High Resolution Gray-scale Image Research Articles

Automated void detection in high resolution x-ray printed circuit boards (PCBs) images with deep segmentation neural network

Defect detection and quantification on printed circuit board (PCB) assemblies are crucial for ensuring the quality of electronic products. X-ray inspection is commonly used to detect internal defects, in which high-resolution gray-scale images are captured to reveal the internal structure, particularly the defect features, of an assembled PCB. To detect defect features, conventional computer vision techniques require hand-crafted feature filters and usually have a narrow application scope. This study introduces an automated method for detecting voids using supervised machine learning. The method employs end-to-end segmentation models to identify pixels that belong to the void and integrated circuit (IC) regions in X-ray PCB images. The segmentation results are then used to compute the percentage of voids within each IC, which is a key measure of the quality of the inspected PCB. Accurate predictions with an intersection over union of over 0.95 have achieved. A challenge in this development is the large size of the images, which can reach to millions of pixels, and the small scale of defect features. Training a deep segmentation model for large-scale images using conventional methods requires a lot of memory. Downscaling high-resolution images result in the loss of defect features. In this study, a unique training method utilizing the local nature of the defects is proposed, which reduces memory consumption and speeds up the training process. Additionally, to overcome the limited training data, various augmentation methods are applied and transfer learning is employed to construct segmentation models for different types of PCBs.

Ptychographic intensity interferometry imaging under low dynamic ranges

Typically, high gray-scale imaging requires a high dynamic range camera. High dynamic range is even more crucial to conventional lensless imaging methods such as coherent diffraction imaging, since the dynamic range highly determines the resolution of recovered images. We here propose that ptychographic intensity interferometry imaging (PIII) can detect a complicated-structure object under 1-bit dynamic range (each pixel outputs zero or one only), and reconstruct a high resolution gray-scale image. PIII ptychographically illuminates an object with random speckle light, generating a speckle-like intensity pattern on a detection plane. The second-order correlation of the speckle pattens reveals the power spectrum of the object. Although the depth information of the speckle patterns will be lost because of low dynamic range detections, a small number of multiple detections with different illuminating fields can effectively recover a high dynamic range power spectrum, resulting in a high resolution gray-scale image. A theoretical analysis and comprehensive simulations for the “cameraman” photo are given in this work, which shows that the image under 1-bit dynamic range deteriorates no more than 0.4 dB (peak-signal-to-noise ratio) in comparison to the 16-bit dynamic range one. This method reduces the cost and complexity of implementing a lensless imaging.

Sonographic and Duplex Evaluation of Synovial activity in Wrist and Hand Joints in Rheumatoid Arthritis

Abstract Background Rheumatoid arthritis is a long-term autoimmune disease and inflammatory disorder. The damaging effect on cartilage, bone, ligaments, and tendons has raised the importance of the accurate diagnosis of structural damage, disease activity and severity assessment to enable therapeutic decisions and to evaluate disease outcome. US is non invasive, relatively cheap and widely accessible imaging tool that facilitates the detection of synovitis joint effusin and erosions more better than clinical, laboratory investigations alone and x-ray. Aim of the Work assess the role of of gray-scale and Doppler ultrasound early detection and characterization of synovitis and structural bone changes in wrist and hand joints in patients with Rheumatoid Arthritis by comparing qualitative and quantitative US parameters with clinical and laboratory indicators of disease activity. Patients and Methods A cross sectional study conducted onthirty five adult patients with RA . All the patients were diagnosed according to the 2010 ACR/European League . The patients were recruited from the Rheumatology and Rehabilitation Outpatient Clinic, Faculty of Medicine, Ain Shams Hospitals .The study was approved by the ethical committee, and consents were taken from all patients enrolled in the study. Patients assessed by history taking, Clinical examination, Laboratory investigations and US gray scale and US power Doppler was done for each patient. Results This study included 35 patients with established RA, 27 females (77.1%) and 8 males (22.9%). Ranged in age between 20-70 years with mean age [45.66±12.76],the mean CDAS28 was [4.62±1.37], ESR [44.93±20.79], CRP [15.92±9.03], 33 patients (94.3%) were found to have synovial thickening, 14 patient (40%) were found to have increased vascularity by PD, joint effusion was detected in 12 patient (34.3%) particularly in MCP joints, 13 (37.1%) had bone erosion and only 9 patients (25.7%) had Tenosynovitis, most of them were detected at the extensor compartment of the wrist joint.positive correlations found between the clinical disease activity indices, laboratory investigations, duration of illness and components of the US findings. Conclusion Ultrasound is non invasive, relatively cheap and widely accessible imaging tool that facilitates the detection of synovitis and erosions,, high resolution gray scale images combined with Doppler technique have made it possible to detect slow low volume blood flow, thus improving the outcome of the standard clinical assessment in Rheumatoid synovial inflammation.

Cross-nanofin-based waveplate pixels for broadband hybrid polarization coding in near-field

Abstract As an inherent characteristic of light, polarization plays important roles in information storage, display and even encryption. Metasurfaces, composed of specifically designed subwavelength units in a two-dimensional plane, offer a great convenience for polarization manipulation, yet improving their integrability and broadband fidelity remain significant challenges. Here, based on the combination of various subwavelength cross-nanofins (CNs), a new type of metasurface for multichannel hybrid polarization distribution in near-field is proposed. Sub-wavelength CN units with various waveplate (WP) functionalities, such as frequency-division multiplexing WP, half-WP and quarter-WP are implemented with high efficiency in broadband. High-resolution grayscale image encryption, multi-image storage and rapid polarization detection are demonstrated by encoding the WP pixels into single, double and four channels, respectively. All these applications possess good fidelity in an ultrabroad wavelength band from 1.2 to 1.9 µm, and the high degree of integrability, easy fabrication and multifunction make the CN-shaped WP pixels a promising candidate in optical device miniaturization, quantum applications and imaging technologies.

Morphological and mechanical properties of bone tissues

Introduction: Adult human skeletal system consists of 206 bones and this system gives the human body its shape, supports it, and helps in movements. These bones are made of living bones tissues which replenish throughout the lifetime of an individual. There are different bone diseases associated to these bone tissues like osteoporosis, low bone density, osteogenesis imperfecta, and Paget’s disease of bones which happen when these bone tissues synthesis is not normal, and can cause fracture. The most common bone disease is osteoporosis which causes bones to become less dense and more fragile. It affects the entire skeletal system and causes fracture in hips, wrists, ankles, and spine commonly.Methodology: CT ScanningThree calcaneus bone samples were scanned using micro CT (SkyScan 1172, Aarteslaar, Belgium) at the voxel size of 17.41 µm, rotating at increments of 0.7˚ for 180˚, and the data was stored in numbered 16bit high resolution grayscale images. Results: The analysis of bone properties has not been limited to mechanical testing only. With the development of computer tomography techniques and finite element modelling software, the researchers have started using simulations to study bone morphology and properties. The previous studies indicate that not much has been done to study the fracture mechanism of calcaneal trabeculae. So, this study was designed to conduct compression test on sections of calcaneal trabeculae and compare it with the available results.Conclusion: The study focuses on the mechanical properties of trabecular bone incompression. The main purpose of the study is investigating the factors which could influence the mechanical properties of the trabecular bone.Summary: The human skeletal system suffers from number of diseases like osteoporosis, osteoarthritis, and Paget’s disease which impair its function and cause discomfort and fracture to patients. The study of bone properties have helped in treating a variety of bone diseases. This study involved non-destructive finite element analysis of calcaneal trabecular bone specimens under compressive loading. Three calcaneal trabecular bone specimens were scanned using micro CT and 3D models were reconstructed using the image data. The reconstructed models were assigned material heterogeneous properties based on grayscale values from the images. These models were converted to FE models with a variety of mesh coarseness and analysed, and the best models were used for further finite element analysis. The results were compared with previous studies and matched subject to certain errors. It was concluded that mesh parameters affect the quality of finite element simulation and the heterogeneous bone material properties caused non-uniform deformation in the trabeculae structure.

Nonlinear Vectorial Metasurface for Optical Encryption

In the manipulation of the propagation of light, nonlinear optical metasurfaces have enabled a plethora of applications. A key issue in this area is how to arbitrarily control the vectorial polarization profile of nonlinear optical waves. This study demonstrates an ultrathin nonlinear photonic metasurface that can generate a vectorial polarization profile of the second-harmonic-generation beam, and therefore encodes a high-resolution grayscale image. This rich polarization information has significant potential for nonlinear optical image encryption and other security applications, such as anticounterfeiting.

Image restoration and color fusion of digital microscopes.

Traditional microscopes do not meet a wide field of view and high resolution at the same time. We propose a method for image restoration and color fusion of digital microscopes. It combines a single high-resolution gray scale hologram with a low-resolution color image to obtain a high-resolution color image. Specifically, the high-resolution gray scale image is obtained by reconstructing three different height holograms using a wavelet-based method, and the color information is obtained using a portable cell phone microscope. The subsequent calibration and blending of colors ultimately results in a high-resolution, wide-field color map that can be of great help in the study of pathology or biomedicine. This method breaks the rule that the large field of view and high resolution of a traditional microscope cannot be simultaneously satisfied, which can realize a more comprehensive observation of the shape and details of the slice.

High-resolution grayscale image hidden in a laser beam

Images perceived by human eyes or recorded by cameras are usually optical patterns with spatially varying intensity or color profiles. In addition to the intensity and color, the information of an image can be encoded in a spatially varying distribution of phase or polarization state. Interestingly, such images might not be able to be directly viewed by human eyes or cameras because they may exhibit highly uniform intensity profiles. Here, we propose and experimentally demonstrate an approach to hide a high-resolution grayscale image in a square laser beam with a size of less than half a millimeter. An image with a pixel size of 300 × 300 nm is encoded into the spatially variant polarization states of the laser beam, which can be revealed after passing through a linear polarizer. This unique technology for hiding grayscale images and polarization manipulation provides new opportunities for various applications, including encryption, imaging, optical communications, quantum science and fundamental physics.

Grayscale image recording on Ge2Sb2Te5 thin films through laser-induced structural evolution

Chalcogenide Ge2Sb2Te5 thin films have been widely exploited as binary bit recording materials in optical and non-volatile electronic information storage, where the crystalline and amorphous states are marked as the information bits “0” and “1”, respectively. In this work, we demonstrate the use of Ge2Sb2Te5 thin films as multi-level grayscale image recording materials. High-resolution grayscale images are recorded on Ge2Sb2Te5 thin films through taking advantage of laser-induced structural evolution characteristic. Experimental results indicate that the change of laser energy results in the structural evolution of Ge2Sb2Te5 thin films. The structural evolution induces the difference of electronic polarizability and reflectivity, and high-resolution grayscale images are recorded on Ge2Sb2Te5 thin films through direct laser writing method, accordingly.

Grayscale transparent metasurface holograms

We demonstrate transparent metaholograms based on silicon metasurfaces that allow high-resolution grayscale images to be encoded. The holograms feature the highest diffraction and transmission efficiencies, and operate over a broad spectral range.

Performance Evaluation of Color Models in the Fusion of Functional and Anatomical Images.

Fusion of the functional image with an anatomical image provides additional diagnostic information. It is widely used in diagnosis, treatment planning, and follow-up of oncology. Functional image is a low-resolution pseudo color image representing the uptake of radioactive tracer that gives the important metabolic information. Whereas, anatomical image is a high-resolution gray scale image that gives structural details. Fused image should consist of all the anatomical details without any changes in the functional content. This is achieved through fusion in de-correlated color model and the choice of color model has greater impact on the fusion outcome. In the present work, suitability of different color models for functional and anatomical image fusion is studied. After converting the functional image into de-correlated color model, the achromatic component of functional image is fused with an anatomical image by using proposed nonsubsampled shearlet transform (NSST) based image fusion algorithm to get new achromatic component with all the anatomical details. This new achromatic and original chromatic channels of functional image are converted to RGB format to get fused functional and anatomical image. Fusion is performed in different color models. Different cases of SPECT-MRI images are used for this color model study. Based on visual and quantitative analysis of fused images, the best color model for the stated purpose is determined.

Main Road Extraction from ZY-3 Grayscale Imagery Based on Directional Mathematical Morphology and VGI Prior Knowledge in Urban Areas.

Main road features extracted from remotely sensed imagery play an important role in many civilian and military applications, such as updating Geographic Information System (GIS) databases, urban structure analysis, spatial data matching and road navigation. Current methods for road feature extraction from high-resolution imagery are typically based on threshold value segmentation. It is difficult however, to completely separate road features from the background. We present a new method for extracting main roads from high-resolution grayscale imagery based on directional mathematical morphology and prior knowledge obtained from the Volunteered Geographic Information found in the OpenStreetMap. The two salient steps in this strategy are: (1) using directional mathematical morphology to enhance the contrast between roads and non-roads; (2) using OpenStreetMap roads as prior knowledge to segment the remotely sensed imagery. Experiments were conducted on two ZiYuan-3 images and one QuickBird high-resolution grayscale image to compare our proposed method to other commonly used techniques for road feature extraction. The results demonstrated the validity and better performance of the proposed method for urban main road feature extraction.

The treatment of tendon injury with electromagnetic fields evidenced by advanced ultrasound image processing

This article presents a novel modality for accelerating the repair of tendon and ligament lesions by means of a specifically designed electromagnetic field in an equine model. This novel therapeutic approach employs a delivery system that induces a specific electrical signal from an external magnetic field derived from Superconductive QUantum Interference Device (SQUID) measurements of injured vs. healthy tissue. Evaluation of this therapy technique is enabled by a proposed new technology described as Predictive Analytical Imagery (PAI™). This technique examines an ultrasound grayscale image and seeks to evaluate it by means of look-ahead predictive algorithms and digital signal processing. The net result is a significant reduction in background noise and the production of a high-resolution grayscale or digital image.

Application of Multi-Class AdaBoost Algorithm to Terrain Classification of Satellite Images

Terrain classification is still a challenging issue in image processing, especially with high resolution satellite images. The well-known obstacles include low accuracy in the detection of targets, especially for the case of man-made structures, such as buildings and roads. In this paper, we present an efficient approach to classify and detect building footprints, foliage, grass and road from high resolution grayscale satellite images. Our contribution is to build a strong classifier using AdaBoost based on a combination of co-occurrence and Haar-like features. We expect that the inclusion of Harr-like feature improves the classification performance of the man-made structures, since Haar-like feature is extracted from corner features and rectangle features. Also, the AdaBoost algorithm selects only critical features and generates an extremely efficient classifier. Experimental result indicates that the classification accuracy of AdaBoost classifier is much higher than that of the conventional classifier using back propagation algorithm. Also, the inclusion of Harr-like feature significantly improves the classification accuracy. The accuracy of the proposed method is 98.4% for the target detection and 92.8% for the classification on high resolution satellite images.

A Variational Approach for Sharpening High Dimensional Images

Earth-observing satellites usually not only take ordinary red-green-blue images but also provide several images including the near-infrared and infrared spectrum. These images are called multispectral, for about four to seven different bands, or hyperspectral, for higher dimensional images of up to 210 bands. The drawback of the additional spectral information is that each spectral band has rather low spatial resolution. In this paper we propose a new variational method for sharpening high dimensional spectral images with the help of a high resolution gray-scale image while preserving the spectral characteristics used for classification and identification tasks. We describe the application of split Bregman minimization to our energy, prove convergence speed, and compare the split Bregman method to a descent method based on the ideas of alternating directions minimization. Finally, we show results on Quickbird multispectral as well as on AVIRIS hyperspectral data.

Defect analysis for patterned media

Imprint lithography has been shown to be an effective technique for the replication of nanoscale features. Acceptance of imprint lithography for manufacturing will require a demonstration of defect levels commensurate with cost-effective device production. This article summarizes the results of defect inspections of hard disks patterned using jet and flash imprint lithography (J-FIL™). This work presents a methodology for automated pattern inspection and defect classification for imprint-patterned media. Candela CS20 and 6120 tools from KLA-Tencor map the optical properties of the disk surface, producing high-resolution grayscale images of surface reflectivity and scattered light. Defects that have been identified in this manner are further characterized according to the morphology. The imprint process was tested after optimizing both the disk cleaning and adhesion layer processes that precede imprinting. Two extended imprint runs were performed and both the defect types and trends are reported.

Interacting and merging galaxies from the second Byurakan survey

We present new results from HI observations of 53 previously undetected interacting and merging galaxies from the Second Byurakan Survey (SBS), in which 30 systems have been detected (detection rate 56%). High-resolution gray-scale optical images and isophotal maps of the HI detected galaxy systems are presented, in addition to comments on these systems. The possibility of confusion arising from known objects within the telescope beam is discussed for each case. For nine unconfused mergers, global HI parameters are determined. These objects are found to be HI-rich and have normal values of (total) mass-to-luminosity ratios. At least 18 objects in the present sample are found to have radio continuum counterparts above the milli-Jansky level near 1 GHz. Throughout this paper we use a value of H 0 = 72 km s -1 Mpc -1 for the Hubble constant.

Personal recognition based on an image of the palmar surface of the hand

This paper describes the design and development of a multimodal biometric personal recognition system based on features extracted from a set of 14 geometrical parameters of the hand, the palmprint, four digitprints, and four fingerprints. The features are extracted from a single high-resolution gray-scale image of the palmar surface of the hand using the linear discriminant analysis (LDA) appearance-based feature-extraction approach. The information contained in the extracted features is combined at the matching-score level. The resolutions of the palmprint, digitprint and fingerprint sub-images, the similarity/dissimilarity measures, the matching-score normalization technique, and the fusion rule at the matching-score level, which optimize the system performance, were determined experimentally. The biometric system, when using a system configuration with optimum parameters, showed an average equal error rate (EER) of 0.0005%, which makes it sufficiently accurate for use in high-security biometric systems.

Two-Dimensional Direction-Based Interpolation with Local Centered Moments

Interpolation is generally needed to visualize medical images from a limited number of sliced tomographic images such as CT. In this paper, a novel gray-scale image interpolation method, for interpolating two-dimensional images accurately and efficiently, called direction-based interpolation, is investigated. In this method, the digital image is considered a sampling of the underlying continuous function, which is also called the image field. If the image is interpolated along the isovalue curves in the image field, instead of along the coordinate axes, both the edges and the internal structures of the objects in the image are well preserved. Initially, the isovalue direction at each point is calculated from the local centered moments of the image. A specific type of image, called the direction image, is composed from the isovalue directions. Then, the direction image is interpolated into a high-resolution direction image. The isovalue curve through any point in the image field is determined from the high-resolution direction image using a path-finding technique. A high-resolution gray-scale image with satisfactory object structure is then generated by interpolating the original image linearly along the isovalue curves. Experiments on a set of CT images show that this method not only preserves the shapes of complicated structures but also has an efficient computation. The comparison between the digitally reconstructed radiographs generated from the interpolated result using the direction-based interpolation method, the traditional linear interpolation method, and the traditional cubic spline interpolation method shows the promise of the proposed method in radiation treatment planning.

Visual And Tactile Sensing System For Robotic Acquisition Of Jumbled Parts

A flexible, adaptive, and programmable sensory control system for robotic acquisition of jumbled parts is described. The system consists of inde-pendent modules for vision and gripper control that guide a robot to acquire unoriented parts from a bin. The acquired parts are transported to a fixture and placed according to a desired alignment. The parts in the bin have either elongated or spherical symmetry, and all these parts are identical except for minor dimensional and textural variations. These objects may be colored or contain graphics, possess variable cross sections across their length, and have mixed material content and reflectivities. The system operates by taking a high resolution gray-scale image of the bin of parts using an overhead camera under ambient illumination. The overlapping parts in the image are separated by selectively removing the high spatial frequencies at the touching or occluding edges. These portions of the image are removed by dynamic range expansion, histogram-based adaptive image enhancement, and nonlinear homomorphic filtering. Algorithms are developed for fast and iterative data compression and segmentation and for estimation of the location and orientation of a cluster, irrespective of its shape. The photobeam, collision, and pressure sensors on the parallel jaw gripper are monitored during the process of parts acquisition and transport of experimental workpieces such as fuel filters, curved plier blanks, multicolored felt pens, L-shaped fuel links, ball bearings, and a mixture of shiny, semirusted, threaded, and unthreaded bolts of various lengths. In one image-processing cycle of 2 s or less, this system can compute locations and orientations of three objects at a successful acquisition rate of approximately 95%.