Digital Image Enhancement Techniques Research Articles

Lineament mapping of structural-trend analysis over the Niger-Benue River-confluence and its environs, a case study of North-Central Nigeria

Evaluation, analysis and interpretation of aeromagnetic and satellite imagery data acquired over the Nigeria confluence and environs; Northcentral Nigeria were carried out in order to characterise the structural framework of the study area. Fourier domain of digital filtering tools and reduction to magnetic equator (RTE) operations were achieved to enhance the available data’s results. The geomagnetic field of the earth was removed from the aeromagnetic data using the IGRF- 12 model. Results from the 2D radially average power spectrum of the enhanced magnetic data estimate the depth of the magnetic sources as 20m. Several digital image enhancement techniques such as edge enhancement and general contrast stretching were applied to the satellite imagery after which the lineaments extracted from the magnetic data and images were mapped out on-screen using ArcMap 10.8. The RTE map showed a high magnetic intensity values ranging from 33051. 93 nT to 33165.3 nT and trend approximately E -W direction at the eastern and northwestern parts. The digital elevation model (DEM) of the confluence and environs was used to enhance geomorphic features. The structural lineaments orientation obtained from the analysis showed that the primary structural lineaments bearing is NE – SW, ENE -WSW and NNW – SSE and the structural directions derived from the 2D maps are aligned along NE – SW and NW – SE. This conforms to the general trend of structures produced by the Pan African events.

Evaluating possible prehistoric cave art in the central Mediterranean: Analyses of pigment traces and identification of taphonomic processes at Għar Ħasan, Malta

The archaeology of the Maltese Islands, particularly the megalithic ‘temple’ structures and underground mass burial sites (hypogea) of the ‘Temple Period’ (ca. 3800 – 2300 BCE), has been the subject of considerable interest. Less is known about the prehistoric use of caves. In particular reports of prehistoric cave art at Għar Ħasan (Hasan’s Cave) have remained controversial, and have been argued to reflect an otherwise unknown pre-Neolithic occupation on the islands.Here, we report a reinvestigation of Għar Ħasan. To distinguish graffiti that have accumulated over the last century and possible older rock art, a range of non-invasive methods were used to determine the chemical properties and colour spectrum of the pigment traces: portable energy-dispersive X-ray fluorescence spectrometry (p-ED-XRF) and visible (VIS) and near-infrared (NIR) spectroscopy. In addition, pigment traces were analyzed with digital microscopy and image enhancement techniques (DStretch).Most of the previously reported cave paintings were shown to have been produced in the last century. One key panel may be older, but vandalism and other destructive processes make a definitive assessment challenging. While we therefore consider the evidence for ‘Palaeolithic’ cave art at Għar Ħasan to be inconclusive, our study also identified complex taphonomic processes that pose severe limitations on the identification of pigment via p-ED-XRF and spectroscopy and can inform and guide future initiatives for rock art conservation.

Efficient method for real-time range enhancement of electro-optical imaging system

Electro-optical (EO) imaging sensors are employed for object detection, recognition, identification, and tracking. The observation range of EO systems is defined as the maximum distance at which a target of interest can be seen and perceived. The performance of these systems deteriorates under degraded weather conditions, which severely affects the image quality and thus the observation range of EO surveillance systems. An improved image quality results in an enhanced observation range. Image quality can be improved by applying suitable digital image enhancement techniques by considering target/background signature knowledge. Under bad weather conditions, these digital techniques become ineffective due to the presence of scattered background signals. To reduce the effect of scattering, optical methods are also used to mitigate degradation caused by the atmosphere. It is observed that the optical method alone cannot produce the desired result. Observation range enhancement in surveillance system is achieved using the proposed hybrid method, which utilizes the optimal combination of optical and digital techniques in real-time. The proposed method not only improves human visual perception but also reveals more image content for better image analysis. The performance of the proposed range enhancement technique is compared with the predicted observation range model. The processed images using the hybrid method show more than 30% observation range enhancement under bad weather conditions. In addition to the subjective evaluation, qualitative and quantitative evaluations of image quality achieved through the proposed method are also presented. It is observed that the proposed hybrid method significantly improves the observation range and image quality of EO sensors under degraded weather in real time.

RETRACTED ARTICLE: A brain tumor image segmentation technique in image processing using ICA-LDA algorithm with ARHE model

In digital image processing, image segmentation is the key methodology which is to be used frequently. In digital image processing, noise reduction and enhancement techniques are plays as a vital role. Brain is major and major organ of the human body which is to be controlled by the nervous system. In this paper, we proposed a brain tumor image enhancement technique with the help of the ICA-LDA (independent component analysis-linear discriminate analysis algorithm with ARHE (adaptive region based histogram enhancement) model. Image fusion technique is to apply for combination of the two or more input image. In this paper, the weighted average technique is to be used for image fusion techniques. The noise reduction and enhancement techniques are to be applied in preprocessing stage. The adaptive median filter is to be used for preprocessing stage. The ARHE (adaptive region based histogram enhancement) model is to be used for enhancement present in the preprocessing stage. The feature extraction and the feature optimization have to be utilized with the ICA (independent component analysis). The LDA (linear discriminate analysis) is to be used for the classification techniques. Using this classifier which is to separate the abnormal and normal stages. When the brain tumor is denoted as abnormal case then the morphological based segmentation is to be done. The simulation and result shows the analysis of various parameters such as specificity, sensitivity, positive predictive value, negative predictive value, accuracy, precision, and recall.

Design and simulate different digital image enhancement techniques for biomedical applications using VIVADO system generator

In the proposed work, different techniques of the image processing in spatial domain in the field of biomedical applications has been presented. The proposed techniques are image inverting, image brightness addition, image brightness subtraction, threshold operation and contrast stretching technique. Here, the main purpose is to achieve better appearance and visuality with higher execution speed when implemented on real time hardware. The proposed system is developed and simulated using Xilinx System Generator with fewest possible blocks. Simulation results under FPGA Zynq 7000 series ZedBoard have been presented to validate the proposed techniques.

DRAINAGE BASIN MORPHOLOGY AND TERRAIN ANALYSIS OF THE LOWER BENUE RIVER BASIN, NIGERIA

The Lower Benue Trough is part of the Benue Trough of Nigeria and it consists of a series of rift basins which form a part of the Central West African Rift System of the Niger, Chad, Cameroon and Sudan Basement fragmentations. This research attempts to evaluate the geomorphological changes on the drainage basin interpreted using several techniques including the use of Remote Sensing and GIS. Several digital image enhancement techniques such as general contrast stretching and edge enhancement were applied to the Landsat image in ARCGIS, after which structures were mapped out on-screen using ArcGIS. The Digital Elevation Model (DEM) of the Trough was also generated from Shuttle RADAR Topographic Mission and used to enhance geomorphic features. The analysis carried out on the images revealed that the slope tool calculates the maximum rate of changes between each cell and its neighbors. The drainage density calculated shows that the drainage area = 86282.1km 2 , while the drainage density is 0.39872 km/km -2 . The result from the modeling concludes by revealing four sub-basins in the Lower Benue Trough with maximum thickness of 7-10km. Keywords: Benue, Remote Sensing, GIS, Geomorphology, River Basin

Interactive relighting, digital image enhancement and inclusive diagrammatic representations for the analysis of rock art superimposition: The main Pleito cave (CA, USA)

This paper deals with the documentation, and virtual visual analysis of pictographs using interactive relighting, digital image enhancement techniques and diagrammatic representations. It discusses areas of interest for the analysis of low surface detail, large and geometrically complex superimposed pictographs. The synergy of reflectance transformation imaging (RTI) and decorrelation stretch (DS) aimed to improve the study of superimposition via the enhanced visualization of the surface morphology, dominant features, paint characteristics and layering. Additionally, diagrammatic representations of the results of the image-based analysis provided a valuable tool for interpretation and integration of the diverse dataset from the ongoing research in the Pleito Cave in California. This method allows revisiting unresolved hypotheses concerning the site by unpacking chemical and visual data in superimposed sequences.

Investigation of ignition process from visible to infrared by a high speed colour camera

From the image processing of high speed colour images of flame ignition, areas of dominant infrared emission have been noticed, which has stimulated the more in depth investigation in this paper. Two test cases for propane and methane with co-flow air were carried out. By applying selective digital image enhancement technique, the weak chemiluminescence-induced visible flame and infrared signals are simultaneously resolved together with the much stronger visible soot radiation. It is found that the pockets of soot only emitting infrared signal exists in both propane and methane ignition process cases. In the ignition process, the chemiluminescence-induced blue flame is observed first, which is followed by soot only having infrared emission. The visible orange coloured sooty flame only appears afterwards. The soot only emitting infrared is found in between the blue flame and the visible sooty flame. The co-flow air is found to accelerate the ignition process and it also brings forward soot formation. The investigation demonstrates that a proper image enhancement technique is essential in the further understanding of combustion process taking place when using a high speed camera.

Image Enhancement of Underwater Digital Images by Utilizing L*A*B* Color Space on Gradient and CLAHE based Smoothing

The underwater digital images generally suffer from blur, low contrast, non-uniform lighting, and diminished color. This research paper proposed a preprocessing technique based on image to improve the quality of underwater digital images. The mixed Contrast Limited Adaptive Histogram Equilization (CLAHE) has actually neglected the utilization of L*A*B color image space to improve the image in an effective way. Also the uneven illumination problem is also ignored by many researchers. To conquer the problems of on hand technique a brand new L*A*B color image space as well as CLAHE based digital image enhancement technique is proposed in this paper. To conquer the problem of uneven illumination in the resultant image of the CLAHE image output has been further removed by utilizing the smoothing process of image gradient. The main objective of the planned algorithm is to enhance the accuracy of the underwater digital image enhancement methods/techniques. Various types of digital images will be considered for experimental point of view to estimate the efficacy of the image enhancement methods or techniques. Also, various types of image top-quality metrics have been utilized in order to check the significant improvement of the recommended technique over the offered techniques. The significant improvements have shown in the comparative analysis of the proposed algorithm over the available mixed CLAHE.

Structural study of Wamba and Environs, north-central Nigeria using aeromagnetic data and NigeriaSat-X image

Wamba 1:100,000 sheet 210 covers Wamba and Nassarawa Eggon area of North-Central Nigeria and consists of basement rocks, biotite granites and Older Granites in most parts of the northern part and by sedimentary rocks of the Cretaceous Middle Benue Trough in the southern part. High resolution aeromagnetic data was interpreted and the results integrated in a GIS environment with data from NigeriaSat-X image to map out the major structural trends within the area.Reduction-to-the-equator (RTE) operation was carried out on the aeromagnetic data after which several data transforms/derivatives such as horizontal derivative, analytical signal, and tilt derivative were calculated to highlight subsurface boundaries and the major structures within the area. Several digital image enhancement techniques such as general contrast stretching and edge enhancement were applied to the NigeraSat-X image in ERDAS IMAGINE 9.2 after which structures from the interpreted magnetic data and the image were mapped out on-screen using ArcMap 10.The results show that the RTE produced a reasonable geological picture of the area. Also the basement configuration consists of several NE–SW and NW–SE structures that range from 1 km to about 17 km in length with the NE–SW structures being the major trend within the area. The lineaments are mainly within the basement and the Older granites and may be related to the Pan-African Orogeny. This study was also able to map out more accurately the contact between the basement and the sediments hence a modified geological map of the area was produced.

Image Enhancement using Hardware co-simulation for Biomedical Applications

Digital image enhancement techniques are to improving the visual quality of images. Main objective of image enhancement is to process an image so that result is more suitable than original image for specific application. Image is one of the most fundamental and significant features. The correctness and reliability of its results affect directly the comprehension machine system made for objective world. The implementation of image enhancement algorithms on a field programmable gate array (FPGA) is having advantage of using large memory and embedded multipliers. FPGAs are providing a platform for processing real time algorithms on application-specific hardware with substantially higher performance than programmable digital signal processors (DSPs). This project focus on implementation issues of image enhancement algorithms like brightness control, contrast stretching, negative transformation, thresholding, filtering techniques on FPGA that have become a competitive alternative for high performance digital signal processing applications. This project will use System Generator tool and modular construction methods to build a image algorithm platform in MATLAB. By a brief analysis about display image and resource cons umption after achieving on Spartan-3E development board, we can see the image using System Generator for FPGA algorithm design superiority, have the vast application prospects

Lineament Extraction from SPOT 5 and NigeriaSat-X Imagery of the Upper Benue Trough, Nigeria

Abstract. The Upper Benue Trough is part of the Benue Trough of Nigeria and is comprised of three basins: the east–west trending Yola Basin (Yola Arm), the north–south trending Gongola Basin (Gongola Arm) and the northeast–southwest trending Lau Basin (Main Arm). This research is an ongoing research at understanding the structural framework of the Upper Benue Trough using several techniques including the use of Remote Sensing and GIS. Several digital image enhancement techniques such as general contrast stretching and edge enhancement were applied to the NigeriaSat-X and SPOT 5 image in ERDAS IMAGINE 9.2 after which structures were mapped out on-screen using ArcMap 10. The Digital Elevation Model (DEM) of the Trough was also used to enhance geomorphic features. The analysis carried out on the images revealed that lineaments are abundant in the Upper Benue Trough and they can be subdivided into four major trends, NE–SW, NW–SE, W–E and N–S in order of abundance and range in length from about 300 m to 26 km. Several faults were also mapped out within the Basin such as a sinistral fault around Bakoreji village in Bauchi, a dextral fault close to Kalmai town in Gombe and a dextral fault close to Wong in Taraba. It was discovered that some of the sites where minerals such as lead and zinc ores are being mined occur in the zones of high lineament density. This study shows the capability of the DEM, SPOT 5 and NigeriaSat-X images for lineament/structural interpretations.

Contrast echocardiography--limits and possibilities in cardiologic diagnosis

After injection of biocompatible fluids, contrast echocardiograms are obtained by ultrasound reflection from microbubbles in the streaming blood, which is thus opacified analogous to angiocardiography. As the microbubbles cannot pass the pulmonary capillaries, left heart contrasts are usually not seen after peripheral venous injection. Especially intracardiac shunts and valvular deficiencies may be recognized by this technique, which became an important diagnostic tool in the diagnosis of congenital heart disease and in critically ill patients. The blurred border between the opacified cavity and the myocardium may be abolished by digital image enhancement techniques, applied to contrast echocardiograms, thus making these pictures more suitable for volume determination and ventricular function analysis than non-contrast echocardiograms. Newer contrast agents such as mini-microbubbles are able to pass the pulmonary vascular bed after venous injection. Furthermore, myocardial perfusion studies are being conducted in animals by opacification of the myocardium with echo contrast agents in order to detect ischaemic areas.

Superresolution Digital Image Enhancement by Subpixel Image Translation With a Scanning Micromirror

This paper reports on a superresolution digital image enhancement technique using subpixel image translation with a scanning micromirror. We demonstrate that the spatial resolution of digital photomicrography, employing typical black-and-white pixelated image sensors, can be improved by acquiring multiple images with predetermined subpixel shifts and combining them with a superresolution image reconstruction algorithm. A two-axis gimbaled micromirror fabricated with a bulk-micromachining process is used to control the translational image displacements with subpixel accuracy

Reduction of Metal Artifact around Titanium Alloy-based Pedicle Screws on CT Scan Images: An Approach using a Digital Image Enhancement Technique

Reduction of Metal Artifact around Titanium Alloy-based Pedicle Screws on CT Scan Images: An Approach using a Digital Image Enhancement Technique

Radiographic image enhancement. Part I: spatial domain techniques.

Digital image enhancement techniques provide a multitude of choices for improving the visual quality of diagnostic images. Appropriate choice of such techniques is greatly influenced by the imaging modality, task at hand and viewing conditions. This sequence of two articles will provide an overview of underlying concepts, along with algorithms commonly used for radiographic image enhancement. The first article focuses on spatial domain techniques for radiographic image enhancement, with particular reference to point processing methods, histogram modification and unsharp masking.

Electric current injection NDE using a SQUID magnetometer

We built a portable low-cost superconducting quantum interference device (SQUID) magnetometer to be used as the sensing element of an electric current injection NDE system. Using this system, we measured the magnetic fields associated with aluminum plate with single flaws in the millimeter range (2 to 8 mm), at lift-off distances up to ten times the size of the flaw, with injection currents in the order of a few amps. Because the system is at a relatively large distance from the test plate, the signal generated by the flaw is masked by the sinal generated by the edges of the plate. This is independent of the amount of current injected. Due to this, visual inspection is difficult when the distance from the sensor to the flaw exceeds five times its size. To intensify the magnetic field disturbance due to the flaws, we used digital image-enhancement techniques. Applying the enhancement algorithm, magnetic field disturbances were visualized at distances up to ten times the size of the flaw.

Clinical applications of myocardial contrast echocardiography

Myocardial contrast echocardiography is a new technique that uses microbubbles of air in conjunction with simultaneously performed 2-dimensional echocardiographic imaging. Currently, it can be used to determine myocardial perfusion in the cardiac catheterization laboratory and the operating room. For myocardial contrast echocardiography to find a broader clinical application for the assessment of myocardial perfusion, it will be necessary to opacity the myocardium from venous injection of contrast in humans. In this regard, enhancement in bubble engineering, optimization of echocardiographic systems (greater sensitivity and dynamic range), and availability of digital image enhancement techniques will be required for myocardial contrast echocardiography to realize its full clinical potential by the year 2000.

Automatic tracking and digitization of multiple radiopaque myocardial markers

An 80386 PC-based system was designed to track automatically multiple, miniature radiopaque markers implanted in the heart wall. This system eliminated the need for tedious, time-consuming manual digitization of marker coordinates. Use of a MATROX MVP-AT/NP image processing board incorporated advanced image processing and graphics features into the low-cost PC environment. Digital image enhancement and segmentation techniques (such as limiting analysis to predefined windows of interest, spatial band-pass and matched filtering, contrast stretching and clipping, linear adaptive prediction, intensity histogram analysis, adaptive binary thresholding, region growing, expanding region of analysis, and feature extraction) were incorporated into a user-friendly integrated marker processing software environment. Improved speed, accuracy, and reproducibility of the marker digitizing process were realized. These basic techniques have broad applications to other image processing needs in biomedical research.

Detection and Classification of Muskox Habitat on Banks Island, Northwest Territories, Canada, Using Landsat Thematic Mapper Data

The feasibility of using Landsat Thematic Mapper data for mapping muskox summer habitat was tested on northern Banks Island, Northwest Territories. Digital image enhancement and classification techniques were examined to determine if summer foraging habitats could be detected and mapped using Thematic Mapper imagery. Interpretations of the satellite data were verified in the field during the summers of 1988 and 1989. The most important summer foraging habitats for muskoxen included the wet sedge meadow, graminoid tundra and graminoid/dwarf shrub tundra cover types. These lowland habitats were generally distinguishable on enhanced colour images and were easily differentiated from upland areas. The most suitable colour composite for differentiating muskox summer habitats was the near-infrared (band 4), shortwave infrared (band 5) and red (band 3) spectral bands displayed in red, green and blue respectively. Upland cover types, including dwarf shrub tundra, hummocky tundra and dwarf shrub/lichen barrens, were more difficult to differentiate because of spectral variability resulting from differences in plant cover and site characteristics. The classified image had an overall accuracy of 88%. The summer habitats of particular importance to muskoxen had classification accuracies of 84-89%. Detection of important foraging habitats on Thematic Mapper imagery is attributable to the spectral distinctiveness of wet graminoid communities and the high spectral sensitivity and spatial resolution of the infrared sensors, which allow detection of differences in surface moisture and vegetation physiognomy.Key words: bison habitat, boreal forest, digital image analysis, supervised classification, Landsat Thematic Mapper data, habitat mapping, Bison bison athubuscue, remote sensing