Bikram Koirala

ORCID: 0000-0002-8887-8197
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Research Areas
  • Remote-Sensing Image Classification
  • Advanced Image Fusion Techniques
  • Remote Sensing and Land Use
  • Remote Sensing in Agriculture
  • Spectroscopy and Chemometric Analyses
  • Smart Agriculture and AI
  • Image and Signal Denoising Methods
  • Date Palm Research Studies
  • Leaf Properties and Growth Measurement
  • Soil Moisture and Remote Sensing
  • Image Enhancement Techniques
  • Industrial Vision Systems and Defect Detection
  • Soil Geostatistics and Mapping
  • Color Science and Applications
  • Field-Flow Fractionation Techniques
  • High-Temperature Coating Behaviors
  • Infrastructure Maintenance and Monitoring
  • Planetary Science and Exploration
  • Cultural Heritage Materials Analysis
  • Sparse and Compressive Sensing Techniques
  • Building materials and conservation
  • Silymarin and Mushroom Poisoning
  • Mass Spectrometry Techniques and Applications
  • Conservation Techniques and Studies
  • Advanced Data Compression Techniques

University of Houston
2023-2024

University of Antwerp
2018-2024

Transformers have intrigued the vision research community with their state-of-the-art performance in natural language processing. With superior performance, transformers found way field of hyperspectral image classification and achieved promising results. In this article, we harness power to conquer task unmixing propose a novel deep neural network-based model transformers. A transformer network captures nonlocal feature dependencies by interactions between patches, which are not employed...

10.1109/tgrs.2022.3196057 article EN IEEE Transactions on Geoscience and Remote Sensing 2022-01-01

In this article, we introduce a deep learning-based technique for the linear hyperspectral unmixing problem. The proposed method contains two main steps. First, endmembers are extracted using geometric endmember extraction method, i.e., simplex volume maximization in subspace of data set. Then, abundances estimated image prior. motivation work is to boost abundance estimation and make problem robust noise. prior uses convolutional neural network estimate fractional abundances, relying on...

10.1109/tgrs.2021.3067802 article EN IEEE Transactions on Geoscience and Remote Sensing 2021-03-31

In this article, we propose a minimum simplex convolutional network (MiSiCNet) for deep hyperspectral unmixing. Unlike all the learning-based unmixing methods proposed in literature, encoder–decoder architecture incorporates spatial information and geometrical of data addition to spectral information. The is incorporated using filters implicitly applying prior on abundances. exploited by incorporating volume penalty term loss function endmember estimation. This beneficial when there are no...

10.1109/tgrs.2022.3146904 article EN IEEE Transactions on Geoscience and Remote Sensing 2022-01-01

In this letter, we propose a sparse unmixing technique using convolutional neural network (SUnCNN) for hyperspectral images. SUnCNN is the first deep learning-based proposed unmixing. It uses encoder–decoder to generate abundances relying on spectral library. We reformulate into an optimization over network's parameters. Therefore, learns in unsupervised manner map fixed input optimum abundances. Additionally, holds sum-to-one constraint softmax activation layer. The method compared with...

10.1109/lgrs.2021.3100992 article EN IEEE Geoscience and Remote Sensing Letters 2021-08-06

Accurate anatomical matching for patient-specific electromyographic (EMG) mapping is crucial yet technically challenging in various medical disciplines. The fixed electrode construction of multielectrode arrays (MEAs) makes it nearly impossible to match an individual's unique muscle anatomy. This mismatch between the MEAs and target muscles leads missing relevant activity, highly redundant data, complicated placement optimization, inaccuracies classification algorithms. Here, we present...

10.1093/pnasnexus/pgac291 article EN cc-by PNAS Nexus 2023-01-01

This paper proposes a blind nonlinear unmixing technique for intimate mixtures using the Hapke model and convolutional neural networks (HapkeCNN). We use fully encoder-decoder deep network unmixing. Additionally, we propose novel loss function that includes three terms; 1) quadratic term based on model, captures nonlinearity, 2) reconstruction error of reflectances, to ensure fidelity reconstructed reflectance, 3) minimum volume total variation exploits geometrical information estimate...

10.1109/tgrs.2022.3202490 article EN IEEE Transactions on Geoscience and Remote Sensing 2022-01-01

Button mushrooms (Agaricus bisporus) grow in multilayered Dutch shelves with limited space between two shelves. As an alternative to conventional hand-picking, automated harvesting recent times has gained widespread popularity. However, of faces critical challenges the form growing environment, spaces, picking forces, and efficiency. End effectors for button are integral part process. The end developed so far oversized, bulky, slow thus unsuitable commercial mushroom applications. This paper...

10.3390/act13080287 article EN cc-by Actuators 2024-07-29

The mushroom farming industry struggles to automate harvesting due limited large-scale annotated datasets and the complex growth patterns of mushrooms, which complicate detection, segmentation, pose estimation. To address this, we introduce a synthetic dataset with 40,000 unique scenes white Agaricus bisporus brown baby bella capturing realistic variations in quantity, position, orientation, stages. Our two-stage estimation pipeline combines 2D object detection instance segmentation 3D point...

10.20944/preprints202501.2361.v1 preprint EN 2025-01-31

Automating agricultural processes holds significant promise for enhancing efficiency and sustainability in various farming practices. This paper contributes to the automation of by providing a dedicated mushroom detection dataset related automated harvesting, 3D pose estimation, growth monitoring button produced using Agaricus Bisporus fungus. With total 2,000 images object detection, instance segmentation, estimation containing over 100,000 instances an additional 3,838 yield 8 scenes...

10.20944/preprints202504.2103.v1 preprint EN 2025-04-25

Due to the complex interaction of light with moist soils, soil moisture content (SMC) is hard estimate from spectral reflectance. Spectral variability, caused by variations in viewing and illumination angle between-sensor further complicates estimation. In this work, we developed a supervised methodology accurately SMC The method determines proxy for soil, making use reflectance spectra an air-dried saturated sample. made invariant angle, sensor type. next step, normalized respect...

10.1109/tgrs.2022.3212600 article EN IEEE Transactions on Geoscience and Remote Sensing 2022-01-01

Optical hyperspectral cameras (HSCs) capture the spectral reflectance of materials. Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, relationship between and material composition is very complex. Quantitative validation unmixing algorithms requires high-quality ground-truth fractional abundance data, are difficult to obtain. In this work, we generated a comprehensive laboratory dataset intimately mixed mineral powders. For this,...

10.1109/jsen.2023.3343552 article EN IEEE Sensors Journal 2023-12-28

10.1109/tgrs.2024.3422495 article EN IEEE Transactions on Geoscience and Remote Sensing 2024-01-01

Due to the complex interaction of light with Earth’s surface, reflectance spectra can be described as highly nonlinear mixtures reflectances material constituents occurring in a given resolution cell hyperspectral data. Our aim is estimate fractional abundance maps materials from The main disadvantage using mixing models that model parameters are not properly interpretable terms abundances. Moreover, all dataset necessarily follow same particular model. In this work, we present supervised...

10.3390/rs11202458 article EN cc-by Remote Sensing 2019-10-22

Spectral measurements are commonly applied for the nondestructive estimation of leaf parameters, such as concentrations chlorophyll a and b, carotenoid, anthocyanin, brown pigment, water content, mass per area quantification vegetation physiology. The most popular way to estimate these parameters is by using spectral indices. use biochemical models allows us full wavelength range (400-2500 nm) physically interpret result. However, their performance usually lower than that supervised machine...

10.1109/tgrs.2020.2982263 article EN IEEE Transactions on Geoscience and Remote Sensing 2020-04-02

Due to the complex interaction of light with mixed materials, reflectance spectra are highly nonlinearly related pure material endmember spectra, making it hard estimate fractional abundances materials. Changing illumination conditions and cross-sensor situations cause spectral variability, further complicating unmixing procedure. In this work, we propose a supervised approach unmix mineral powder mixtures, containing variability. First, estimated by calculating geodesic distances between...

10.1109/tgrs.2020.3031012 article EN IEEE Transactions on Geoscience and Remote Sensing 2020-10-30

Hyperspectral linear unmixing and denoising are highly related hyperspectral image (HSI) analysis tasks. In particular, with the assumption of Gaussian noise, model assumed for HSI in case low-rank is often same as one used unmixing. However, optimization criterion assumptions on constraints different. Additionally, noise reduction a preprocessing step data ignored. The main goal this paper to study experimentally influence process by: (1) investigating effect performance unmixing; (2)...

10.3390/rs12111728 article EN cc-by Remote Sensing 2020-05-28

In this work, we studied the potential of visible, near-infrared, and shortwave infrared wavelength regions for monitoring oil spill incidents using optical reflectance. First, a simple physical model was designed accurate thickness volume estimation The developed method made invariant to changes in acquisition illumination conditions. next step, an algorithm based on artificial neural network detect spilled oil. training samples that are required optimize parameters were generated by...

10.3390/rs15204950 article EN cc-by Remote Sensing 2023-10-13

10.1109/tgrs.2024.3505292 article EN IEEE Transactions on Geoscience and Remote Sensing 2024-01-01

Because of the complex interaction light with Earth surface, a hyperspectral pixel can be composed highly nonlinear mixture reflectances materials on ground. When mixing models are applied, estimated model parameters usually hard to interpret and link actual fractional abundances. Moreover, not all spectral in real scene follow same particular model. In this paper, we present supervised learning method for unmixing. method, neural network is applied learn mappings true that would obtained if...

10.1109/igarss.2018.8518995 article EN IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium 2018-07-01

Currently, this paper is under review in IEEE. Transformers have intrigued the vision research community with their state-of-the-art performance natural language processing. With superior performance, transformers found way field of hyperspectral image classification and achieved promising results. In article, we harness power to conquer task unmixing propose a novel deep model transformers. We aim utilize ability better capture global feature dependencies order enhance quality endmember...

10.48550/arxiv.2203.17076 preprint EN cc-by arXiv (Cornell University) 2022-01-01

In this work, we propose a supervised framework for spectral unmixing of binary intimate mixtures. The core idea is based on geodesic distance measurements and regression to estimate the fractional abundances. main assumption that reflectances mixtures form curve between two endmembers, mixture's relative position serves as an indicator its We four novel approaches approximate position. From this, abundances are obtained using Gaussian process regression. proposed simultaneously copes with...

10.1109/jstars.2024.3387750 article EN cc-by-nc-nd IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2024-01-01
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