The Megapixel Race and its Clear Winner

Like any Moore’s Law-inspired race, the megapixel race in digital cameras in the late 1990s and into the 2000s was a harsh battleground for every manufacturer. With the development of the smartphone, it became a war on two fronts, with Samsung eventually cramming twenty megapixels into a handheld. Although no clear winner of consumer-grade cameras was ever announced (and Samsung ended up reducing their flagship phone’s cameras to sixteen megapixels for reasons we’ll discuss) it seems as though this race is over, fizzling out into a void where even marketing and advertising groups don’t readily venture. What happened?

The Technology

A brief overview of Moore’s Law predicts that transistor density on a given computer chip should double about every two years. A digital camera’s sensor is remarkably similar, using the same silicon to form charge-coupled devices or CMOS sensors (the same CMOS technology used in some RAM and other digital logic technology) to detect photons that hit it. It’s not too far of a leap to realize how Moore’s Law would apply to the number of photo detectors on a digital camera’s image sensor. Like transistor density, however, there’s also a limit to how many photo detectors will fit in a given area before undesirable effects start to appear.

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CMOS Image Sensor Mechanism Illustration, By User:たまなるたみ – drawing created myself, GPL, https://commons.wikimedia.org/w/index.php?curid=371238. Note that each pixel has its own amplifier.

Image sensors have come a long way since video camera tubes. In the ’70s, the charge-coupled device (CCD) replaced the cathode ray tube as the dominant video capturing technology. A CCD works by arranging capacitors into an array and biasing them with a small voltage. When a photon hits one of the capacitors, it is converted into an electrical charge which can then be stored as digital information. While there are still specialty CCD sensors for some niche applications, most image sensors are now of the CMOS variety. CMOS uses photodiodes, rather than capacitors, along with a few other transistors for every pixel. CMOS sensors perform better than CCD sensors because each pixel has an amplifier which results in more accurate capturing of data. They are also faster, scale more readily, use fewer components in general, and use less power than a comparably sized CCD. Despite all of these advantages, however, there are still many limitations to modern sensors when more and more of them get packed onto a single piece of silicon.

While transistor density tends to be limited by quantum effects, image sensor density is limited by what is effectively a “noisy” picture. Noise can be introduced in an image as a result of thermal fluctuations within the material, so if the voltage threshold for a single pixel is so low that it falsely registers a photon when it shouldn’t, the image quality will be greatly reduced. This is more noticeable in CCD sensors (one effect is called “blooming“) but similar defects can happen in CMOS sensors as well. There are a few ways to solve these problems, though.

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A sunrise picture taken with an entry-level DSLR at 1600 ISO. At this sensitivity, noise in the clouds can be seen in the form of random fluctuations of some pixels. This effect would be mitigated by a camera with a larger sensor, a lower sensor sensitivity with a longer shutter speed (which would blur the turbine blades) or a scene with more light. Photo  © 2016 by Bryan Cockfield

 

First, the voltage threshold can be raised so that random thermal fluctuations don’t rise above the threshold to trigger the pixels. In a DSLR, this typically means changing the ISO setting of a camera, where a lower ISO setting means more light is required to trigger a pixel, but that random fluctuations are less likely to happen. From a camera designer’s point-of-view, however, a higher voltage generally implies greater power consumption and some speed considerations, so there are some tradeoffs to make in this area.

Another reason that thermal fluctuations cause noise in image sensors is that the pixels themselves are so close together that they influence their neighbors. The answer here seems obvious: simply increase the area of the sensor, make the pixels of the sensor bigger, or both. This is a good solution if you have unlimited area, but in something like a cell phone this isn’t practical. This gets to the core of the reason that most modern cell phones seem to be practically limited somewhere in the sixteen-to-twenty megapixel range. If the pixels are made too small to increase megapixel count, the noise will start to ruin the images. If the pixels are too big, the picture will have a low resolution.

There are some non-technological ways of increasing megapixel count for an image as well. For example, a panoramic image will have a megapixel count much higher than that of the camera that took the picture simply because each part of the panorama has the full mexapixel count. It’s also possible to reduce noise in a single frame of any picture by using lenses that collect more light (lenses with a lower f-number) which allows the photographer to use a lower ISO setting to reduce the camera’s sensitivity.

Gigapixels!

Of course, if you have unlimited area you can make image sensors of virtually any size. There are some extremely large, expensive cameras called gigapixel cameras that can take pictures of unimaginable detail. Their size and cost is a limiting factor for consumer devices, though, and as such are generally used for specialty purposes only. The largest image sensor ever built has a surface of almost five square meters and is the size of a car. The camera will be put to use in 2019 in the Large Synoptic Survey Telescope in South America where it will capture images of the night sky with its 8.4 meter primary mirror. If this was part of the megapixel race in consumer goods, it would certainly be the winner.

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LSST Image Sensor, By Todd Mason, Mason Productions Inc. / LSST Corporation – https://www.lsst.org/sites/default/files/photogallery/Camera_CU-full.jpg, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=52230238

With all of this being said, it becomes obvious that there are many more considerations in a digital camera than just the megapixel count. With so many facets of a camera such as physical sensor size, lenses, camera settings, post-processing capabilities, filters, etc., the megapixel number was essentially an easy way for marketers to advertise the claimed superiority of their products until the practical limits of image sensors was reached. Beyond a certain limit, more megapixels doesn’t automatically translate into a better picture. As already mentioned, however, the megapixel count can be important, but there are so many ways to make up for a lower megapixel count if you have to. For example, images with high dynamic range are becoming the norm even in cell phones, which also helps eliminate the need for a flash. Whatever you decide, though, if you want to start taking great pictures don’t worry about specs; just go out and take some photographs!

(Title image: VISTA gigapixel mosaic of the central parts of the Milky Way, produced by European Southern Observatory (ESO) and released under Creative Commons Attribution 4.0 International License. This is a scaled version of the original 108,500 x 81,500, 9-gigapixel image.)

CNC-Telescope With Semi-Nasmyth Mount

[GregO29] had a 10″ GoTo telescope but at 70lbs, it wasn’t really portable. And so he did what any self-respecting CNC enthusiast would do, he put his CNC skills to work to make an 8″ Newtonian reflector, semi-Nasmyth mount telescope of his own design. It also gave him a chance to try out his new Chinese 6040 router/engraver with 800W water-cooled spindle.

What’s all that fancy terminology, you say? “Newtonian reflector” simply means that there’s a large concave mirror at one end that reflects a correspondingly large amount of light from the sky to a smaller mirror which then reflects it toward your eye, preferably along with some means of focusing that light. “Semi-Nasmyth mount” means that the whole thing pivots around the eyepiece so that you can keep your head relatively still (the “semi” is because the eyepiece can also be pivoted, in which case you would have to move your head a bit).

We really like the mechanism he came up with for rotating the telescope in the vertical plane. Look closely at the photo and you’ll see that the telescope is mounted to a pie-shaped piece of wood. The curved outer circumference of that pie-shape has gear teeth on it which he routed out. The mechanism that moves these teeth is a worm screw made from a 1″ spring found at the hardware store that’s on a 3/4″ dowel. Turn the worm screw’s crank and the telescope rotates.

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Modified Servo Adds Focus Control to Telescope

Scanning the heavens with a telescope is a great way to spend long, clear winter nights, but using a manual telescope can get to be a drag. A motorized mount with altitude and azimuth control is basic equipment for the serious observer, but adding a servo to control the focus of your telescope is one step beyond your average off-the-shelf instrument.

Having already motorized the two axes of the equatorial mount of his modest telescope as a senior project, [Eric Seifert] decided to motorize the focus rack as well. His first inclination was to use a stepper motor like he did on the other two axes, but with a spare high-torque servo at hand, he hacked a quick proof-of-concept. The servo was modified for continuous rotation in the usual way, but with the added twist of replacing the internal potentiometer with an external linear pot. Attached to the focus tube, the linear pot allows [Eric] to control the position and speed of the modified servo. Sounds like controlling the focus will be important to [Eric]’s planned web interface for his scope; we’ll be looking for details on that project soon.

We like the simplicity of this solution, and it’s a trick worth keeping in mind for other projects.  But if fancy steppers and servos aren’t your thing, fear not — astrophotography is as easy as slapping a couple of boards together with a hinge.

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Skynet Takes Over…Academia?

A telescope isn’t an unusual thing to own if you are technically inclined. You might have even made one, at some point. However, despite improvements in optical technology and computer aiming devices, your four to twenty-inch instrument is never going to show you images like you see from big giant telescopes. The problem is, going really big requires a lot of investment in time, money, and sometimes even real estate. The big scopes get buildings constructed for them, and in exotic locations; why would you build a 24-inch scope only to try to see through the light pollution in your backyard?

Here’s an idea: take an astronomy class at a college and use their big telescope. Well, who has the time and money for that? Actually, you do. Skynet is a global network of telescopes headquartered at the University of North Carolina. As part of their mandate, they offer several tuition-free astronomy classes over the Internet. The best part? You also get free time on Skynet’s telescopes to complete your class assignments. There is a small fee (between $45 and $65) to a “benefit corporation” to administer assignments. You do get a certificate upon graduation. If you don’t want to do the assignments and you don’t want a certificate, you can still “take” the classes by simply watching them on YouTube. You can see one of the classes in the video below.

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A Star Tracking Telescope Mount

[Chris] recently got his hands on an old telescope. While this small refractor with an altitude-azimuth mount is sufficient for taking a gander at big objects in our solar system, high-end telescopes can be so much cooler. Large reflecting telescopes can track the night sky for hours, and usually come with a computer interface and a GOTO button. Combine this with Stellarium, the open source sky map, and you can have an entire observatory in your back yard.

For [Chris]’ entry into the 2016 Hackaday Prize, he’s giving his old telescope an upgrade. With a Raspberry Pi, a few 3D printed adapters, and a new telescope mount to create a homebrew telescope computer.

The alt-az mount really isn’t the right tool for the astronomical job. The earth spins on a tilted axis, and if you want to hold things in the night sky still, it has to turn in two axes. An equatorial mount is much more compatible with the celestial sphere. Right now, [Chris] is looking into a German equatorial mount, a telescope that is able to track an individual star through the night sky using only a clock drive motor.

To give this telescope a brain, he’ll be using a Raspberry Pi, GPS, magnetometer, and ostensibly a real-time clock to make sure the build knows where the stars are. After that, it’s a simple matter of pointing the telescope via computer and using a Raspberry Pi camera to peer into the heavens with a very, very small image sensor.

While anyone with three or four hundred dollars could simply buy a telescope with similar features, that’s really not the point for [Chris], or for amateur astronomy. There is a long, long history of amateur astronomers building their own mirrors, lenses, and mounts. [Chris] is just continuing this very long tradition, and in the process building a great entry for the 2016 Hackaday Prize

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Misleading Tech: Kickstarter, Bomb Sights, and Medical Rejuvinators

Every generation thinks it has unique problems and, I suppose, sometimes it is true. My great-grandfather didn’t have to pick a cell phone plan. However, a lot of things you think are modern problems go back much further than you might think. Consider Kickstarter. Sure, there have been plenty of successful products on Kickstarter. There have also been some misleading duds. I don’t mean the stupid ones like the guy who wants to make a cake or potato salad. I mean the ones that are almost certainly vaporware like the induced dream headgear or the Bluetooth tag with no batteries.

Overpromising and underdelivering is hardly a new problem. In the 30’s The McGregor Rejuvenator promised to reverse aging with magnetism, radio waves, infrared and ultraviolet light. Presumably, this didn’t work. Sometimes products do work, but they don’t live up to their marketing hype. The Segway comes to mind. Despite the hype that it would revolutionize transportation, the scooter is now a vehicle for tourists and mall cops.

One of my favorite examples of an overhyped product comes from World War II: The Norden Bomb Sight. What makes the Norden especially interesting is that even today it has a reputation for being highly accurate. However, if you look into it, the Norden–although a marvel for its day–didn’t always live up to its press.

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Hackaday Tours Northrop: Space Telescopes and Jet Planes

I was invited to tour the Northrop Grumman Aerospace Systems campus in Los Angeles this spring and it was fantastic! The Northrop Grumman lists themselves as “a leading global security company” but the project that stole my heart is their work on the James Webb Space Telescope (JWST) for NASA. On the one hand, I don’t see how it could possibly be pulled off as the telescope seems to cram every hard engineering challenge you can think of into one project. On the other hand, Northrop (plus NASA and all of their subcontractors) has been doing tough stuff for a very long time.

How Do You Tour Northrop Grumman?

This opportunity fell in my lap since [Tony Long] is a Hackaday reader and an engineer at Northrop. He’s the founder of their FabLab (which I’ll talk about a bit later) and was so bold as to send an email asking if one of the crew would like to stop by. Yes Please!

I was already headed out to the Supplyframe offices (Hackaday’s parent company) in Pasadena. [Tony] offered to pick me up at LAX and away we went to Redondo Beach, California for an afternoon adventure.

James Webb Space Telescope: Everything Hard About Engineering

James Webb Space Telescope (JWST)

I had heard of the James Webb Space Telescope (JWST) but had never looked closely at the particulars of the project. Above you can see a scale model which Northrop built. I didn’t actually see this on my tour. It travels to different places, taking two semi trucks, with a dozen people spending four days to set it up each time. And that’s a not-real, relegated to the surface of the planet, item. What is it going to take to put the real one into space?

It’s not just going into space. It’s going to the second Lagrangian point. This is past the moon, about 1.5 million kilometers from the earth. If this thing breaks we can’t go out there and fix it. There’s a lot of pressure for success.

The main problem facing this satellite is heat. It will use a mirror array to harvest infrared radiation from very distant astronomical bodies. For this to happen it needs to have a very good optical array to gather infrared light and focus it on a collector, and it must be isolated from the heat of the sun, earth, and moon.

There is an array of 18 hexagonal mirrors which reflect the infrared onto a collecting mirror and in turn to the sensors. These mirrors are not made by Northrop, but they did have a prototype on display and it was incredible! Each mirror is made by Ball Aerospace out of beryllium. The concave surface is coated in gold for reflectivity and an actuator mounted on the back of each mirror can flex the surface to adjust the concavity and thereby the focal length. This is in addition to the ability to adjust the roll and pitch of each segment.

In the Northrop high bay they were working on the mounting system for these mirrors. It showed much more progress than the two images seen above. This is the central mount structure for the optics. The width of this structure is dictated by the size of the rocket which will launch it into space. When I saw it, folding wings had been added to either side of this main structure to host a dual-row of mirrors which are folded back into the telescopes during its storage position. The black material itself is a composite manufactured by Northrop. The cross-section they showed as an example was not much thicker than your fingernail but obviously quite rigid in the cast pipe shape.

You can see an animation of the unfolding process which was playing in the high-bay viewing room during the tour. Note the five-layer heat shield that needs to automatically unfold without snagging. This reminds me of [Ed van Cise’s] recollection of solar panel unfolding issues on the ISS. It’s a tough problem and it looks like much time has been spend making sure this design learns from past issues. That animation doesn’t show too many details about the mirror mechanics. I found video demonstrating how the mechanical part of the mirrors work to be quite interesting.

Learning more about what goes into the James Webb Space Telescope project is worth a lot of your time. I’m not joking about this including everything hard about engineering. The challenges involved in meeting the specification of this telescope are jaw-dropping and I’m certain the people working on the project across many different companies will make this happen.

Hackerspace Driving Corporate Culture

fablab-wide-shot

It was nice that [Tony] and his colleague [Adam] came right out and told me they reached out to Hackaday because they want to get the message out that Northrop is rejuvenating their corporate culture. They’re in the process of hiring thousands of engineers and part of this process is making the job fit with the lifestyle that these engineers want.

One big move in this direction is the formation of their FabLab. [Tony] is an engineer but 50% of his workload is tending to the FabLab. This is basically a hackerspace open to any of the roughly 20k employees at this particular location. Northrop fabricates amazing things, and when equipment is no longer used, the FabLab gets dibs on it. Imagine the possibilities!

unexploded-armament-removalPart of this initiative is to get more engineers learning about the fabrication process. [Tony] used the example of researching by fabricating a simple proof-of-concept in the FabLab. This is an avenue to that buzzword: fail-fast. Before getting your department on board with what might be a costly and time-consuming project you can test out some of the parts which are a little hazy in your mind.

The device seen here is the product of a challenge that one of the groups participated in last year. They had about six months to develop a robot which can clear unexploded armaments. It was hanging out in one part of the hackerspace and is a great build. You can just make out a blue sphere hiding in the underbody. That’s a huge jamming gripper powered by the black and yellow shop-vac perched atop the chassis. The robot is remote controlled, with wireless GoPro cameras mounted all around and underneath. Of course the thing wouldn’t be complete without a giant silver air-horn. Safety first!

It will be interesting to see if the FabLab can build the kind of grass-roots community often associated with standalone hackerspaces. You can get a glimpse at the grand opening of the space in this video. We don’t quite remember seeing a hackerspace marketed in this manner. But if that’s what it takes to get the company on board it’s well worth it. A huge space, amazing tools, and no monthly membership fee make for a sweet deal. Oh, and the name FabLab apparently came from their mascot, the Fabulous Labrador, who can be seen in the clip wearing a string of pearls.

F/18 Assembly Plant

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We wrapped up the day by touring the F/A 18 E/F Super Hornet assembly line. This is a huge plant. I don’t know how to better describe the sheer size of the assembly line than saying it took no less than twenty minutes to walk back to the parking lot at the end of this tour.

00036301Northrop Grumman serves as the principal subcontractor for Boeing on this project, so the end of the line isn’t quite a fully assembled airplane. But the fuselage — less cockpit, nose, wings, and engines — is still a formidable sight. I’ve never been this close to a fighter jet before and the size is impressive. Equally impressive is the building housing the line, which was build in 1942 and is still wood-framed to this day. They have huge engineered columns which have since been reinforced with steel. But that fact makes it no-less impressive.

The top concern during assembly is FOD, or Foreign Object Detection. These vehicles are exposed to huge forces and vibrations that will shake anything that’s not supposed to be there loose, and that can mean horrible damage to an expensive machine or much worse. Some of the things I found really interesting were the systems in place to make sure no part goes missing. All components come in cases that have an individual cutout area for each. Tools are scanned to each employee, if broken or worn out there are vending machines throughout the plant keeping track of them through a computerized system.

As part of the tour we walked through the composites plant next door. There are massive autoclaves for curing the resins. These are like a pipe sitting on its side with hemispherical doors on each end. I’m a poor judge of time and distance but I’d estimate these to be 18 feet in diameter and at least 35 feet long. Traditional composite fabrication — a worker laying down sheets of carbon-fiber on a mold — were under way. But the room next door housed a robot that looked like it was born in The Matrix. The spider-like head works next to a turning mandrel fitted with the form of the piece being fabricated. It lays out about seven strands of carbon fiber, building up a part that has no seams whatsoever. After curing the resin the mold is removed manually, piece by piece, from the inside of the part. To me the parts being built looked like air intake channels approximately 15 feet long and maybe 5 feet in diameter, although they were winding and not exactly cylindrical in shape. I wasn’t able to get very many details about them, but I was told these parts are for the F-35 Joint Strike Fighter. This is another subcontract Northrop Grumman has for Lockheed Martin.

Conclusion

Thank you to [Tony Long] and [Adam Gross] for spending to give Hackaday this tour. I had the impression that I was living an episode of one of my favorite programs How It’s Made, and that was awesome! Northrop Grumman has an educational outreach program so if you’re associated with a school in the area set up a tour of the JWST!

[Tony] ducked out with me for dinner; some excellent tacos — a quest I’ve been on during each visit to LA. He joined me afterward on a trip to Null Space Labs for their open night. They had moved since the last time I was there and if you’re in town you should check it out.

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One thing I should mention is that I was not able to take any photographs on the premises. My story above is original but all the photos are stock or provided by Northrop at my request.

Main Post Image via JWST Flickr

Front Mirror via YouTube thumb.

Extended Reflection Mirror via YouTube video.