It is well known that light signal gets weaker in the imaging process through the imaging chain. To make it possible that
the output image is of enough brightness for the human eye to "see" the information from the final image, we modeled
the light signal passing through the x-ray imaging chain. The imaging chain is composed of several optoelectronic
devices with characteristics, so the model elements mainly include spectral matching and inverse square distance for it is
assumed that the imaging system runs under the fine condition and without noise disturbance. This paper can be valuable
and referential for designing an x-ray imaging system and it is the same for other kinds of imaging systems.
In this paper, a novel x-ray imaging system was introduced. It was a CCD based system, but different from the traditional
CCD based x-ray imaging system, which was composed of the x-ray intensifying screen, the CCD and the low light level
image intensifier, specially using the zoom lens for coupling. Zoom lens can give a continuous variable visual field,
which not only reduce the geometrical blur but also can produce several image pairs for stereo imaging. It is convenient
for three dimension information extraction from a group of two dimension x-ray images and is valuable for stereovision
radiography in the application of medical diagnosis, security checking, non-destructive testing, and industry detection.
This stereo imaging method is also referential for the three dimension reconstruction daily living.
CCD technology has kept developing since CCD was invented and has very wide application in all kinds of imaging
field. In the fields of security checking, non-destructive testing, and industry detection, CCD makes it possible that the
digital radiography appears and accelerates the x-ray imaging performance improvement. So in this paper, CCD
technology was introduce and its development was analyzed, then how it affect the x-ray imaging performance was
conducted through the mathematical theory was model, which includes the pixel size and the pixel amount although the
cooling condition is very important. This paper can be valuable and referential for designing an x-ray imaging system
and it is the same for other kinds of imaging systems.
The low light level image intensifier was usually applied in the night observation, and it has been developed and
improved for a long history. While it can also be used in the x ray imaging system for its specialty in photos multiplying
and conversion, so in this paper, the technology development of the low light level image intensifier was described at
first and then a novel x ray image intensifier designed by our research group is introduced. The x ray intensifying screen
was the x ray sensor converting the x ray into the visible light. For the visible light from the x ray image intensifier was
too weak to see the image, the low light level image intensifier was used to intensify the light further. When the low light level image intensifier was selected, the novel x ray image intensifier's performance was modeled, which can given the comparison in resolution and brightness between with and without the low light level image intensifier. In conclusion, the novel x ray imaging system's performance is good enough to be applied to security checking, non-destructive testing, and industry detection.
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, assess pain 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.
The x-ray imaging technology has been improved greatly since Roentgen discovered x-ray in 1895 and it is very important in some fields such as medical treatment, nondestructive test and industrial detection. At present, there are many kinds of x-ray imaging technologies based on the different image detectors. To meet the requirement of real time observation, digital image processing and long-distance communication, digital radiography (DR) and direct digital radiography (DDR) are advantageous. The image intensifier is often used by large number of hospitals due to its affordable cost. As the key device of the x-ray imaging system, the conventional x-ray detector is mainly imported from Japan, or France because there is no domestic manufacture, which increases the cost of the whole x-ray imaging system, moreover the imported x-ray image intensifier has 9 inch visual field, thus limiting its application in some fields further. By combing the x-ray imaging technology and the low light level (L3) imaging technology, our research group designed the novel combined x-ray image intensifier, which means it is composed of the x-ray intensifying screen, zoom lens and the L3 image intensifier. In this paper, the principles on how to match the components of the x-ray image detector and how to design the structure of the x-ray image detector are introduced. At the end of the paper, the imaging performance of the x-ray image detector is given by showing the produced images and the MTF curve of the whole x-ray imaging system, which proved that the novel combined x-ray image intensifier is a good choice for many users and can be applied in many fields, such as the medical treatment, nondestructive test and industrial detection and even takes the place of the conventional x-ray image intensifier in some application fields.
In this paper, a new kind of x-ray imaging system designed by our laboratory is introduced in detail. Different from the traditional x-ray imaging system, its image intensifier is a combined one. The system's main components are the intensifying screen and the brightness intensifier and they are coupled by lens. Compared with the traditional x-ray imaging system, it has the advantages of low cost, big visual field and convenient installation. At the very beginning of this paper, the structure and the imaging principle of the new kind of x-ray imaging system are described, then requirements for the key components of this system are discussed and put forward. At the end of this paper, we give the images of the foot and the bag, which are the imaging results of the system. It indicates that the x-ray imaging system is satisfied and just for its low price, the usual users such as the middle and small hospitals can afford the system. As for the imaging performance of the system as concerned, it can be applied to security checking, medical treatment, nondestructive testing and many other fields of the science and technology.
At the present time, there are many kinds of x-ray imaging machines, and the x-ray image intensifier is the key component of it. In the hospitals, those x-ray imaging machines, which are equipped with the vacuum image-intensifier tubes (very heavy), are very ponderous (up- to-100-pound heft). It is particularly difficult to move and operate; by using the MCP x-ray intensifier-tube (it is also a vacuum tube), the system can be simplified, but the field of view is small because of the complex technics of MCP. These years, although the flat-panel detector is very advanced and it has big visual field, it is too expensive to be used in the daily living. In this paper, a new kind of x-ray image intensifier is put forward, which is coupled to million-pixel CCD by lens, is mainly composed of the intensifying screen and the brightness intensifier. It has the advantages of big visual field and low price. At the very beginning of this paper, the new kind of image intensifier and its imaging performance are introduced in detail. Then the performance characteristics of the intensifier are described. It is concluded that the relation between the output brightness that the brightness intensifier detects and the size of the intensifying screen obeys the inverse square law and the resolution of the image intensifier depends on the resolution of its components. After we discussed all these relations among the visual field and the output brightness and the resolution, we put forward the optimal coupling among all parts of the x-ray machine.