We might have come across various high-speed cameras performing at startling speeds. However, the matter in question is what constitutes the best high-speed camera? To solve this query; let us probe into the definition.
A high-speed camera represents a device used for capturing images of fast moving objects with exposures more than 250 frames per second or less than 1/1000 seconds. This camera records photographic images of fast-moving objects onto a storage medium for onward playing back those images in slow motion. Before the advent of electronic devices, films were used in early high-speed cameras for recording high speed events. However, the discovery of electronic devices superseded the conventional technology by utilizing either CMOS active pixel sensor technology or Charged coupled device (CCD) structure. This technology allowed to record 1000 frames per second onto a DRAM memory chip for onward playing back in slow motion to be used for studying any transient phenomena pertaining to any scientific study.
High speed cameras are also termed as trouble-shooting cameras and can be classified as high-speed film camera for film recording, high-speed framing camera for recording at multiple frames, high-speed video cameras based on electronic memory and high-speed streak camera for recording on either film or electronic memory. When it comes to industrial applications, high-speed cameras are mainly used to trouble shoot high speed events beyond the visibility of human eye. The needed exposure required by them is very high to film at 40,000 frames per second accompanied by monochromatic filming for reducing light intensity. Further, to enable high speed imaging over 25 million frames per second, specialized CCD imaging systems are deployed for attaining extraordinary speed. The high-speed film cameras instead of using a shutter rely over a mirror or rotating prism to film up to quarter of a million frames per second for increasing super slow-motion playback time. However, film cameras have become obsolete due to operational and cost overruns as compared to digital video cameras which are more in light.
What is The Fastest High-Speed Camera
With so many technological advancements each year, it is difficult to keep pace with the frequent technology devices as most of them even go overlooked unfortunately. According to a research in 2011, the fastest high-speed camera can be attributed to light capturing camera which can take images at stunning one trillion frames per second. However, this amazing discovery couldn’t do justice with human brain and eye coupled ability to register hardly 1000 frames per second.
Another research was carried out by scientists in Japan in year 2014, which led to the unearthing of motion-picture camera regarded as being the fastest high-speed camera able to record at astounding 4.4 trillion frames per second. This camera is based on Sequentially Time All Optical Mapping Photography (STAMP) technique strives to develop improved understanding of laser processing in semiconductor and auto factories alongside aiding ultrasonic therapy in the field of medicine. Nevertheless, the STAMP technique still needs several improvements for more practical applications.
Yet another time bending world’s fastest high-speed camera captures slow motion videos at over five trillion frames per second capable of encoding several images into a single picture by utilizing Frequency Recognition Algorithm for Multiple Exposures (FRAME) technique. The flashing laser pulse is embedded with a unique code which illuminates the scene. These pulses altogether merge into a single image which can be rearranged later into sequential order for playing back videos. This technique also complements scientific investigations pertaining to ultra high spectroscopic videography not possible with previous techniques. The advancements in slow motion photography causes trickle-down effect eventually and set next technological milestones to be achieved.
How Much is a High-Speed Camera?
To capture most fleeting moments of life, the super slow-motion videos are visually intoxicating as these events allow the brain to catch-up the dynamics, emotions and physics involved that become apparent in the blink of an eye. As far as the price of a best high-speed camera is concerned, it varies with regards to different vendors offering different camera features along-with associated technology for creating their value preposition.
What is The Fastest Frames Per Second?
The fastest frames per second can be attributed to the camera constituting unbelievable trillion frames per second, which is fast enough to capture light in motion. The high-speed camera uses laser pulses as a flash which lasts less than one trillionth of a second. This camera comprises of femto photography technique constituting mathematical reconstruction technique, picosecond accurate detectors and femtosecond laser illumination. The Titanium Sapphire laser emits pulses at every 13 nanoseconds at regular intervals which illuminates the scene and trigger streak tube for capturing light back from the scene. These fast yet best high-speed cameras transpire capturing light in motion at around 480 frames per second with effective exposure timings of around 1.71 picoseconds.
How Does High-Speed Cameras Work?
The working of high-speed camera basically initiates with custom design high-speed camera sensors which are built in accordance with the specifications and requirements of vision systems. These camera sensors are extraordinary in terms of speed performance due to fast CMOS image sensor technology and high parallelism. However, varied applications prefer high resolution images more than speed for getting improved spatial resolution and detailed images.
To render high-speed performance for high-speed cameras, high light sensitivity is indispensable as the sensor exposure time to light is very limited. That is why, an engineering trade-off always exists between high resolution, high light sensitivity and high speed in a custom based sensor design. For instance, to gain high resolution the pixel size must be smaller which may lead to low sensitivity gain turning into an opportunity cost. Similarly, every high-speed camera comprises of a native throughput which handles all the sensor data specified in gigapixels/second which implies increasing the resolution may resultantly reduce the speed. Henceforth, new performance levels in speed imaging can only be attained by incorporating state-of-the-art sensor design to induce high sensitivity. Once the sensor is operational, the next phase is to drag sensor data as a single image frame on to the digital cameras.
These customized sensors simply work by counting the photons that hit the pixels of the sensor. The high-speed cameras sends a signal to the sensor to start the photon count and to stop the count at some time later. Meanwhile, each photo site gains an electrical charge proportional to the photon number being counted. By the end of this digital exposure time usually expressed in micro or milliseconds, the electrical charge of each photo site while using an analog to digital converter (A/D) is converted into a digital number.
The pixel charge as represented by a digital number is stored along with all other pixels from that image in the camera memory. To account for small pixel variations relative to the other pixels, the calibration frame is used for correcting these values. All this takes place at millions of frames per second while using very fast memory and high-speed electronics along with a pipelined structural design. These high-speed cameras are also used widely for video trouble shooting applications by means of specialist triggering modes for storing pre-and post-event images continuously. They are also capable of self-triggering a small region of image by identifying trigger point for bringing any change. The image sequence thus generated showcase before and after images of changed trigger region.
These portable high-speed cameras utilize standard technology for storing and playing back videos in real time. The availability of high-speed cameras without built-in memory also exists, wherein the memory is integrated into the PC systems instead of camera which limits the interface speed up to 10x slower as compared to built-in camera memory. Consequently, the best high-speed camera is a combination of pipelined architecture, specialized image processing algorithms, high parallelism, high-speed memory, fast sensor and high-speed electronics for capturing incredibly slow-motion images at outstanding speeds.