.  If the first run sells out, which I think may be likely, there could be a lag before a second printing appears.

The best way to get started with P5, of course, is to download the program from the P5 community site and start writing some simple programs. The syntax of P5 is similar to C, which most of you have seen in the first year programming classes. However, you’ll soon realize that P5 can be much more fun than C, because it is much easier to get interesting graphical output. Many experienced programmers use P5 as a prototyping tool as they find it is an excellent system for sketching ideas and trying things out. There are lots of libraries for doing all kinds of things such as 3D graphics, computer vision, sound, simulation etc… All completely free, because the developers are believers in open software and sharing. As it turns out P5 is more stable, and much more user-friendly than many expensive software development environments.

It’s possible to get by just with the online documentation, tutorials, and help files included with P5 itself. But having an introductory book does help a great deal. I had a look at the Japanese edition of Getting Started with Processing this afternoon and liked the fact that it includes a glossary of the core P5 functions.

In our era, ignorance of programming is akin to an inability to read and write for someone born after Gutenberg. If your experience with C turned you off, why not give programming another try with P5? I guarantee you that a little effort will reward fun and understanding. These books are available at Amazon, linked to the images above.

Epicycles & Visual Music

I spent some time this evening looking again at the motion of particles moving along epicyclic trajectories. The motion of a single particle q in the complex plane, z, is given by the following parametric function of t:

z_{q}(t) = Re^{i\omega_{q} t} - re^{i\Omega_{q} t} \;\;\; with \; \Omega_{q} > \omega_{q}, \;\; R > r

The animation above is generated using 50 particles moving according to the same parametric equation, with angular velocities given as integer multiples of a fundamental value:

\omega_{q} = q \omega_{1}, \;\;\; \Omega_{q} = q \Omega_{1}, \;\;\; q = 1, 2, 3 \cdots

With the velocities distributed in this way, the angular positions attain various kinds of harmonic relations, whence the arrangement of the particles in the complex plane falls into simple symmetric patterns. The animation bears some resemblance to the visual music of James and John Whitney. In his later work John Whitney made use of digital computer programs to create visual music animations (Whitney, 1981), using particle systems related to the one described here.

[1] John Whitney, Digital Harmony: On the Complementarity of Music and Visual Art , New York, McGraw-Hill, Inc., (1981).

What’s Wrong with Wikipedia?

This is a topic of general importance to everyone in the seminar. No doubt you have had the opportunity to make use of the information in the Wikipedia for your homework or research. You have also, no doubt, observed some of your professors (including me) sometimes cite the Wikipedia. The ones who don’t may be using the Wikipedia privately without admitting so publicly. The fact of the matter is the Wikipedia is a very convenient and often compelling source of information about most common topics, and a wide range of uncommon ones too. But is the Wikipedia a valid source for studying or conducting research? Let’s see what that venerable institution, Harvard University, which ranks at the top of most rankings of academic institutions, has to say about the matter. When I was an undergraduate student, Harvard was my dream graduate school and, in fact, I  was accepted into the Harvard PhD program. But I found my guru elsewhere so, finally, I did not enroll at Harvard. However, when it comes to academic policy, one can do much worse than have a look at what Harvard does. In Harvard University’s official pages on using sources we find the following statement (page accessed 20.02.2012):

There’s nothing more convenient than Wikipedia if you’re looking for some quick information, and when the stakes are low (you need a piece of information to settle a bet with your roommate, or you want to get a basic sense of what something means before starting more in-depth research), you may get what you need from Wikipedia. In fact, some instructors may advise their students to read entries for scientific concepts on Wikipedia as a way to begin understanding those concepts.

Nevertheless, when you’re doing academic research, you should be extremely cautious about using Wikipedia. As its own disclaimer states, information on Wikipedia is contributed by anyone who wants to post material, and the expertise of the posters is not taken into consideration. Users may be reading information that is outdated or that has been posted by someone who is not an expert in the field or by someone who wishes to provide misinformation. (Case in point: Four years ago, an Expos student who was writing a paper about the limitations of Wikipedia posted a fictional entry for himself, stating that he was the mayor of a small town in China. Four years later, if you type in his name, or if you do a subject search on Wikipedia for mayors of towns in China, you will still find this fictional entry.) Some information on Wikipedia may well be accurate, but because experts do not review the site’s entries, there is a considerable risk in relying on this source for your essays.

The fact that Wikipedia is not a reliable source for academic research doesn’t mean that it’s wrong to use basic reference materials when you’re trying to familiarize yourself with a topic. In fact, the library is stocked with introductory materials, and the Harvard librarians can point you to specialized encyclopedias in different fields. These sources can be particularly useful when you need background information or context for a topic you’re writing about.

 

This position on the use of the Wikipedia as a source is fairly close to my own opinion. I would explicitly add, however, that no source should be categorically excluded. To do so is the equivalent of burning (or banning) certain books – the sign of an authoritarian, or at least, elitist mindset. Instead, what is needed (when using any source, for that matter) is the ability to evaluate the quality and reliability of the source. Within the Wikipedia itself, you will find a broad spectrum of reliability. One of the merits of regularly using (and preferably contributing in some way) to the Wikipedia, is that this offers a training ground for honing one’s ability to evaluate the quality of a source.

As a guideline I encourage using the Wikipedia to get an overview of a topic and pointers to the primary and secondary literature on a topic. But it should not be your only entry point into the literature and certainly not the final source you consult. Moreover, one needs to constantly bear in mind the nature of the Wikipedia, the manner in which information is added, and the inherent limitations. The standard of articles seems to vary significantly by topic. Articles in rapidly developing technical areas such as computer science and media technology can be of fairly high quality, often containing information and citations to current primary sources that cannot be found in more archival media such as books or journals, as these suffer publication lag. At the other end of the spectrum are articles about controversial topics such as political disputes. In these cases, it may be more instructive to read the behind-the-scenes disputes (talk pages) about what is to be included or excluded from the main article, than it is to read the article itself, because this offers a quick look at various conflicting viewpoints.

In summary, the Wikipedia is a novel and exciting development in the cooperative   organization and communication of knowledge. It remains to be seen what it will become, but the Wikipedia is worthy of our attention and should not be banned or dismissed offhand.