Design and realization of high resolution optical micro-scanning thermal microscope imaging system

High-resolution over-sampling reconstruction algorithm for a microscanning thermal microscope imaging system

Infrared imaging theory is an important theoretical basis for the design of infrared imaging systems, but there is no research on infrared imaging theory for designing thermal microscope imaging systems. Therefore, we studied the performance evaluation and optimization theory of thermal microscope imaging systems. In this paper, we analyzed the difference in spectral radiant flux between thermal microscope imaging and telephoto thermal imaging. The expression of signal-to-noise ratio of the output image of the thermal microscope imaging systems was derived, based on the analysis of the characteristics of thermal microscope imaging. We studied the performance evaluation model of thermal microscope imaging systems based on the minimum resolvable temperature difference and the minimum detectable temperature difference. Simulation and analysis of different detectors (ideal photon detector and ideal thermal detector) were also carried out. Finally, based on the conclusion of theoretical research, we carried out a system design and image acquisition experiment. The results show that the theoretical study of thermal microscope imaging systems in this paper can provide reference for the performance evaluation and optimization of thermal microscope imaging systems.

Thermal imaging systems can perform many functions in marine service. They can be used for navigation, surveillance, search and rescue, safety inspection, and communications. The range, sensitivity, resolution, and response time of different thermal imaging systems vary sufficiently to accommodate the operational requirements and pocketbooks of most potential users. The theory of operation, design approaches, materials of construction, and performance levels for different thermal imaging systems are discussed and salient features shown. Typical areas of application in marine service for the thermal imaging systems will be looked at and cost-effective solutions suggested.

Oil and gas pipelines require systematic supervision and control in order to ensure their safe exploitation, even more so during spring/autumn/summer thawing, freezing and flooding seasons when soil deformation is at its highest. In the article, several ways of Earth’s surface space monitoring are considered. It’s pointed out that infrared sounding appears to be the most promising method of space monitoring the condition of main and production pipelines. It’s due to infrared sounding’s unique capability to detect pipeline’s construction flaws and breaches. However, thermal imaging systems are still in need of significant development, due to high noise and low image contrast levels. As of present time, there are no universally applicable filters, capable of detecting and suppressing all types and levels of noise. Further development in this sphere requires broadening of the arsenal of algorithmic processing facilities, which remains insufficient. The quality of thermal imaging depends on temperature distribution on the surface of the examined object as well as characteristics and parameters of thermal imaging systems themselves. The variety of parameters in photosensitive elements of photodetective device’s matrix leads to the appearance of so-called geometric noises in thermal imaging devices. Correction of geometrical noises in thermal imaging systems is one of the key problems. The approach to the solution of this problem is considered in the article.

Non-contact physiological measurements have been under investigation for many years, and among these measurements is non-contact spirometry, which could provide acute and chronic pulmonary disease monitoring and diagnosis. This work presents a feasibility study for non-contact spirometry measurements using a mobile thermal imaging system. Thermal images were acquired from 19 subjects for measuring the respiration rate and the volume of inhaled and exhaled air. A mobile application was built to measure the respiration rate and export the respiration signal to a personal computer. The mobile application acquired thermal video images at a rate of nine frames/second and the OpenCV library was used for localization of the area of interest (nose and mouth). Artificial intelligence regressors were used to predict the inhalation and exhalation air volume. Several regressors were tested and four of them showed excellent performance: random forest, adaptive boosting, gradient boosting, and decision trees. The latter showed the best regression results, with an R-square value of 0.9998 and a mean square error of 0.0023. The results of this study showed that non-contact spirometry based on a thermal imaging system is feasible and provides all the basic measurements that the conventional spirometers support.

To provide theoretical support for study of locust phototactic vision nature, the locust phototactic physiology and visual spectrum effects were investigated by stimulating the visual system using light from an AvaSpec fiber-optic spectrometer and Flir thermal imaging system. When light stimulated the locust visual system, the biological photoelectric transformation effect of the visual system caused by photon energy, presented with the higher physiological temperature on the forehead, as tested by the Flir thermal system. After stimulation with light, the different absorption degrees of the vision system on the spectral photons, as tested by the AvaSpec spectrometer, showed that the phototactic response to light had the simultaneous requirements of lighting intensity and time. The absorbing differences of spectral photons by the vision system demonstrated the absorption selectivity under light stimulation, as exhibited by the sensitive absorption of spectral energy at 430 nm, 545 nm and 615 nm. Moreover, the higher forehead temperature increment indicated and induced the stronger physiology activity which was the reason that causing the good phototactic response degree of locusts with 30 min light stimulation, and the adaption time was about 60 min. Therefore, only when the visual reaction effect was stimulated to absorb sensitive spectral energy and generate the physiological exciting response could cause the phototactic behavior. Keywords: Phototactic pest control, physiological response, Locusta migratoria, spectral illumination, phototactic vision, spectrum absorption, light simulation DOI: 10.3965/j.ijabe.20160902.1249 Citation: Liu Q H, Zhou Q. Physiological response of locusts to eye stimulation by spectral illumination for phototactic pest control. Int J Agric & Biol Eng, 2016; 9(2): 186－194.

The thermal camera systems can be used in all kinds of applications that require the detection of heat change, but thermal imaging systems are highly costly systems. In recent years, developments in the field of deep learning have increased the success by obtaining quality results compared to traditional methods. In this paper, thermal images of neonates (healthy - unhealthy) obtained from a high-resolution thermal camera were used and these images were evaluated as high resolution (ground truth) images. Later, these thermal images were downscaled at 1/2, 1/4, 1/8 ratios, and three different datasets consisting of low-resolution images in different sizes were obtained. In this way, super-resolution applications have been carried out on the deep network model developed based on generative adversarial networks (GAN) by using three different datasets. The successful performance of the results was evaluated with PSNR (peak signal to noise ratio) and SSIM (structural similarity index measure). In addition, healthy - unhealthy classification application was carried out by means of a classifier network developed based on convolutional neural networks (CNN) to evaluate the super-resolution images obtained using different datasets. The obtained results show the importance of combining medical thermal imaging with super-resolution methods.

Influence of image resolution on the performance of remote breathing rate measurement using thermal imaging technique

Development of a low-cost thermal imaging system for water stress monitoring in indoor farming

With the wide application of unmanned aerial vehicles (UAVs), UAV thermal imaging technology has been brought to the attention of numerous experts and scholars. At present, the application of UAV thermal imaging technology is limited by the problem of low resolution of the images captured by the thermal imaging system itself. In order to solve this problem, this paper proposes a UAV thermal image super-resolution reconstruction method based on bimodal image feature fusion, which improves the UAV thermal image super-resolution characterization capability by making use of the feature information provided by the UAV visible image to compensate for the lack of texture and edge information perception in thermal images. The proposed methodology consists of two tasks: The first task involves a bimodal image feature fusion network that extracts texture and edge information from visible images. This addresses the lack of detailed feature information in thermal images with a differential complementary modal feature fusion module, ultimately producing a fused image with high-quality feature information. The second task entails the integration of a gated multilevel feature fusion module into the UAV thermal image reconstruction network as an attention mechanism, thereby improving the use of fused image feature information for generating high-resolution UAV thermal images. Finally, a joint adaptive training strategy is utilized to further enhance the super-resolution effect of UAV thermal images. The experimental results show that the proposed method can effectively extract the visible image information to compensate for the characterization information in the UAV thermal image super-resolution, and achieves the optimal values of 31.53 dB and 0.9116 in PSNR and SSIM metrics, respectively, providing a new solution for the thermal image super-resolution of UAVs.

This paper reports a digital noise reduction method for a low-cost thermal imaging system using IR-to-visible transducers. Due to the weak intensity of luminescence from the transducers, an optical measurement method used in the system produces relatively large noise. To reduce the noise without any hardware modification, two digital filters, one of which is based on a finite impulse response filter and the other is based on a Kalman filter, were proposed and applied to the thermal imaging system. Both filters could successfully reduce the noise in the thermal image, however the Kalman filtered result had higher time response, which is more suitable for the real-time thermal imaging.

With optical micro-scanning technology, the spatial resolution of the thermal microscope imaging system can be increased without reducing the size of the detector unit or increasing the detector dimensions. Due to optical micro-scanning error, the four low-resolution images collected by micro-scanning thermal micro- scope imaging system are not standard down-sampled images. The reconstructed image quality is degraded by the direct image interpolation with error, which influences the performance of the system. Therefore, the technique to reduce the system micro-scanning error need to be studied. Based on micro-scanning technology and combined with new edge directed interpolation(NEDI) algorithm, an error correction technique for the micro-scanning instrument is proposed. Simulations and experiments show that the proposed technique can reduce the optical micro-scanning error, improve the imaging effect of the system and improve the systems spatial resolution. It can be applied to other electro-optical imaging systems to improve their resolution.

High-resolution UAV-based thermal imaging to estimate the instantaneous and seasonal variability of plant water status within a vineyard

A new coded aperture thermal neutron imager system has been developed at Brookhaven National Laboratory. The cameras use a new type of position-sensitive 3 He-filled ionization chamber, in which an anode plane is composed of an array of pads with independent acquisition channels. The charge is collected on each of the individual 5x5 mm 2 anode pads, (48x48 in total, corresponding to 24x24 cm 2 sensitive area) and read out by application specific integrated circuits (ASICs). The new design has several advantages for coded-aperture imaging applications in the field, compared to the previous generation of wire-grid based neutron detectors. Among these are its rugged design, lighter weight and use of non-flammable stopping gas. The pad-based readout occurs in parallel circuits, making it capable of high count rates, and also suitable to perform data analysis and imaging on an event-by-event basis. The spatial resolution of the detector can be better than the pixel size by using a charge sharing algorithm. In this paper we will report on the development and performance of the new pad-based neutron camera, describe a charge sharing algorithm to achieve sub-pixel spatial resolution and present the first stereoscopic coded aperture images of thermalized neutron sources using the new coded aperture thermal neutron imager system.

A line of tube transfering 300°C vapour at high pressure has been surveyed by means of thermography to obtain its surface temperature. The tube is 529 mm in diameter. A great number of thermal images are observed and analysed. Heat leakage is shown by much higher temperature area on these thermal images. One can find different causes of these heat leakage, for example, from imperfect parts of insulation meterial around tube, or from the connection gap between block-shape insulation material. A thermal imaging system with capability of digital processing image is used. A practical method to calculate the heat flux density from the image is developed. The program is executed in the same time with the measurement. Such quantitative results may be compared in the field with other ordinary measurements, such as heat flux meter, and enthalpy variation calculation. Over 1.62km distance, a variety of thermal patterns are processed digitally, an average of heat flux density 110 kcal/m2h is obtained, which is in good coincidence with other measurements. Other results, such as the highest and average surface temperaturea,the percentage of heat leakage contribution from different areas, etc., are also obtained. This digital processing method can provide a standard to check the quality of heat insulation. Experiments with different insulation materials are also made, and useful results are obtained from their comparison.