Passive Image Research Articles

Velocity changes after the 2021 MS 6.4 Yangbi earthquake based on passive image interferometry

An MS 6.4 earthquake occurred in Yangbi, Yunan Province, China, on 21 May 2021. The epicenter was on the blind branch fault in the west of the Weixi–Qiaohou–Weishan fault, but no surface rupture was obvious. In the present study, the continuous vertical component of waveforms that were recorded in six nearby permanent stations was collected and the noise cross-correlation and autocorrelation techniques were utilized to investigate velocity changes that were induced by the Yangbi Earthquake. Velocity changes based on the single-station autocorrelation method reveal mainly coseismic declines, and a maximum of .09% was recorded in the EYA station. Results from the cross-correlation technique show both positive and negative velocity changes, and these lasted for approximately 3 months. The volumetric strain that was generated by the Yangbi Earthquake at a depth of 5 km exhibits an obvious four-quadrant distribution. Station pairs in the dilatation region (e.g., EYA–HEQ) mainly display a decrease in velocity, whereas those in the contraction region (e.g., BAS–TUS, TUS–YUL, and LUS–TUS) show an increase in velocity. Based on the depth sensitivity of scattered waves, velocity changes that were obtained using the noise cross-correlation involve the highest weight coefficients near the related two stations. Regarding stations of one station pair in different stress loading regions, the static stress of the station that is nearest to the epicenter exerted a greater impact on the velocity change. The observed velocity changes are likely attributed to a combination of near-surface physical damage and static stress changes. The validation of clock errors with magnitudes of seconds that were obtained using the noise cross-correlation and effects of these errors on measured velocity changes are also discussed.

HE‐DETR‐DC5 method to rapidly detect objects on passive THz images in human safety inspection

As worldwide counterterrorism operations grow, screening people for concealed objects in public places utilizing Terahertz security technology is becoming increasingly critical. In this letter, a passive THz Human security image Intelligent detection method (HE-DETR-DC5) is proposed that combines histogram equalization (HE) processing and DEtection TRansformer (DETR). The proposed method first performs histogram equalization on passive THz images to improve image contrast. In addition, the cavity convolution is added to the ResNet-50 backbone network to enhance the model's attention to the concealed object in the passive THz image and improve the accuracy. The corresponding model is called DETR-DC5. The experimental results show that the average precision mAP of the proposed method can achieve 99.9%. At the same time, compared to other image enhancement methods, the histogram equalization method used in this letter has better performance and higher detection accuracy. The detection speed of the proposed method is about 0.5 FPS, which can meet the demand for real-time detection. Therefore, the proposed model can efficiently and automatically detect hidden objects in passive THz human security images.

A Novel Passive Millimeter Wave Image Noise Suppression Method Based on Pixel Non-local Self-similarity

A Novel Passive Millimeter Wave Image Noise Suppression Method Based on Pixel Non-local Self-similarity

Efficacy of Residual Methods for Passive Image Forensics Using Four Filtered Residue CNN

Efficacy of Residual Methods for Passive Image Forensics Using Four Filtered Residue CNN

Commentary: Connecting Müller's Philosophical Position-Taking Theory of Emotional Feelings to Mechanistic Emotion Theories in Psychology

Müller proposes a position-taking theory to account for the manifest image of emotional feelings as “feelings towards”. He reduces the process of position-taking to goal-based construal, which is akin to the stimulus-goal comparison process central in appraisal theories. Although this reduction can account for the heat of emotional feelings and the intuition that non-linguistic organisms can also have feelings, it may fail to keep the position-taking aspect on board. Moreover, the image of emotional feelings as active position-takings may itself be questioned and replaced with a passive image. I end by acknowledging that a passive image is still compatible with an active underlying mechanism as is the case in appraisal theories but even more so in the goal-directed theory.

A New Adaptive Visual Tracking Scheme for Robotic System Without Image-Space Velocity Information

In this article, we investigate the adaptive visual tracking problem for uncertain robotic system with time-varying depth, in the case of no image-space velocity information. Existing works dealing with this problem either assume the estimated time-varying depth is invertible or require the priori information of the system kinematics. This case potentially leads to the singularity of the control scheme and requirement for a high gain feedback. In this brief, a new image-space observer which does not involve the inversion of the estimated depth is proposed, upon which, we design an adaptive visual tracking controller without using the image-space velocity information. More importantly, the observer employs a passive image Jacobian matrix-based constant feedback instead of high gain feedback and the priori information is no longer demanded. Additionally, the proposed control scheme enjoys a desirable separation property for the robotic dynamics and kinematics which makes it applicable to most industrial/commercial robots having a closed torque control loop and only permitting the joint velocity command. By using the Lyapunov stability analysis, the asymptotical convergence of both image-space tracking errors and observation errors are obtained. Numerical simulations and implementation issues concerning the application to industrial/commercial robots are presented to verify the efficacy of the control scheme.

Improved Passive Gamma Emission Tomography image quality in the central region of spent nuclear fuel

Reliable non-destructive methods for verifying spent nuclear fuel are essential to draw credible nuclear safeguards conclusions from spent fuel. In Finland, spent fuel items are verified prior to the soon starting disposal in a geological repository with Passive Gamma Emission Tomography (PGET), a uniquely accurate method capable of rod-level detection of missing active material. The PGET device consists of two highly collimated detector banks, collecting gamma emission data from a 360° rotation around a fuel assembly. 2D cross-sectional activity and attenuation images are simultaneously computed. We present methods for improving reconstructed image quality in the central parts of the fuel. The results are based on data collected from 2017 to 2021 at the Finnish nuclear power plants with 10 fuel assembly types of varying characteristics, for example burnups from 5.7 to 55 GWd/tU and cooling times from 1.9 to 37 years. Data is acquired in different gamma energy windows, capturing the peaks of Cs-137 (at 662 keV) and Eu-154 (at 1274 keV), abundant isotopes in long-cooled spent nuclear fuel. Data from these gamma energy windows at well-chosen angles are used for higher-quality images, resulting in more accurate detection of empty rod positions. The method is shown to detect partial diversion of nuclear material also in the axial direction, demonstrated with a novel measurement series scanning over the edge of partial-length rods.

SHALLOW WATERS DEPTH ESTIMATION USING EMPIRICAL SATELLITE DERIVED BATHYMETRY AND SENTINEL-2 DATA, CASE STUDY: EAST COASTAL WATERS OF JAVA ISLAND

Abstract. Hydrographic survey is an activity to provide spatial information in the marine sector. To produce accurate data, hydrographic surveys require very large costs. With the vast sea area in Indonesia, this becomes a very big challenge. In addition, there are some areas that cannot be reached by survey vessels (limited to a depth of > 25 m). Therefore, an alternative method is needed to provide bathymetry data in Indonesia. There is a new technique that is being developed and does not require high costs to obtain water depth data, by using remote sensing technology, especially by using passive sensor image technology. This technique or method is known as Satellite Derived Bathymetry (SDB) which can estimate depths of up to 30 meters. The SDB technique which is often used is empirical SDB. The empirical SDB has the principle of connecting the spectral value of the image with the measured depth. With the use of Sentinel-2 satellite imagery which has high temporal and spatial resolution, the SDB capability is expected to be improved. East coastal waters of Java Island are in the Bali Strait. This strait separates the island of Java from the island of Bali. In the Bali Strait there is a busy ferry shipping lane and there are also underwater cables used to supply electricity to Bali Island from Java Island. On the Java side, there are also many beaches and underwater tourism that must be preserved. Therefore, it is very important to be able to know the hydrographic data such as bathymetry data in the east coastal waters of Java Island. The objective of this work is thus to estimate shallow water depths using empirical SDB and Sentinel-2 images in the east coastal waters of Java Island. With two band combinations applied in the algorithm, best combination to produce the best depth map for the study area can be obtained. Comparing with reference data, the results show Band 1&3 combination give the better correlation and RMSE (0.76 and 0.026) than Band 2&3 combination (0.64 and 0.075).

Coupled body and surface wave sensitivity kernels for coda-wave interferometry in a three-dimensional scalar scattering medium

SUMMARY Analysis of long recordings of ambient seismic noise has shown to be effective for estimation of seismic responses between points located on the surface. This includes both the ballistic and the coda part of the waveforms. Passive image interferometry is used to analyse perturbations in the reconstructed coda, to detect and locate changes in the medium. This method has been shown to be effective in monitoring variations in seismic velocity produced by a wide range of phenomena. However, localization of the sources of these changes is still an open problem for a 3-D half-space, given the difficulties of integrating body and surface waves within the same framework. In this study, we approach this problem by developing the sensitivity kernels of a scalar model that integrates the body and surface scalar waves. First, we establish a parallel between the penetration depth of the surface waves for the elastic and scalar cases, which equips the latter with a natural scaling with frequency that is otherwise not included in the model. Next, using a variational approach, we quantify how a velocity perturbation in the medium affects the propagation velocity of the surface waves. Based on these results, we extend the sensitivity theory to include the body and surface waves as modes of propagation and detection, as restricted to a 1-D depth-dependent perturbation description, for simplicity. The obtained kernel can be expressed as the sum of a surface and a body waves sensitivity kernels, which are inter-dependent through a set of traveltime distributions. These distributions are estimated with Monte Carlo simulations based on the radiative transfer equations of the system, with the source and the receiver located in the same position at the surface. The sensitivity at depth is in good agreement with previous results based on full wavefield elastic simulations in 3-D inhomogeneous half-space. The temporal evolution of the body and surface waves sensitivity is quantified, as well as the contribution of all the possible modes of propagation and detection to each of these sensitivities. We show how the position of the source affects the sensitivity between the two types of waves. We find that the efficacy of energy conversion from surface to body waves is controlled by the ratio between the surface wave penetration depth and the mean free path, a feature that has not been reported in previous studies. This means that configurations that share this ratio have the same sensitivity as long as all the spatial and temporal variables (e.g. elapsed time, depth) are non-dimensionalized with the mean free path and the mean free time, respectively.

A Novel Approach for the Detection of Every Significant Collapsing Bubble in Passive Cavitation Imaging.

Passive cavitation image (PCI) shows the power distribution of the acoustic emissions resulting from cavitation bubble collapses. The conventional PCI convolves the emitted cavitation signals with the point spread function of an imaging system, and it suffers from a low spatial resolution and contrast due to the increased sidelobe artifacts accumulated during the temporal integral process. To overcome the problems, the present study considers a 3-D time history of instantaneous PCIs where cavitation occurs at the local maxima of the main lobes of the beamformed cavitation field surrounded by the sidelobes largely spreading out in a time-space domain. A spatial and temporal gating technique was employed to detect the local maxima so that cavitation bubbles can be identified with their collapsing strength. The proposed approach was verified by the simulation for single and multiple cavitation bubbles, proving that it accurately detects the location and strength of the collapsing bubbles. An experimental test was also carried out for the cavitation bubbles produced by a clinical extracorporeal shock wave therapeutic device, which underpins that the proposed method successfully identifies every individual cavitation bubble.

Seamless Copy–Move Replication in Digital Images

The importance and relevance of digital-image forensics has attracted researchers to establish different techniques for creating and detecting forgeries. The core category in passive image forgery is copy–move image forgery that affects the originality of image by applying a different transformation. In this paper, a frequency-domain image-manipulation method is presented. The method exploits the localized nature of discrete wavelet transform (DWT) to attain the region of the host image to be manipulated. Both patch and host image are subjected to DWT at the same level l to obtain sub-bands, and each sub-band of the patch is pasted to the identified region in the corresponding sub-band of the host image. Resulting manipulated host sub-bands are then subjected to inverse DWT to obtain the final manipulated host image. The proposed method shows good resistance against detection by two frequency-domain forgery detection methods from the literature. The purpose of this research work is to create a forgery and highlight the need to produce forgery detection methods that are robust against malicious copy–move forgery.

A passive image forensic scheme based on an adaptive and hybrid techniques

A passive image forensic scheme based on an adaptive and hybrid techniques

A THz Passive Image Generation Method Based on Generative Adversarial Networks

A terahertz (THz) passive imager with automatic target detection is an effective solution in the field of security inspection. The high-quality training datasets always play a key role in the high-precision target detection applications. However, due to the difficulty of passive image data acquisition and the lack of public dataset resources, the high-quality training datasets are often insufficient. The generative adversarial network (GAN) is an effective method for data augmentation. To enrich the dataset with the generated images, it is necessary to ensure that the generated images have high quality, good diversity, and correct category information. In this paper, a GAN-based generation model is proposed to generate terahertz passive images. By applying different residual connection structures in the generator and discriminator, the models have strong feature extracting ability. Additionally, the Wasserstein loss function with gradient penalty is used to maintain training stability. The self-developed 0.2 THz band passive imager is used to carry out imaging experiments, and the imaging results are collected as a dataset to verify the proposed method. Finally, a quality evaluation method suitable for THz passive image generation task is proposed, and classification tests are performed on the generated images. The results show that the proposed method can provide high-quality images as supplementary.

AAPM Task Group Report 290: Respiratory motion management for particle therapy.

Dose uncertainty induced by respiratory motion remains a major concern for treating thoracic and abdominal lesions using particle beams. This Task Group report reviews the impact of tumor motion and dosimetric considerations in particle radiotherapy, current motion‐management techniques, and limitations for different particle‐beam delivery modes (i.e., passive scattering, uniform scanning, and pencil‐beam scanning). Furthermore, the report provides guidance and risk analysis for quality assurance of the motion‐management procedures to ensure consistency and accuracy, and discusses future development and emerging motion‐management strategies. This report supplements previously published AAPM report TG76, and considers aspects of motion management that are crucial to the accurate and safe delivery of particle‐beam therapy. To that end, this report produces general recommendations for commissioning and facility‐specific dosimetric characterization, motion assessment, treatment planning, active and passive motion‐management techniques, image guidance and related decision‐making, monitoring throughout therapy, and recommendations for vendors. Key among these recommendations are that: (1) facilities should perform thorough planning studies (using retrospective data) and develop standard operating procedures that address all aspects of therapy for any treatment site involving respiratory motion; (2) a risk‐based methodology should be adopted for quality management and ongoing process improvement.

Is the Revised Bloom’s Taxonomy Revisited in the EFL/ESL Reading Textbooks?

Benjamin Bloom and his colleagues produced a cognitive model for classifying educational objectives. This model has not been properly utilized by teachers and university instructors in their teaching settings. This cognitive model covers six main levels as knowledge, comprehension, application, analysis, synthesis, and evaluation which, after knowledge, were displayed as skills and abilities, with the fact that knowledge was the essential prerequisite for putting these skills and abilities into practice. In the taxonomy, each category bears a continuum from concrete to abstract and simple to complex. In 2001, a group of cognitive psychologist revisited and modernized Bloom’s Taxonomy for teaching, learning, and assessment. Accordingly, the revised Bloom’s taxonomy drew attention away from the partially passive image of educational objectives and hints on a more active conception of categorization. The revised taxonomy employs verbs and gerunds to refer to cognitive levels unlike the nouns employed in the original taxonomy. The dynamic words in the revised taxonomy define the cognitive processes through which thinkers confront and work with knowledge. The learning goals are significant to form a pedagogical interchange in order that learners and instructors perceive the aim of that interchange. Having and classifying objectives support teachers in planning and supplying quality education, forming proper assessment tasks, and ensuring teaching to go parallel with the objectives. Hence, this research paper hints on investigating to what extent the revised Bloom’s taxonomy is employed in the reading comprehension questions of an EFL reading textbook. Thus, two research questions were developed to find out the state of cognitive skills stated in the revised taxonomy, the first question aiming at evaluating the lower level while the second one involving the higher cognition level. The investigated EFL reading textbook was analyzed through descriptive content analysis. The findings of the study showed that the examined textbook lacked the higher level cognitive skills highlighted in the revised version of the taxonomy. Related assumptions have been accordingly provided to recommend how the reading textbooks which are being written or will be written should be integrated with the revised Bloom’s taxonomy when assessing reading skills.

Perfection of aesthetic ideals (illustrated through the example of Shireen's image)

This article briefly examines the genesis of Shireen's image, which has become the image of an aesthetic ideal heroine not only in Uzbek classical literature, but also in Persian, Azerbaijani and Turkic literature. The poets of all time did not share the image of Shireen. The article collected the opinions of many literary scholars about the image of Shireen created by such poets as Firdowsi, Nizami, Dehlavi, Navoi, and its development in the transition from epics to epics. It is a question of the etymology of the word Shireen, its historical origin, and lastly, that this image became more refined from year to year, from century to century, from people to people, which has attained the poetic perfection from the usual historical and passive image of the woman, acquiring the embodiment of divine beauty, as well as the socio-political activity of women in it. Thisimplies that the image of Shireen created by AlisherNavoi is a symbol of such perfection and divine love.

State-of-the-art techniques for passive image forgery detection: a brief review

State-of-the-art techniques for passive image forgery detection: a brief review

Image Splicing Detection Scheme Using Surf and Mean-LBP Based Morphological Operations


 Tampering with images and changing them without giving any evidence has become very popular because of the presence of an enormous degree of intense altering device. The image forensics technique has grown popular for deciding whether a picture has been changed with a copy-move, splicing, or different forgery techniques. This paper present’s a novel passive image splicing forgery detection technique which includes three steps. Firstly, extracting an interest region (ROI) by using SURF descriptor (Speed up Robust Transform) Points is concerned based on the morphological procedure. Secondly, the Extraction of Mean-LBP (Mean Local Binary Pattern) Highlights on ROI is carried out. Lastly, a Classification of Mean- LBP characteristics is done with the SVM classifier. This novel method has shown the best outcome as SVM is used for classification. As well as it has shown a higher accuracy on the standard three datasets CASIA TIDE V1.0, CASIA TIDE V2.0, and Columbia University, revealed that current method has achieved higher accuracy of 97.9%, 98.2%, and 98.9% respectively. Finally, in terms of accuracy, the proposed SFD scheme outperformed the best recent works in this area.

AC‐SDBSCAN: Toward concealed object detection of passive terahertz images

The passive terahertz (THz) detection on objects concealed under clothing is quite challenging due to the heavy noise interference. In this paper, an active-contour-based self-adaptive DBSCAN (AC-SDBSCAN) detection algorithm is proposed. The core of AC-SDBSCAN algorithm lies in that the object contours are first extracted by AC method in a noise scenario and then the statistical features of the contours are used to motivate a SDBSCAN to complete clustering without initialization. Benefiting from the strong robustness of AC and DBSCAN to the noise, the concealed objects in the noisy THz images can be detected accurately. Extensive simulations are verified on four passive THz image datasets. The results indicate that the AC method in our solution can achieve over 87% accuracy for contour extraction of passive THz images, while the classical methods achieve less than 77%; in addition, the SDBSCAN can achieve over 90% clustering accuracy without manual initialization which is significantly superior to the conventional DBSCAN. Eventually, the proposed method completes the object detection of passive THz images with a maximum recall of 90.38% and a maximum precision of 94%.

Imaging crustal structures through a passive seismic imaging approach in a mining area in Saxony, Germany

Abstract. We have used several flooding-induced microseismic events that occurred in an abandoned mining area to image geological structures close to the hypocentres in the vicinity of the mine. The events have been located using a migration-based localization approach. We used the recorded full waveforms of these localized microseismic events and have processed these passive source data as if they resulted from active sources at the known hypocentre location and origin time defined by the applied location approach. The imaging was then performed using a focusing 3D prestack depth migration approach for the secondary P-wave arrivals. The needed 3D migration velocity model was taken from a recent 3D active (controlled-source) seismic survey in that area. We observed several clear and pronounced reflectors in our obtained 3D seismic image cube, some of them related to a major fault zone in that area and some correlating well with information from the nearby mining activities. We compared our results to the 3D seismic image cube obtained directly from the 3D active seismic survey and have found new structures with our approach that were not known yet, probably because of their steep dips which the 3D active seismic survey had not illuminated. The location of the hypocentres at depth with respect to the illumination angles of those structures proved to be favourable in that case, and our 3D passive image complements the 3D active seismic image in an elegant way, thereby revealing new structures that cannot be imaged otherwise with surface seismic configurations alone.