BackgroundThree-dimensional digital image correlation (3d-dIC) is a non-contact monitoring technique that is able to provide accurate three-dimensional strain anddisplacement measurements. Previous research has shown...
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BackgroundThree-dimensional digital image correlation (3d-dIC) is a non-contact monitoring technique that is able to provide accurate three-dimensional strain anddisplacement measurements. Previous research has shown that 3d-dIC can detect micron-scale cracks in structures as they emerge;however, because 3d-dIC is an optical sensing technique, unfavorable visual conditions due to high heat, large deformations, or a significant distance between the structure and the 3d-dIC cameras can make crack detection difficult or *** research aims to develop machine learning algorithms capable of detecting characteristic crack signals in these *** point velocities obtained via 3d-dIC were transformed into 2d color images for machine learning segmentation. A novel dataset processing technique was utilized to produce the training dataset, which overlayed simplistic crack analogs on top of the first 50 images from the test. different parameters from this technique were investigated to determine their effect on the model's accuracy and *** resulting model detected the onset of significant cracking with an accuracy comparable to acoustic emissions sensors. Varying the processing parameters yielded models that coulddetect evidence of cracking earlier, at the cost of potentially higher false positive rates. The model also performed well on structures imaged in similar testing setups that were not included in the training *** data processing technique enables crack detection in scenarios where acoustic emissions and other sensors cannot be used. It additionally allows processes already utilizing 3d-dIC to obtain additional information about material performance during testing or operation.
depth perception plays an essential role in the viewer experience for immersive virtual reality (VR) visual environments. However, previous research investigations in the depth quality of 3d/stereoscopic images are ra...
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depth perception plays an essential role in the viewer experience for immersive virtual reality (VR) visual environments. However, previous research investigations in the depth quality of 3d/stereoscopic images are rather limited, and in particular, are largely lacking for 3d viewing of 360-degree omnidirectional content. In this work, we make one of the first attempts to develop an objective quality assessment model nameddepth quality index (dQI) for efficient no-reference (NR) depth quality assessment of stereoscopic omnidirectional images. Motivated by the perceptual characteristics of the human visual system (HVS), the proposeddQI is built upon multi-color-channel, adaptive viewport selection, and interocular discrepancy features. Experimental results demonstrate that the proposed method outperforms state-of-the-art image quality assessment (IQA) anddepth quality assessment (dQA) approaches in predicting the perceptual depth quality when tested using both single-viewport and omnidirectional stereoscopic imagedatabases. Furthermore, we demonstrate that combining the proposeddepth quality model with existing IQA methods significantly boosts the performance in predicting the overall quality of 3d omnidirectional images.
Monocular 3d object tracking is a challenging task because monocular image lacks depth information necessary for 3d scene understanding. Modern methods typically rely on deep learning to reconstruct 3dinformation fro...
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Monocular 3d object tracking is a challenging task because monocular image lacks depth information necessary for 3d scene understanding. Modern methods typically rely on deep learning to reconstruct 3dinformation from learned prior, which demands strenuous effort on acquiring ground-truth annotateddata anddoes not generalize for various camera settings. We present a method to continuously track 3d location and orientation of the target object from a monocular image sequence from 2d instance segmentation methods. We reconstruct the structure and trajectory of the objects using factor graph optimization incorporating reprojection error of keypoint tracks, kinematic motion model and bounding box constraints. We propose a combined ellipsoid-cuboid object representation and bounding box constraint to model the object dimension. We evaluate our algorithm in simulation dataset generated using CARLA, and the result indicates that the method is robust to 2d bounding box error and the proposed object representation yields more accurate pose and size estimation compared to solely using either representation.
Structured light 3d imaging is often used for obtaining accurate 3dinformation via phase retrieval. Single-pattern structured light 3d imaging is much faster than multi-pattern versions. current phase retrieval metho...
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Structured light 3d imaging is often used for obtaining accurate 3dinformation via phase retrieval. Single-pattern structured light 3d imaging is much faster than multi-pattern versions. current phase retrieval methods for single-pattern structured light 3d imaging are however not accurate enough. Besides, the projector resolution in a structured light 3d imaging system is expensive to improve due to hardware costs. To address the issues of low accuracy and low resolution of single-pattern structured light 3d imaging, this work proposes a super-resolution phase retrieval network (SRPRNet). Specifically, a phase-shifting module is proposed to extract multi-scale features with different phase shifts, and a refinement and super-resolution module is proposed to obtain refined and super-resolution phase components. After phase demodulation and unwrapping, high-resolution absolute phase is obtained. A sine shifting loss and a cosine shifting loss are also introduced to form the regularization term of the loss function. As far as can be ascertained, the proposed SRPRNet is the first network for super-resolution phase retrieval by using a single pattern, and it can also be used for standard-resolution phase retrieval. Experimental results on three datasets show that SRPRNet achieves state-of-the-art performance on 1x , 2x , and 4x super-resolution phase retrieval tasks.
With the development of the Internet,image encryption technology has become critical for network *** methods often suffer from issues such as insufficient chaos,low randomness in key generation,and poor encryption ***...
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With the development of the Internet,image encryption technology has become critical for network *** methods often suffer from issues such as insufficient chaos,low randomness in key generation,and poor encryption *** enhance performance,this paper proposes a new encryption algorithm designed to optimize parallel processing and adapt to images of varying sizes and *** method begins by using SHA-384 to extract the hash value of the plaintext image,which is then processed to determine the chaotic system’s initial value and block *** image is padded anddivided into blocks for further processing.A novel two-dimensional infinite collapses hyperchaotic map(2dICHM)is employed to generate the intra-block scrambling sequence,while an improved variable Joseph traversal sequence is used for inter-block *** removing the padding,3d forward and backward shift diffusions,controlled by the 2d-ICHM sequences,are applied to the scrambledimage,producing the *** results demonstrate that the proposed algorithm outperforms others in terms of entropy,anti-noise resilience,correlation coefficient,robustness,and encryption efficiency.
In traditional clinical practice, doctors often have to deal with 3dinformation based on 2d-displayed medical images. There is a considerable mismatch between the 2d and3ddimensions in image interaction during clin...
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In traditional clinical practice, doctors often have to deal with 3dinformation based on 2d-displayed medical images. There is a considerable mismatch between the 2d and3ddimensions in image interaction during clinical diagnosis, making image manipulation challenging and time-consuming. In this study, we explored3d sketching for medical images using true 2d-3d interlinked visualization and interaction, presenting a novel AR environment named ARMedicalSketch. It supports imagedisplay enhancement preprocessing and3d interaction tasks for original 3d medical images. Our interaction interface, based on 3d autostereoscopic display technology, provides both floating 3ddisplay and 2d tablet display while enabling glasses-free visualization. We presented a method of 2d-3d interlinked visualization and interaction, employing synchronized projection visualization and a virtual synchronized interactive plane to establish an integrated relationship between 2d and3ddisplays. Additionally, we utilized gesture sensors and a 2d touch tablet to capture the user's handinformation for convenient interaction. We constructed the prototype and conducted a user study involving 23 students and 2 clinical experts. The controlled study compared our proposed system with a 2ddisplay prototype, showing enhanced efficiency in interacting with medical images while maintaining 2d interaction accuracy, particularly in tasks involving strong 3d spatial correlation. In the future, we aim to further enhance the interaction precision and application scenarios of ARMedicalSketch.
UAV-based intelligent data acquisition for 3d reconstruction and monitoring of infrastructure has experienced an increasing surge of interest due to recent advancements in imageprocessing anddeep learning-based tech...
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UAV-based intelligent data acquisition for 3d reconstruction and monitoring of infrastructure has experienced an increasing surge of interest due to recent advancements in imageprocessing anddeep learning-based techniques. View planning is an essential part of this task that dictates the information capture strategy and heavily impacts the quality of the 3d model generated from the captureddata. Recent methods have used prior knowledge or partial reconstruction of the target to accomplish view planning for active reconstruction;the former approach poses a challenge for complex or newly identified targets while the latter is computationally expensive. In this work, we present Bag-of-Views (BoV), a fully appearance-based model used to assign utility to the captured views for both offline dataset refinement and online next-best-view (NBV) planning applications targeting the task of 3d reconstruction. With this contribution, we also developed the View Planning Toolbox (VPT), a lightweight package for training and testing machine learning-based view planning frameworks, custom view dataset generation of arbitrary 3d scenes, and3d reconstruction. Through experiments which pair a BoV-based reinforcement learning model with VPT, we demonstrate the efficacy of our model in reducing the number of required views for high-quality reconstructions in dataset refinement and NBV planning.
As neural radiance fields continue to advance in 3d content representation,the copyright issues surrounding 3d models oriented towards implicit representation become increasingly *** response to this challenge,this pa...
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As neural radiance fields continue to advance in 3d content representation,the copyright issues surrounding 3d models oriented towards implicit representation become increasingly *** response to this challenge,this paper treats the embedding and extraction of neural radiance field watermarks as inverse problems of image transformations and proposes a scheme for protecting neural radiance field copyrights using invertible neural network *** 2dimage watermarking technology for 3d scene protection,the scheme embeds watermarks within the training images of neural radiance fields through the forward process in invertible neural networks and extracts them from images rendered by neural radiance fields through the reverse process,thereby ensuring copyright protection for both the neural radiance fields and associated3d ***,challenges such as information loss during rendering processes anddeliberate tampering necessitate the design of an image quality enhancement module to increase the scheme’s *** module restores distortedimages through neural network processing before watermark ***,embedding watermarks in each training image enables watermark information extraction from multiple *** proposed watermarking method achieves a PSNR(Peak Signal-to-Noise Ratio)value exceeding 37 dB for images containing watermarks and 22 dB for recovered watermarkedimages,as evaluated on the Lego,Hotdog,and Chair datasets,*** results demonstrate the efficacy of our scheme in enhancing copyright protection.
To improve the performance of 3d light fielddisplay(LFd) devices and optimize their display effects, a depth-offield (dOF) enhancement in LFd based on fusion of voxel information on the depth plane is proposed. In pr...
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To improve the performance of 3d light fielddisplay(LFd) devices and optimize their display effects, a depth-offield (dOF) enhancement in LFd based on fusion of voxel information on the depth plane is proposed. In previous research, a calculation method was developed to calculate the voxel size on the depth plane. According to this calculation method, a distribution model of voxel varying with display depth is established. A dOF determination criterion based on voxel distribution from visual perspective is proposed, and its accuracy is validated through subjective experiments involving multiple participants. By fusing the voxels on the depth plane, the phenomenon of voxel overlap is improved, resulting in enhanceddefinition of 3dimages on the depth plane. Under the condition that the structure and parameters of the 3d LFddevice are determined, the maximum achievable display depth will be increased significantly. Finally, experimental validation of the method's feasibility is conducted using multiple 3d light fielddevices for display.
Three-dimensional (3d) ultrasound (US) imaging is widely used for real-time, non-ionizing, and cost-effective medical diagnostics. However, using a one-dimensional (1d) transducer often results in limited elevational ...
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Three-dimensional (3d) ultrasound (US) imaging is widely used for real-time, non-ionizing, and cost-effective medical diagnostics. However, using a one-dimensional (1d) transducer often results in limited elevational resolution due to the inherent beam thickness. In this paper, we introduce an elevational Synthetic Aperture Focusing (SAF) algorithm specifically designed for rotational 3d US imaging. Unlike previous methods requiring channel data, our approach operates on in-plane beamformed radio-frequency (RF) data, making it more accessible on many commercial scanners. Through simulations and experiments, we demonstrate significant improvements in elevational resolution (up to 96.4%) and contrast (up to 274.7%). These findings highlight the potential of the proposed algorithm to enhance both research and clinical applications of rotational 3d US imaging.
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