Towards Using Virtual Acoustics for Evaluating Spatial Ecoacoustic Monitoring Technologies - Data

About This database contains the raw data and certain outputs used for the project 'Towards Using Virtual Acoustics for Evaluating Spatial Ecoacoustic Monitoring Technologies'. In this work, we developed an ambisonic Virtual Sound Environment (VSE) for simulating real natural soundscapes to evaluate spatial PAM technologies in a more controlled and repeatable manner. We set three objectives to validate this approach: (O1) to determine whether the VSE could replicate natural soundscapes well enough to be a test environment; (O2) to pilot the VSE as a test environment for Passive Acoustic Monitoring (PAM) hardware; and, (O3) to pilot the VSE as a test platform for PAM software. To meet these objectives, we used a recently-developed, open source six-microphone field recorder to capture recordings of six field sites and their VSE-based simulations. Sites were based at the Imperial College Silwood Park Campus (Ascot, UK). For O1, we compared field and VSE recordings using a typical suite of ecoacoustic metrics. For O2, we used the VSE to explore how orientation impacts the performance of the six-microphone array. We extended the suite of metrics from O1 to compare VSE recordings from this array at various pitch angles: vertical (as in the field), 45° pitch, and horizontal. For O3, we investigate how BirdNET and HARKBird, software for classifying and localising avian calls, respectively, perform on bird calls added to the VSE-replicated soundscapes. We compare adding calls by encoding to the ambisonics domain and by playback from individual loudspeakers. The data is organised as follows: '6mic Audio O1O2': contains the six-channel field and VSE-based recordings of all six sites. Recordings are approximately 10 minutes long. Note that there are three VSE-based recording per site, for each recording orientation used in the VSE (vertical, 45°, and horizontal). Several of our analyses used low-passed versions of these recordings (4 kHz cutoff and 12 dB roll-off); note that the recordings provided here are raw and therefore not low-passed. File names indicate whether the recording was performed in the field or VSE ('Field' vs 'ReRec') and the orientation of the 6mic array for the latter ('V', '45', or 'H'). The final number in each filename indicates the Site the recording corresponds to (1-6). '6mic Audio O3': contains the six-channel VSE recordings of five of the original sites with additional avian calls located at certain moments in space and time in each recording. 10 bird calls were added to the soundscapes, each one in its own soundscape recording (each of the five sites' soundscapes was therefore used twice). Four methods of adding the bird calls were trialled, hence there are 40 files in this folder – 10 for each of: ambisonic encoding, playback from individual loudspeakers, playback from individual loudspeakers with no reverb, and playback from individual loudspeakers with no reverb or background soundscape (i.e., 'soloed'). Our analyses focussed on comparing the first two of these methods. The filenames are structured as follows: "sXsYbirdNameEmbeddingMethod', where X corresponds to the site the background soundscape was recorded at, Y indicates the position of the sinusoidal sweep used to create simulated reverb of the bird call (1-4 for 0°, 90°, 180°, or 270° around the device used to capture the ambisonic soundscape recordings), 'birdName' is the common name of the added species, and 'EmbeddingMethod' is either: 'Ambi' (ambisonic encoding), 'LSPK' (playback from an individual loudspeaker), 'LSPK-NR' (playback from an individual loudspeaker with no reverb), or 'Solo' (soloed playback from an individual loudspeaker). Note that due to issues of spatial aliasing, we low-passed the 'Ambi' and 'LSPK' recordings in our analyses (as the two main embedding methods compared) using a 4 kHz cutoff and 12 dB roll-off. However, again the raw (not low-passed) audio is shared here. 'Acoustic Indices': contains the CSV files with matrices of the Acoustic Indices extracted from the first channel of the low-passed '6mic Audio O1O2' recordings. Each column is for a different index, rows are the values over time (indices were extracted on 30 s windows). We extracted the following 7 common acoustic indices: Acoustic Complexity Index (ACI; column 1), Acoustic Diversity Index (ADI; column 2), Acoustic Evenness (AEve; column 3), Bioacoustic Index (Bio; column 4), Normalised Difference Soundscape Index (NDSI; column 5) Acoustic Entropy (H; column 6), and Median of the Amplitude Envelope (M; column 7). Filenames indicate: the field site, whether the indices are for a field or VSE ('Lab') recording, and the orientation of the recording for the latter ('Vert', '45', or 'H'). The 'LP' suffix denotes that these indices were extracted from a low-passed version of the 6mic O1O2 recordings (4 kHz cutoff and 12 dB roll-off). 'BirdNET O1O2 Outputs': CSV files generated from avian call classifier BirdNET (using the Winows GUI version) using the first channel ('Mic 1') of the '6mic Audio O1O2' recordings. 'BirdNET O3 Outputs': outputs of BirdNET on the '6mic Audio O3' recordings. Here, rather than the raw CSV files generated by BirdNET, the BirdNET results have been filtered to just those during the added bird calls' start and end times, and have been compiled into two CSV files: one for recordings of VSE-based soundscapes with bird calls added by ambisonic encoding and another for calls added by individual loudspeaker playback. These CSV files also contain columns to specify added birds' site, sweep (used to generate reverberation, see '6mic Audio O3' above), azimuth and elevation. 'HARKBird O1O2 Outputs': outputs of avian call localisation tool HARKBird on the '6mic Audio O1O2' recordings. Note that HARKBird outputs a folder with additional results for each file, however, only the CSV files presented here. These contain the times and estimated azimuth angles of bird calls and were the only HARKBird ouput used for subsequent analyses. Filenames indicate whether recordings are from the field ('Field') or VSE ('ReRec'), and those for the latter also indicate the recording orientation ('Vert', 45' 'H'). The final number in each filename indicates the site the recording corresponds to. 'HARKBird O3 Outputs': CSV files of HARKBird outputs (as described above) for the '6mic Audio O3' recordings. Filenames are based on those for this set of recordings (see '6mic Audio O3' above); names that contain 'LP' were low-passed (with a 4 kHz cutoff frequency and 12 dB roll-off) prior to passing through HARKBird. 'Manual Labels O2': manual labels of audible bird calls' species in the omnidirectional (first) channel of the Zylia ZM-1 ambisonic recordings (see 'Zylia Recordings' below) for all sites. This data was used to calculate the precision and recall of BirdNET's outputs on the 6mic O1O2 recordings for these sites. 'VGGish Features': contains the 128-dimension feature embedding of the pre-trained VGGish convolutional neural network extracted from the '6mic Audio O1O2' recordings. Filenames indicate the site, whether the recording was made in the field or VSE ('Lab'), and the recording's orientation. Note again that recordings were low-passed (4 kHz cutoff and 12 dB roll-off) prior to the feature extraction, hence the 'LP' suffix. 'Zylia Recordings': approximately 10 minute field recordings of the 6 study sites captured with the 19-microphone ZYLIA 'ZM-1' recorder. These recordings have been converted to third order ambisonic 'b-format' (16 channels) using Furse-Malham channel ordering and SN3D normalisation. This was achieved with the 'Zylia Ambisonics Converter' software. These third-order ambisonic recordings were used to replicate the six sites' soundscapes in the VSE. The accompanying code for this dataset has been submitted via ScholarOne with the manuscript for peer-review.本数据集包含用于项目“面向使用虚拟声学技术评估空间生态声学监测技术”的原始数据与衍生输出成果。本研究开发了一套环绕声（ambisonic）虚拟声环境（Virtual Sound Environment, VSE），用于模拟真实自然声景，以在更可控、可重复的实验条件下评估空间被动声学监测（Passive Acoustic Monitoring, PAM）技术。本研究设定三项目标以验证该方法的有效性：(O1) 验证虚拟声环境能否足够逼真地复现自然声景，以作为标准化测试环境；(O2) 探索将虚拟声环境作为被动声学监测硬件的测试环境的可行性；(O3) 探索将虚拟声环境作为被动声学监测软件的测试平台的可行性。 为达成上述目标，研究团队使用一款新近开发的开源六麦克风野外声学记录仪，采集了6个野外测点及其虚拟声环境模拟场景的录音数据。所有测点均位于英国阿斯科特市的帝国学院西尔伍德公园校区。 针对目标O1，研究团队采用一套经典生态声学指标集，对比了野外采集录音与虚拟声环境模拟录音的差异。针对目标O2，研究团队利用虚拟声环境，探究了设备朝向对六麦克风阵列声学性能的影响，并拓展了O1所用的指标体系，对比了该阵列在不同俯仰角下的模拟录音效果：包括野外实际使用的垂直俯仰角、45°俯仰角与水平俯仰角。针对目标O3，研究团队测试了鸟类鸣声分类软件BirdNET与鸣声定位工具HARKBird，在添加至虚拟声环境复现声景中的鸟类鸣声上的表现，并对比了两种鸣声嵌入方式：将鸣声编码至环绕声域，以及通过独立扬声器播放鸣声。 数据集按如下结构组织： 1. **'6mic Audio O1O2'**：包含6个测点的六声道野外录音与虚拟声环境模拟录音。单条录音时长约10分钟。需注意，针对虚拟声环境的每种录制朝向（垂直、45°、水平），每个测点均对应3条虚拟声环境模拟录音。部分分析使用了经低通滤波处理的录音（截止频率4 kHz，滚降速率12 dB），但本数据集提供的均为原始未滤波录音。文件名包含'Field'（代表野外采集录音）或'ReRec'（代表虚拟声环境模拟录音）的标识；若为虚拟声环境录音，还会标注阵列朝向（'V'、'45'或'H'）；文件名末尾的数字代表对应的测点编号（1至6）。 2. **'6mic Audio O3'**：包含5个原始测点的六声道虚拟声环境模拟录音，每条录音中均在特定时空位置添加了人工鸟类鸣声。本次共向声景中添加10种鸟类鸣声，每种鸣声仅在一条独立的声景录音中出现，因此5个测点的声景各被使用两次。本次共测试了4种添加鸟类鸣声的方法，因此该文件夹下共包含40个录音文件：环绕声编码、独立扬声器播放、无混响的独立扬声器播放、无混响且无背景声景（即“独奏”模式）这4种方法各对应10条录音。本研究的分析主要对比前两种嵌入方法。文件名格式为：`sXsYbirdNameEmbeddingMethod`，其中：X代表背景声景的采集测点；Y代表用于生成鸟类鸣声模拟混响的正弦扫频位置（对应环绕声声景录制设备周围0°、90°、180°、270°四个方位，分别用1至4标识）；`birdName`为添加鸟类的通用中文名；`EmbeddingMethod`可选值包括：'Ambi'（环绕声编码）、'LSPK'（独立扬声器播放）、'LSPK-NR'（无混响的独立扬声器播放）、'Solo'（独奏模式的独立扬声器播放）。需注意，由于空间混叠问题，本研究的分析中对作为主要对比对象的'Ambi'与'LSPK'录音进行了低通滤波处理（截止频率4 kHz，滚降速率12 dB），但本数据集提供的仍为原始未滤波音频。 3. **'Acoustic Indices'**：包含存储了从'6mic Audio O1O2'低通滤波录音的第一声道中提取的声学指标矩阵的CSV格式文件。每一列对应一种不同的声学指标，每一行代表一个时间窗口的指标值（指标以30秒为窗口提取）。本次共提取7种常用声学指标：声学复杂度指数（Acoustic Complexity Index, ACI；第1列）、声学多样性指数（Acoustic Diversity Index, ADI；第2列）、声学均匀度指数（Acoustic Evenness, AEve；第3列）、生物声学指数（Bioacoustic Index, Bio；第4列）、归一化差异声景指数（Normalised Difference Soundscape Index, NDSI；第5列）、声学熵（Acoustic Entropy, H；第6列）以及振幅包络中位数（Median of the Amplitude Envelope, M；第7列）。文件名包含测点编号、录音类型（'Field'为野外录音，'Lab'为虚拟声环境录音）；若为虚拟声环境录音，还会标注录制朝向（'Vert'、'45'或'H'）。文件名后缀'LP'代表该指标集是从经低通滤波（截止频率4 kHz，滚降速率12 dB）的'6mic Audio O1O2'录音中提取得到。 4. **'BirdNET O1O2 Outputs'**：由鸟类鸣声分类工具BirdNET（使用Windows GUI版本）对'6mic Audio O1O2'录音的第一声道（'Mic 1'）进行分析生成的CSV格式文件。 5. **'BirdNET O3 Outputs'**：BirdNET对'6mic Audio O3'录音的分析结果。与BirdNET生成的原始CSV文件不同，本数据集的结果已过滤为仅包含人工添加鸟类鸣声的起止时段内的识别结果，并整理为两个CSV格式文件：一个对应通过环绕声编码添加鸣声的虚拟声环境录音，另一个对应通过独立扬声器播放添加鸣声的录音。这两个CSV文件还新增了用于标识添加鸟类所属测点、混响生成扫频位置、方位角与俯仰角的字段。 6. **'HARKBird O1O2 Outputs'**：鸟类鸣声定位工具HARKBird对'6mic Audio O1O2'录音的分析结果。需注意，HARKBird会为每个分析文件生成包含额外结果的文件夹，但本数据集仅提供其中的CSV格式文件。这些文件包含了鸟类鸣声的出现时间与估计方位角，是后续分析中唯一使用的HARKBird输出结果。文件名包含'Field'（野外录音）或'ReRec'（虚拟声环境录音）标识；若为虚拟声环境录音，还会标注录制朝向（'Vert'、'45'或'H'）；文件名末尾的数字代表对应测点编号。 7. **'HARKBird O3 Outputs'**：HARKBird对'6mic Audio O3'录音的分析结果CSV文件（格式与前文一致）。文件名基于该组录音的命名规则（参见前文'6mic Audio O3'部分）；文件名包含'LP'的代表该录音在输入HARKBird前已进行低通滤波处理（截止频率4 kHz，滚降速率12 dB）。 8. **'Manual Labels O2'**：针对所有测点的ZYLIA ZM-1十九麦克风环绕声录音（参见下文'Zylia Recordings'）的全向声道（第一声道）中的可闻鸟类鸣声物种的人工标注数据。该数据用于计算BirdNET对上述测点的'6mic Audio O1O2'录音识别结果的精确率与召回率。 9. **'VGGish Features'**：包含从'6mic Audio O1O2'录音中提取的、由预训练卷积神经网络VGGish生成的128维特征嵌入的文件。文件名包含测点编号、录音类型（'Field'为野外录音，'Lab'为虚拟声环境录音）与录制朝向。需再次说明，特征提取前已对录音进行低通滤波（截止频率4 kHz，滚降速率12 dB），因此文件名带有'LP'后缀。 10. **'Zylia Recordings'**：使用19麦克风ZYLIA ZM-1记录仪采集的6个研究测点的约10分钟野外录音。这些录音已通过Furse-Malham声道排序与SN3D归一化方式，转换为三阶环绕声“B格式”（16声道），该转换工作通过'Zylia Ambisonics Converter'软件完成。该三阶环绕声录音被用于在虚拟声环境中复现6个测点的原始声景。 本数据集的配套代码已随稿件通过ScholarOne平台提交，用于同行评审。