International Journal of Imaging Systems and Technology最新文献

The rising prevalence of lumbar spine disorders demands scalable solutions for mass screening and automated diagnosis. Accurate analysis of specific MRI slices, such as mid-sagittal or transverse mid-height intervertebral disc (IVD) slices, is essential but currently relies on time-consuming, error-prone manual selection. Automating this process is crucial to enhance the efficiency and accuracy of computer-aided diagnostic systems. To address this need, this study introduces a novel deep learning-based framework—SpineDeep-Net that integrates self-attention mechanisms within a multi-layer convolutional neural network for automatic selection of optimal transverse planes of lumbar spine MRI disc slices. By focusing on mid-height slices of L3/L4, L4/L5, and L5/S1 IVDs—the most diagnostically relevant slices, SpineDeep-Net eliminates the reliance on manual selection processes, thereby accelerating and improving the diagnostic pipeline. Unlike standard attention, the proposed dual-self-attention employs two sequential attention stages that jointly enhance long-range spatial cue extraction and emphasize subtle disc-level differences. This mechanism enables the model to focus more effectively on diagnostically relevant regions within lumbar MRI slices by dynamically recalibrating feature maps and strengthening feature dependencies. Experimental evaluations demonstrate the superior performance of SpineDeep-Net, achieving 96.83% accuracy and 98.41% specificity, outperforming state-of-the-art methods. By automating the selection and classification of clinically critical disc slices, SpineDeep-Net addresses a key challenge in lumbar spine diagnostics, providing a reliable, scalable, and efficient tool that aids radiologists in making informed clinical decisions. The proposed framework highlights the transformative potential of self-attention-guided deep learning in advancing healthcare diagnostics. The source code is publicly available at https://github.com/rakeshchandrajoshi/spinedeepnet.

Accurate identification and segmentation of teeth in cone-beam computed tomography (CBCT) images are essential for dental diagnosis and treatment in digital dentistry. However, extracting regions of interest (ROI) from maxillofacial CBCT images remains difficult due to the low pixel ratio of tooth structures, especially in the apical area. Traditional tooth segmentation methods such as threshold-based, region-based, and edge-based methods address limited accuracy under challenging imaging conditions. In this paper, we propose TTNNet, a three-stage tooth instance segmentation network designed to improve tooth segmentation from CBCT images. The proposed TTNet employs an intersection-based refinement of the tooth centroid heatmap, retaining only pixels that simultaneously lie within the predicted tooth mask and high-probability heatmap regions. This intersection operation eliminates noise in the tooth centroid heatmap, such as regions that may have been labeled as teeth incorrectly. Extensive experiments on publicly available CBCT tooth dataset demonstrate that TTNet achieves superior performance compared to recent state-of-the-art methods.

Whole-slide imaging assisted by deep learning has been employed to help the digital pathology, while limited by the scarcity of paired label data. To address this issue, a novel self-supervised image modeling framework, PathMAE, is proposed to effectively enlarge the labeled dataset in a cross-domain way, where cross-dataset and even cross-disease histopathological images can be used for model training. PathMAE integrates masked image modeling and contrastive learning to effectively learn transferable visual representations from unlabeled WSIs. The framework comprises two key components: a Swin-Transformer-based encoder-decoder (SMED) with a window-masking strategy for local feature reconstruction, and a Dynamic Memory Contrastive Learning (DMCL) module for enhancing global semantic alignment via memory-guided feature comparison. Experimental results on three public histopathology datasets demonstrate the robustness and generalizability of the proposed method. In cross-disease transfer (BreakHis → Osteosarcoma), PathMAE achieved 97.15% accuracy and 99.03% AUC; in cross-dataset transfer (BreakHis → Camelyon16), it obtained 84.67% accuracy and 88.04% AUC. These findings validate the capability of PathMAE as a scalable and domain-adaptive image analysis framework, offering new potential for building reliable computational pathology systems under limited supervision.

This study focuses on iris recognition using deep learning techniques. The EfficientDet network model was employed for both iris detection and recognition tasks. Four datasets were utilized to train and evaluate the deep learning network. The model was trained to extract iris features and classify individuals based on their unique iris patterns. The proposed method achieved a high recognition rate of over 98% across multiple dataset evaluations. For real-time implementation on an embedded system, the trained model was quantized to an 8-bit integer format to accommodate resource-constrained devices. Despite this quantization, the recognition accuracy remained high, reaching 97%. By incorporating an Edge TPU accelerator alongside a Raspberry Pi system, the processing speed reached up to 10 frames per second during real-time iris camera testing, demonstrating the feasibility of real-time iris recognition. An intruder test was conducted to assess the system's robustness in preventing unauthorized access. The False Acceptance Rate (FAR) was measured to assess the likelihood of incorrectly accepting an unauthorized individual. Experimental results show that the FAR can be reduced to zero by applying additional temporal constraints, effectively preventing unauthorized individuals from passing the iris recognition-based access control system.

An ultrafast two-dimensional (2D) imaging system with large field of view is proposed by leveraging virtually imaged phased array through Galilean beam expanding. By integrating wavelength division multiplexing technology of a virtual imaging phased array with spatial spectroscopy of a grating, broadband spectra of an ultrafast laser pulse are mapped onto a 2D plane. Subsequently, Galilean structure is employed for beam expansion, thereby achieving a large field-of-view 2D imaging capability. A dispersion Fourier transform module is also incorporated into the system, enabling the mapping of wavelength to time, facilitating ultrafast imaging through the detection of pulse signals by high-speed photodetector. The experimental setup employs a home-made mode-locked laser with a spectral bandwidth of 12 nm, capable of large-field imaging of 6 × 20 mm², representing a 20-fold expansion compared to the unexpanded field of view, and an imaging frame rate of up to 7.75 MHz is obtained. The dynamic imaging capability of the system is demonstrated through imaging a freely falling sphere. The proposed imaging system, with its large field of view and high frame rate, is ideal for high-speed flow diagnostics.

Medical imaging is a core component of modern healthcare, essential for early disease diagnosis and effective treatment planning. Deep learning has emerged as a powerful tool to enhance medical image analysis, particularly in tasks such as segmentation, which is essential for identifying and delineating anatomical structures. A notable segmentation challenge involves accurately detecting narrow and elongated features. A novel DenseUNet architecture, enhanced with asymmetric convolutional kernels and a squeeze-and-excitation block, is proposed. It is specifically designed to adapt to such shape characteristics. The iterated local search metaheuristic is employed to optimize the kernel size within a search space of $��{15}^2�$, and a squeeze-and-excitation block is integrated to enhance feature recalibration and network efficiency. The best-performing asymmetric kernel achieved a processing time 5423 s faster than that of the conventional kernels. The proposed architecture is evaluated using the Dice coefficient and benchmarked against state-of-the-art architectures using three databases (TMJ: Temporomandibular joints, DCA1: Coronary arteries, and ICA: Coronary arteries), achieving Dice scores of 0.7800, 0.8231, and 0.8862, respectively. These enhancements demonstrate improved segmentation performance and contribute to the development of more accurate and robust medical imaging tools.

This study proposes a novel diagnostic approach to retinal disease detection by combining deep learning-based segmentation with fractal dimension (FD) analysis on optical coherence tomography (OCT) images. Our primary goal is to enhance early detection of retinal diseases such as age-related macular degeneration (AMD), diabetic retinopathy (DR), central serious retinopathy (CSR), and macular hole (MH). We introduce the Attention U-shaped Network (AUNet), which builds upon the UNet architecture with Attention Gates (AGs) to improve focus on pathological structures in complex cases, achieving a high segmentation accuracy of 98.5% and a mean Intersection over Union (mIoU) of 0.91, outperforming existing models like UNet++ and DeepLabV3+. Coupled with Fourier and Higuchi FD analysis, our method quantitatively assesses the complexity of retinal layers, identifying structural patterns that serve as early indicators of neural degeneration. Statistical tests reveal significant differences in FD values between diseased and healthy groups, underscoring the predictive power of retinal layers like the retinal pigment epithelium (RPE), inner nuclear layer (INL), outer nuclear layer (ONL), and ellipsoid zone (EZ). This combined AUNet-FD approach represents an innovative tool for early diagnosis of retinal diseases, potentially enhancing clinical decision-making through precise, non-invasive analysis.

Diabetic retinopathy (DR), one of the most prevalent microvascular complications of diabetes, stands as a leading cause of vision loss globally. Due to its asymptomatic nature in early stages, delayed diagnosis and staging may result in irreversible visual impairment. Therefore, accurate and simultaneous lesion segmentation and stage classification of DR are of critical clinical importance. In this study, a two-stage, end-to-end, holistic framework is proposed for automated DR diagnosis. In the first stage, an Improved U-Net architecture enhanced with residual blocks and additional convolutional layers is employed to segment small and low-contrast lesions such as microaneurysms, hemorrhages, and hard/soft exudates with high precision. Model hyperparameters are optimized using the harmony search algorithm to enhance training efficiency. In the second stage, lesion-based weight maps obtained from the segmentation step are applied to fundus images from the APTOS dataset, generating enriched inputs for classification. A vision transformer (ViT)-based model, augmented with a Convolutional Block Attention Module (CBAM), is utilized to improve feature extraction. In addition, features derived from ViT are further refined using a graph convolutional network (GCN) and traditional machine-learning classifiers. The proposed approach achieves high performance in multi-class DR stage classification. Compared to existing studies, the framework demonstrates notable improvements in both segmentation and classification accuracy, offering a robust and generalizable solution for DR diagnosis.