Classification Of Light Detection And Ranging Data Research Articles

A novel graph-attention based multimodal fusion network for joint classification of hyperspectral image and LiDAR data

The joint classification of hyperspectral image (HSI) and Light Detection and Ranging (LiDAR) data can provide complementary information for each other, which has become a prominent topic in the field of remote sensing. Nevertheless, the common CNN-based fusion techniques still suffer from the following drawbacks. (1) Most of these models omit the correlation and complementarity between different data sources and always fail to model the long-distance dependencies of spectral information well. (2) Simply splicing the multi-source feature embeddings overlooks the deep semantic relationships among them. To tackle these issues, we propose a novel graph-attention based multimodal fusion network (GAMF). Specifically, it employs three major components, including an HSI–LiDAR feature extractor, a graph-attention based fusion module and a classification module. In the feature extraction module, we consider the correlation and complementarity between multi-sensor data by parameter sharing and employ Gaussian tokenization for feature transformation additionally. To address the problem of long-distance dependencies, the deep fusion module utilizes modality-specific tokens to construct an undirected weighted graph, which is essentially a heterogeneous graph. And the deep semantic relationships between them are exploited utilizing a graph-attention based fusion framework. At the end, two fully connected layers classify the fused embeddings. Experiment evaluations on several benchmark HSI–LiDAR datasets (Trento, University of Houston 2013 and MUUFL) show that GAMF achieves more accurate prediction results than some state-of-the-art baselines. The code is available at https://github.com/tyust-dayu/GAMF.

Joint Classification of Hyperspectral and LiDAR Data Using Binary-Tree Transformer Network

The joint utilization of multi-source data is of great significance in geospatial observation applications, such as urban planning, disaster assessment, and military applications. However, this approach is confronted with challenges including inconsistent data structures, irrelevant physical properties, scarce training data, insufficient utilization of information and an imperfect feature fusion method. Therefore, this paper proposes a novel binary-tree Transformer network (BTRF-Net), which is used to fuse heterogeneous information and utilize complementarity among multi-source remote sensing data to enhance the joint classification performance of hyperspectral image (HSI) and light detection and ranging (LiDAR) data. Firstly, a hyperspectral network (HSI-Net) is employed to extract spectral and spatial features of hyperspectral images, while the elevation information of LiDAR data is extracted using the LiDAR network (LiDAR-Net). Secondly, a multi-source transformer complementor (MSTC) is designed that utilizes the complementarity and cooperation among multi-modal feature information in remote sensing images to better capture their correlation. The multi-head complementarity attention mechanism (MHCA) within this complementor can effectively capture global features and local texture information of images, hence achieving full feature fusion. Then, to fully obtain feature information of multi-source remote sensing images, this paper designs a complete binary tree structure, binary feature search tree (BFST), which fuses multi-modal features at different network levels to obtain multiple image features with stronger representation abilities, effectively enhancing the stability and robustness of the network. Finally, several groups of experiments are designed to compare and analyze the proposed BTRF-Net with traditional methods and several advanced deep learning networks using two datasets: Houston and Trento. The results show that the proposed network outperforms other state-of-the-art methods even with small training samples.

Hyperspectral and LiDAR Data Classification Based on Structural Optimization Transmission.

With the development of the sensor technology, complementary data of different sources can be easily obtained for various applications. Despite the availability of adequate multisource observation data, for example, hyperspectral image (HSI) and light detection and ranging (LiDAR) data, existing methods may lack effective processing on structural information transmission and physical properties alignment, weakening the complementary ability of multiple sources in the collaborative classification task. The complementary information collaboration manner and the redundancy exclusion operator need to be redesigned for strengthening the semantic relatedness of multisources. As a remedy, we propose a structural optimization transmission framework, namely, structural optimization transmission network (SOT-Net), for collaborative land-cover classification of HSI and LiDAR data. Specifically, the SOT-Net is developed with three key modules: 1) cross-attention module; 2) dual-modes propagation module; and 3) dynamic structure optimization module. Based on above designs, SOT-Net can take full advantage of the reflectance-specific information of HSI and the detailed edge (structure) representations of multisource data. The inferred transmission plan, which integrates a self-alignment regularizer into the classification task, enhances the robustness of the feature extraction and classification process. Experiments show consistent outperformance of SOT-Net over baselines across three benchmark remote sensing datasets, and the results also demonstrate that the proposed framework can yield satisfying classification result even with small-size training samples.

A Multi-Scale Pseudo-Siamese Network with an Attention Mechanism for Classification of Hyperspectral and LiDAR Data

For the remote sensing classification task, the ability of a single data source to identify the ground objects remains limited due to the lack of feature diversity. As the typical remote sensing data sources, hyperspectral imagery (HSI) and light detection and ranging (LiDAR) data can provide complementary spectral features and elevation information, respectively. To enhance classification ability, a multi-scale Pseudo-Siamese Network with attention mechanism (MA-PSNet) is proposed by fusing HSI and LiDAR data. In the network, two sub-branch networks are designed for extracting the features from HSI and LiDAR, respectively, and the connection is further established between these two branches. Specifically, a multi-scale feature learning module is incorporated, enabling the image features to be fully extracted at different scales. Similarly, a convolutional attention module is also embedded to highlight the saliency information of the objects, which makes the network training can be more targeted, thereby eventually improving the model performance for classification. The evaluation experiments of the proposed model are carried out on an urban dataset from Houston, USA, and a rural dataset from Trento, Italy. The overall accuracy (OA) of the model can reach 95.03% on the Houston data and 99.16% on the Trento data. The experimental results fully demonstrate that the proposed model has competitive performance compared with several state-of-the-art methods.

Local Information Interaction Transformer for Hyperspectral and LiDAR Data Classification

The multisource remote sensing classification task has two main challenges. 1) How to capture hyperspectral image (HSI) and light detection and ranging (LiDAR) features cooperatively to fully mine the complementary information between data. 2) How to adaptively fuse multisource features, which should not only overcome the imbalance between HSI and LiDAR data but also avoid the generation of redundant information. The local information interaction transformer (LIIT) model proposed herein can effectively address these above issues. Specifically, multibranch feature embedding is first performed to help in the fine-grained serialization of multisource features; subsequently, a local-based multisource feature interactor (L-MSFI) is designed to explore HSI and LiDAR features together. This structure provides an information transmission environment for multibranch features and further alleviates the homogenization processing mode of the self-attention process. More importantly, a multisource feature selection module (MSTSM) is developed to dynamically fuse HSI and LiDAR features to solve the problem of insufficient fusion. Experiments were carried out on three multisource remote-sensing classification datasets, the results of which show that LIIT has more performance advantages than the state-of-the-art CNN and transformer methods.

Collaborative Contrastive Learning for Hyperspectral and LiDAR Classification

Using single-source remote sensing (RS) data for classification of ground objects has certain limitations, however, multi-modal RS data contain different types of features, such as spectral features and spatial features of hyperspectral image (HSI) and elevation information of light detection and ranging (LiDAR) data, which can be used to extract and fuse high-quality features to improve the classification accuracy. Nevertheless, the existing fusion techniques are mostly limited by the number of labeled samples due to the difficulty of label collection in the multi-modal RS data. In this article, a fusion method of collaborative contrastive learning (CCL) is proposed to tackle the abovementioned issues for HSI and LiDAR data classification. The proposed CCL approach includes two stages of pre-training (CCL-PT) and fine-tuning (CCL-FT). In the CCL-PT stage, a collaborative strategy is introduced into contrastive learning (CL), which can extract features from HSI and LiDAR data separately, and achieve the coordinated feature representation and matching between the two-modal RS data without labeled samples. In the CCL-FT stage, a multi-level fusion network is designed to optimize and fuse the unsupervised collaborative features which are extracted in the CCL-PT stage for the classification tasks. Experimental results on three real-world data sets show that the developed CCL approach can perform excellently on the small sample classification tasks and CL is feasible for the fusion of multi-modal RS data.

Nearest Neighbor-Based Contrastive Learning for Hyperspectral and LiDAR Data Classification

The joint hyperspectral image (HSI) and light detection and ranging (LiDAR) data classification aims to interpret ground objects at more detailed and precise level. Although deep learning methods have shown remarkable success in the multisource data classification task, self-supervised learning has rarely been explored. It is commonly nontrivial to build a robust self-supervised learning model for multisource data classification, due to the fact that the semantic similarities of neighborhood regions are not exploited in the existing contrastive learning framework. Furthermore, the heterogeneous gap induced by the inconsistent distribution of multisource data impedes the classification performance. To overcome these disadvantages, we propose a nearest neighbor-based contrastive learning network (NNCNet), which takes full advantage of large amounts of unlabeled data to learn discriminative feature representations. Specifically, we propose a nearest neighbor-based data augmentation scheme to use enhanced semantic relationships among nearby regions. The intermodal semantic alignments can be captured more accurately. In addition, we design a bilinear attention module to exploit the second-order and even high-order feature interactions between the HSI and LiDAR data. Extensive experiments on four public datasets demonstrate the superiority of our NNCNet over state-of-the-art methods. The source codes are available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/summitgao/NNCNet</uri> .

Multimodal Attention-Aware Convolutional Neural Networks for Classification of Hyperspectral and LiDAR Data

The attention mechanism is one of the most influential ideas in the deep learning community, which has shown excellent efficiency in various computer vision tasks. Thus, this article proposes the convolution neural network method with the attention mechanism to enhance the feature extraction of light detection and ranging (LiDAR) data. Meanwhile, our elaborately designed cascaded block contains a short path architecture beneficial for multistage information exchange. With the full exploitation of elevation information from LiDAR data and efficient utilization of the spatial-spectral information underlying hyperspectral data, our method provides a novel solution for multimodal feature fusion. Experiments are conducted on the LiDAR and hyperspectral dataset provided by the 2013 IEEE GRSS Data Fusion Contest and multisource Trento dataset to demonstrate the effectiveness of the proposed method. The experimental results have shown the superior results of the proposed method on both LiDAR and multimodality remote sensing data in comparison with several popular baselines.

Joint Classification of Hyperspectral and LiDAR Data Using a Hierarchical CNN and Transformer

The joint use of multisource remote-sensing (RS) data for Earth observation missions has drawn much attention. Although the fusion of several data sources can improve the accuracy of land-cover identification, many technical obstacles, such as disparate data structures, irrelevant physical characteristics, and a lack of training data, exist. In this article, a novel dual-branch method, consisting of a hierarchical convolutional neural network (CNN) and a transformer network, is proposed for fusing multisource heterogeneous information and improving joint classification performance. First, by combining the CNN with a transformer, the proposed dual-branch network can significantly capture and learn spectral–spatial features from hyperspectral image (HSI) data and elevation features from light detection and ranging (LiDAR) data. Then, to fuse these two sets of data features, a cross-token attention (CTA) fusion encoder is designed in a specialty. The well-designed deep hierarchical architecture takes full advantage of the powerful spatial context information extraction ability of the CNN and the strong long-range dependency modeling ability of the transformer network based on the self-attention (SA) mechanism. Four standard datasets are used in experiments to verify the effectiveness of the approach. The experimental results reveal that the proposed framework can perform noticeably better than state-of-the-art methods. The source code of the proposed method will be available publicly at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/zgr6010/Fusion_HCT.git</uri> .

Coupled adversarial learning for fusion classification of hyperspectral and LiDAR data

Hyperspectral image (HSI) provides rich spectral–spatial information and the light detection and ranging (LiDAR) data reflect the elevation information, which can be jointly exploited for better land-cover classification. However, due to different imaging mechanisms, HSI and LiDAR data always present significant image difference, current pixel-wise feature fusion classification methods relying on concatenation or weighted fusion are not effective. To achieve accurate classification result, it is important to extract and fuse similar high-order semantic information and complementary discriminative information contained in multimodal data. In this paper, we propose a novel coupled adversarial learning based classification (CALC) method for fusion classification of HSI and LiDAR data. In specific, a coupled adversarial feature learning (CAFL) sub-network is first trained, to effectively learn the high-order semantic features from HSI and LiDAR data in an unsupervised manner. On one hand, the proposed CAFL sub-network establishes an adversarial game between dual generators and discriminators, so that the learnt features can preserve detail information in HSI and LiDAR data, respectively. On the other hand, by designing weight-sharing and linear fusion structure in the dual generators, we can simultaneously extract similar high-order semantic information and modal-specific complementary information. Meanwhile, a supervised multi-level feature fusion classification (MFFC) sub-network is trained, to further improve the classification performance via adaptive probability fusion strategy. In brief, the low-level, mid-level and high-level features learnt by the CAFL sub-network lead to multiple class estimation probabilities, which are then adaptively combined to generate a final accurate classification result. Both the CAFL and MFFC sub-networks are collaboratively trained by optimizing a designed joint loss function, which consists of unsupervised adversarial loss and supervised classification loss. Overall, by optimizing the joint loss function, the proposed CALC network is pushed to learn highly discriminative fusion features from multimodal data, leading to higher classification accuracies. Extensive experiments on three well-known HSI and LiDAR data sets demonstrate the superior classification performance by the proposed CALC method than several state-of-the-art methods. The source code of the proposed method will be made publicly available at https://github.com/Ding-Kexin/CALC.

Hyperspectral and LiDAR Data Classification Using Joint CNNs and Morphological Feature Learning

Convolutional Neural Networks (CNNs) have been extensively utilized for Hyperspectral (HSI) as well as Light Detection and Ranging (LiDAR) data Classification. However, CNNs have not been much explored for joint HSI and LiDAR image classification. Therefore, this article proposes a joint feature learning (HSI and LiDAR) and fusion mechanism using CNN and Spatial Morphological blocks which generates highly accurate land-cover maps. The CNN model comprises three Conv3D layers and is directly applied to the HSIs for extracting discriminative spectral-spatial feature representation. On the contrary, the spatial morphological block is able to capture the information relevant to the height or shape of the different land-cover regions from LiDAR data. The LiDAR features are extracted using morphological dilation and erosion layers which increase the robustness of the proposed model by considering elevation information as an additional feature. Finally, both the obtained features from CNNs and spatial morphological blocks are combined using an additive operation prior to the classification. Extensive experiments are shown with widely used HSIs and LiDAR datasets, i.e., University of Houston (UH), Trento, and MUUFL Gulfport scene. The reported results show that the proposed model significantly outperforms traditional methods and other state-of-the-art deep learning models. The source code for the proposed model will be made available publicly at https://github.com/AnkurDeria/HSI+LiDAR.

Multiview Hierarchical Network for Hyperspectral and LiDAR Data Classification

In recent times, multisource remote sensing technology [e.g., hyperspectral image (HSI) and light detection and ranging (LiDAR) data] has been widely used in urban land-use recognition owing to its high classification effectiveness compared to using only single-source data. In this study, a multiview hierarchical network (MVHN) technique is developed for HSI and LiDAR data classification, which conducts the following execution procedures. First, based on the a preset band step length, the original HSI is sampled and divided into multiple groups with exactly the same number of bands to obtain spectral features. Then, principal components analysis is performed on the raw HSI to extract the first principal components (PCs) that meet the size of the LiDAR image. The Gabor filters are applied to the PCs and LiDAR to capture spatial details (i.e., textural features) of scenes. Specifically, a stacking mechanism is employed to generate fusion features once the above features are available. Next, a three-dimensional ResNet-like deep CNN is designed to extract the spectral–spatial information of the fusion feature. Finally, majority-voting is introduced into the classification results of the network trained using each fusion feature to achieve high-confidence final results. Experiments on three well-known HSI and LiDAR datasets (i.e., Houston, MUUFL, and Trento datasets) demonstrate the effectiveness of the proposed MVHN method compared to state-of-the-art comparable classification methods.

MSLAENet: Multiscale Learning and Attention Enhancement Network for Fusion Classification of Hyperspectral and LiDAR Data

The effective use of multimodal data to obtain accurate land cover information has become an interesting and challenging research topic in the field of remote sensing. In this paper, we propose a new method, multi-scale learning and attention enhancement network (MSLAENet), to implement Hyperspectral image (HSI) and light detection and ranging (LiDAR) data fusion classification in an end-to-end manner. Specifically, our model consists of three main modules. First, we design the composite attention (CA) module, which adopts self-attention to enhance the feature representations of HSI and LiDAR data, respectively, and cross-attention to achieve cross-modal information enhancement. Second, the proposed multi-scale learning (MSL) module combines self-calibrated convolutions and hierarchical residual structure to extract different scales of information to further improve the representation capability of the model. Finally, the attention-based feature fusion (FF) module fully considers the complementary information properties between different modalities and adaptively fuses heterogeneous features from different modalities. To test the performance of MSLAENet, we conduct experiments on three multimodal remote sensing datasets and compare them with the state-of-the-art fusion model, which demonstrates the effectiveness and superiority of the model.

A Triplet Semisupervised Deep Network for Fusion Classification of Hyperspectral and LiDAR Data

Data fusion of hyperspectral and light detection and ranging (LiDAR) is conducive to obtain more comprehensive surface information and thereby achieve better classification result in Earth Monitoring Systems. However, lack of labeled samples usually limits the performance of supervised classifiers, and the heterogeneity of multi-source data also brings great challenges to data fusion. Aiming to address these issues, we propose a triplet semi-supervised deep convolutional neural network (TSDN) for fusion classification of hyperspectral and LiDAR. Specifically, we utilize three basic pathways to extract deep learning features: 1D-CNN for spectral features in hyperspectral, 2D-CNN for spatial features in hyperspectral and Cascade Net for elevation features in LiDAR data. Furthermore, a novel label calibration module (LCM) is proposed to generate effective pseudo labels with high confidence based on the superpixel segmentation by comparing the multi-view classification results for assisting semi-supervised model training. In addition, we design a novel 3D-Cross Attention Block to enhance the complementary spatial features of multi-source data. Experiments on three public HSI-LiDAR benchmarks: Houston, Trento, and MUUFL Gulfport have demonstrated the effectiveness and superiority of our proposed method.

Global–Local Transformer Network for HSI and LiDAR Data Joint Classification

Hyperspectral images (HSI) contain rich spatial and spectral detail information, while light detection and ranging (LiDAR) data can provide the elevation information. Thus, the fusion of HSI and LiDAR data can help for more accurate image classification, which becomes a hot research topic. However, it is difficult to capture complex local and global spatial-spectral associations, meanwhile, how to build an effective interaction between multi-modal data is another important issue. To this end, a novel global-local transformer network (GLT-Net) is proposed for the joint classification of HSI and LiDAR data, in this paper. The main idea is to fully exploit the advantage of the convolution operator in characterizing locally correlated features and the promising capability of transformer architecture in learning long-range dependencies. Moreover, multi-scale feature fusion and probabilistic decision fusion strategies are also designed in one framework, in order to further improve classification performance. Here, the proposed GLT-Net mainly consists of multi-scale local spatial feature learning, global spectral feature learning, and global-local feature fusion classification. In specific, multi-modal image cubes of different sizes are firstly extracted and sent into convolutional neural networks (CNNs) to learn local spatial features, which is followed by multi-modal information propagation and spatial-attention guided multi-scale feature fusion. Afterwards, by considering spectral feature channels from a sequential perspective, vision transformers are introduced to model the global spectral dependencies. Finally, multiple class estimations based on local and global features are integrated via a probabilistic decision fusion strategy. In this way, complementary information of multi-modal data as well as local/global spectral-spatial information can be fully mined and jointly utilized. Extensive experiments on three popular HSI and LiDAR datasets demonstrate that the proposed method performs superiority over state-of-the-art methods. The source code of the proposed method will be made publicly available at https://github.com/Ding-Kexin/GLT-Net.

Detection of urban features by multilevel classification of multispectral airborne LiDAR data fused with very high-resolution images

A complex pattern of urban demographic transition has been taking shape since the onset of the COVID-19 pandemic. The long-standing rural-to-urban route of population migration that has propelled waves of massive urbanization over the decades is increasingly being juxtaposed with a reverse movement, as the pandemic drives urban dwellers to suburban communities. The changing dynamics of the flow of residents to and from urban areas underscore the necessity of comprehensive urban land-use mapping for urban planning/management/assessment. These maps are essential for anticipating the rapidly evolving demands of the urban populace and mitigating the environmental and social consequences of uncontrolled urban expansion. The integration of light detection and ranging (LiDAR) and imagery data provides an opportunity for urban planning projects to take advantage of its complementary geometric and radiometric characteristics, respectively, with a potential increase in urban mapping accuracies. We enhance the color-based segmentation algorithm for object-based classification of multispectral LiDAR point clouds fused with very high-resolution imagery data acquired for a residential urban study area. We propose a multilevel classification using multilayer perceptron neural networks through vectors of geometric and spectral features structured in different classification scenarios. After an investigation of all classification scenarios, the proposed method achieves an overall mapping accuracy exceeding 98%, combining the original and calculated feature vectors and their output space projected by principal components analysis. This combination also eliminates some misclassifications among classes. We used splits of training, validation, and testing subsets and the k-fold cross-validation to quantitatively assess the classification scenarios. The proposed work improves the color-based segmentation algorithm to fit object-based classification applications and examines multiple classification scenarios. The presented scenarios prove superiority in developing urban mapping accuracies. The various feature spaces suggest the best urban mapping applications based on the available characteristics of the obtained data.

LiDAR Data Classification Based on Automatic Designed CNN

Recently, convolutional neural networks (CNNs) have been widely used for light detection and ranging (LiDAR) data classification. Although CNNs achieve good classification performance for LiDAR data classification, a lot of efforts are needed to design a proper architecture. In this letter, the automatic modularized design of CNN is explored for LiDAR data classification for the first time. First, a searchable architecture containing convolution and pooling operations is used to establish the search space. Then, the optimal building block (i.e., cell), which is the basic part of a deep CNN, is obtained from search space by a gradient decent-based algorithm. At last, by stacking several optimal building blocks, a deep CNN can be formulated for LiDAR data classification. Moreover, in order to mitigate the overfitting problem in training a CNN, improved label smoothing and feature regularization are proposed to further improve the classification performance of LiDAR data. The proposed classification models are evaluated on two popular LiDAR data sets (i.e., the Bayview Park and Houston data sets). The experimental results show that the proposed models provide the competitive results compared to the state-of-the-art methods.

Land Cover Classification of Multispectral LiDAR Data With an Efficient Self-Attention Capsule Network

Periodically conducting land cover mapping plays a vital role in monitoring the status and changes of the land use. The up-to-date and accurate land use database serves importantly for a wide range of applications. This letter constructs an efficient self-attention capsule network (ESA-CapsNet) for land cover classification of multispectral light detection and ranging (LiDAR) data. First, formulated with a novel capsule encoder–decoder architecture, the ESA-CapsNet performs promisingly in extracting high-level, informative, and strong feature semantics for pixel-wise land cover classification by using the five types of rasterized feature images. Furthermore, designed with a novel capsule-based attention module, the channel and spatial feature encodings are comprehensively exploited to boost the feature saliency and robustness. The ESA-CapsNet is evaluated on two multispectral LiDAR data sets and achieves an advantageous performance with the overall accuracy, average accuracy, and kappa coefficient of over 98.42%, 95.15%, and 0.9776, respectively. Comparative experiments with the existing methods also demonstrate the effectiveness and applicability of the ESA-CapsNet in land cover classification tasks.

Tree species classification of LiDAR data based on 3D deep learning

Accurate tree species identification is essential for ecological evaluation and other forest applications. In this paper, we proposed a point-based deep neural network called LayerNet. For light detection and ranging (LiDAR) data in forest regions, the network can divide multiple overlapping layers in Euclidean space to obtain the local three-dimensional (3D) structural features of the tree. The features of all layers are aggregated, and the global feature is obtained by convolution to classify the tree species. To validate the proposed framework, multiple experiments, including airborne and ground-based LiDAR datasets, are conducted and compared with several existing tree species classification algorithms. The test results show that LayerNet can directly use 3D data to accurately classify tree species, with the highest classification accuracy of 92.5%. Also, the results of comparative experiments demonstrate that the proposed framework has obvious advantages in classification accuracy and provides an effective solution for tree species classification tasks.

Classification of raw LiDAR point cloud using point-based methods with spatial features for 3D building reconstruction

Building extraction from light detection and ranging (LiDAR) data for 3-dimensional (3D) reconstruction requires accurately classified LiDAR points. In recent years, approaches developed for the classification mostly based on gridded LiDAR data. In the gridding process of LiDAR data, there is a characteristic point loss which results in reduced height accuracy. The effect of such loss can be eliminated using classified raw LiDAR data. In this study, an automatic point-based classification approach for raw LiDAR data classification with spatial features has been proposed for 3D building reconstruction. Using spatial features, the hierarchical rules have been determined. The spatial features, such as height, the local environment, and multi-return, of the LiDAR points were analyzed, and every single LiDAR points automatically assigned to the classes based on these features. The proposed classification approach based on raw LiDAR data had an overall accuracy of 79.7% in the test site located in Istanbul, Turkey. Finally, 3D building reconstruction was performed using the results of the proposed automatic point-based classification approach.