High-speed photography
The second requires some means of capturing successive frames, either with a mechanical device or by moving data off electronic sensors very quickly.
[1] German weapons scientists applied the techniques in 1916,[2] and The Japanese Institute of Aeronautical Research manufactured a camera capable of recording 60,000 frames per second in 1931.
[7][8] He eventually helped found EG&G, which used some of Edgerton's methods to capture the physics of explosions required to detonate nuclear weapons.
The images on 35 mm high-speed film are typically more rectangular with the long side between the sprocket holes instead of parallel to the edges as in standard photography.
Register pins, which secure the film through perforations in final position while it is being exposed, after the pulldown claws are retracted are also multiplied, and often made from exotic materials.
The rotary prism camera allowed higher frame rates without placing as much stress on the film or transport mechanism.
Many cameras use ultra high speed shutters such as those employing explosives to shatter a block of glass, rendering it opaque.
The raster can be made with lenticular sheets, a grid of opaque slits, arrays of tapered (Selfoc) fiber optics, etc.
When the motion of the film is opposite to that of the subject with an inverting (positive) lens, and synchronized appropriately, the images show events as a function of time.
By combining this technique with a diffracted wavefront of light, as by a knife-edge, it is possible to take photographs of phase perturbations within a homogeneous medium.
In December 2011, a research group at MIT reported a combined implementation of the laser (stroboscopic) and streak camera applications to capture images of a repetitive event that can be reassembled to create a trillion-frame-per-second video.
Illuminating a scene with a laser that emits pulses of light every 13 nanoseconds, synchronized to the streak camera with repeated sampling and positioning, researchers have demonstrated collection of one-dimensional data which can be computationally compiled into a two-dimensional video.
Although this approach is limited by time resolution to repeatable events, stationary applications such as medical ultrasound or industrial material analysis are possibilities.
[22] High-speed photographs can be examined individually to follow the progress of an activity, or they can be displayed rapidly in sequence as a moving film with slowed-down motion.
Early video cameras using tubes (such as the Vidicon) suffered from severe "ghosting" due to the fact that the latent image on the target remained even after the subject had moved.
The target in Vidicon type camera tubes can be made of various photoconductive chemicals such as antimony sulfide (Sb2S3), lead(II) oxide (PbO), and others with various image "stick" properties.
[citation needed] The mechanical shutter, invented by Pat Keller and others at China Lake in 1979, helped freeze the action and eliminate ghosting.
The image, while in this photoelectron state, could be shuttered on and off as short as a few nanoseconds, and deflected to different areas of the large 70 and 90 mm diameter phosphor screens to produce sequences of up to 20+ frames.
Kodak MASD group also introduced an ultra high-speed CCD camera called the HS4540 that was designed and manufactured by Photron in 1991[25] that recorded 4,500 frame/s at 256 x 256.
The HS4540 was used extensively by companies manufacturing automotive air bags to do lot testing which required the fast record speed to image a 30 ms deployment.
This plate is given a high-voltage charge such that electrons coming from the input photocathode to the holes create a cascading effect, thereby amplifying the image signal.
The output of the MCP is coupled to a CCD, usually by means of a fused fiber-optic taper, creating an electronic camera with very high sensitivity and capable of very short exposure times, though also one that is inherently monochrome due to wavelength information being lost in the photon-electron-photon conversion.
[26] Another approach for capturing images at extremely high speeds is with an ISIS (In Situ storage CCD chip, such as in the Shimadzu HPV-1 and HPV-2 cameras.
ISIS sensors have achieved rates of more than 3.5 terapixels per second, hundreds of times better than the state of the art high speed readout cameras.
The first patent of an Active Pixel Sensor (APS), submitted by JPL's Eric Fossum, led to the spin-off of Photobit, which was eventually bought by Micron Technology.
However, Photobit's first interest was in the standard video market; the first high-speed CMOS system was NAC Image Technology's HSV 1000, first produced in 1990.
These systems quickly made inroads into the 16 mm high-speed film camera market despite resolution and record times (the Phantom 4 was a 1024 x 1024 pixel, or 1 megapixel, with a run capacity of 4 s at full frame and 1000 frame/s).
IMEC in 2000 spun the research group off as FillFactory which became the dominant player in the design of streaming high speed image sensors.
Photobit eventually introduced a 500 frame/s 1.3 megapixel sensor, a true camera-on-chip device found in many low-end high-speed systems.
Subsequently, several camera manufacturers compete in the high-speed digital video market, including iX-Cameras, AOS Technologies, Fastec Imaging, Mega Speed Corp, NAC, Olympus, Photron, Mikrotron, Redlake, Vision Research, Slow Motion Camera Company and IDT, with sensors developed by Photobit, Cypress, CMOSIS, and in-house designers.
