Ma.gnolia: John Lam's Bookmarks

Light Field Photography with a Hand-Held Plenoptic Camera

jlam — Fri, 15 Aug 2008 20:52:16 PDT

This paper presents a camera that samples the 4D light field on its sensor in a single photographic exposure. This is achieved by inserting a microlens array between the sensor and main lens, creating a plenoptic camera. Each microlens measures not just the total amount of light deposited at that location, but how much light arrives along each ray. By re-sorting the measured rays of light to where they would have terminated in slightly different, synthetic cameras, we can compute sharp photographs focused at different depths. We show that a linear increase in the resolution of images under each microlens results in a linear increase in the sharpness of the refocused photographs. This property allows us to extend the depth of field of the camera without reducing the aperture, enabling shorter exposures and lower image noise. Especially in the macrophotography regime, we demonstrate that we can also compute synthetic photographs from a range of different viewpoints. These capabilities argue for a different strategy in designing photographic imaging systems.

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Tags: plenoptic camera, light field, imaging, optics, Fourier optics, computational holography

Dappled Photography: Mask Enhanced Cameras for Heterodyned Light Fields and Coded Aperture Refocusing · SIGGRAPH 2007

jlam — Fri, 15 Aug 2008 20:45:21 PDT

This awesome project uses a Fourier mask to capture the holographic light field and thus multiple images of the subject, and then computes and renders new view of the subject.

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Tags: light field, imaging, optics, Fourier optics, computational holography

P3P: The Platform for Privacy Preferences · World Wide Web Consortium (W3C)

jlam — Wed, 23 Jul 2008 07:53:26 PDT

Platform for Privacy Preferences Project (P3P) lets websites express their privacy practices in a standard format for automatic retrieval and easy interpretation by User Agents. P3P-capable browsers then inform users of site practices (in both machine- and human-readable formats) and aid and automate decision-making based on these practices when appropriate. Thus for standard and common practices, users need not read privacy policies at every site they visit.

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Tags: privacy, policy, browser, Extensible Markup Language

Papers Written by Googlers

jlam — Wed, 16 Jul 2008 18:30:38 PDT

A partial trove of publications by Google employees, organized by category, plus organized by year and also fed via Atom…

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Tags: computer science, algorithms, research, papers, Google

Google Base

jlam — Tue, 15 Jul 2008 03:57:53 PDT

Currently in beta and free, for indexing into Google search, Base lets sellers and providers upload or feed listings of products, jobs, events, recipes, and whatever item readers and consumers might seek.

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Tags: market, search, items, events, aggregator, Google

Sense Array: a collaborative filter

jlam — Fri, 04 Jul 2008 00:46:57 PDT

SenseArray combines true collaborative filtering with demographics and taxonomies/folksonomies to prime its recommendations without much tedium of training the filter. Its “core recommendation algorithm has been extensively tested against standardized metrics. For example, when tested using 100 million ratings of half a million Netﬂix users, SenseArray performed 5% better than Netﬂix’ own recommendation algorithm.” Newsgator uses it for its online article recommendation algorithm.

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Tags: collaborative filtering, folksonomies, Ian Clarke

Magnolia marker widget :: Firefox Add-ons

jlam — Sun, 01 Jun 2008 14:36:53 PDT

This Firefox add-on widget, even in 0.8.01 beta, lacks only two features of the official marklets: the ability to post to groups and to select from existing tagsets. Compared to the official marklets, this marker widget load faster. With it, just right-click the page or invoke this widget from its toolbar icon, then mark, tag, and post the link to Magnolia.

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Tags: linkmarking, widget, Firefox, tagging, social computing, Web 2.0

Quicksort, Heapsort, Fast Heapsort, and Entropy

jlam — Sat, 24 May 2008 07:55:11 PDT

In asking why Heapsort works using twice the comparisons of Quicksort but in practice works 20% faster and yet both scale N·log·N on average, David Mackay uses entropy to tweak it and devise a simple and clever sort yet even closer to the information theoretic optimum: Fast Heapsort. He also suggests improvements to Quicksort, and poses a simple puzzle to convey why using entropy works better.

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Tags: Quicksort, Heapsort, Fast Heapsort, sorting, algorithm, programming, entropy, information theory, computer science, David Mackay

The Scheme Programming Language

jlam — Thu, 08 May 2008 11:07:44 PDT

All about Scheme, its many implementations, the documentation in full, resources, friends, mailing lists and news groups, a general rundown and a few links on the future of Scheme, it's delicious reading.

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Tags: Scheme, programming, computer science, Lisp

Structure and Interpretation of Computer Programs

jlam — Thu, 08 May 2008 05:21:26 PDT

Not merely one of my favorite programming books, but one of my favorite books all-time, “sick-pee” is what i imagine a first-time ride on Ecstacy might be like, a headrush of neural connection-making gone wild. No, seriously, it's a good book, endorsed by many. See http://eli.thegreenplace.net/2008/04/18/sicp-conclusion/ Buy the dead tree edition, or read the book in its entirety online here free.

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Tags: computer science, programming, software, Scheme, book, Massachusetts Institute of Technology, Harold Abelson, Gerald Sussman

FriendFeed API

jlam — Wed, 26 Mar 2008 00:24:43 PDT

The FriendFeed application programming interface lets programs interact with FriendFeed to lever and integrate it with other applications, such as a widget for your blog or an interface for mobile via HTTP Get and Post requests. FriendFeed also created a repository at Google Code and posted Python and PHP libraries.

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Tags: social media, social computing, aggregator, syndicator, messaging, protocols

Affordable and Free WiFi Internet • Meraki Wireless

jlam — Thu, 20 Mar 2008 20:43:07 PDT

“Meraki's mesh networks cover dramatically more geographic area and users than previous generations of wireless networks by relying on sophisticated mesh routing technology to increase range and network capacity. Instead of relying on a single large antenna to cover every user, each radio in a Meraki network cooperates to find the best path to carry a user's traffic to the Internet. As they operate, every network re-evaluates thousands of routing paths every minute, resulting in amazing reliability and network capacity. Meraki's intelligent mesh routing means every repeater you add extends the reach of the network and makes the mesh more reliable by adding additional links.”

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Tags: Internet, access, wireless, Wi-Fi, network, carrier, mesh routing, access point

NewsFire (for Mac OS X)

jlam — Wed, 05 Mar 2008 01:27:47 PST

For those who like Safari’s clean interface and want a more fully featured feedreader, but hesitate to buy products, NewsFire (for Mac OS X) is now free, two months after Newsgator made NetNewsWire free, likely in response to opportunities and competitive offerings by Google Reader, NetVibes and other web-based aggregators. For those who have yet to try any feedreader, they make lifehacking your information load a whole lot more worthwhile.

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Tags: feedreader, OS X, Macintosh, David Watanabe

Acquisition (for Mac OS X)

jlam — Wed, 05 Mar 2008 00:54:35 PST

Search and download files from millions of Mac and Windows users. Speed is everything, so Acquisition is optimized for the fastest Gnutella and BitTorrent transfers. It can also automatically send downloaded files to iTunes, iPod and iPhone.

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Tags: Gnutella, BitTorrent, iTunes, OS X, Macintosh, David Watanabe

Inquisitor 3 · Spotlight for the web.

jlam — Wed, 05 Mar 2008 00:47:59 PST

Like Google Toolbar search suggestions, but styled and only for Safari so far, Inquisitor also works like OS X Spotlight. Developer David Watanabe calls it Spotlight for the web.“Start typing and websites pop up immediately, along with ideas to refine your search.It'll autocomplete your words (is it reading your mind?) and you can add more search engines to Safari with customized keyboard shortcuts.Oh, and it's free.”

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Tags: search, tool, browser, free, Safari, OS X, Macintosh, David Watanabe

NoseRub: a decentralized, social network integration protocol

jlam — Fri, 15 Feb 2008 08:27:34 PST

A protocol, implementation, exemplar and inspiration for a decentralized social network, NoseRub uses already available standards such as OpenID, FOAF, and RSS to support truly decentralized social networks. Several sites, such as sister site Identoo, already implement it. Based in Bonn and Köln, Germany, but under an MIT license, and hosted at Google Code, it's free and opensource.

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Tags: social networks, social media, opensource, OpenID, Friend of a Friend, Open Social, social networking

kuler · Adobe Labs

jlam — Sun, 10 Feb 2008 01:00:12 PST

An experimental palette sharing site for graphic designers, based on Shockwave Flash and Adobe Air, here create harmonious color themes online and publish them as resources for others. Explore, create and share color palettes. For sharing swatches, it's the neatest thing i've seen since the Pantone color Matching System. Now, go calibrate your monitor!

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Tags: graphic design, color, palettes, tool, tags, folksonomy, social media, Adobe

Barnraiser

jlam — Thu, 07 Feb 2008 03:49:20 PST

Barnraiser builds opensource OpenID servers and a collaboration package which uses OpenID, which install on Apache with PHP5 and MySql. Though many people already have OpenID identities at America Online, Yahoo, and Live.com, this gives organizations ability to create user identities on their own server, free from commercial sites, large identity providers, and even smaller providers.

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Tags: OpenID, social media, social computing, identity, Apache, server

Yahoo! OpenID

jlam — Thu, 24 Jan 2008 13:46:50 PST

Yahoo now supports OpenID 2. At http://flickr.com/photos/{nickname} Flickr users can also use their Flickr identity! “Why OpenID? Are you tired of creating a new account on every web site you use? Do you avoid new web sites because they come with yet another username and password? Do you paste stickies with password hints all over your computer monitor? “OpenID, an open technology standard that solves all of these problems, lets you use your many accounts and now Yahoo! accounts to sign into hundreds of web sites! And this list grows every day! “Once you enable your Yahoo! account for OpenID access, you can simply tell any OpenID enabled web site that you are a Yahoo! user. You will be sent to Yahoo! to verify your Yahoo! ID and password and then signed in to the web site. It's that easy.”

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Tags: OpenID, identity, social media, social computing, Flickr, Yahoo!

Meeting Facilitation: The No-Magic Method • from the classic by Berit Lakey

jlam — Wed, 10 Oct 2007 18:18:25 PDT

I first learned of this via the Burning Man Webteam. Hosted at Reclaiming, a site devoted to modern witchcraft and paganism, yet subtitled “No-Magic” and originating from the short classic by Berit Lakey of the Movement for a New Society, a reform movement within the Society of Friends, commonly known as the Quakers, this document may sound like a contradiction. Instead widespread adoption likely attests to the practical success of things that work. And what works for pagans and Quakers, and Burners and hackers, ought also work for many of us.

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Tags: facilitation, civics, consensus, meetings, agendas, social capital, Nash equilibrium, Quaker