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Russell Stern: Yes, yes, yes, and yes. It's one of the hottest pulls on our product. When we go and show them our technology working, accelerating in our virtualized environment, people are just besides themselves--on how simple we've made it and how easy it is. You see it when you talk to guys like Dell--they just pre... |
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Table of contents: VOL. 153, NO. 6 - April 3, 2006 |
Jamie Dimon, the new CEO of J.P. Morgan Chase is taking a shot at the title of world's most important banker and trying to whip a sprawling financial conglomerate into shape. (more) |
Why on earth has KB Home CEO Bruce Karatz launched a major building project in the wildly uncertain New Orleans real estate market? (more) |
best buy's bet |
Brad Anderson's consumer electronics superstore rules the market. So why is he messing with his business model? (more) |
Here's how hard-headed business practices can help the world's wealthiest nation deal with the hard-core homeless. (more) |
business life |
If having kids is more fraught with complications than you expected, cheer up. As three new books show, you're normal. (more) |
Apple takes on digital stereo with a new speaker dock--and it rocks. (more) |
business life: your money at play |
Limber up with an on-course massage. (more) |
c-suite strategies |
CIO Rob Carter tells FORTUNE's Geoffery Colvin what it takes to ship six million packages a day without a glitch. (more) |
Ukraine's Orange Revolution has run aground. Investors are sidelined, hopes have soured, and old rivals are battling for power. (more) |
Mosul, Iraq (more) |
first: news - analysis - data - informed opinion |
A Compendium of Revealing Stats (more) |
What TO Watch In The Weeks Ahead (more) |
Mega-mergers and explosive growth in user-generated content are raising the stakes. A battlefield guide. (more) |
Think Trans Fats Are Scary? Try Fixing This Doughnut-Nut Maker. (more) |
Beyond $50 Billion (more) |
Equity Firms Team Up to Take Companies Private (more) |
Steve Ballmer, CEO of Microsoft is ready to take the offensive. (more) |
Thriving on Their Own (more) |
To reap gains overseas, Phoenix fund manager Rajiv Jain focuses on great companies, not sizzling markets. (more) |
The same competitive pressures that led the Big Board to go public create uncertainty for its shares. (more) |
investing: your money at work |
Companies are buying record amounts of their own stock. But only some will get a share-price boost. (more) |
Slowdown in the Housing Market (more) |
Step right up! Test your knowledge of political reality! (more) |
ukraine elections |
A year after a popular uprising in Ukraine, hopes have soured and old rivals are at it again. (more) |
value driven |
The merger of AT&T and BellSouth will be a loser for investors. (more) |
while you were out |
The U.S. created slightly more middle-wage jobs, but we're certainly not out of the woods. |more| |
Google Maps Back On iPhone As CEO Apologises |
Google Maps has found its way back onto the iPhone as a free app alongside Apple's own Maps service. |
The return of the world's most popular online mapping system came nearly three months after Apple replaced Google Maps as the device's built-in navigation system. |
It inserted its own Maps app into the latest version of its mobile operating system, iOS 6. |
The new OS brought in more than 200 new features, including Apple's new Passbook service and full Facebook integration. |
However, Apple's Maps product proved to be far inferior to Google's. |
The Apple service was based on Dutch navigation equipment and digital mapmaker TomTom's data. |
But users complained it contained glaring geographical errors and lacked features that made Google Maps so popular. |
For example, police in Australia warned drivers not to use the Apple software after a number of people ended up lost in the wilderness in scorching temperatures. |
Motorists trying to find the town of Mildura became lost after following the map system, which locates it about 43 miles (70km) from its actual position in the state of Victoria. |
The product's shoddiness prompted Apple CEO Tim Cook to issue a rare public apology. |
He recommend that iPhone owners consider using Google Maps through a mobile web browser or seek other alternatives until his company could fix the problem. |
Google said its new Maps app is better than the one that used to be on the iPhone. |
Active pixel sensor |
From Wikipedia, the free encyclopedia |
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An active-pixel sensor (APS) is an image sensor consisting of an integrated circuit containing an array of pixel sensors, each pixel containing a photodetector and an active amplifier. There are many types of active pixel sensors including the CMOS APS used most commonly in cell phone cameras, web cameras, most digital... |
CMOS image sensor |
The term active pixel sensor is also used to refer to the individual pixel sensor itself, as opposed to the image sensor;[1] in that case the image sensor is sometimes called an active pixel sensor imager,[2] active-pixel image sensor,[3] or active-pixel-sensor (APS) imager. |
The term active pixel sensor was coined by Tsutomu Nakamura who worked on the Charge Modulation Device active pixel sensor at Olympus,[4] and more broadly defined by Eric Fossum in a 1993 paper.[5] |
Image sensor elements with in-pixel amplifiers were described by Noble in 1968,[6] by Chamberlain in 1969,[7] and by Weimer et al. in 1969,[8] at a time when passive-pixel sensors – that is, pixel sensors without their own amplifiers – were being investigated as a solid-state alternative to vacuum-tube imaging devices.... |
Another type of active pixel sensor is the hybrid infrared focal plane array (IRFPA) designed to operate at cryogenic temperatures in the infrared spectrum. The devices are two chips that are put together like a sandwich: one chip contains detector elements made in InGaAs or HgCdTe, and the other chip is typically made... |
By the late 1980s and early 1990s, the CMOS process was well established as a well controlled stable process and was the baseline process for almost all logic and microprocessors. There was a resurgence in the use of passive-pixel sensors for low-end imaging applications,[11] and active-pixel sensors for low-resolution... |
Eric Fossum, et al., invented the image sensor that used intra-pixel charge transfer along with an in-pixel amplifier to achieve true correlated double sampling (CDS) and low temporal noise operation, and on-chip circuits for fixed-pattern noise reduction, and published the first extensive article[5] predicting the eme... |
In 1995, personnel from JPL founded Photobit Corp., who continued to develop and commercialize APS technology for a number of applications, such as web cams, high speed and motion capture cameras, digital radiography, endoscopy (pill) cameras, DSLRs and of course, camera-phones. Many other small image sensor companies ... |
Comparison to CCDs[edit] |
APS pixels solve the speed and scalability issues of the passive-pixel sensor. They generally consume less power than CCDs, have less image lag, and require less specialized manufacturing facilities. Unlike CCDs, APS sensors can combine the image sensor function and image processing functions within the same integrated... |
Advantages of CMOS compared to CCD[edit] |
The biggest advantage of a CMOS sensor is that it is typically less expensive than a CCD sensor. A CMOS camera also has weaker blooming effects if a light source has overloaded the sensitivity of the sensor, causing the sensor to bleed the light source onto other pixels. |
Disadvantages of CMOS compared to CCD[edit] |
Since a CMOS video sensor typically captures a row at time within approximately 1/60th or 1/50th of a second (depending on refresh rate) it may result in a "rolling shutter" effect, where the image is skewed (tilted to the left or right, depending on the direction of camera or subject movement). For example, when track... |
A three-transistor active pixel sensor. |
The standard CMOS APS pixel today consists of a photodetector (a pinned photodiode), a floating diffusion, a transfer gate, reset gate, selection gate and source-follower readout transistor—the so-called 4T cell. The pinned photodiode was originally used in interline transfer CCDs due to its low dark current and good b... |
APS using TFTs[edit] |
A two-transistor active/passive pixel sensor |
For applications such as large-area digital X-ray imaging, thin-film transistors (TFTs) can also be used in APS architecture. However, because of the larger size and lower transconductance gain of TFTs compared to CMOS transistors, it is necessary to have fewer on-pixel TFTs to maintain image resolution and quality at ... |
A typical two-dimensional array of pixels is organized into rows and columns. Pixels in a given row share reset lines, so that a whole row is reset at a time. The row select lines of each pixel in a row are tied together as well. The outputs of each pixel in any given column are tied together. Since only one row is sel... |
The size of the pixel sensor is often given in height and width, but also in the optical format. |
Design variants[edit] |
Many different pixel designs have been proposed and fabricated. The standard pixel is the most common because it uses the fewest wires and the fewest, most tightly packed transistors possible for an active pixel. It is important that the active circuitry in a pixel take up as little space as possible to allow more room... |
Hard reset[edit] |
Operating the pixel via hard reset results in a Johnson–Nyquist noise on the photodiode of V_n^2= kT/C or N_e= \frac{\sqrt{kTC}}{q}, but prevents image lag, sometimes a desirable tradeoff. One way to use hard reset is replace Mrst with a p-type transistor and invert the polarity of the RST signal. The presence of the p... |
Combinations of hard and soft reset[edit] |
Techniques such as flushed reset, pseudo-flash reset, and hard-to-soft reset combine soft and hard reset. The details of these methods differ, but the basic idea is the same. First, a hard reset is done, eliminating image lag. Next, a soft reset is done, causing a low noise reset without adding any lag.[14] Pseudo-flas... |
Active reset[edit] |
A more radical pixel design is the active-reset pixel. Active reset can result in much lower noise levels. The tradeoff is a complicated reset scheme, as well as either a much larger pixel or extra column-level circuitry. |
See also[edit] |
1. ^ Alexander G. Dickinson et al., "Active pixel sensor and imaging system having differential mode", US 5631704 |
2. ^ Zimmermann, Horst (2000). Integrated Silicon Optoelectronics. Springer. ISBN 3-540-66662-1. |
3. ^ Lawrence T. Clark, Mark A. Beiley, Eric J. Hoffman, "Sensor cell having a soft saturation circuit"US 6133563 [1] |
4. ^ Kazuya Matsumoto et al., "A new MOS phototransistor operating in a non-destructive readout mode" Jpn. J. Appl. Phys. 24 (1985) L323 |
5. ^ a b Eric R. Fossum (1993), "Active Pixel Sensors: Are CCD's Dinosaurs?" Proc. SPIE Vol. 1900, p. 2–14, Charge-Coupled Devices and Solid State Optical Sensors III, Morley M. Blouke; Ed. |
6. ^ Peter J. W. Noble (Apr. 1968). Self-Scanned Silicon Image Detector Arrays. ED-15 (4). IEEE. pp. 202–209. |
7. ^ Savvas G. Chamberlain (December 1969). "Photosensitivity and Scanning of Silicon Image Detector Arrays". IEEE Journal of Solid-State Circuits SC–4 (6): 333–342. |
8. ^ P. K. Weimer, W. S. Pike, G. Sadasiv, F. V. Shallcross, and L. Meray-Horvath (March 1969). "Multielement Self-Scanned Mosaic Sensors". IEEE Spectrum 6 (3): 52–65. doi:10.1109/MSPEC.1969.5214004. |
9. ^ R. Dyck and G. Weckler (1968). "Integrated arrays of silicon photodetectors for image sensing". IEEE Trans. Electron Devices. ED-15 (4): 196–201. |
10. ^ Richard F. Lyon (1981). "The Optical Mouse, and an Architectural Methodology for Smart Digital Sensors". In H. T. Kung, R. Sproull, and G. Steele. CMU Conference on VLSI Structures and Computations. Pittsburgh: Computer Science Press. |
11. ^ D. Renshaw, P. B. Denyer, G. Wang, and M. Lu (1990). "ASIC image sensors". IEEE International Symposium on Circuits and Systems 1990. |
12. ^ M. A. Mahowald and C. Mead (12 May 1989). "The Silicon Retina". Scientific American 264 (5): 76–82. doi:10.1038/scientificamerican0591-76. PMID 2052936. |
13. ^ F. Taghibakhsh and k. S. Karim (2007). "Two-Transistor Active Pixel Sensor for High Resolution Large Area Digital X-Ray Imaging". IEEE International Electron Devices Meeting: 1011–1014. |
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