Characteristics and seasonal variations of cirrus clouds from ground-based lidar and satellite observations over Shouxian Area, China.

This study investigates the macroscopic and optical properties of cirrus clouds in the 32N region from July 2016 to May 2017, leveraging data from ground-based lidar observations and CALIOP to overcome the inconsistencies in detected cirrus cloud samples. Through extensive data analysis, statistical characteristics of cirrus clouds were discerned, revealing lidar ratio values of 28.5 ± 10.8 from ground-based lidar and 27.4 ± 11.2 from CALIOP. Validation with a decade of CALIOP data (2008-2018) confirmed these findings, presenting a consistent lidar ratio of 27.4 ± 12.0. A significant outcome of the analysis was the identification of a positive correlation between the lidar ratio and cloud centroid temperature, indicating a gradual decrease in the lidar ratio as temperatures dropped. The study established a fundamental consistency in their macroscopic properties, including cloud base height, cloud top height, cloud thickness, cloud centroid height, and cloud centroid temperature. The results for ground-based lidar (CALIOP) are: 10.0 ± 2.1 km (10.0 ± 2.2 km), 11.8 ± 2.1 km (11.5 ± 2.3 km), 1.87 ± 0.83 km (1.52 ± 0.71 km), and 10.5 ± 2.2 km, -46.9 ± 9.7°C (-47.1 ± 10.0°C).These properties exhibited seasonal variations, with cirrus clouds reaching higher altitudes in summer and lower in winter, influenced by the height of the tropopause. The optical properties of cirrus clouds were also analyzed, showing an annual average optical depth of 0.31 ± 0.35 for ground-based lidar and 0.32 ± 0.44 for CALIOP. The study highlighted the distribution of subvisible, thin, and thick cirrus clouds, with a notable prevalence of subvisible clouds during summer, suggesting their frequent formation above 14 km. Furthermore, the study observed linear growth in geometric thickness and optical depth up to 2.5 km from CALIOP and 2.9 km from ground-based lidar. Maximum optical depth was observed at cloud centroid temperatures of -35°C for CALIOP and -40°C for ground-based lidar, with optical depth decreasing as temperatures fell. This suggests that fully glaciated cirrus clouds exhibit the highest optical depth at warmer temperatures, within the complete glaciation temperature range of -35°C to -40°C.

The role of IgG4 in systemic lupus erythematosus: Implications for pathogenesis and therapy.

Immunoglobulin (Ig) G4 has a distinctive nature, and its involvement in autoimmune disorders is a subject of ongoing debate and uncertainty. A growing body of evidence indicates that IgG4 may play a pathogenic role in the development of systemic lupus erythematosus (SLE). The IgG4 autoantibodies have the capability to bind autoantigens in a competitive manner with other Ig classes, thereby forming immune complexes (ICs) that are noninflammatory in nature. This is due to the low affinity of IgG4 for both the Fc receptors and the C1 complement molecule, which results in a diminished inflammatory response in individuals with SLE. The present study aims to elucidate the significance of IgG4 in SLE. The present discourse pertains to the nascent and suggested modalities through which IgG4 might participate in the pathogenesis of SLE and the potential ramifications for therapeutic interventions in SLE.

Learning curve in relation to health-related quality of life in long-term, disease free survivors after McKeown minimally invasive esophagectomy.

BACKGROUND: The potential impact of learning curve on long-term health-related quality of life (QoL) after esophagectomy for cancer has not been investigated. The aim of this article is to investigate the relationship between learning curve for McKeown minimally invasive esophagectomy (MIE) and health-related quality of life (QoL) in long-term, disease free survivors up to 10 years after esophageal cancer resection. METHODS: Esophageal cancer patients who underwent McKeown MIE between 2009 and 2019 were identified in which 280 who were free of disease at the time of survey and completed health-related QoL and symptom questionnaires, including EORTC QLQ-C30, EORTC QLQ-OES18, and Digestive Symptom Questionnaire. Patients were assessed in 3 cohorts according to the learning phases of expertise reported by our previous study: initial phase; plateau phase, and; experienced phase. RESULTS: Median time from operation to survey was 5.8 years (interquartile range 4.6-8.2). The QLQ-C30 mean scores of functional scales, and symptom scales of respiratory and digestive systems including dyspnea (P = 0.006), shortness of breath (P = 0.003), and dysphagia (P = 0.031) were significantly better in experienced phase group. Furthermore, in the subgroup analyses for patients without postoperative major complications, patients in the initial learning phase remained suffering from more symptoms of dyspnea (P = 0.040) and shortness of breath (P = 0.001). CONCLUSION: Esophageal cancer patients undergoing McKeown MIE in initial learning phase tend to suffer from a deterioration in long-term health-related QoL and higher symptomatic burden as compared to experienced learning phase, which did not improved over time and warranted more attention.

Lidar signal processing method for atmospheric coherence length measurement based on the WD-ADMF.

A denoising method applied to atmospheric coherent length lidar is proposed. Wavelet decomposition (WD) and the adaptive median filter (ADMF) are combined in this method. In this research, the effectiveness of the WD-ADMF has been verified through simulation and measurement. The results show that this filter algorithm, when applied to lidar data, improves the average peak signal-to-noise ratio (PSNR) and centroid error while maintaining data integrity such that the measurement of coherence length or the inference of C n2 from coherence length more closely matches simulated truth and measured data.

Long-range Fourier ptychographic imaging of the dynamic object with a single camera.

Fourier ptychographic imaging technology is a new imaging method proposed in recent years. This technology captures multiple low-resolution images, and synthesizes them into a high-resolution image in the Fourier domain by a phase retrieval algorithm, breaking through the diffraction limit of the lens. In the field of macroscopic Fourier ptychographic imaging, most of the existing research generally focus on high-resolution imaging of static objects, and applying Fourier ptychographic imaging technology to dynamic objects is a hot research area now. At present, most of the researches are to use camera arrays combined with multiplexed lighting, deep learning or other algorithms, but the implementation of these methods is complicated or costly. Based on the diffraction theory of Fourier optics, this paper proposes that by expanding and focusing the illumination area, we can apply Fourier ptychographic imaging technology with a single camera to moving objects within a certain range. Theoretical analysis and experiments prove the feasibility of the proposed method. We successfully achieve high-resolution imaging of the dynamic object, increasing the resolution by about 2.5 times. This paper also researches the impact of speckles in the illuminated area on imaging results and proposes a processing method to reduce the impact of speckles.

Impact of perioperative decreased serum albumin level on anastomotic leakage in esophageal squamous cell carcinoma patients treated with neoadjuvant chemotherapy followed by minimally invasive esophagectomy.

BACKGROUND: Anastomotic leakage (AL) is a severe complication following esophagectomy with high mortality. Perioperative decreased serum albumin level is considered a predictive of AL, however, its impact on AL incidence in patients treated with neoadjuvant chemotherapy (NCT) followed by minimally invasive esophagectomy (MIE) is not well defined. METHODS: The data of 318 consecutive esophageal cancer patients who underwent MIE were collected retrospectively from January 2021 to December 2021. The perioperative level of albumin was detected and the baseline of altering levels for albumin was established. The incidence of postoperative complications and survival rate were analyzed between groups. RESULTS: After exclusion, 137 patients were enrolled and assigned to more decreased albumin (MA) and less decreased albumin (LA) groups. The levels of albumin descended significantly after MIE (p < 0.0001). There was no significant difference in the clinicopathologic characteristics or surgical outcomes between groups. The incidence of postoperative AL was 10.2% in MA group and 1.4% in LA group (p = 0.033). Three patients died due to AL in MA group, while no mortality was observed in LA group (p = 0.120). The rate of other postoperative complications was similar between groups. Progression-free survival (PFS) in LA group was a little higher than that in MA group, but it was no significant difference (p = 0.853). Similarly, no difference was observed in overall survival (OS) between groups (p = 0.277). CONCLUSIONS: Severely deficient serum albumin after MIE was an indicator of AL in esophageal cancer patients treated with NCT. TRIAL REGISTRATION: Chinese clinical trial registry: ChiCTR2200066694, registered December14th,2022. https://www.chictr.org.cn/edit.aspx?pid=185067&htm=4 .

Effect of pleural adhesions on short- and long-term outcomes after minimally invasive esophagectomy: a propensity score matching analysis.

BACKGROUND: The extent to which the presence of pleural adhesions affects the surgical and oncological outcomes of patients undergoing McKeown minimally invasive esophagectomy (MIE) for esophageal cancer (EC) has not previously been studied. METHODS: Data of consecutive EC patients undergoing McKeown MIE by a single surgeon in the Department of Thoracic Surgery at Daping Hospital from November 2015 to December 2020 were collected. Patients were grouped according to the presence or absence of pleural adhesions when entering the chest cavity. Propensity score matching (PSM) was used to reduce selection bias from confounding factors. Kaplan-Meier was used to assess the survival differences. RESULTS: A total of 617 consecutive EC patients underwent McKeown MIE were enrolled. There were 116 patients with pleural adhesions (Group A) and 501 patients without pleural adhesions (Group B). Patients in Group A were more likely to be older than those of patients in Group B: (66.26 vs. 63.27, P = 0.001). In addition, Group A had more patients with chronic obstructive pulmonary disease (COPD) (24.1% vs. 16.8%, P = 0.04). After propensity score matching (102 matched patients in Group A and 185 matched patients in Group B), these findings were no longer statistically significant. Postoperative pulmonary infection occurred in 57 patients in Group A and in 15 patients in Group B (53.9% vs. 13.0%, P < 0.001). In addition, the presence of pleural adhesions was significantly associated with the prolonged operation time (232 min vs. 210 min, P < .001), length of stay (12 days vs. 10 days, P = 0.001), and hydrothorax requiring drainage (12.7% vs. 5.4%, P = 0.04). However, the disease-specific survival and disease-free survival rates were comparable between the two groups (P = 0.40 and 0.13, respectively). CONCLUSIONS: The presence of pleural adhesions predicted an increased operation time, length of stay, postoperative pneumonia, and hydrothorax requiring drainage of EC patients undergoing McKeown MIE, but did not exert unfavourable effect on long-term survival.

Concurrent radiotherapy cannot provide superiority of surgical oncological outcome and long-term survival rate in locally advanced esophageal squamous cell carcinoma patients receiving neoadjuvant chemotherapy followed by minimally invasive esophagectomy.

BACKGROUND: To evaluate effectiveness of concurrent radiotherapy in esophageal cancer patient treated with neoadjuvant therapy. METHODS: The data of 1026 consecutive esophageal squamous cell carcinoma (ESCC) patients who underwent minimally invasive esophagectomy (MIE) were retrospectively collected. The main inclusion criteria were patients with locally advanced (cT2-4N0-3M0) ESCC who underwent neoadjuvant chemoradiotherapy (NCRT) or neoadjuvant chemotherapy (NCT) followed by MIE, and divided into two groups according to different neoadjuvant strategies. Propensity score matching was performed to improve the comparability between the two groups. RESULTS: After exclusion and matching, 141 patients were enrolled retrospectively: 92 received NCT, and 49 received NCRT. No difference in clinicopathologic characteristics or incidence of adverse events between groups. A shorter operation time (215.7 ± 35.5 min) (p < 0.001), less blood loss (111.2 ± 67.7 ml) (p = 0.0007) and a greater number of lymph nodes retrieved (33.8 ± 11.7) (p = 0.002) were observed in NCT group than in NCRT group. The incidence of postoperative complications was similar between groups. Although patients in NCRT group had better pathological complete response (16, 32.7%) (p = 0.0026) and ypT0N0 (10, 20.4%) (p = 0.0002) rates, there was no significant difference in 5-year progression-free survival (p = 0.1378) or disease-specific survival (p = 0.1258) between groups. CONCLUSIONS: Compared with NCRT, NCT has certain advantages in that it can simplify the surgical procedure and decrease the surgical technique required without compromising the surgical oncological outcomes and long-term survival of patients.

Safety and feasibility of three-dimensional McKeown minimally invasive esophagectomy.

BACKGROUND: To compare the perioperative outcomes from McKeown minimally invasive esophagectomy (MIE) when performed in three-dimensional versus two-dimensional visualization system, and investigate the learning curve of a single surgeon who implemented three-dimensional McKeown MIE. METHODS: A total of 335 consecutive cases (three-dimensional or two-dimensional) were identified. Perioperative clinical parameters were compared and cumulative sum learning curve was plotted. Propensity score matching was used to reduce selection bias from confounding factors. RESULTS: Patients in three-dimensional group were associated with more chronic obstructive pulmonary disease (23.9% vs 3.0%, p < 0.01). After propensity score matching (108 matched patients in each groups), this finding was no longer statistically significant. Comparing to two-dimensional group, significant improvement in total retrieved lymph nodes (28 vs 33, p = 0.003) was observed in three-dimensional group. In addition, more lymph nodes around the right recurrent laryngeal nerve were harvested in three-dimensional group than that in two-dimensional group (p = 0.045). However, there were no significantly differences were found between the two groups in terms of other intraoperative parameters (e.g., operative time) and postoperative relevant outcomes (e.g., lung infection). Furthermore, the change point in the cumulative sum learning curves for intraoperative blood loss and thoracic procedure time was 33 procedures, respectively. CONCLUSION: Three-dimensional visualization system appears to be superior in performing lymphadenectomy during McKeown MIE to that of a two-dimensional technique. For surgeons proficient in performing two-dimensional McKeown MIE, the learning curve for a three-dimensional procedure appears to begin near proficiency after more than 33 cases.

Simulation and optimization of Fe resonance fluorescence lidar performance for temperature-wind measurement.

Fe resonance fluorescence lidar (Fe lidar) is considered an ideal candidate for temperature and wind measurement in the mesosphere and lower thermosphere region. However, considering the complexity of it, only a few Fe lidars have been operated in a few locations. To develop a Fe lidar with high performance, simulation work is the first important step. A simulation model is built in this paper. The expressions for the temperature-wind uncertainties are derived using the error propagation method. Within the limit of saturation effect, an index decomposition of the lidar and atmospheric parameters are performed. When the dwell time and central frequency shift are optimized to 0.205 and 932 MHz at night and 0.212 and 687 MHz during the day, night and daytime calibration curves are acquired, and after confirming the simulation parameters, the performance of Fe lidar is also evaluated. The simulation model could provide a valuable guidance for Fe lidar design.

Cosinusoidal encoding multiplexed structured illumination multispectral ghost imaging.

The information dimension obtained by multispectral ghost imaging is more abundant than in single-band ghost imaging. Existing multispectral ghost imaging systems still meet some shortages, such as complex structure or reconstruction time-consuming. Here, an approach of cosinusoidal encoding multiplexed structured illumination multispectral ghost imaging is proposed. It can capture the multispectral image of the target object within one projection cycle with a single-pixel detector while maintaining high imaging efficiency and low time-consuming. The core of the proposed approach is the employed novel encoding strategy which is apt to decode and reconstruct the multispectral image via the Fourier transform. Specifically, cosinusoidal encoding matrices with specific frequency characteristics are fused with the orthogonal Hadamard basis patterns to form the multiplexed structured illumination patterns. A broadband photomultiplier is employed to collect the backscattered signals of the target object interacted by the corresponding structured illumination. The conventional linear algorithm is applied first to recover the mixed grayscale image of the imaging scene. Given the specific frequency distribution of the constructed cosinusoidal encoding matrices, the mixed grayscale image can be converted to the frequency domain for further decoding processing. Then, the pictures of multiple spectral components can be obtained with some manipulations by applying Fourier transform. A series of numerical simulations and experiments verified our proposed approach. The present cosinusoidal encoding multiplexed structured illumination can also be introduced in many other fields of high-dimensional information acquisition, such as high-resolution imaging and polarization ghost imaging.

Scanning single-pixel imaging lidar.

Long-range light detection and ranging (lidar) of active illumination optical imaging has widespread applications, such as remote sensing, satellite-based global topography, and target recognition and identification. Here, to make trade-offs among imaging efficiency, resolution, receiving field of view, divergence angle, and detected distance, we demonstrate a scanning single-pixel imaging lidar (SSPIL), enjoying the merits of the traditional pointing-by-pointing scanning imaging and single-pixel imaging. The imaging strategy of SSPIL is divided into scanning search and staring imaging processes. These strategies can save most time consumption for imaging background areas and thus improve imaging efficiency. Three imaging experiments were conducted in real urban atmospheric conditions. The preliminary results show SSPIL has the ability for long-range imaging with high efficiency, high resolution, and a large receiving field of view. Also, from the imaging results, we found that multiple samples can improve the SNR of imaging in the real urban atmosphere. The present work may provide a valuable alternative approach in the long-range active illumination optical imaging fields.

Detecting aerosol backscattering coefficient across the whole troposphere by the sidescattering lidar system with three CCD cameras.

Due to geometric overlap factor, the backscattering lidar is not suitable to detect atmospheric characteristics near the ground. A new sidescattering lidar system consisting of three CCD cameras and one CW laser is developed for the first time to measure the profiles of the backscattering coefficient of atmospheric aerosols across the whole troposphere, which has no detection blind zone near the ground. The aerosol relative phase function was detected by its horizontal CCD channel. The vertical distribution of aerosol backscattering coefficient across the whole troposphere was observed by the other two CCD cameras of vertical channel. The reasons for choosing three CCD cameras and their respective functions are analyzed in detail. Comparative experiments and continuous observations indicate that the new sidescattering lidar system including three CCD cameras is simple in structure and reliable in performance with low cost as well.

Characterizing warm atmospheric boundary layer over land by combining Raman and Doppler lidar measurements.

PBL plays a critical role in the atmosphere by transferring heat, moisture, and momentum. The warm PBL has a distinct diurnal cycle including daytime convective mixing layer (ML) and nighttime residual layer developments. Thus, for PBL characterization and process study, simultaneous determinations of PBL height (PBLH) and ML height (MLH) are necessary. Here, new approaches are developed to provide reliable PBLH and MLH to characterize warm PBL evolution. The approaches use Raman lidar (RL) water vapor mixing ratio (WVMR) and Doppler lidar (DL) vertical velocity measurements at the Southern Great Plains (SGP) atmospheric observatory, which was established by the Atmospheric Radiation Measurement (ARM) user facility. Compared with widely used lidar aerosol measurements for PBLH, WVMR is a better trace for PBL vertical mixing. For PBLH, the approach classifies PBL water vapor structures into a few general patterns, then uses a slope method and dynamic threshold method to determine PBLH. For MLH, wavelet analysis is used to re-construct 2-D variance from DL vertical wind velocity measurements according to the turbulence eddy size to minimize the impacts of gravity wave and eddy size on variance calculations; then, a dynamic threshold method is used to determine MLH. Remotely-sensed PBLHs and MLHs are compared with radiosonde measurements based on the Richardson number method. Good agreements between them confirm that the proposed new algorithms are reliable for PBLH and MLH characterization. The algorithms are applied to warm seasons' RL and ML measurements at the SGP site for five years to study warm season PBL structure and processes. The weekly composited diurnal evolutions of PBLHs and MLHs in warm climate were provided to illustrate diurnal and seasonal PBL evolutions. This reliable PBLH and MLH dataset will be valuable for PBL process study, model evolution, and PBL parameterization improvement.

Anti-motion blur single-pixel imaging with calibrated radon spectrum.

Single-pixel imaging (SPI), a novel computational imaging technique that has emerged in the past decades, can effectively capture the image of a static object by consecutively measuring light intensities from it. However, when SPI is applied to imaging the dynamic object, severe motion blur in the restored image tends to appear. In this Letter, a new SPI scheme is proposed to largely alleviate such a problem by leveraging a calibrated radon spectrum. Such a spectrum is obtained by translating the acquired one-dimensional projection functions (1DPFs) according to the positional relationship among the 1DPFs. Simulation and experimental results demonstrate that, without prior knowledge, our approach can effectively reduce motion blur and restore high-quality images of the fast-moving object. In addition, the proposed scheme can also be used for fast object tracking.

Complementary moment detection for tracking a fast-moving object using dual single-pixel detectors.

Target tracking has found important applications in particle tracking, vehicle navigation, aircraft monitoring, etc. However, employing single-pixel imaging techniques to track a fast-moving object with a high frame rate is still a challenge, due to the limitation of the modulation frequency of the spatial light modulator and the number of required patterns. Here we report a complementary single-pixel object tracking approach which requires only two geometric moment patterns to modulate the reflected light from a moving object in one frame. Using the complementary nature of a digital micromirror device (DMD), two identical single-pixel detectors are used to measure four intensities which can be used to acquire the values of zero-order and first-order geometric moments to track the centroid of a fast-moving object. We experimentally demonstrate that the proposed method successfully tracks a fast-moving object with a frame rate of up to 11.1 kHz in the first two experiments. In the third experiment, we compare previous works and find that the method can also accurately track a fast-moving object with a changing size and moving speed of 41.8 kilopixel/s on the image plane. The root mean squared errors in the transverse and axial directions are 0.3636 and 0.3640 pixels, respectively. The proposed method could be suitable for ultrafast target tracking.

Detection and imaging of distant targets by near-infrared polarization single-pixel lidar.

Single-pixel imaging (SPI) is a new technology with many applications and prospects. Polarization detection technology can improve the detection and identification ability of the imaging system. A near-infrared polarization SPI lidar system is designed to realize detection and polarization imaging of outdoor long-range targets. The depth, intensity, linear polarization, and polarization degree images of typical remote targets are obtained. The results show that the polarization image contains many details and contour information of the target, and the intensity image contains brightness and reflectivity information. Intensity and polarization information complement each other. The characteristics of intensity and polarization images at different spatial frequencies are analyzed for the first time, to our knowledge, by taking advantage of the Fourier modulation mode. We found that the proportion of high-frequency information in the polarization image is much higher than that of the intensity image. The sampling strategy of collecting only low-frequency components is applicable in intensity imaging but needs further improvement in polarization imaging. The polarization SPI lidar system can enrich the target information acquired, improve imaging contrast, and have significant application value for target detection and identification in complex backgrounds.

Multi-Object Positioning and Imaging Based on Single-Pixel Imaging Using Binary Patterns.

Single-pixel imaging (SPI) is a new type of imaging technology that uses a non-scanning single-pixel detector to image objects and has important application prospects and value in many fields. Most of the modulators currently used in SPI systems are digital micromirror device (DMD) modulators, which use a higher frequency for binary modulation than other alternatives. When modulating grayscale information, the modulation frequency is significantly reduced. This paper conducts research on multiple discrete objects in a scene and proposes using binary patterns to locate and image these objects. Compared with the existing methods of using gray patterns to locate and image multiple objects, the method proposed in this paper is more suitable for DMD-type SPI systems and has wider applicability and greater prospects. The principle of the proposed method is introduced, and the effectiveness of the method is experimentally verified. The experimental results show that, compared to traditional SPI methods, the number of patterns required by the proposed method is reduced by more than 85%.

Design of Lidar Data Acquisition and Control System in High Repetition Rate and Photon-Counting Mode: Providing Testing for Space-Borne Lidar.

For ground-based lidars in atmospheric observation, their data acquisition unit and control unit usually work independently. They usually require the cooperation of large-volume, high-power-consumption Industrial Personal Computer (IPC). However, the space-borne lidar has high requirements on the stability and integration of the acquisition control system. In this paper, a new data acquisition and lidar control system (DALCS) was developed based on System-on-Chip Field-Programmable Gate Array (SoC FPGA) technology. It can be used in lidar systems with high repetition rate and photon-counting mode and has functions such as data storage, laser control, automatic collimation, wireless communication, and fault self-test. DALCS has two working modes: in online mode, the echo data collected by DALCS are transmitted to the computer for display in real-time and then stored with the current time as the file name; in offline mode, the data are stored in local non-volatile memory, which can be read remotely and can work autonomously when there is no IPC. The test results showed that in the frequency range of 0-70 M, the counting linearity of DALCS reached 0.9999, and the maximum relative error between the DALCS card and the standard signal source was 0.211%. The comparison results showed that the correlation coefficient between DALCS and MCS-PCI was as high as 0.99768. The DALCS was placed in a self-developed lidar sensor system for continuous observation, and the system worked stably under different weather conditions. The range-squared-corrected signal profiles obtained from the observations reflect the spatial and temporal distribution characteristics of aerosols and clouds well. This provides scheme verification and experimental support for the development of space-borne lidar data acquisition and control system.

Optical system design for a hyperspectral imaging lidar using supercontinuum laser and its preliminary performance.

To meet the urgent need for surveying and mapping using remote sensing instruments, a hyperspectral imaging lidar using a supercontinuum laser is proposed. This novel lidar system can solve the problem of the mismatching of the traditional lidar retrieved elevation data and hyperspectral data obtained by passive imaging instruments. The optical design of the lidar receiving system is described, developed, and tested in this study. An off-axis parabolic mirror is used as the receiving telescope of the system, and a transmissive grating is used to split the received hyperspectral light to each detection channel. A fiber array equipped with a micro-lens is used to guide the split light to the detectors. In practice, several fibers can be coupled to one detector according to the wavelength sensitivity of different objects. A reference laser is used to monitor the possible energy jitter of each transmitted laser pulse in real time. A spectrum calibration of the receiving system is accomplished in the laboratory, and radiation calibration is applied by receiving the backscattered light reflected by a standard white board. The spectral resolution of a single fiber is approximately 3 nm. An outdoor 500-m distance experiment was carried out for green and yellow leaves in day and evening settings. During the experiment, the wavelength of the laser was 460-900 nm. The reflection spectra collected by the lidar system in day and evening were consistent, indicating that the design of the optical receiving system is reliable and can be used for airborne hyperspectral imaging lidar.