Automatic Digital Image Processing Research Articles

Quantification of fibrosis extend and airspace availability in lung: A semi-automatic ImageJ/Fiji toolbox.

The evaluation of the structural integrity of mechanically dynamic organs such as lungs is critical for the diagnosis of numerous pathologies and the development of therapies. This task is classically performed by histology experts in a qualitative or semi-quantitative manner. Automatic digital image processing methods appeared in the last decades, and although immensely powerful, tools are highly specialized and lack the versatility required in various experimental designs. Here, a set of scripts for the image processing software ImageJ/Fiji to easily quantify fibrosis extend and alveolar airspace availability in Sirius Red or Masson's trichrome stained samples is presented. The toolbox consists in thirteen modules: sample detection, particles filtration (automatic and manual), border definition, air ducts identification, air ducts walls definition, parenchyma extraction, MT-staining specific pre-processing, fibrosis detection, fibrosis particles filtration, airspace detection, and visualizations (tissue only or tissue and airspace). While the process is largely automated, critical parameters are accessible to the user for increased adaptability. The modularity of the protocol allows for its adjustment to alternative experimental settings. Fibrosis and airspace can be combined as an evaluation of the structural integrity of the organ. All settings and intermediate states are saved to ensure reproducibility. These new analysis scripts allow for a rapid quantification of fibrosis and airspace in a large variety of experimental settings.

Monitoring Regional Urban Dynamics Using DMSP/OLS Nighttime Light Data in Zhejiang Province

Accurate monitoring of urban regions and urban sprawls is critical to the detection and assessment of regional development. The nighttime light images of Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS) provide us direct solutions to make spatial descriptions of urban regions. Unfortunately, accurate monitoring of urban regions is apt to be hampered due to the shortages of the DMSP/OLS data. In this study, we utilized a new urban region extraction strategy based on the edge-detection method which is widely applied in automatic digital image processing. The edges of urban areas in Zhejiang province were identified based on the distributions and values of pixels. Compared with other traditional methods, the urban regions extracted in this study present a higher overall accuracy and kappa coefficient (OA = 93.1409%; Kappa = 0.8755). Two periods of the urban dynamic process and urban sprawl pattern in Zhejiang from 1992–2013 were further detected by the proposed method. At city level, the drastic increase in urban areas was found in cities of Hangzhou and Ningbo. This study provides an objective and convenient solution to the accurate identification of urban regions, which is also an important step to better understand the urban dynamics and urban development.

A 3D printed smartphone optosensing platform for point-of-need food safety inspection

The deficiency in rapid and in-field detection methods and portable devices that are reliable, easy-to-use, and low cost, results in the difficulties to uphold the high safety standards in China. In this study, we introduce a rapid and cost-effective smartphone-based method for point-of-need food safety inspection, which employs aptamer-conjugated AuNPs as the colorimetric indicator, and a battery-powered optosensing accessory attached to the camera of a smartphone for transmission images capture. A user-friendly and easy-to-use Android application is developed for automatic digital image processing and result reporting. Streptomycin (STR) is selected as the proof-of-concept target, and its specific quantitation can be realized with a LOD of 12.3 nM (8.97 μg kg−1) using the reported smartphone-based method. The quantitation of STR in honey, milk and tap water confirm the reliability and applicability of the reported method. The extremely high acceptance of smartphone in remote and metropolitan areas of China and ease-of-use of the reported method facilitate active food contaminant and toxicant screening, thus making the implementation of the whole food supply chain monitoring and surveillance possible and hence significantly improving the current Chinese food safety control system.

An experimental study of bubble sliding characteristics in narrow channel

An experimental investigation was conducted to study bubble sliding in subcooled flow boiling of water in a vertical narrow rectangular channel. Bubble behaviors were recorded using a high speed digital camera and an automatic digital image processing algorithm dealing with bubble sliding parameters (including bubble numbers, bubble velocities and bubble equivalent diameters) was proposed. The bubble image sequences were analyzed to obtain the distribution of bubble diameters and bubble velocities as well as their mean spatial-temporal value. Most of the bubbles in the experiments slide along the heated surface, but not lift off the surface, as is usual in a conventional channel. Two types of bubbles with different behaviors were observed in the experiments. The first type has a shorter lifetime and their diameters or volumes change a lot through rapid vaporizing and condensing. On the contrary, bubbles which were classified as the second type have a longer lifetime and their diameters or volumes change slowly. Bubble sliding velocity and bubble equivalent diameter distribution profiles were obtained based on the results of the automated analysis. The distribution of bubble sliding velocities and bubble equivalent diameters indicates that both of them cover a wide range. At last, mean bubble velocities, mean relative velocities between bubbles and local liquids and bubble densities under different working conditions were obtained to manifest the effects of mass flow rate, inlet subcooling and heat flux.

Measurement of Vehicle Tire Footprint Pattern and Pressure Distribution Using Piezoresistive Force Sensor Mat and Image Analysis

In this paper, a novel method to measure the footprint pattern of a vehicle tire and its pressure distribution will be put forward. The measurement principle will be presented. The automatic digital image processing methods of the footprint pattern and pressure distribution images, which are used to characterize the footprint pattern, are described. Especially, a novel envelope curve calculation algorithm for finding a pattern boundary is introduced. The experimental results have shown that the methods mentioned in the paper are of robustness and high accuracy.

Measurement of the degraded depth in cementitious materials by automatic digital image processing

The combination of a staining method and an automatic digital image-processing algorithm is presented here, to measure degradation depths in cementitious materials. The measurement of those degraded depths is usually made by direct visual measurements, resulting in many errors and low reproducibility. The automatic digital image analysis (ADIA) method proposed here is mainly based on the differentiation of the degraded zone and the sound zone on the basis of the image histogram. The method comprises several steps, such as sample alignment, image calibration, background subtraction, image filtering, automatic segmentation and final measurement of the degraded depth. The algorithm developed has been used to measure the degraded depths of a set of decalcified cement mortars, made from different cement types and with varying w/b ratios. Relative to previous methods, this automatic procedure improves the precision (about 0.03 mm) and the statistical representation of the measurements. The results obtained by ADIA were compared with direct visual measurements with a very good correlation (R2 = 0.96) and a mean error of 6%.

Application of a histogram modification algorithm to the processing of raindrop images

Automatic processing of digital images of falling raindrops is complicated by a less than ideal grayscale image histogram. These his- tograms do not display a bimodal shape and lack an easily defined mini- mum, making it difficult to choose a threshold for creating a binary im- age. To help identify peaks in these histograms, and simplify threshold selection, a histogram modification technique originally developed by Peleg is used. This method was modified slightly and then applied to raindrop image processing. Its performance is quantified. © 2008 Society of

Deleted DOI: Film Thickness Analysis for EHL Contacts under Steady-State and Transient Conditions by Automatic Digital Image Processing

Deleted DOI: Film Thickness Analysis for EHL Contacts under Steady-State and Transient Conditions by Automatic Digital Image Processing

Film Thickness Analysis for EHL Contacts under Steady‐State and Transient Conditions by Automatic Digital Image Processing

The knowledge of the film thickness values is very important in lubricated contacts to verify the lubrication conditions. Optical interferometry is one of the most used methodologies for film thickness and shape determination of Elastohydrodynamic‐lubricated contacts. An image processing programme has been developed for the analysis of white light interferograms. The programme, based on the analysis of the hue channel, has been developed in order to process big amounts of images, as often generated under transient conditions. The measurement range is currently limited to a maximum film thickness of 0.7 μm. The programme has been used for analysing several images recorded in tests carried out with a ball on disc contact under steady‐state as well as transient conditions for different velocities and slide‐to‐roll ratios. Under transient conditions, the entraining velocity is varied with a sinusoidal law for two different frequencies. The results obtained evidenced an asymmetric reduction of the film thickness when increasing the percentage of sliding, both for stationary and transient conditions. Under transient conditions with increasing test frequency, film thickness loops of increasing amplitude have been found that reduce their amplitude more when the ball is running faster than the disc. Squeeze and thermal effects can explain the results obtained.

Longshore drift estimation using fluorescent tracers: New insights from an experiment at Comporta Beach, Portugal

A fluorescent sand-tracer experiment was performed at Comporta Beach (Portugal) with the aim of acquiring longshore sediment transport data on a reflective beach, the optimization of field and laboratory tracer procedures and the improvement of the conceptual model used to support tracer data interpretation. The field experiment was performed on a mesotidal reflective beach face in low energetic conditions (significant wave height between 0.4 and 0.5 m). Two different colour tracers (orange and blue) were injected at low tide and sampled in the two subsequent low tides using a high resolution 3D grid extending 450 m alongshore and 30 m cross-shore. Marked sand was detected using an automatic digital image processing system developed in the scope of the present experiment. Results for the two colour tracers show a remarkable coherence, with high recovery rates attesting data validity. Sand tracer displayed a high advection velocity, but with distinct vertical distribution patterns in the two tides: in the first tide there was a clear decrease in tracer advection velocity with depth while in the second tide, the tracer exhibited an almost uniform vertical velocity distribution. This differing behaviour suggests that, in the first tide, the tracer had not reached equilibrium within the transport system, pointing to a considerable time lag between injection and complete mixing. This issue has important implications for the interpretation of tracer data, indicating that short term tracer experiments tend to overestimate transport rates. In this work, therefore, longshore estimates were based on tracer results obtained during the second tide. The estimated total longshore transport rate at Comporta Beach was 2 × 10 − 3 m 3/s, more than four times larger than predicted using standard empirical longshore formulas. This discrepancy, which results from the unusually large active moving layer observed during the experiment, confirms the idea that most common longshore transport equations under-estimate total sediment transport in plunging/surging waves.

Retrieving Cloud Characteristics from Ground-Based Daytime Color All-Sky Images

Abstract A discussion is presented of daytime sky imaging and techniques that may be applied to the analysis of full-color sky images to infer cloud macrophysical properties. Descriptions of two different types of sky-imaging systems developed by the authors are presented, one of which has been developed into a commercially available instrument. Retrievals of fractional sky cover from automated processing methods are compared to human retrievals, both from direct observations and visual analyses of sky images. Although some uncertainty exists in fractional sky cover retrievals from sky images, this uncertainty is no greater than that attached to human observations for the commercially available sky-imager retrievals. Thus, the application of automatic digital image processing techniques on sky images is a useful method to complement, or even replace, traditional human observations of sky cover and, potentially, cloud type. Additionally, the possibilities for inferring other cloud parameters such as cloud brokenness and solar obstruction further enhance the usefulness of sky imagers.

Partition of Charpy fracture surface with digital image processing

The fracture surface of a Charpy specimen contains information that can enrich the outcome of the test which at present is only the total energy absorbed. An automatic digital image processing technique based on the Horowitz and Pavlidis (1976) split-and-merge algorithm is proposed for partitioning Charpy fracture surface into regions with clear physical and mechanical meaning. Initial ductile fracture region, brittle zone and post-cleavage ductile shear region can be identified based on their relative brightness. Various geometrical properties of each region can then be easily calculated. The technique has been tested on a group of 773 broken Charpy samples made of TMCR and ship steels. The percentage of crystallinity calculated with the proposed technique agrees reasonably well with that obtained with visual inspection. Finally the potential of the technique and the ambiguity of the partition criterion based on surface light reflectivity are discussed.

Simultaneous multiple site arteriolar vasomotion measurement using digital image analysis

An automatic digital image processing technique for simultaneous vasomotion analysis in peripheral microcirculation at multiple sites and in real time is presented. The algorithm utilizes either fluorescent or bright field micro-images of the vasculature as input. The video images are digitized and analyzed on-line by an IBM RT PC, using digital filtering and edge detection. The sampling frequency is higher than 5 Hz when only one site is tracked and decreases as the number of sites is incremented. Performance of the algorithm was tested for a hamster cutaneous microcirculation model.

Displacement and strain calculations by the phase shift method

The phase shift method, well known in holographic interferometry, is applied to the deformation of line gratings. The method uses the moire effect but it determines local displacement or strain from the grey values of three shifted images instead of the coordinates of the fringes. The basic equations are derived from the transmittance function. The theoretical error with respect to a given displacement field is calculated by simulation. Real errors are investigated by related plotter-generated line gratings. The phase shift method is especially suitable for automatic digital image processing.

Review of automatic image processing

This paper presents a review of automatic image processing and in the first section the main parts of an automatic digital image processing system (scanning, preprocessing, feature extraction, image interpretation) are shortly discussed. In the second section the characteristics of an optical processor, the operations which can be performed with such a processor and an evaluation of its performance are described. After this general introduction to automatic image processing, some of the main features (image enhancement, feature extraction, image segmentation) have been selected and will be discussed in detail in the third section. Finally the review is closed with an introduction to hardware structures of digital processors for image processing.