I own a few slide rules, and know how to use (most of the) scales on them. I keep one of my favorites on my desk at work, and even use it occasionally. (If you care, it's currently a late-model K&E 4081-3 LogLog Duplex DeciTrig, "like my Dad used to use", although it is sometimes a Post 1461 Versalog. I own a plastic DeciLon and a beautiful plastic Faber 2/83N and an aluminum Pickett or two and a few others, but I like the classic laminated wood rules. Somehow they just FEEL like precision instruments.)
My work doesn't call for much on-the-fly number-crunching, and I find that my slide rule that actually gets the most use is a Concise 28N, a little pocket-sized plastic disk that hardly even looks like a slide rule. As a result, it's easieast to carry with me everywhere, and easiest to hold in one hand and shift the inner disk with my thumb. It's a snap to figure gas mileage, restaurant taxes and tips, or the cheapest cereal or cat food or just about any bulk grocery items.
I own calculators too, a high-end model with more buttons than I understand, and even a cheapie with just the basic functions. And they get used at the appropriate times. But their UI is very ill-suited to the task of quickly evaluating bulk food prices while pushing a shopping cart. My pilot friends tell me the same thing, that their onboard computer is capable of computing airspeed, fuel consumption and lots of other things, but that their round E6-B is their favorite tool for such calculations because it's far easier to use with one hand while flying the plane with the other.
People talk about the importance of slide rules, tradition, math skills and the elusive "feel" of numbers and their precision and magnitude. And they're right, these are all important skills that I still wish were emphasized more in school. But it seems to me that the thing that's overlooked the most is the importance of selecting the appropriate tool. You wouldn't swat a fly with a bazooka, and you wouldn't use a slide rule to balance your checkbook. But they're perfect for lots of calculations, and it really is a shame that they have become so marginalized.
Everybody remembers the Pricess Leia "hologram" that was really just a movie optical effect. But nobody remembers the REAL hologram that appeared in a major movie in 1975, two years BEFORE the first Star Wars.
Near the end of Logan's Run, Michael York's character undergoes an interrogation surrounded by surrogate projected heads that rotate and repeatedly drone catchphrases like "There is no sanctuary." Those heads are not optical effects. They are real, physical holograms of Michael York, made earlier and installed and properly lit on-set as the scene was filmed. Although they give the appearance of being animated, they are really a standard mylar-based hologram which was captured using a rotating slit; on-set, walking around the hologram would make it appear to move.
I've always wondered why this technique was never expanded upon. It satisfies the basic criteria, of being mounted into a cylindrical shape so that the entire audience may surround it. Surely by now some clever folks should have been able to figure out some way of using double-scanning slits or somesuch to allow each horizontal slice of the cylinder to represent one moment in time, while the entire cylinder was pulled vertically like movie film. Is there some elusive but fundamental piece of hologram physics that prevents this? Or it is just that nobody has actually tried it yet?
You're confusing physics "heat energy" calories with "nutitrition" calories -- the two unfortunately use the same name but are measuring different things.
I've been in the graphics field in one way or another for twenty-five years (Siggraph member since 1982), so you know I love GCI and am familiar with its strengths and weaknesses. I also have tremendous respect for traditional film FX, and am sometimes saddened by the present overemphasis on CGI for everything when many types of effects could still benefit from a more traditional approach. So my question -- what are your CGI pet peeves, and why? Unrealistic design choices of shapes/colors/textures? Poor/no use of physics-based motion? The difficulty in compositing a unnaturally-crisp CGI object into an inherently-grainy film background? The insistence of certain studio execs to use CGI for effects that would be better served by other FX technologies?
The inevitable tradeoffs of time/money/ quality? Or something else entirely?
I once worked for a company in Minnesota -- "The Land of Ten Thousand Lakes" -- with a group who preferred pronouncable names over cryptic acronyms. Their first few servers had been named after local lakes, and the convention stuck. It was certainly friendly and easy to use; for example, our main internet firewall and internal email server was Superior. I suppose, with a little advance planning, it would even be possible to map out the LAN connections using river names.
It reminded me of the story of a book collector who owned a large number of books on the US, but had trouble finding a satisfactory way to arrange them on his bookshelves. He tried alphabetical by author, by title, by state, even chronological by publishing date, and still couldn't quickly locate a particular book when needed. Until he hit on the idea of grouping his New England books on the upper-right shelves, his Southern books on the lower shelves, etc.
I once had a manager who was repeatedly unable to fulfill his weekly duty of approving my hours via the company's web-based timesheet forms, resulting in occasionally delayed paychecks. Finally, after he claimed that he had submitted his approval for the same hours THREE TIMES in one week, I sat and watched over his shoulder as he attempted it a fourth time. He nagivated to the appropriate page displaying my hours, fumed that the system had STILL not accepted his change, pointed repeatedly at the unchecked box. Checked it. Then left the web page without ever submitting his change.
Lockheed Martin evaluated a number of LCD displays for use by the FAA in airport control towers. Mission-critical, with contrast and legibility requirements from the darkest night to the brightest sunlight.
There are plenty of display vendors, but very few companies that actually manufacture the glass. So differences from one vendor's displays to another's are almost entirely in the way the glass is packaged. You'll need three things: an anti-glare coating (pick your favorite one) front-bonded to the LCD glass, a backlighting unit capable of putting out some serious lumens, and a cooling system that can keep the whole thing from melting. Simple, right?
The few displays that met the FAA's requirements were custom designs, built like tanks. I doubt you'd want one in your car. But anything less, and you'll be hard-pressed to meet your requirements. You've got a tough battle ahead. Good luck.
Sorry I'm late joining this conversation! I've worked on color-science software at three firms now, and I think I can cut through the murk here and give you a short and practical answer.
In general, to do any kind of color science, you'll need to do three things:
1. Convert the "pixel" RGB values into "linear luminance" RGB values in your favorite luminance units. These are your transfer functions.
2. Convert the linear RGB values into CIE XYZ values using your monitor's chromaticities.
3. Convert the CIE XYZ values into your favorite perceptual space using an appropriate white point. CIE L*a*b* is popular, and good enough for most uses.
(Step 4 would involve deciding how to handle out-of-gamut colors -- a topic in itself! -- but you won't need to worry about this.)
Clearly, you've missed step 1. A few of the previous responders have already pointed this out. Most CRTs are sufficiently well-behaved that their transfer functions can be adequately described with a simple power function described by a single gamma value. (1.7, 2.2 and 2.7 are popular values. 1.7 is "lighter" and 2.7 is "darker".) But don't assume that LCD monitors can be described this way! My experience has shown that some models come close, while others can only be adequately modeled by interpolating tables of gray values laboriously measured with a photometer.
One additional piece of advice. If your final goal is to determine the legibility of one color of text over a different-colored background, you may want to ignore the 3-D color difference formulas entirely, and simply compute the contrast from the L* values alone.
Whatever you decide, let us know how it turns out!
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I own a few slide rules, and know how to use (most of the) scales on them. I keep one
of my favorites on my desk at work, and even use it occasionally. (If you care, it's
currently a late-model K&E 4081-3 LogLog Duplex DeciTrig, "like my Dad used to use",
although it is sometimes a Post 1461 Versalog. I own a plastic DeciLon and a beautiful
plastic Faber 2/83N and an aluminum Pickett or two and a few others, but I like the
classic laminated wood rules. Somehow they just FEEL like precision instruments.)
My work doesn't call for much on-the-fly number-crunching, and I find that my slide
rule that actually gets the most use is a Concise 28N, a little pocket-sized plastic
disk that hardly even looks like a slide rule. As a result, it's easieast to carry
with me everywhere, and easiest to hold in one hand and shift the inner disk with my
thumb. It's a snap to figure gas mileage, restaurant taxes and tips, or the cheapest
cereal or cat food or just about any bulk grocery items.
I own calculators too, a high-end model with more buttons than I understand, and even a
cheapie with just the basic functions. And they get used at the appropriate times. But
their UI is very ill-suited to the task of quickly evaluating bulk food prices while
pushing a shopping cart. My pilot friends tell me the same thing, that their onboard
computer is capable of computing airspeed, fuel consumption and lots of other things,
but that their round E6-B is their favorite tool for such calculations because it's far
easier to use with one hand while flying the plane with the other.
People talk about the importance of slide rules, tradition, math skills and the elusive
"feel" of numbers and their precision and magnitude. And they're right, these are all
important skills that I still wish were emphasized more in school. But it seems to me
that the thing that's overlooked the most is the importance of selecting the appropriate
tool. You wouldn't swat a fly with a bazooka, and you wouldn't use a slide rule to
balance your checkbook. But they're perfect for lots of calculations, and it really is
a shame that they have become so marginalized.
The right tool for the right job!
Here's a plug for my favorite introductory book on the subject, Fundamentals of Astrodynamics by Roger R. Bate, Donald D. Mueller and Jerry E. White.
Amazon link
Barnes & Noble link
I didn't even have to special-order my copy. I walked into my nearest B&N and it was on the shelf. Your mileage may vary.
The book is Copyright © 1971, during the heyday of the Apollo moon missions, but its content was developed during the 1960s as part of US Air Force Academy classes for astronautics or aerospace engineering students. It covers computing orbital elements from various combinations of knowns/unknowns, refining initial estimates with additional observations, prediction problems, intercept problems, targeting problems, orbital perterbances, orbit changes, mission planning and more. Many of its chapter-ending problems are intended to be solved with a slide rule.
No one book can cover all of orbital mechanics. This is, after all, rocket science. But this is the best introductory book I know.
Everybody remembers the Pricess Leia "hologram" that was really just a movie optical effect. But nobody remembers the REAL hologram that appeared in a major movie in 1975, two years BEFORE the first Star Wars.
Near the end of Logan's Run, Michael York's character undergoes an interrogation surrounded by surrogate projected heads that rotate and repeatedly drone catchphrases like "There is no sanctuary." Those heads are not optical effects. They are real, physical holograms of Michael York, made earlier and installed and properly lit on-set as the scene was filmed. Although they give the appearance of being animated, they are really a standard mylar-based hologram which was captured using a rotating slit; on-set, walking around the hologram would make it appear to move.
I've always wondered why this technique was never expanded upon. It satisfies the basic criteria, of being mounted into a cylindrical shape so that the entire audience may surround it. Surely by now some clever folks should have been able to figure out some way of using double-scanning slits or somesuch to allow each horizontal slice of the cylinder to represent one moment in time, while the entire cylinder was pulled vertically like movie film. Is there some elusive but fundamental piece of hologram physics that prevents this? Or it is just that nobody has actually tried it yet?
You're confusing physics "heat energy" calories with "nutitrition" calories -- the two unfortunately use the same name but are measuring different things.
I've been in the graphics field in one way or another for twenty-five years (Siggraph member since 1982), so you know I love GCI and am familiar with its strengths and weaknesses. I also have tremendous respect for traditional film FX, and am sometimes saddened by the present overemphasis on CGI for everything when many types of effects could still benefit from a more traditional approach. So my question -- what are your CGI pet peeves, and why? Unrealistic design choices of shapes/colors/textures? Poor/no use of physics-based motion? The difficulty in compositing a unnaturally-crisp CGI object into an inherently-grainy film background? The insistence of certain studio execs to use CGI for effects that would be better served by other FX technologies? The inevitable tradeoffs of time/money/ quality? Or something else entirely?
I once worked for a company in Minnesota -- "The Land of Ten Thousand Lakes" -- with a group who preferred pronouncable names over cryptic acronyms. Their first few servers had been named after local lakes, and the convention stuck. It was certainly friendly and easy to use; for example, our main internet firewall and internal email server was Superior. I suppose, with a little advance planning, it would even be possible to map out the LAN connections using river names.
It reminded me of the story of a book collector who owned a large number of books on the US, but had trouble finding a satisfactory way to arrange them on his bookshelves. He tried alphabetical by author, by title, by state, even chronological by publishing date, and still couldn't quickly locate a particular book when needed. Until he hit on the idea of grouping his New England books on the upper-right shelves, his Southern books on the lower shelves, etc.
Don't underestimate the power of mnemonics!
I once had a manager who was repeatedly unable to fulfill his weekly duty of approving my hours via the company's web-based timesheet forms, resulting in occasionally delayed paychecks. Finally, after he claimed that he had submitted his approval for the same hours THREE TIMES in one week, I sat and watched over his shoulder as he attempted it a fourth time. He nagivated to the appropriate page displaying my hours, fumed that the system had STILL not accepted his change, pointed repeatedly at the unchecked box. Checked it. Then left the web page without ever submitting his change.
I'm sure he must use AOL at home.
Lockheed Martin evaluated a number of LCD displays for use by the FAA in airport control towers. Mission-critical, with contrast and legibility requirements from the darkest night to the brightest sunlight.
There are plenty of display vendors, but very few companies that actually manufacture the glass. So differences from one vendor's displays to another's are almost entirely in the way the glass is packaged. You'll need three things: an anti-glare coating (pick your favorite one) front-bonded to the LCD glass, a backlighting unit capable of putting out some serious lumens, and a cooling system that can keep the whole thing from melting. Simple, right?
The few displays that met the FAA's requirements were custom designs, built like tanks. I doubt you'd want one in your car. But anything less, and you'll be hard-pressed to meet your requirements. You've got a tough battle ahead. Good luck.
Sorry I'm late joining this conversation! I've worked on color-science software at three firms now, and I think I can cut through the murk here and give you a short and practical answer.
In general, to do any kind of color science, you'll need to do three things:
1. Convert the "pixel" RGB values into "linear luminance" RGB values in your favorite luminance units. These are your transfer functions.
2. Convert the linear RGB values into CIE XYZ values using your monitor's chromaticities.
3. Convert the CIE XYZ values into your favorite perceptual space using an appropriate white point. CIE L*a*b* is popular, and good enough for most uses.
(Step 4 would involve deciding how to handle out-of-gamut colors -- a topic in itself! -- but you won't need to worry about this.)
Clearly, you've missed step 1. A few of the previous responders have already pointed this out. Most CRTs are sufficiently well-behaved that their transfer functions can be adequately described with a simple power function described by a single gamma value. (1.7, 2.2 and 2.7 are popular values. 1.7 is "lighter" and 2.7 is "darker".) But don't assume that LCD monitors can be described this way! My experience has shown that some models come close, while others can only be adequately modeled by interpolating tables of gray values laboriously measured with a photometer.
One additional piece of advice. If your final goal is to determine the legibility of one color of text over a different-colored background, you may want to ignore the 3-D color difference formulas entirely, and simply compute the contrast from the L* values alone.
Whatever you decide, let us know how it turns out!