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Automated Optical Flow Based Registration For Adaptive Optics Scanning Laser Ophthalmoscope
摘要： This study presents an automated registration method based on optical flow for an adaptive optics scanning laser ophthalmoscope. The method was designed to align and average images to obtain a higher signal-to-noise ratio image. A correlation based optical flow image registration method, which has large registration degrees of freedom, is adopted as a local registration method. By comparing the images before and after image registration, we show the effectiveness of our method. Furthermore, the advantage of our method, which is the containment of large registration degrees of freedom, is confirmed.
关键词： Retinal images,Image processing,Imaging systems,Optical flow,Active or adaptive optics,Ophthalmology
更新于2025-09-16 10:30:52
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[ACM Press the 2nd International Conference - Sydney, NSW, Australia (2018.10.06-2018.10.08)] Proceedings of the 2nd International Conference on Graphics and Signal Processing - ICGSP'18 - Development of Communication Aid Device for Disabled Persons Using Corneal Surface Reflection Image
摘要： Improving quality of life (QOL) has become an important issue for patients with neurological diseases such as ALS (amyotrophic lateral sclerosis) and SMA (spinal atrophy). At the same time, it is indispensable to secure a communication device that displays its own intention, and various interfaces have been proposed. In this research, we developed a glasses-type switching wearable device focusing on eyeball movement. Here, images around the eyeball were obtained by USB-camera equipped with infrared LEDs, and pupils were extracted by Hough transform procedure. Furthermore, in order to apply a communication aid operation, a detection model of the line-of-sight direction was constructed by acquiring the coordinates of the cornea surface reflection image.
关键词： Image processing,Infrared camera,Eye movement,Non-contact switch
更新于2025-09-16 10:30:52
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An Efficient Design of DCT Approximation Based on Quantum Dot Cellular Automata (QCA) Technology
摘要： Optimization for power is one of the most important design objectives in modern digital image processing applications. The DCT is considered to be one of the most essential techniques in image and video compression systems, and consequently a number of extensive works had been carried out by researchers on the power optimization. On the other hand, quantum-dot cellular automata (QCA) can present a novel opportunity for the design of highly parallel architectures and algorithms for improving the performance of image and video processing systems. Furthermore, it has considerable advantages in comparison with CMOS technology, such as extremely low power dissipation, high operating frequency, and a small size. Therefore, in this study, the authors propose a multiplier-less DCT architecture in QCA technology. The proposed design provides high circuit performance, very low power consumption, and very low dimension outperform to the existing conventional structures. The QCADesigner tool has been utilized for QCA circuit design and functional verification of all designs in this work. QCAPro, a very widespread power estimator tool, is applied to estimate the power dissipation of the proposed circuit. The suggested design has 53% improvement in terms of power over the conventional solution. The outcome of this work can clearly open up a new window of opportunity for low power image processing systems.
关键词： DCT,low power,QCA,quantum-dot cellular automata,image processing
更新于2025-09-16 10:30:52
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[IEEE 2019 11th International Conference on Knowledge and Systems Engineering (KSE) - Da Nang, Vietnam (2019.10.24-2019.10.26)] 2019 11th International Conference on Knowledge and Systems Engineering (KSE) - A Fast Denoising Algorithm for X-Ray Images with Variance Stabilizing Transform
摘要： We propose a fast denoising algorithm for X-Ray images with variance stabilizing transformations. The variance stabilizing transformations are used to transform Poisson noisy images to Gaussian noisy images. Therefore, we can utilize advantages of the fast denoising algorithm based on the alternative direction method of multipliers. In experiments, we evaluate denoising quality by the Peak signal-to-noise ratio and the Structure Similarity metrics. Comparing results show that our method outperforms other similar denoising methods.
关键词： ROF model,Variance Stabilizing Transformations,Image Denoising,Poisson Noise,Medical Image Processing
更新于2025-09-12 10:27:22
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Size measurement of Daphnia pulex using low-coherence Gabor digital holography
摘要： We measured the size of Daphnia pulex (D. pulex), which is an indicator organism used for examining toxicity, under freely-swimming and stress-free conditions, made possible by the post-focusing ability of digital holography (DH). This environmental measurement is a new application of DH. This implementation, which is a key point of this research, should be applicable to real on-site use in non-sterile and unstable mechanical situations. Through trial and error, we arrived at the simplest interferometer configuration using a single beam line that can withstand vibrations, a low-coherence light source for reducing coherent noise, and single-shot image capturing. Automatic size measurement based on DH with image processing was performed. The originality of this research is the quantitative size measurement and performance estimation achieved by comparing the results with those from conventional manual eye measurement using ordinary optical microscope observation and image processing software. The estimation also allowed us to determine the proper parameters in the image processing for DH measurement.
关键词： Digital holography,Size measurement,Daphnia pulex,Image processing,Low-coherence light
更新于2025-09-12 10:27:22
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Industrial Optical Character Recognition System in Printing Quality Control of Hot-Rolled Coils Identification
摘要： This work presents a system designed to detect printing errors and misidentifications on steel coils that could lead to tracking problems and even guide to the delivery of the wrong product to the final client. An optical character recognition system is proposed to extract the printed identification of steel coils from images captured by a fixed camera in an industrial environment. The method considers different digital image processing techniques to deal with the significant lighting and printing variation observed, followed by a segmentation process that extracts and aligns the characters originally printed in an arch form, ending with a classification routine based on a convolutional neural network. The proposed system presents an approach to treat lighting variations in images, covering low contrast, darker and brighter images. Experiment carried out on a data set with approximately 20,000 images achieved an accuracy higher than 98%, supporting the validity of the proposed method.
关键词： Digital image processing,Convolutional neural networks,Optical character recognition,Intelligent manufacturing
更新于2025-09-12 10:27:22
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Vision technique for deflection measurements based on laser positioning
摘要： This paper proposes a vision-based target-free deflection measurement method of bridge. This method eliminates the trouble of installing artificial targets on the structure. The proposed method utilizes multi-point laser projection as a reference point, which can eliminate the error caused by vibration at the camera position, and also avoids the difficulty of finding the background building as a reference point. The proposed method controls the measurement accuracy by adjusting the size of the captured video area. Through the method of camera scanning, large-scale multi-point deflection measurement is carried out under the premise of certain precision. The video laser spot reference point (LSRP) before loading is selected by the image segmentation algorithm. The Oriented features from accelerated cegment Test (FAST) and rotated binary robust independent elementary features (BRIEF) (ORB) feature detection and extraction algorithm is used to detect and extract key features in the region of interest (ROI) near the LSRP. The extracted key feature points calculate the displacement of each frame of the entire video by using the Lucas-Kanade Tracking (KLT) algorithm, which ensures the maximum number of matches of key points between consecutive images. The mismatched outliers are discarded by using the Random Sampling Consistency (RANSAC) algorithm. The accuracy of the proposed method was verified by an indoor and outdoor beam experiment. In the experiment, the results obtained by the proposed method are compared with the vertical displacement values of the corresponding positions acquired by the displacement meter obtained by the high-precision DH3816N dynamic strain test system to verify the validity and accuracy of the proposed method.
关键词： multi-point deflection measurement,laser spot reference point,image processing,vision-based,Bridge deflection,high precision,target-free
更新于2025-09-12 10:27:22
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Machine learning as a comparative tool to determine the relevance of signal features in laser welding
摘要： In laser welding, real-time process information is required for quality assurance and process control. The challenge on sensor technology and processing is determined by dynamic process behavior in the interaction zone. The dimensionality of spatial process information however can be used to determine different process conditions and quality faults. In this paper, a laser welding process is coaxially observed using a high-speed mid-infrared-camera in combination with near-infrared CMOS-camera. The signals are evaluated by extracting geometrical and statistical features. These features are subsequently used by machine learning techniques to predict quality-relevant process variables. The work identifies and compares the importance of the extracted features based on their prediction performance. This importance is used to reassess the sensors and underlying signal analyses in order to enhance the relevance of the acquired process information.
关键词： machine learning,quality diagnosis,image processing,feature importance,Laser welding
更新于2025-09-12 10:27:22
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Quality Inspection System for Robotic Laser Welding of Double-Curved Geometries
摘要： The quality of robotic laser welded parts is related to the joint location, the trajectory of the laser focal point and the process parameters. By performing in-process monitoring, it is possible to acquire sufficient process knowledge for post-inspection to evaluate the geometrical weld quality. The existing solutions for such systems operate along linear welds. This paper contributes with a quality inspection system for robot laser welding, that can handle double-curved geometries. The data acquisition system includes a CMOS camera, which is mounted such that it looks through the laser optics, external LED illumination and matching optical filters. During the process, the area around the moving laser focal point is captured, resulting in a sequence of images. The trajectory of the focal point is determined by estimating the 2D displacement field between each image using template matching and subsequently filtering the data through a Kalman filter to improve the accuracy and robustness of the system. The joint location is determined by applying a Canny edge detector and a standard Hough transform within a specified region of interest. As this paper deals with double-curved geometries, the region of interest is moved in relation to the laser trajectory, such that it always contains the visible part of the joint, that is closest to the focal point. The developed post-inspection system evaluates the quality of the weld by comparing the estimated trajectory relative to the determined location of the joint. The performance of the proposed quality inspection system was validated empirically on 18 samples. The tests showed promising results, as the system was able to accurately detect changes in the welding trajectory relative to the location of the joint with an accuracy of ± 0.2 mm.
关键词： Vision system,Image processing,Quality inspection,Laser welding,Welding trajectory
更新于2025-09-12 10:27:22
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Review on feature extraction for 3D incoherent image processing using optical scanning holography
摘要： The advancement of digital holography in the past 2 decades has enabled precise capturing of three-dimensional (3-D) images of physical objects. This important technology has been widely applied in numerous industrial sectors such as, but not limited to remote sensing, metrology, bio-medical imaging, advertising, and entertainment. Most of the hologram acquisition techniques developed to date are employing digital cameras for recording the hologram, hence imposing rigid restrictions on the size and resolution of the captured 3-D image. This limitation, however, is not found in optical scanning holography (OSH). Based on a scanning mechanism and a single pixel sensor, OSH is capable of capturing digital holograms of both macroscopic and microscopic, as well as fluorescent objects with high precision. Since its invention in the late 70s, numerous research works have been conducted to enhance this technology, optimizing important factors such as acquisition speed, precision, data size, and security. The objective of this review paper is to provide a walkthrough of the state-of-the-art of the OSH technology, from its original principle, to different variants that have been developed over the years with emphasis on their feature extraction capabilities under the incoherent mode of operation. Whenever possible, we shall provide the key formulations of each approach, and experimental outcomes for demonstrating the pros and cons of the method.
关键词： generalized two-pupil image processing system,spiral-phase pupil,anisotropic edge detection,feature extraction,annular pupil,Optical Scanning Holography (OSH)
更新于2025-09-12 10:27:22