oracle
01-08-2003, 02:14 PM
The Next Photography Revolution (http://www.discover.com/issues/dec-02/features/featphoto/)
Here comes a digital-camera chip that could change everything
By Eric Levin
Photography by Tom Tavee
"It's easy to have a complicated idea," Carver Mead used to tell his students at Caltech. "It's very, very hard to have a simple idea."
The genius of Carver Mead is that over the past 40 years, he has had many simple ideas. More than 50 of them have been granted patents, and many involved him in the start-up of at least 20 companies, including Intel. Without the special transistors he invented, cell phones, fiber-optic networks, and satellite communications would not be ubiquitous. Last year, high-tech high priest George Gilder called him "the most important practical scientist of the late 20th century."
"Nobody," Bill Gates once said, "ignores Carver Mead."
http://www.discover.com/dec_02/images/digital_1.gif
<font size=1>Digital cameras have relied on image sensors that can't do what color film does: record all three primary colors of light at each point in the image. Instead, each light-sensitive point in the sensor measures just one color--blue, green, or red--and complicated software in the camera calculates the missing colors. Foveon's breakthrough X3 chip solves the problem with a three-layer design that captures red, blue, and green light at each point. To demonstrate quality differences, the monarch butterfly on this page was photographed with three cameras: an $1,800 Sigma SD9 with an X3 chip; a $300 Nikon Coolpix 2500; and a $2,300 Nikon 35 mm F5 film camera. Insets show magnified detail from each camera's image.</font>
And now one of Mead's simplest ideas--a digital camera should see color the way the human eye does--is poised to change everything about photography. Its first embodiment is a sensor--called the X3--that produces images as good as or better than what can be achieved with film. That would make the X3 the most important advance in photography in nearly 70 years, but the long-term implications are even richer. In a year or two, you will be able to pack a true hybrid camera on vacation. It will take high-resolution stills, or upon the flip of a switch, it will take full-length, full-motion video far exceeding the capabilities of present-day hybrid cameras. In the long run, X3 technology could even make cell-phone video sharp enough to project onto a big-screen TV, which would make dandy travelogues to send back to the folks at home, or enhance collision-avoidance systems in automobiles, or improve robot vision.
X3 is the latest and most innovative product from Foveon Inc., the Silicon Valley digital-imaging company that Mead, 68, founded in 1997. Named for the fovea centralis--the part of the human retina where vision is sharpest and most color perception is located--Foveon took as its mission another radically simple idea Mead loves: "Use all the light."
Don't cameras already use all the light that enters the lens? Film cameras do, but digital cameras, with few exceptions, don't. As Mead puts it, "They throw away two-thirds of the light." That makes sense only if you understand how a typical image sensor works. It's basically a rectangle of silicon on which millions of microscopic light-sensitive pixels (technically they're not pixels, but that's what these light-sensing points have come to be called in the digital-camera business) are arranged in a grid. Pixels can't sense color. So a checkerboard of tiny red, green, or blue filters must be bonded to the surface of the sensor so that each pixel lets in one of the three primary colors of light. In so doing, it blocks out the other two.
By comparing each pixel's single-color reading with that of its neighbors, software can derive the values of the two missing colors at each site. That takes approximately 100 calculations per pixel. In a four-mega-pixel camera, a size commonly available today, that adds up to a lot of number crunching. The process is called interpolation, and Mead has a less kind name for it.
"It's a hack," he says. "They have to do all this guesswork to figure out what they threw away. They end up with a lot of data, but two-thirds of it is made up. We end up with the same amount of data, except ours is real."
That is because X3 does what until now only film has been able to do: in one exposure, on one image plane, measure all three primary colors of light at every point on the picture. By doing so, it does away with the bugaboo of so-called mosaic sensors, which often guess wrong, especially at the edges of complicated patterns, introducing moiré effects and jagged color errors called artifacts.
Sensing all three colors at each pixel sounds simple, but more than one industry analyst has described it as "the holy grail" of digital photography. "Engineers have been trying to solve this since the earliest days of digital imaging," says Alexis Gerard, publisher of The Future Image Report. Phil Askey, whose exacting equipment tests on his Web site, dpreview.com, are must reading in the trade, says, "This could be the first sensor to truly surpass film."
...
Click here to read more (http://www.discover.com/issues/dec-02/features/featphoto/)
Here comes a digital-camera chip that could change everything
By Eric Levin
Photography by Tom Tavee
"It's easy to have a complicated idea," Carver Mead used to tell his students at Caltech. "It's very, very hard to have a simple idea."
The genius of Carver Mead is that over the past 40 years, he has had many simple ideas. More than 50 of them have been granted patents, and many involved him in the start-up of at least 20 companies, including Intel. Without the special transistors he invented, cell phones, fiber-optic networks, and satellite communications would not be ubiquitous. Last year, high-tech high priest George Gilder called him "the most important practical scientist of the late 20th century."
"Nobody," Bill Gates once said, "ignores Carver Mead."
http://www.discover.com/dec_02/images/digital_1.gif
<font size=1>Digital cameras have relied on image sensors that can't do what color film does: record all three primary colors of light at each point in the image. Instead, each light-sensitive point in the sensor measures just one color--blue, green, or red--and complicated software in the camera calculates the missing colors. Foveon's breakthrough X3 chip solves the problem with a three-layer design that captures red, blue, and green light at each point. To demonstrate quality differences, the monarch butterfly on this page was photographed with three cameras: an $1,800 Sigma SD9 with an X3 chip; a $300 Nikon Coolpix 2500; and a $2,300 Nikon 35 mm F5 film camera. Insets show magnified detail from each camera's image.</font>
And now one of Mead's simplest ideas--a digital camera should see color the way the human eye does--is poised to change everything about photography. Its first embodiment is a sensor--called the X3--that produces images as good as or better than what can be achieved with film. That would make the X3 the most important advance in photography in nearly 70 years, but the long-term implications are even richer. In a year or two, you will be able to pack a true hybrid camera on vacation. It will take high-resolution stills, or upon the flip of a switch, it will take full-length, full-motion video far exceeding the capabilities of present-day hybrid cameras. In the long run, X3 technology could even make cell-phone video sharp enough to project onto a big-screen TV, which would make dandy travelogues to send back to the folks at home, or enhance collision-avoidance systems in automobiles, or improve robot vision.
X3 is the latest and most innovative product from Foveon Inc., the Silicon Valley digital-imaging company that Mead, 68, founded in 1997. Named for the fovea centralis--the part of the human retina where vision is sharpest and most color perception is located--Foveon took as its mission another radically simple idea Mead loves: "Use all the light."
Don't cameras already use all the light that enters the lens? Film cameras do, but digital cameras, with few exceptions, don't. As Mead puts it, "They throw away two-thirds of the light." That makes sense only if you understand how a typical image sensor works. It's basically a rectangle of silicon on which millions of microscopic light-sensitive pixels (technically they're not pixels, but that's what these light-sensing points have come to be called in the digital-camera business) are arranged in a grid. Pixels can't sense color. So a checkerboard of tiny red, green, or blue filters must be bonded to the surface of the sensor so that each pixel lets in one of the three primary colors of light. In so doing, it blocks out the other two.
By comparing each pixel's single-color reading with that of its neighbors, software can derive the values of the two missing colors at each site. That takes approximately 100 calculations per pixel. In a four-mega-pixel camera, a size commonly available today, that adds up to a lot of number crunching. The process is called interpolation, and Mead has a less kind name for it.
"It's a hack," he says. "They have to do all this guesswork to figure out what they threw away. They end up with a lot of data, but two-thirds of it is made up. We end up with the same amount of data, except ours is real."
That is because X3 does what until now only film has been able to do: in one exposure, on one image plane, measure all three primary colors of light at every point on the picture. By doing so, it does away with the bugaboo of so-called mosaic sensors, which often guess wrong, especially at the edges of complicated patterns, introducing moiré effects and jagged color errors called artifacts.
Sensing all three colors at each pixel sounds simple, but more than one industry analyst has described it as "the holy grail" of digital photography. "Engineers have been trying to solve this since the earliest days of digital imaging," says Alexis Gerard, publisher of The Future Image Report. Phil Askey, whose exacting equipment tests on his Web site, dpreview.com, are must reading in the trade, says, "This could be the first sensor to truly surpass film."
...
Click here to read more (http://www.discover.com/issues/dec-02/features/featphoto/)