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Tea Diseases Detection Based on Fast Infrared Thermal Image Processing Technology
摘要： The overall goal of this study is to develop an effective, simple, aptly computer vision algorithm to detect tea disease area using infrared thermal image processing techniques and to estimate tea disease. This paper finds that the area of tea disease has certain regularity with its infrared image gray distribution. Using this rule, we extracted two characteristic parameters into a classifier to help achieve rapid tea disease detection, which increase the accuracy of detection a small amount. Tea plant images were taken from Jiangsu Tea Expo Park, China during daylight and the tea disease detection algorithm were tested on 116 images collected from 57 trees. The tea disease detection algorithm consisted of the following steps: classify canopy infrared thermal image, convert red, green and blue (RGB) image to hue, saturation and value (HSV), thresholding, color identification, noise filtering, binarization, closed operation and counting. A correlation coefficient of 0.97 was obtained between the tea disease detection algorithm and counting performed through human observation, 2% higher than traditional algorithms without classifiers.
关键词： Color detection,Tea disease,Infrared thermal image,Fast classification,Image processing
更新于2025-09-23 15:23:52
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Single track scanning experiment in laser powder bed fusion process
摘要： Laser powder bed fusion (LPBF) process utilizes laser source to melt the powder particles. As a result, melt pool is formed which develops along the scan track. In this study, single track scanning with Ti-6Al-4V alloy is performed in alternate layers over the supporting base pad. Multiple single scan tracks with scanning speeds of 200mm/s, 400 mm/s and 600 mm/s are defined and thermal responses are captured using infrared camera. The thermal images record the apparent temperature measurements; therefore, derivate method is used to find the liquidus-solidus transition region which is required to estimate the melt pool length and width. Based on the estimation, the average melt pool width of the single track decreased with increasing speed while the average melt pool length for 200 mm/s scanning speed was 438.62 μm, for 400 mm/s was 432.27 μm and for 600 mm/s was 451.2 μm. Besides, cylindrical powder container samples with enclosed single tracks were designed to investigate internal features using computed tomography (CT). The CT images showed that the scanning speed of 200 mm/s and 400 mm/s resulted in formation of significant number of pores due to keyhole formation which may contribute to variation in melt pool length.
关键词： Thermal image,Single track,Infrared Camera,Porosity,Melt pool
更新于2025-09-12 10:27:22
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Light transmission and internal scattering in pulsed laser-etched partially-transparent silicon wafers
摘要： Continuing trend in silicon wafer thickness directed at cost reduction approaches basic boundaries created by: (a) mismatch between Al paste and Si wafer thermal expansion and (b) incomplete optical absorption. With its symmetrical front and back electrical contacts, the bifacial solar cell setup reduces stress due to mismatch thermal expansion, decreases metal use and increases high temperature efficiency. Efficiency improvement is accomplished in bifacial solar cells by capturing light from the back surface. Partially transparent wafers provide an option to improve near-infrared radiation absorption within Si wafer. To fully absorb optical radiation, three-dimensional texture of these kinds of wafers is essential. Pulsed laser interactions, thermal oxidation, and wet chemical etching are included in this research. A feature of its energy and pattern setup is the interaction of pulsed laser with Si, running at 1.064 μm wavelength and micro-second length. Two experimental settings were explored: (a) post-laser chemical etching with potassium hydro-oxide etching with thermal oxide as etching mask and (b) post-laser heat Si surface oxidation. Due to fast melting and recrystallization, laser pulsed processing inherently produces its own texture. Some of these spherically-shaped, randomly focused characteristics improve inner scattering and boost near-infrared absorption within the wafer. These characteristics are separated during chemical etching with the thermally-grown oxide layer as an etch mask. Comparison of optical absorption in both surfaces shows almost a rise in the magnitude of absorption in non-etched surfaces. Detailed optical (optical microscope and IR absorption), morphological (field emission scanning electron microscope) and heat imaging (far IR camera) analyses were performed to comprehend physical processes that contribute to near-IR absorption improvement. Such kinds of partially-transparent, three-dimensional textured Si wafers are anticipated to discover applications for bifacial solar cells as substrates.
关键词： Thru-holes,Optics,Silicon wafer,Materials physics,Thermal image,Partial transparent,Nanotechnology,Trench,Energy,IR transmission,Materials characterization
更新于2025-09-11 14:15:04
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Molten Steel Level Detection From Thermal Image Sequence Based on the Characteristics of Adhesive Flux
摘要： High-temperature medium and time-varying covering flux lead to the difficulty of molten steel level measurement. For the measurement, in our previous work, a novel principle by using temperature gradient was proposed by us, and a refractory sensor was inserted into the metallurgical container to sense the temperature gradients of the flux and the molten steel. However, sometimes liquid adhesive flux on the sensor surface disables the extraction of true temperature gradients. To fix this problem, two new models, the adhesion thickness model and the adhesion flowability model, which are inspired by the adhesion mechanism of the flux, are proposed to detect the steel-flux interface. A unified approach, sequential clustering of the shapes of the pixel gray-time curves, is introduced to conduct the detection. On this basis, the thermal image sequence with 4-D spacetime information of the sensor is used for clustering. First, gray values of each pixel in the sequence are sorted in the time dimension, and grouping of the pixels in space dimension is done. Then, the region of interest is extracted from the image sequence to remove the invalid pixels, and sequential clustering is conducted with each group. Finally, the confidence of the clustering results is measured and the clustering results with the confidence higher than the threshold are retained to detect the steel-flux interface. By utilizing the two new models, the standard deviation of the measurement errors reduces from 4.8 to 3.7 mm.
关键词： thermal image sequence,steel-flux interface detection,Adhesion characteristic,4-D spacetime information,sequential clustering
更新于2025-09-09 09:28:46