The multiple capture image on the left can be used to create the high dynamic range image on the right
DigitalPro Shooter Volume 2, Issue 4, February 16th, 2003
Welcome to DPS 2-4. For those interested in color and color management the publication of Real World Color Management is exciting news. We've got a full review of the book later in the issue. But first there is some big news on the "Perfect Pixel" front. Pixim is introducing their Digital Pixel System this week, which promises to change the way that image sensors will work in the future. --David
Tomorrow, Pixim will unveil their Digital Pixel System (DPS) at the DEMO conference. It is a revolutionary new approach to camera imaging systems and important enough to our future photographic tools that it is worth knowing about.
DPS is exciting because for the first time real intelligence is being added at the pixel level. Pixim's initial product use this intelligence to create hugely extended dynamic range, but the possibilities for having processing at the pixel level at the camera are as unlimited as our imaginations. For now though, the best way to think about what DPS can do for images is providing a greatly extended dynamic range automatically. As a practical matter, think of a camera where your highlights never blow out and your shadows always have detail. If you're one of the folks who suffers through a Raw mode workflow to correct for exposure and range issues, you'll be able to dump it. If you're taking multiple exposures and stapling them together in Photoshop, you can forget having to do that either.
Before you get too excited Pixim is currently only producing imaging systems for the security video market--since the need for increased dynamic range is a no-brainer in security. A bank camera is useless if the glare from the window renders all the faces too dark to recognize. But their technology, spun out of Stanford and protected by an array of patents, is appropriate for higher resolution still cameras including D-SLRs in the future.
Every pixel in a DPS has its own analog to digital converter. For starters that means less noise, as the analog signal does not need to be run across the sensor before being converted to digital. But even more importantly it means that each pixel can be captured at the appropriate time. So a capture in a DPS can actually be a whole series of multiple captures, with each pixel being measured at the optimum time. For example, if you have a scene where you need 1/2 second to get shadow detail and 1/100th of a second to keep detail in the highlights, you would normally have to pick one or the other. But a DPS exposure can read the highlight pixels as they start to saturate (say at 1/128th), the mid-tones as they start to saturate (1/64, 1/32, 1/16, 1/8 and 1/4) and the shadows at 1/2 second. All seamlessly, as the built-in DPS does the math to combine the individual pixel information into an enhanced higher dynamic range image.
Each portion of the scene is captured when it has the best signal to noise ratio
While Pixim is of course focused on delivering its initial products the prospect of multiple captures and per pixel intelligence is tantalizing for the future of digital photography. Let's take the issue of flash photography. Even with TTL flash current cameras are forced to make a compromise between the perfect flash exposure and the perfect background exposure--since the shutter can only be open for a single interval. But with a DPS it would be possible to take one capture at high speed to capture the light of the flash and another at an ambient exposure level. Then the flash balancing can be done "after the fact" in the DPS in a way that retains both subject and background detail.
A more general application is providing the digital equivalent of Kodak's Max film. As serious photographers we're expected to get the exposure right. But most people would prefer to just point and shoot. With today's low-end digital cameras that is often a recipe for disappointing images. A DPS could be used to capture the extended range of information in the scene and turn it into a usable image.
As with any new technology, DPS creates new challenges. An obvious one is potential motion artifacts from the differing capture intervals. Pixim has spent a great deal of time and effort creating imaging algorithms in their chipset to eliminate or at least minimize these issues. And in fact current digital cameras either need mechanical shutters or wind up with motion artifacts from reading out part of the image at a time. For many applications Pixim actually has an advantage in this area. From seeing a demo of what their DPS can capture compared to current security cameras, they have done an incredible job and their products are clearly head and shoulders above what is out there. We'll have to stay tuned to see how well the technology adapts to the still camera market.
For now this is a moot point for digital photographers of all kinds, since only X3 is available in still cameras and only DPS is available for video, but clearly both of these companies have created remarkable new solutions for creating better digital images by innovating at the sensor and pixel level. The X3 system measures all three primary colors at each pixel, while the DPS relies on traditional Bayer mosaics but can capture extended range data at each pixel. Leaving aside the business and technical issues involved, as photographers we'd clearly love to see an imaging system that was able to accomplish both. Being able to use 100% of the light falling on a sensor to create a full color image at the same time as having nearly unlimited dynamic range would certainly put us very close to the Perfect Pixel!
Until now you've had to read several different books, many web sites and probably attend at least one seminar to build a complete understanding of color reproduction and color management in digital photography. Now all the pieces are in one place. Real World Color Management, by Bruce Fraser, Chris Murphy and Fred Bunting is an ambitious volume which takes the reader on a journey starting with a chapter on human vision all the way through suggested color managed workflows for your digital studio.
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Capsule Summary: The ultimate reference book on Color Management? Bruce Fraser has teamed up with Chris Murphy and Fred Bunting to create Real World Color Management--the single best overall reference for those wanting to learn more about a color managed workflow. It complements the nitty-gritty style of Dan Margulis's Professional Photoshop: The Classic Guide to Color Correction, which focuses more on the specific issues of image correction. |
If you are looking for an immersion course in color as it applies to digital imaging, this is the single best book to get. The first half combines the highlights of books on perception, color science and digital imaging. While it is not as thorough as reading textbooks in each of those areas, it is certainly much faster and easier to read. The second half focuses on the practical applications of color in building a digital workflow. Topics range from incredibly pragmatic sections on how to properly profile your scanner and monitors as well as set up the color settings for your applications through to fairly technical descriptions of what a color management system actually does and how profiles are constructed.
This book is particularly well suited for those who are really curious about how color reproduction works and want to know why profiles are used and why they work. At the same time, it can serve as a practical guide for those who use it as a reference and look up topics as needed. You won't have the same full understanding of the issues involved if you just refer to it one answer at a time, but that may be a more practical place to start if you don't have a couple days to digest all the content from cover to cover.
The final chapters of the book focus on the specifics of how to use color management on the Mac, in Windows, and in your favorite applications, including Photoshop and Acrobat/PDF. For some readers these sections will only reinforce their hard earned knowledge, but for anyone who has not yet wrestled the complex color settings to the ground this is a much more straightforward way to learn how to use all those daunting dialogs than piecing it together from vendor documentation and message board posts. Unlike other books which have chapters just on how to use the color settings in your applications, Real World Color Management describes why the settings are there, and provides a fairly deep background of how they relate to the actual science of color and the art and science of digital photography and color reproduction.
In fact, the only real weakness I could find in the book was the organization into thorough topic by topic sections. For those who want a full understanding of the issues this is perfect. But if you're looking for a "how-to" on a particular topic the book switches back and forth between the practical and the theoretical. I've written several technical volumes, so I completely sympathize. There is an irresistible urge to explain as you go. As the author these explanations appear essential and invaluable. But for the photographer hoping to get quick improvement in his print colors or a digital workflow designer looking for answers, it may be difficult to appreciate some of the subtleties or take time to fully appreciate the complexities involved in a color reproduction system. The result in this case is a book which mixes issues with are major and critical with those which are minor and less consequential without fully explaining to the reader which are most important to grasp and implement.
If you are a photographer who captures images and sends them off to others for printing you can definitely survive with out this book. It covers many more topics in color management than you're likely to need. But if you're curious about how the entire color workflow fits together--and perhaps why it seems your images never print in the magazine the way you think they should--then you'll learn a lot from reading it. Conversely, if you do your own fine art or pre-press work, then this book is a must. And if you've already made the decision to invest in profiling software or hardware then reading this book will help you understand how it works and get the most out of it. No matter how much you know, it is almost certain you'll learn at least a couple facts that will be useful in your work from reading it.
We're over-hauling nikondigital.org to make it easier to find the information you need, and easier to read it when you do. Check out the new look as it unfolds over the next few weeks, and please let us know if there is information you'd like to see there.
It seems color reproduction and color management are hot topics this week. There are several lively threads on camera profiling and comparisons of camera profiling software and techniques in the Color forum.
Many users don't realize how easy it is to create their own print template for DigitalPro. We've posted some step by step instructions on how to modify one of the supplied templates to meet your needs on the DigitalPro2 page.