scholarly journals Low resolution accelerometers can be used to develop time-energy budgets of wild fur seals from captive surrogates

2018 ◽  
Author(s):  
Monique A Ladds ◽  
Marcus Salton ◽  
David P Hocking ◽  
Rebecca R McIntosh ◽  
Adam P Thompson ◽  
...  
Keyword(s):  
High Resolution ◽  
Energy Expenditure ◽  
Energetic Cost ◽  
Energy Budgets ◽  
Gradient Boosting ◽  
Low Resolution ◽  
Fur Seals ◽  
Long Duration ◽  
Fur Seal ◽  
Significant Difference

Background. Accurate time-energy budgets summarise an animal’s energy expenditure in a given environment and are potentially a sensitive indicator of how an animal responds to changing resources. Deriving accurate time-energy budgets requires a precise measure of time spent in different activities, and an estimate of the energetic cost of that activity. Bio-loggers such as accelerometers may provide a solution for monitoring animals such as fur seals that make long-duration foraging trips over multiple days or weeks. Monitoring such behaviour may require low resolution recording due to the memory constraints of bio-loggers. The aim of this study was to evaluate if accelerometers recording at a low resolution could accurately classify and determine the cost of fur seal activity. Methods. Diving and movement data were collected from nine wild juvenile Australian fur seals equipped with tri-axial accelerometers. To validate time-energy budgets for the fur seals, energy consumption during a range of behaviours was determined from twelve captive surrogates. The time wild fur seals spent in four behavioural states - foraging, grooming, travelling and resting - was quantified with low- and high-resolution data from accelerometers using gradient boosting models (GBM). The daily energy expenditure (DEE) from these four activities was estimated using a relatively simple energetics model developed using their location (land, surface or underwater) and estimates of the energetic cost of each behaviour. Models developed from captive seals were applied to accelerometry data collected from wild juvenile Australian fur seals and their time-energy budgets were reconstructed. Results. Low resolution accelerometery was better at classifying fur seal behaviour over long durations than high resolution accelerometry in captive surrogates. The low resolution model was therefore applied to wild data. This revealed that Juvenile fur seals expended more energy than adults of similar species, but there was no significant difference in DEE across sex or season (winter or summer). Juvenile fur seals used behavioural compensatory techniques to conserve energy during activities that were expected to have high energetic outputs (such as diving). Discussion. Behaviours that are displayed over a long duration can be captured accurately by low-resolution accelerometry and these models can be used to develop time-energy budgets of wild animals. In this study we were able to use such models to monitor juvenile fur seals over multiple foraging trips. This revealed that juvenile fur seals appear to be working energetically harder than their adult counterparts, likely due to the relative novelty of diving and foraging, their smaller body size and the additional cost of growth they sustain. Developing time-energy budgets from accelerometers is an efficient method of estimating energy expenditure from individuals over time.

scholarly journals Low resolution accelerometers can be used to develop time-energy budgets of wild fur seals from captive surrogates

2018 ◽  
Author(s):  
Monique A Ladds ◽  
Marcus Salton ◽  
David P Hocking ◽  
Rebecca R McIntosh ◽  
Adam P Thompson ◽  
...  
Keyword(s):  
High Resolution ◽  
Energy Expenditure ◽  
Energetic Cost ◽  
Energy Budgets ◽  
Gradient Boosting ◽  
Low Resolution ◽  
Fur Seals ◽  
Long Duration ◽  
Fur Seal ◽  
Significant Difference

Background. Accurate time-energy budgets summarise an animal’s energy expenditure in a given environment and are potentially a sensitive indicator of how an animal responds to changing resources. Deriving accurate time-energy budgets requires a precise measure of time spent in different activities, and an estimate of the energetic cost of that activity. Bio-loggers such as accelerometers may provide a solution for monitoring animals such as fur seals that make long-duration foraging trips over multiple days or weeks. Monitoring such behaviour may require low resolution recording due to the memory constraints of bio-loggers. The aim of this study was to evaluate if accelerometers recording at a low resolution could accurately classify and determine the cost of fur seal activity. Methods. Diving and movement data were collected from nine wild juvenile Australian fur seals equipped with tri-axial accelerometers. To validate time-energy budgets for the fur seals, energy consumption during a range of behaviours was determined from twelve captive surrogates. The time wild fur seals spent in four behavioural states - foraging, grooming, travelling and resting - was quantified with low- and high-resolution data from accelerometers using gradient boosting models (GBM). The daily energy expenditure (DEE) from these four activities was estimated using a relatively simple energetics model developed using their location (land, surface or underwater) and estimates of the energetic cost of each behaviour. Models developed from captive seals were applied to accelerometry data collected from wild juvenile Australian fur seals and their time-energy budgets were reconstructed. Results. Low resolution accelerometery was better at classifying fur seal behaviour over long durations than high resolution accelerometry in captive surrogates. The low resolution model was therefore applied to wild data. This revealed that Juvenile fur seals expended more energy than adults of similar species, but there was no significant difference in DEE across sex or season (winter or summer). Juvenile fur seals used behavioural compensatory techniques to conserve energy during activities that were expected to have high energetic outputs (such as diving). Discussion. Behaviours that are displayed over a long duration can be captured accurately by low-resolution accelerometry and these models can be used to develop time-energy budgets of wild animals. In this study we were able to use such models to monitor juvenile fur seals over multiple foraging trips. This revealed that juvenile fur seals appear to be working energetically harder than their adult counterparts, likely due to the relative novelty of diving and foraging, their smaller body size and the additional cost of growth they sustain. Developing time-energy budgets from accelerometers is an efficient method of estimating energy expenditure from individuals over time.

scholarly journals Using accelerometers to develop time-energy budgets of wild fur seals from captive surrogates

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5814 ◽  
Author(s):  
Monique A. Ladds ◽  
Marcus Salton ◽  
David P. Hocking ◽  
Rebecca R. McIntosh ◽  
Adam P. Thompson ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
High Accuracy ◽  
Energetic Cost ◽  
Energy Budgets ◽  
Similar Species ◽  
Low Resolution ◽  
Sea Lions ◽  
Movement Data ◽  
Fur Seals ◽  
Very High

BackgroundAccurate time-energy budgets summarise an animal’s energy expenditure in a given environment, and are potentially a sensitive indicator of how an animal responds to changing resources. Deriving accurate time-energy budgets requires an estimate of time spent in different activities and of the energetic cost of that activity. Bio-loggers (e.g., accelerometers) may provide a solution for monitoring animals such as fur seals that make long-duration foraging trips. Using low resolution to record behaviour may aid in the transmission of data, negating the need to recover the device.MethodsThis study used controlled captive experiments and previous energetic research to derive time-energy budgets of juvenile Australian fur seals (Arctocephalus pusillus)equipped with tri-axial accelerometers. First, captive fur seals and sea lions were equipped with accelerometers recording at high (20 Hz) and low (1 Hz) resolutions, and their behaviour recorded. Using this data, machine learning models were trained to recognise four states—foraging, grooming, travelling and resting. Next, the energetic cost of each behaviour, as a function of location (land or water), season and digestive state (pre- or post-prandial) was estimated. Then, diving and movement data were collected from nine wild juvenile fur seals wearing accelerometers recording at high- and low- resolutions. Models developed from captive seals were applied to accelerometry data from wild juvenile Australian fur seals and, finally, their time-energy budgets were reconstructed.ResultsBehaviour classification models built with low resolution (1 Hz) data correctly classified captive seal behaviours with very high accuracy (up to 90%) and recorded without interruption. Therefore, time-energy budgets of wild fur seals were constructed with these data. The reconstructed time-energy budgets revealed that juvenile fur seals expended the same amount of energy as adults of similar species. No significant differences in daily energy expenditure (DEE) were found across sex or season (winter or summer), but fur seals rested more when their energy expenditure was expected to be higher. Juvenile fur seals used behavioural compensatory techniques to conserve energy during activities that were expected to have high energetic outputs (such as diving).DiscussionAs low resolution accelerometry (1 Hz) was able to classify behaviour with very high accuracy, future studies may be able to transmit more data at a lower rate, reducing the need for tag recovery. Reconstructed time-energy budgets demonstrated that juvenile fur seals appear to expend the same amount of energy as their adult counterparts. Through pairing estimates of energy expenditure with behaviour this study demonstrates the potential to understand how fur seals expend energy, and where and how behavioural compensations are made to retain constant energy expenditure over a short (dive) and long (season) period.

scholarly journals The energetic cost of parasitism in a wild population

2018 ◽  
Vol 285 (1879) ◽  
pp. 20180489 ◽  
Author(s):  
Olivia Hicks ◽  
Sarah J. Burthe ◽  
Francis Daunt ◽  
Mark Newell ◽  
Adam Butler ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Wild Population ◽  
Population Level ◽  
Parasite Load ◽  
Energetic Cost ◽  
Energy Budgets ◽  
Flight Duration ◽  
Flight Costs ◽  
History Of ◽  
Time And Energy

Parasites have profound fitness effects on their hosts, yet these are often sub-lethal, making them difficult to understand and quantify. A principal sub-lethal mechanism that reduces fitness is parasite-induced increase in energetic costs of specific behaviours, potentially resulting in changes to time and energy budgets. However, quantifying the influence of parasites on these costs has not been undertaken in free-living animals. We used accelerometers to estimate energy expenditure on flying, diving and resting, in relation to a natural gradient of endo-parasite loads in a wild population of European shags Phalacrocorax aristotelis . We found that flight costs were 10% higher in adult females with higher parasite loads and these individuals spent 44% less time flying than females with lower parasite loads. There was no evidence for an effect of parasite load on daily energy expenditure, suggesting the existence of an energy ceiling, with the increase in cost of flight compensated for by a reduction in flight duration. These behaviour specific costs of parasitism will have knock-on effects on reproductive success, if constraints on foraging behaviour detrimentally affect provisioning of young. The findings emphasize the importance of natural parasite loads in shaping the ecology and life-history of their hosts, which can have significant population level consequences.

High Impact of Human Leukocyte Antigen Matching On Overall Survival and Transplant Related Mortality in Allogeneic Hematopoietic Stem Cell Transplantation for CLL: Long-Term Study From the EBMT Registry.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2286-2286
Author(s):  
Mauricette Michallet ◽  
Mohamad Sobh ◽  
Stéphane Morisset ◽  
Dietger Niederwieser ◽  
Vladimir Koza ◽  
...  
Keyword(s):  
Overall Survival ◽  
High Resolution ◽  
Total Population ◽  
Human Leukocyte ◽  
Disease Status ◽  
Hla Matching ◽  
Low Resolution ◽  
Hematopoietic Stem ◽  
Significant Difference ◽  
Unrelated Donors

Abstract Abstract 2286 Poster Board II-263 Background: The outcomes of related and unrelated donor hematopoietic stem cell transplantations (HSCT) are strongly affected by the degree of human leukocyte antigen (HLA) matching between the transplant recipient and the donor or cord blood unit. HLA matching plays an important role in engraftment, incidence and severity of graft-versus-host disease (GVHD) and also in overall survival; although this factor is still not validated yet in many hematological malignancies. Objective: To evaluate the impact of HLA matching and difference in matching degree among transplants from unrelated donors (UD) on different outcomes in chronic lymphocytic leukemia (CLL). Materials & methods: We have analyzed 370 CLL patients who underwent an allogeneic HSCT reported to the EBMT registry. There were 280 males (75%) and 90 females with a median age of 53 years (24-69). Forty-five patients (12%) have received a previous HSCT. At transplant, 294 among 317 evaluated patients had a good performance status (PS) (93%), 43 patients were in CR (12%), 160 in PR (46%), 44 in SD (13%) and 103 in PD (29%) among 349 evaluated patients. Two hundred and sixty six patients received a reduced intensity conditioning regimen (RIC) and 103 a standard (Std) conditioning; 313 patients received PBSC, 56 BM and 2 cord blood cells from 198 HLA siblings, and 172 unrelated donors (UD). There were 136 (36%) sex-mismatched (91 F/M and 45 M/F), 150 pairs (40%) had an ABO incompatibility (61 minor, 89 major) and for CMV: 78 pairs were +, 146 - and 111 mixed. The median interval between diagnosis and transplantation was 53 months (3-308). According to the registry, there were 198 HLA siblings, 135 matched UD (MUD) and 37 mismatched UD (MMUD). We focused on UD and re-analyzed all HLA typings for patients and donors, after classification we found: 24 well matched (10/10 in high resolution), 28 partially matched (7/7, 8/8 or 9/9 in high resolution), 30 matched in low resolution and 90 mismatched in high resolution, which was different from the registry classification. Results: After transplantation, 359 patients engrafted, 199 developed an AGVHD (gr I: 74, gr II: 79, gr III: 29 and gr IV: 17) and 171 presented a cGVHD (83 limited and 88 extensive). The cumulative incidence of AGVHD for the total population was 22% for gr II and 13% for gr > II. [Siblings: 19% and 12%; well & patially matched: 37% and 10%; low resolution & MMUD: 19.6% and 15.3% for grII & gr > II respectively]. At 1 year after transplant for the total population, the cumulative incidence of limited and extensive cGVHD was 17 % (15-19) and 18.4% (16.4-20.4)[ Siblings: 16.2% (13.6-19) and 17.2% (14.5-20); well & patially matched: 23% (17.2-29) and 23.1% (17.2-29); low resolution & MMUD: 15.8% (12.3-19.1) and 18.3% (14.8-21.8)] respectively. With a median follow up of 48 months, the probability of 3 and 5-years overall survival (OS) for the total population were 62% (56-67) and 52% (45-57) respectively. We found a high significant difference in term of OS between the siblings, well & partially matched groups versus low & MMUD groups (p=0.002) (figure 2). [OS at 3 & 5 years; Siblings: 68.3% (61.8-75.5) and 57.2% (49.8-65.6); well & patially matched: 60.8% (47.6-77.7) and 53.3% (39.2-72.4), low resolution & MMUD: 49% (40.3-59.5) and 38.5% (29.5-50.2) respectively]. We observed also a high significant difference in term of transplant related mortality (TRM) between the same groups (p=0.0022) (figure 4). The multivariate analysis using Cox model studying age, pre-transplant status; gender, PS, cells source, ABO compatibility, conditioning and different HLA groups, showed a significant impact of 4 factors on OS: age: HR=1.04 (1.01-1.6) p=0.001, disease status (PD): HR=3.08 (1.2-7.1) p=0.02, PS: HR=2.37 (1.1-5.1) p=0.02 and HLA MMUD group: HR= 1.62 (1.02-2.59) p=0.03. The same factors were also highly significant in multivariate analysis in term of TRM (age: HR=1.04 (1.001-1.07) p=0.009, disease status (PD): HR=5.49 (1.29-23.4) p=0.02, PS: HR=3.8 (1.7-8.4) p=0.01 and HLA MMUD group: HR= 1.9 (1.07-3.37) p=0.02. Conclusion: This large retrospective analysis pointed out the high impact of HLA matching in terms of OS and TRM (in addition of age, disease status and PS), without any difference between HLA siblings, MUD and partially matched groups. Moreover, we demonstrated the importance of HLA classification when registering patients in the EBMT registry and its impact on different outcomes. Disclosures: No relevant conflicts of interest to declare.

scholarly journals IUE observations of CI Cygni during 1979–1981

1982 ◽  
Vol 70 ◽  
pp. 145-146
Author(s):  
G.B. Baratta ◽  
A. Altamore ◽  
A. Cassatella ◽  
M. Friedjung ◽  
D. Ponz ◽  
...  
Keyword(s):  
High Resolution ◽  
Emission Lines ◽  
Low Resolution ◽  
High Resolution Data ◽  
Line Intensities ◽  
Activity Phase ◽  
Peculiar Behaviour ◽  
Large N ◽  
Significant Difference ◽  
Intercombination Line

High and low resolution IUE spectra of CI Cyg were obtained at VTLSPA during 1979-81 allowing for an analysis of the spectral variations related to the decreasing activity of the star, and to the eclipse (June 1980).In the high resolution spectra the emission lines have a width slightly larger than the instrumental one. This fact is particularly evident in the HeII 1640 A line and could be related to the peculiar behaviour of this line at low resolution as reported by Michalitsianos et al. (this volume). A systematic radial velocity difference between permitted and intercombination lines was found; this difference should be connected with the structure of the emitting region(s). “Secular” and eclipse varia tion was found in particular in the intercombination line intensities (Viotti et al. 1980). An electron density of ∼ 0.3–1.5×1010 cm–3 was evaluated from the intensity ratios of the NIII] emission lines. No significant difference in these ratios and in the CIII]/NIII] ratio as well was found,during 1979, 1980 (eclipse) and 1981 suggesting no large Ne variation with both the activity phase and eclipse of the star. This result should imply a low density gradient in the partially eclipsed NIII] and CIII] regions. A more detailed analysis of the high resolution data is in course to better clearfy these points, and their implications on the possible models for CI Cyg.

scholarly journals Accuracy of High- and Low-Resolution Cone-Beam Computed Tomographic Scans in the Detection of Impacted Tooth-Induced External Root Resorption: An Ex-Vivo Study

2020 ◽  
Author(s):  
Arash Dabbaghi ◽  
Sanaz Sharifi ◽  
Masoud Esmaeili
Keyword(s):  
High Resolution ◽  
Diagnostic Accuracy ◽  
Cone Beam ◽  
Low Resolution ◽  
Impacted Tooth ◽  
External Root Resorption ◽  
Tooth Impaction ◽  
Significant Difference ◽  
High Resolution Images ◽  
Low Resolution Images

Objectives: Cone-beam computed tomography (CBCT) is used in diagnostic situations, as well as tooth impaction and its complications. A possible sequela of tooth impaction is resorption of adjacent teeth, complicating the treatment plans. This study aimed to determine the diagnostic accuracy of high- and low-resolution CBCT scans in the detection of external root resorptions (ERRs), caused by an adjacent impacted tooth in the cementoenamel junction (CEJ), mid-root, and apical areas. Materials and Methods: Forty-five intact single-rooted teeth were divided into three groups of 15. Each group was dedicated to each zone of the root. Slight, moderate, and severe ERRs were formed, and CBCT scans were taken before and after the formation of ERRs. The diagnostic accuracy was assessed, and the Proportion test was used to compare the results. Results: The statistical analyses of high- and low-resolution images showed a significant difference (P<0.05), which implies the higher accuracy of high-resolution images. The highest diagnostic accuracy among different zones was related to the mid-root, and the lowest was related to the apical zone. In terms of the size of ERRs, the diagnostic accuracy was the lowest for slight ERRs. Conclusion: The most reliable and accurate diagnostic mode was found in high-resolution images, in the mid-root zone, and with severe ERRs. The lowest diagnostic accuracy was found in low-resolution images, in the apical zone, and with slight ERRs.

scholarly journals The Role of Transthoracic Ultrasound in the Study of Interstitial Lung Diseases: High-Resolution Computed Tomography Versus Ultrasound Patterns: Our Preliminary Experience

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 439
Author(s):  
Donato Lacedonia ◽  
Giulia Scioscia ◽  
Angelamaria Giardinelli ◽  
Carla Maria Irene Quarato ◽  
Ennio Vincenzo Sassani ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Lung Diseases ◽  
Interstitial Lung Diseases ◽  
High Resolution Computed Tomography ◽  
Pleural Line ◽  
Complementary Role ◽  
Number Of Patients ◽  
Significant Difference ◽  
Transthoracic Ultrasound

Transthoracic ultrasound (TUS) is a readily available imaging tool that can provide a quick real-time evaluation. The aim of this preliminary study was to establish a complementary role for this imaging method in the approach of interstitial lung diseases (ILDs). TUS examination was performed in 43 consecutive patients with pulmonary fibrosis and TUS findings were compared with the corresponding high-resolution computed tomography (HRCT) scans. All patients showed a thickened hyperechoic pleural line, despite no difference between dominant HRCT patterns (ground glass, honeycombing, mixed pattern) being recorded (p > 0.05). However, pleural lines’ thickening showed a significant difference between different HRCT degree of fibrosis (p < 0.001) and a negative correlation with functional parameters. The presence of >3 B-lines and subpleural nodules was also assessed in a large number of patients, although they did not demonstrate any particular association with a specific HRCT finding or fibrotic degree. Results allow us to suggest a complementary role for TUS in facilitating an early diagnosis of ILD or helping to detect a possible disease progression or eventual complications during routine clinical practice (with pleural line measurements and subpleural nodules), although HRCT remains the gold standard in the definition of ILD pattern, disease extent and follow-up.

scholarly journals Multimodal Low Resolution Face and Frontal Gait Recognition from Surveillance Video

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1013
Author(s):  
Sayan Maity ◽  
Mohamed Abdel-Mottaleb ◽  
Shihab S. Asfour
Keyword(s):  
Face Recognition ◽  
High Resolution ◽  
Gait Cycle ◽  
Gait Recognition ◽  
Recognition System ◽  
Multimodal Fusion ◽  
Surveillance Video ◽  
Low Resolution ◽  
Model Free ◽  
Face Images

Biometric identification using surveillance video has attracted the attention of many researchers as it can be applicable not only for robust identification but also personalized activity monitoring. In this paper, we present a novel multimodal recognition system that extracts frontal gait and low-resolution face images from frontal walking surveillance video clips to perform efficient biometric recognition. The proposed study addresses two important issues in surveillance video that did not receive appropriate attention in the past. First, it consolidates the model-free and model-based gait feature extraction approaches to perform robust gait recognition only using the frontal view. Second, it uses a low-resolution face recognition approach which can be trained and tested using low-resolution face information. This eliminates the need for obtaining high-resolution face images to create the gallery, which is required in the majority of low-resolution face recognition techniques. Moreover, the classification accuracy on high-resolution face images is considerably higher. Previous studies on frontal gait recognition incorporate assumptions to approximate the average gait cycle. However, we quantify the gait cycle precisely for each subject using only the frontal gait information. The approaches available in the literature use the high resolution images obtained in a controlled environment to train the recognition system. However, in our proposed system we train the recognition algorithm using the low-resolution face images captured in the unconstrained environment. The proposed system has two components, one is responsible for performing frontal gait recognition and one is responsible for low-resolution face recognition. Later, score level fusion is performed to fuse the results of the frontal gait recognition and the low-resolution face recognition. Experiments conducted on the Face and Ocular Challenge Series (FOCS) dataset resulted in a 93.5% Rank-1 for frontal gait recognition and 82.92% Rank-1 for low-resolution face recognition, respectively. The score level multimodal fusion resulted in 95.9% Rank-1 recognition, which demonstrates the superiority and robustness of the proposed approach.

scholarly journals Comparison and Evaluation of Different Pit-Filling Methods for Generating High Resolution Canopy Height Model Using UAV Laser Scanning Data

2021 ◽  
Vol 13 (12) ◽  
pp. 2239
Author(s):  
Ying Quan ◽  
Mingze Li ◽  
Yuanshuo Hao ◽  
Bin Wang
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Evaluation Framework ◽  
Canopy Height ◽  
Filter Method ◽  
Individual Tree ◽  
Significant Difference ◽  
Point Interpolation ◽  
Canopy Height Model ◽  
Height Model

As a common form of light detection and ranging (LiDAR) in forestry applications, the canopy height model (CHM) provides the elevation distribution of aboveground vegetation. A CHM is traditionally generated by interpolating all the first LiDAR echoes. However, the first echo cannot accurately represent the canopy surface, and the resulting large amount of noise (data pits) also reduce the CHM quality. Although previous studies concentrate on many pit-filling methods, the applicability of these methods in high-resolution unmanned aerial vehicle laser scanning (UAVLS)-derived CHMs has not been revealed. This study selected eight widely used, recently developed, representative pit-filling methods, namely first-echo interpolation, smooth filtering (mean, medium and Gaussian), highest point interpolation, pit-free algorithm, spike-free algorithm and graph-based progressive morphological filtering (GPMF). A comprehensive evaluation framework was implemented, including a quantitative evaluation using simulation data and an additional application evaluation using UAVLS data. The results indicated that the spike-free algorithm and GPMF had excellent visual performances and were closest to the real canopy surface (root mean square error (RMSE) of simulated data were 0.1578 m and 0.1093 m, respectively; RMSE of UAVLS data were 0.3179 m and 0.4379 m, respectively). Compared with the first-echo method, the accuracies of the spike-free algorithm and GPMF improved by approximately 23% and 22%, respectively. The pit-free algorithm and highest point interpolation method also have advantages in high-resolution CHM generation. The global smooth filter method based on the first-echo CHM reduced the average canopy height by approximately 7.73%. Coniferous forests require more pit-filling than broad-leaved forests and mixed forests. Although the results of individual tree applications indicated that there was no significant difference between these methods except the median filter method, pit-filling is still of great significance for generating high-resolution CHMs. This study provides guidance for using high-resolution UAVLS in forestry applications.

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