Thermal imager can transfer difference of temperature to difference of electric signal level, so can be application to
medical treatment such as estimation of blood flow speed and vessel 1ocation<sup></sup>, assess pain<sup></sup> and so on. With the
technology of un-cooled focal plane array (UFPA) is grown up more and more, some simple medical function can be
completed with un-cooled thermal imager, for example, quick warning for fever heat with SARS. It is required that
performance of imaging is stabilization and spatial and temperature resolution is high enough. In all performance
parameters, noise equivalent temperature difference (NETD) is often used as the criterion of universal performance. 320
x 240 α-Si micro-bolometer UFPA has been applied widely presently for its steady performance and sensitive
responsibility. In this paper, NETD of UFPA and the relation between NETD and temperature are researched. several
vital parameters that can affect NETD are listed and an universal formula is presented. Last, the images from the kind
of thermal imager are analyzed based on the purpose of detection persons with fever heat. An applied thermal image
intensification method is introduced.
Since x-ray was discovered and applied to the imaging technology, the x-ray imaging techniques have experienced
several improvements, from film-screen, x-ray image intensifier, CR to DR. To store and transmit the image information
conveniently, the digital imaging is necessary for the imaging techniques in medicine and biology. Usually as the
intensifying screen technique as for concerned, to get the digital image signals, the CCD was lens coupled directly to the
screen, but which suffers from a loss of x-ray signal and resulted in the poor x-ray image perfonnance. Therefore, to
improve the image performance, we joined the brightness intensifier, which, was named the Low Light Level (LLL)
image intensifier in military affairs, between the intensifying screen and the CCD and designed the novel x-ray imaging
system. This design method improved the image performance of the whole system thus decreased the x-ray dose.
Comparison between two systems with and without the brightness intensifier was given in detail in this paper. Moreover,
the main noise source of the image produced by the novel system was analyzed, and in this paper, the original images
produced by the novel x-ray imaging system and the processed images were given respectively. It was clear that the
image performance was satisfied and the x-ray imaging system can be used in security checking and many other
nondestructive checking fields.
Uncooled microbolometer infrared detectors are being developed for a wide range of thermal imaging applications. To design and manufacture high-performance microbolometer infrared detectors, numerical calculation and simulation is necessary. In this work, finite element methods are performed to simulate the transient temperature field of thermistor films of microbolometer infrared detectors. The varisized supporting legs' impacts on the performance of detectors are discussed. At the same time, variation of the bias voltage and the substrate temperature's impacts on total noise, noise equivalent to temperature difference (NETD) and detectivity (D*) are also discussed in details. These performance analyses are helpful for optimum design of microbolometer infrared detectors' structure and rational choice of working temperature of infrared focal plane arrays.
In this paper, on the base of simple introduction of inner structure of 320×240 pixels UFPA in electronics and
calorifics, the relationship of NETD (noise equivalent temperature difference) and bias voltage are researched and
presented through the formulas about noise and NETD. The relation between NETD and four kinds of temperatures is
presented. Moreover the two bias voltages are adjusted to observe the changing of NETD. Some experiments on power
consumption and image quality of thermal imaging system is done, the result data is given. On the basis of the theory and
experiments, how to enhance the NETD performance of UFPA (Focal Plane Array) at much lower or higher than room
temperature is researched by analyzing experiment data. At last, the conclusion is summarized: in order to get the best
image and the lest power consumption, we should adjust these parameters to find the optimized configuration at different