| Recent developments in cooled mercury cadmium | | | | outputting only portions of the camera's detector array. |
| telluride (MCT or HgCdTe) infrared detector | | | | This is ideal when there are smaller areas of interest in |
| technology have made possible the development of | | | | the field-of-view. By observing just "sub-windows" |
| high performance infrared cameras for use in a wide | | | | having fewer pixels than the full frame, the frame |
| variety of demanding thermal imaging applications. | | | | rates can be increased. Some infrared cameras have |
| These infrared cameras are now available with | | | | minimum sub-window sizes. Commonly, a 320x256 |
| spectral sensitivity in the shortwave, mid-wave and | | | | camera has a minimum sub-window size of 64x2 and |
| long-wave spectral bands or alternatively in two bands. | | | | will output these sub-frames at almost 35Khz, a |
| In addition, a variety of camera resolutions are available | | | | 640x512 camera has a minimum sub-window size of |
| as a result of mid-size and large-size detector arrays | | | | 128x1 and will output these sub-frame at faster than |
| and various pixel sizes. Also, camera features now | | | | 3Khz. |
| include high frame rate imaging, adjustable exposure | | | | Because of the complexity of digital camera |
| time and event triggering enabling the capture of | | | | synchronization, a frame rate calculator is a convenient |
| temporal thermal events. Sophisticated processing | | | | tool for determining the maximum frame rate that can |
| algorithms are available that result in an expanded | | | | be obtained for the various frame sizes. |
| dynamic range to avoid saturation and optimize | | | | 3.3 Dynamic range expansion |
| sensitivity. These infrared cameras can be calibrated | | | | One of the complications of having a very high |
| so that the output digital values correspond to object | | | | sensitivity infrared detector is that the overall scene |
| temperatures. Non-uniformity correction algorithms are | | | | dynamic range will be limited. For example, if a raw |
| included that are independent of exposure time. These | | | | count corresponds to 5 mK/digital count, a 14-bit signal |
| performance capabilities and camera features enable | | | | range will deliver less than 80 degrees C in dynamic |
| a wide range of thermal imaging applications that were | | | | range. This range is further reduced because of pixel |
| previously not possible. | | | | non-uniformity. As a consequence, the range of object |
| At the heart of the high speed infrared camera is a | | | | temperatures that can be viewed in one frame may |
| cooled MCT detector that delivers extraordinary | | | | be too narrow for the application. |
| sensitivity and versatility for viewing high speed thermal | | | | To increase the apparent dynamic range, a unique |
| events. | | | | solution can be implemented which allows the user to |
| 1. Infrared Spectral Sensitivity Bands | | | | artificially expand the dynamic range without sacrificing |
| Due to the availability of a variety of MCT detectors, | | | | the high sensitivity performance of the camera. (This |
| high speed infrared cameras have been designed to | | | | mode is sometimes called Dynamic Range ExtendIR, |
| operate in several distinct spectral bands. The spectral | | | | DR-X, superframing, multi-IT). When the dynamic range |
| band can be manipulated by varying the alloy | | | | expansion mode is engaged, the camera sequentially |
| composition of the HgCdTe and the detector set-point | | | | captures multiple frames, each frame having a |
| temperature. The result is a single band infrared | | | | different exposure time. The short sequence includes |
| detector with extraordinary quantum efficiency | | | | frames that are highly sensitive (because of long |
| (typically above 70%) and high signal-to-noise ratio able | | | | exposure times) and also less sensitive frames for |
| to detect extremely small levels of infrared signal. | | | | imaging objects at higher temperatures (because of |
| Single-band MCT detectors typically fall in one of the | | | | shorter exposure times). For the method to be |
| five nominal spectral bands shown: | | | | effective, the overall time for the frame sequence |
| Short-wave infrared (SWIR) cameras - visible to | | | | must be short enough to avoid motion blur. If this is the |
| 2.5 micron | | | | case, then camera software combines the frames into |
| Broad-band infrared (BBIR) cameras - 1.5-5 micron | | | | one image frame having the entire dynamic range for |
| Mid-wave infrared (MWIR) cameras - 3-5 micron | | | | the sequence. |
| Long-wave infrared (LWIR) cameras - 7-10 micron | | | | As an example, consider the following sequence of |
| response | | | | images showing the process of mixing a cold fluid to a |
| Very Long Wave (VLWIR) cameras - 7-12 micron | | | | flask of boiling liquid. If an exposure time was selected |
| response | | | | based on the full temperature range, the thermal |
| In addition to cameras that utilize "monospectral" | | | | resolution of the cooler objects will be poor. |
| infrared detectors that have a spectral response in | | | | Conversely, if the exposure time is selected to |
| one band, new systems are being developed that | | | | improve the thermal resolution of the cold fluid, the |
| utilize infrared detectors that have a response in two | | | | hotter objects may cause saturation. As a result, with |
| bands (known as "two color" or dual band). Examples | | | | dynamic range expansion, multiple integration times can |
| include cameras having a MWIR/LWIR response | | | | be selected that span the entire scene dynamic range. |
| covering both 3-5 micron and 7-11 micron, or | | | | Exposure time 110 microseconds / Frames 1,4,7 / |
| alternatively certain SWIR and MWIR bands, or even | | | | Object Temperature Range 65-150 degrees C |
| two MW sub-bands. | | | | Exposure time 600 microseconds / Frames 2,5,8 / |
| There are a variety of reasons motivating the | | | | Object Temperature Range 35-70 degrees C |
| selection of the spectral band for an infrared camera. | | | | Exposure time 1375 microseconds / Frames 3,6,9 / |
| For certain applications, the spectral radiance or | | | | Object Temperature Range 5-40 degrees C |
| reflectance of the objects under observation is what | | | | In this example, three exposure times have been |
| determines the best spectral band. These applications | | | | selected (1375 microseconds, 600 microseconds, and |
| include spectroscopy, laser beam viewing, detection | | | | 110 microseconds) to cover a wide scene temperature. |
| and alignment, target signature analysis, | | | | The camera then cycle through each exposure time |
| phenomenology, cold-object imaging and surveillance in | | | | at the full frame rate. If the camera is operating at 240 |
| a marine environment. | | | | frames/second, the first frame will be at the first |
| Additionally, a spectral band may be selected because | | | | exposure time, the second frame will be at the second |
| of the dynamic range concerns. Such an extended | | | | exposure time, the third at the third exposure time. The |
| dynamic range would not be possible with an infrared | | | | fourth frame will begin the sequence again at the first |
| camera imaging in the MWIR spectral range. The wide | | | | exposure time. The system will effectively generate |
| dynamic range performance of the LWIR system is | | | | three sequences, three frames apart, each at a rate |
| easily explained by comparing the flux in the LWIR | | | | of 80 frames/second with the three exposures times. |
| band with that in the MWIR band. As calculated from | | | | Through image processing, the sequential frames can |
| Planck's curve, the distribution of flux due to objects at | | | | be recombined into one complete sequence making a |
| widely varying temperatures is smaller in the LWIR | | | | pixel by pixel determination as to the apparent signal, |
| band than the MWIR band when observing a scene | | | | further increasing the dynamic range. The resulting |
| having the same object temperature range. In other | | | | image is shown below (with a 5-150 degrees C object |
| words, the LWIR infrared camera can image and | | | | temperature scale): |
| measure ambient temperature objects with high | | | | The exposure times correspond to different camera |
| sensitivity and resolution and at the same time | | | | sensitivities. In operation, the camera is programmed to |
| extremely hot objects (i.e. >2000K). Imaging wide | | | | select the appropriate exposure time frame by frame. |
| temperature ranges with an MWIR system would | | | | The resulting data will either be multiple sequences |
| have significant challenges because the signal from | | | | created from multiple integration times, or a combined |
| high temperature objects would need to be drastically | | | | sequence that takes the most appropriate data based |
| attenuated resulting in poor sensitivity for imaging at | | | | upon the scene. In addition, the user can choose to |
| background temperatures. | | | | vary the number of frames per integration time, as |
| 2. Image Resolution and Field-of-View | | | | well as have the option to utilize an internal filter |
| 2.1 Detector Arrays and Pixel Sizes | | | | mechanism for attenuation or spectral data. |
| High speed infrared cameras are available having | | | | Certain applications require very wide thermal dynamic |
| various resolution capabilities due to their use of | | | | ranges, which may not be possible with a single |
| infrared detectors that have different array and pixel | | | | integration time. The high speed infrared camera's |
| sizes. Applications that do not require high resolution, | | | | dynamic range expansion mode will allow the user to |
| high speed infrared cameras based on QVGA | | | | cycle through exposure times at the fastest rate |
| detectors offer excellent performance. A 320x256 | | | | possible for the camera. |
| array of 30 micron pixels are known for their | | | | 3.4 Event Triggering |
| extremely wide dynamic range due to the use of | | | | In order to capture high speed events, infrared |
| relatively large pixels with deep wells, low noise and | | | | cameras must be properly synchronized. In the |
| extraordinarily high sensitivity. | | | | tire-testing example in Section 3.1 above, it is possible |
| Infrared detector arrays are available in different sizes, | | | | to have an optical encoder on the rotating tire that |
| the most common are QVGA, VGA and SXGA as | | | | allows precise position location. The TTL signal |
| shown. The VGA and SXGA arrays have a denser | | | | generated by the optical encoder can be fed into the |
| array of pixels and consequently deliver higher | | | | infrared camera to trigger the start of the recording |
| resolution. The QVGA is economical and exhibits | | | | sequence for the camera. The result is that every time |
| excellent dynamic range because of large sensitive | | | | the encoder sends the pulse, the camera exposes the |
| pixels. | | | | infrared detector for a certain exposure time creating |
| More recently, the technology of smaller pixel pitch has | | | | an image. This allows a real-time stop image sequence |
| resulted in infrared cameras having detector arrays of | | | | to be created via software. |
| 15 micron pitch, delivering some of the most impressive | | | | In addition to the ability to accept an external TTL |
| thermal images available today. For higher resolution | | | | trigger, infrared cameras have other capabilities that |
| applications, cameras having larger arrays with smaller | | | | improve their ability to capture high speed events. For |
| pixel pitch deliver images having high contrast and | | | | example, certain trigger features permit the infrared |
| sensitivity. In addition, with smaller pixel pitch, optics can | | | | camera to synchronize the trigger with the desired |
| also become smaller further reducing cost. | | | | image capture. Because digital image frames are |
| 2.2 Infrared Lens Characteristics | | | | captured in real time, a pre-trigger permits the |
| Lenses designed for high speed infrared cameras | | | | software to identify the beginning of a desired |
| have their own special properties. Primarily, the most | | | | sequence that actually occurs before the trigger signal! |
| relevant specifications are focal length (field-of-view), | | | | Post-trigger delays are also available for aligning the |
| F-number (aperture) and resolution. | | | | frame capture with an event that follows the trigger |
| Focal Length: Lenses are normally identified by their | | | | after a programmable delay. |
| focal length (e.g. 50mm). The field-of-view of a camera | | | | In addition, most high speed thermal cameras today |
| and lens combination depends on the focal length of | | | | have the ability to provide a trigger output to allow |
| the lens as well as the overall diameter of the detector | | | | external devices to be synchronized with the thermal |
| image area. As the focal length increases (or the | | | | camera. Therefore the camera can slave or be |
| detector size decreases), the field of view for that | | | | slaved. Having both a trigger input and output is useful |
| lens will decrease (narrow). | | | | in an application that involves using multiple cameras to |
| A convenient online field-of-view calculator for a range | | | | view the same target from different angles. In this |
| of high-speed infrared cameras is available online. | | | | case, the data can be assembled - via software - into |
| In addition to the common focal lengths, infrared | | | | a 3-dimensional rendering of the thermal profile. |
| close-up lenses are also available that produce high | | | | 3.5 Calibration: non-uniformity correction and radiometry |
| magnification (1X, 2X, 4X) imaging of small objects. | | | | One of the challenges in obtaining the best data from |
| Infrared close-up lenses provide a magnified view of | | | | a high performance infrared camera system was in |
| the thermal emission of tiny objects such as electronic | | | | maintaining a proper calibration. Calibration often refers |
| components. | | | | to two different operations. One, non-uniformity |
| F-number: Unlike high speed visible light cameras, | | | | correction, is necessary to calibrate the sensor for |
| objective lenses for infrared cameras that utilize | | | | optimal image quality. The other calibration has to do |
| cooled infrared detectors must be designed to be | | | | with determining the temperature of objects based on |
| compatible with the internal optical design of the dewar | | | | their image brightness. |
| (the cold housing in which the infrared detector FPA is | | | | Non-uniformity correction is required to assure that the |
| located) because the dewar is designed with a cold | | | | infrared detector array delivers the best possible |
| stop (or aperture) inside that prevents parasitic | | | | image quality. Each pixel in the detector array inevitably |
| radiation from impinging on the detector. Because of | | | | has a slightly different gain and offset value. In addition, |
| the cold stop, the radiation from the camera and lens | | | | some pixels may have other anomalous properties |
| housing are blocked, infrared radiation that could far | | | | that deviate from the norm. The gain and offset for all |
| exceed that received from the objects under | | | | the pixels in the array need to be adjusted so that |
| observation. As a result, the infrared energy captured | | | | each pixel performs identically to the others. Variations |
| by the detector is primarily due to the object's radiation. | | | | can occur for a variety of reasons, including detector |
| The location and size of the exit pupil of the infrared | | | | non-uniformity and optical affects such as the lens |
| lenses (and the f-number) must be designed to match | | | | illumination non-uniformity that attenuates the apparent |
| the location and diameter of the dewar cold stop. | | | | radiance near the edge of the image. Anomalous pixel |
| (Actually, the lens f-number can always be lower than | | | | signals must be replaced with nearest neighbor |
| the effective cold stop f-number, as long as it is | | | | averages as is appropriate for the application. |
| designed for the cold stop in the proper position). | | | | To correct for the gain and offset, a calibration called |
| Lenses for cameras having cooled infrared detectors | | | | Non Uniformity Correction (NUC) must be created. The |
| need to be specially designed not only for the specific | | | | process typically requires that the user expose the |
| resolution and location of the FPA but also to | | | | detector to a "cold" and "hot" blackbody source. An |
| accommodate for the location and diameter of a cold | | | | algorithm then corrects the detector signal |
| stop that prevents parasitic radiation from hitting the | | | | non-uniformity. A similar process called Bad Pixel |
| detector. | | | | Replacement (BPR) is required for any pixels that are |
| Resolution: The modulation transfer function (MTF) of a | | | | considered "bad" which means they deviate from |
| lens is the characteristic that helps determine the ability | | | | certain thresholds set for evaluating uniformity or due |
| of the lens to resolve object details. The image | | | | to noisy behavior. |
| produced by an optical system will be somewhat | | | | Non-uniformity correction is complicated because there |
| degraded due to lens aberrations and diffraction. The | | | | are variations in pixel performance for each integration |
| MTF describes how the contrast of the image varies | | | | time. Therefore, this process would need to be |
| with the spatial frequency of the image content. As | | | | performed for every integration time that the user |
| expected, larger objects have relatively high contrast | | | | selects. As high performance cameras can operate |
| when compared to smaller objects. Normally, low | | | | from 1us to >10ms, this means that in theory 10,000 |
| spatial frequencies have an MTF close to 1 (or 100%); | | | | calibrations need to be made. However, because of |
| as the spatial frequency increases, the MTF eventually | | | | the linear response of the detector, recent advances |
| drops to zero, the ultimate limit of resolution for a given | | | | have been possible to make this process transparent |
| optical system. | | | | to the user. A process called TrueThermal allows the |
| 3. High Speed Infrared Camera Features: variable | | | | user to select any integration time and the camera will |
| exposure time, frame rate, triggering, radiometry | | | | automatically reference a look up table of both NUC |
| High speed infrared cameras are ideal for imaging | | | | and BPR properties that were established either at the |
| fast-moving thermal objects as well as thermal events | | | | factory or at the user's site. In this situation, once a |
| that occur in a very short time period, too short for | | | | user selects the appropriate integration time, the |
| standard 30 Hz infrared cameras to capture precise | | | | camera system applies a predefined NUC and BPR |
| data. Popular applications include the imaging of airbag | | | | table to allow instant and seamless operation. |
| deployment, turbine blades analysis, dynamic brake | | | | Once the sensor is calibrated for uniform image quality, |
| analysis, thermal analysis of projectiles and the study | | | | the camera can be calibrated for radiometry, or |
| of heating effects of explosives. In each of these | | | | temperature measurement. If an infrared camera is |
| situations, high speed infrared cameras are effective | | | | properly calibrated, the object temperature can be |
| tools in performing the necessary analysis of events | | | | determined based on the radiance signal in the thermal |
| that are otherwise undetectable. It is because of the | | | | images, the background ambient temperature, possible |
| high sensitivity of the infrared camera's cooled MCT | | | | atmospheric effects and the objects emissive |
| detector that there is the possibility of capturing | | | | properties. It is often particularly useful to be able to |
| high-speed thermal events. | | | | use the infrared camera to measure the temperature |
| The MCT infrared detector is implemented in a | | | | of objects (such as projectiles) traveling at high |
| "snapshot" mode where all the pixels simultaneously | | | | speeds. This finds applicability in several important |
| integrate the thermal radiation from the objects under | | | | situations, including: tracking of missiles, spacecraft and |
| observation. A frame of pixels can be exposed for a | | | | other objects, in determining the trajectory of bullets |
| very short interval as short as | | | | and projectiles and automatically identifying their origin |
| Because of the benefits of the high performance | | | | based on trajectory information, and in creating thermal |
| MCT detector, as well as the sophistication of the | | | | signatures for military targets. |
| digital image processing, it is possible for today's | | | | Some users require that the thermal data be calibrated |
| infrared cameras to perform many of the functions | | | | for radiometry. Again, this radiometric data will be |
| necessary to enable detailed observation and testing | | | | dependent upon a specific integration time and must |
| of high speed events. As such, it is useful to review | | | | include the NUC and BPR corrections. In the past, for |
| the usage of the camera including the effects of | | | | each integration time, a unique radiometric calibration |
| variable exposure times, full and sub-window frame | | | | would be required. Today, the TrueThermal calibration |
| rates, dynamic range expansion and event triggering. | | | | function facilitates the process, not only correcting for |
| 3.1 Short exposure times | | | | NUC and BPR, but also applying the appropriate |
| Selecting the best integration time is usually a | | | | radiometric calibration table to the data. This now |
| compromise between eliminating any motion blur and | | | | allows the user to, in real time, change integration times |
| capturing sufficient energy to produce the desired | | | | and have fully corrected data for NUC, BPR and |
| thermal image. Typically, most objects radiate sufficient | | | | radiometric calibration. |
| energy during short intervals to still produce a very high | | | | 4. Infrared Camera Applications |
| quality thermal image. The exposure time can be | | | | IR Inspection in Design, Test and Manufacturing: |
| increased to integrate more of the radiated energy | | | | Thermal imaging has become an extremely valuable |
| until a saturation level is reached, usually several | | | | technology in many industries as a tool to inspect and |
| milliseconds. On the other hand, for moving objects or | | | | test different designs and processes. The thermal |
| dynamic events, the exposure time must be kept as | | | | signatures can be a result of electrical, |
| short as possible to remove motion blur. | | | | electro-mechanical, chemical or other causes. Thermal |
| Tires running on a dynamometer can be imaged by a | | | | images reveal heat dissipation, thermal conductance, |
| high speed infrared camera to determine the thermal | | | | non-uniformities as well as other important diagnostic |
| heating effects due to simulated braking and cornering. | | | | factors. |
| One relevant application is the study of the thermal | | | | Hyperspectral and Gas Imaging, Remote Sensing: |
| characteristics of tires in motion. In this application, by | | | | Broadband infrared cameras are very useful for |
| observing tires running at speeds in excess of 150 mph | | | | hyperspectral imaging (which involves the accumulation |
| with a high speed infrared camera, researchers can | | | | of a spectral set of times), gas imaging (which occurs |
| capture detailed temperature data during dynamic tire | | | | at a sometimes very narrow portion of the infrared |
| testing to simulate the loads associated with turning | | | | spectrum) and remote sensing (imaging the |
| and braking the vehicle. Temperature distributions on | | | | backscatter, reflection and emission differences of |
| the tire can indicate potential problem areas and safety | | | | various materials). Powerful image processing |
| concerns that require redesign. In this application, the | | | | software is available to facilitate the analysis of the |
| exposure time for the infrared camera needs to be | | | | resulting infrared images. |
| sufficiently short in order to remove motion blur that | | | | Target Signature Measurement and Tracking: |
| would reduce the resulting spatial resolution of the | | | | The spectral characteristics of vehicles, weapons and |
| image sequence. For a desired tire resolution of 5mm, | | | | countermeasures have been found to be important for |
| the desired maximum exposure time can be calculated | | | | many applications. Broad spectral range, high resolution |
| from the geometry of the tire, its size and location with | | | | and high sensitivity are key features of infrared |
| respect to the camera, and with the field-of-view of | | | | cameras for these applications. We offer multi-spectral |
| the infrared lens. The exposure time necessary is | | | | imaging systems with a wide range of optics. In |
| determined to be shorter than 28 microseconds. Using | | | | addition, we offer powerful data acquisition systems |
| a Planck's calculator, one can calculate the signal that | | | | featuring real-time image capture and radiometric |
| would be obtained by the infrared camera adjusted | | | | analysis. |
| withspecific F-number optics. The result indicates that | | | | Research and Development: |
| for an object temperature estimated to be 80°C, an | | | | Thermal imaging is used extensively in engineering and |
| LWIR infrared camera will deliver a signal having 34% | | | | scientific research centers around the world. Thermal |
| of the well-fill, while a MWIR camera will deliver a signal | | | | imaging provides insight into critical information about an |
| having only 6% well fill. The LWIR camera would be | | | | object's thermal and spectral characteristics. In certain |
| ideal for this tire testing application. The MWIR camera | | | | circumstances, information can be obtained on |
| would not perform as well since the signal output in the | | | | high-speed events (available with high frame-rate |
| MW band is much lower requiring either a longer | | | | cameras) as well as circumstances requiring large |
| exposure time or other changes in the geometry and | | | | dynamic range (available with variable integration |
| resolution of the set-up. | | | | cameras). Key to the use of these imagers is often |
| The infrared camera response from imaging a thermal | | | | application-specific software that permits the detailed |
| object can be predicted based on the black body | | | | analysis of both two-dimensional images as well as |
| characteristics of the object under observation, | | | | arrays of image sequences. |
| Planck's law for blackbodies, as well as the detector's | | | | Medical Imaging, Body Temperature Detection: |
| responsivity, exposure time, atmospheric and lens | | | | Many physiological conditions produce variations in |
| transmissivity. | | | | body temperature and temperature distribution across |
| 3.2 Variable frame rates for full frame images and | | | | the human body. As an example, the installation of |
| sub-windowing | | | | thermographic cameras at airports has become a key |
| While standard speed infrared cameras normally | | | | Swine Flu and SARS screening tool for many areas |
| deliver images at 30 frames/second (with an | | | | around the world. Thermography has also been used |
| integration time of 10 ms or longer), high speed infrared | | | | as a screening tool for applications such as breast |
| cameras are able to deliver many more frames per | | | | cancer and pain management. |
| second. The maximum frame rate for imaging the | | | | Non-Destructive Test (NDT): |
| entire camera array is limited by the exposure time | | | | Thermal imaging is a non-invasive technique which |
| used and the camera's pixel clock frequency. Typically, | | | | when applied with specific stimulus provides a view |
| a 320x256 camera will deliver up to 275 frames | | | | into subsurface defects in difficult test samples. |
| second (for exposure times shorter than 500 | | | | Inspection of composite aircraft parts is gaining wide |
| microseconds); a 640x512 camera will deliver up to 120 | | | | acceptance in airframe manufacture and service. |
| frames/second (for exposure times shorter than 3ms). | | | | Advanced materials are finding their way into |
| The high frame rate capability is highly desirable in | | | | automotive and consumer products and thermographic |
| many applications when the event occurs in a short | | | | NDT is a fast and wide area screening technique that |
| amount of time. One example is in airbag deployment | | | | is very cost effective. |
| testing where the effectiveness and safety are | | | | Summary |
| evaluated in order to make design changes that may | | | | Because of the impressive performance of MCT |
| improve performance. A high speed infrared camera | | | | detector technology, high performance infrared |
| reveals the thermal distribution during the 20-30 ms | | | | cameras have become available that enable a wide |
| period of airbag deployment. As a result of the testing, | | | | variety of demanding thermal imaging applications. A |
| airbag manufacturers have made changes to their | | | | selection of infrared cameras are available having |
| designs including the inflation time, fold patterns, tear | | | | mid-format to large-format detectors and with spectral |
| patterns and inflation volume. Had a standard IR | | | | sensitivity ranging in the short, mid and long-wave |
| camera been used, it may have only delivered 1 or 2 | | | | spectral bands. The cameras owe their versatility to |
| frames during the initial deployment, and the images | | | | certain features that include: high frame rate imaging, |
| would be blurry because the bag would be in motion | | | | adjustable exposure time, event triggering enabling the |
| during the long exposure time. | | | | capture of temporal thermal events, dynamic range |
| Airbag effectiveness testing has resulted in the need | | | | expansion, non-uniformity correction and radiometric |
| to make design changes to improve performance. A | | | | calibration. These performance capabilities and camera |
| high speed infrared camera reveals the thermal | | | | features enable a wide range of thermal imaging |
| distribution during the 20-30ms period of airbag | | | | applications that were previously not possible, including: |
| deployment. As a result of the testing, airbag | | | | IR Inspection in design, test and manufacturing, |
| manufacturers have made changes to their designs | | | | hyperspectral imaging, gas detection, remote sensing, |
| including the inflation time, fold patterns, tear patterns | | | | target signature measurement and tracking, R&D, |
| and inflation volume. | | | | medical imaging and NDT. |
| Even higher frame rates can be achieved by | | | | |