Passionate GISer, Remote Sensing Enthusiast and Point Cloud Processor
Exercise 1 Goal 哪些生物物理参数对光谱特征影响最大，在光谱的哪一部分。 PORSAIL = PROSPECT(leaf) + SAIL(canopy) Change soil brightness factor(moisture» brighter= lower) Increasing the soil brightness factor will increase the reflectance (soil looks brighter, probably because the moisture content is lower). 增加土壤亮度系数会增加反射率(土壤看起来更亮，可能是因为含水量更低)。 Cab the leaf chlorophyll content »> BRF Cw the leaf water content »> BRF N internal structure parameter »> BRF LAI ,check the changing in NIR /VIS LIDF leaf inclination angle distribution functions»> canopy reflectance spectra Part 1(Leaf Parameters) Cab: BRF is higher for lower chlorophyll concentrations. The more chlorophyll, the more light is used for photosynthesis, resulting in less reflection in Blue and Red. Therefore, lower BRF values can be observed for higher chlorophyll concentrations. For Green (550 nm), there is a maximum difference between the Cab quantities. Cw: the near infra-red and middle infra-red part of the spectrum (800 nm to 2500 nm) is sensitive to changes to this parameter. The larger the water content, the more light is absorbed, resulting in lower BFR values. N: 如果N大，随着波长的变化更剧烈，但不能说 the more/less leaf layers, the higher /lower BRF value Sensitivities are more pronounced at ==high LAI== because there simply is more leaf mass present. ==答案版：== 叶片叶绿素含量对可见光部分的影响可达750 nm左右。 叶片含水量(Cw)在1000nm以上的红外部分有影响。 叶片结构参数(N)对整个光谱都有影响，但其影响不如其他两个参数那么明显(至少对于所选的设置)。 The leaf chlorophyll content has an effect in the visible part up to about 750 nm. The leaf water content (Cw) has influence in the infrared part beyond 1000 nm. The leaf structure parameter (N) has an effect over the whole spectrum, but its influenced is less pronounced as that of the other two parameters (at least for the settings chosen). Part 2 (Canopy Level) 不同的波长上 In the ==visible== part of the spectrum the highest reflectance is obtained at low LAI because most soil still is visible and the ==soil is brighter than the green leaves.== In the ==NIR== part of the spectrum ==lowest reflectance is obtained at low LAI== (except for the erectophile LIDF) because leaves reflect more than the soil and this effect is enlarged due to ==multiple reflectance== between the leaf layers (leaves are partly transparent for NIR radiation). For the very vertical leaves (erectophile LIDF) the NIR reflectance at low and high LAI is quite similar (there is a cross-over point at about 1000 nm). In the ==MIR== part the effect of absorption of water increases. As a result, ==the low LAI (less leaves, less water absorption) gives the highest reflectance== like in the visible part (although in the visible part it is the chlorophyll that is important). 不同的LIDF 水平A planophile LIDF means leaves are oriented more horizontally. So, you observe relatively more leaf area from nadir and the above effects are very pronounced. ==The reflectance in the NIR also is highest.== 垂直An erectophile LIDF means leaves are oriented more vertically, and the influence of the soil is larger at the lower LAI values. Also more shadows will be visible in the canopy. ==Overall the reflectance in the NIR is lower.== A spherical LIDF is in-between the planophile and erectophile LIDF. 您能否通过比较LAI从低到中与从中到高的阶跃，得出LAI在不同光谱区域灵敏度的线性关系? For all three LIDFs the difference between LAI 0.5 and 2.5 is larger than the difference between LAI 2.5 and 4.5. This underlines the asymptotic nature of the LAI effect on reflectance. This is most pronounced in the visible and middle infrared part of the spectrum. Part 3( Soil background) LAI 的数值影响土壤对LAI的影响 At an LAI of 0.5 there is a clear effect of soil brightness/moisture, meaning that the soil influence still is significant. A lower brightness reduces the reflectance due to increased absorption. At an LAI of 4.0 this effect has nearly completely disappeared, meaning that the soil background has no effect anymore. 基础 LAI lower, the more visible soil , the more mix in the spectrum the more moisture , the darker soil C is defining the slope of the soil line Using the simulated spectrum with LAI = 0.0 and soil brightness = 0.5, assuming that 0.5 is the average across all soil brightness values. The slope is the value of NIR (870 nm) divided by the value of Red (670 nm). WDVI vs NIR WDVI is meant to extract vegetation and ==reduce influence of the soil.== 就是叶片层数越多的时候，土壤越不可见，所以WDVI的作用再减小。 The influence of soil brightness is noticeable in the NIR region because of slightly higher Std Dev for both LAIs. WDVI values are lower for LAI = 0.5 compared to LAI = 4.0, because higher values of WDVI equal to denser vegetation。 The WDVI value increases with greater values for soil brightness, because the dry soil reflects higher the NIR spectrum. Part 4(BRDF双向反射分布函数) 上面的大图 On top we see a so-called polar plot, showing the BRF for all combinations of ==view zenith and azimuth angles== at the set solar zenith angle. Bottom left we see a BRF profile in the ==principal plane== (psi = 0º), and bottom right we see a BRF profile in the ==cross-principal plane== (psi = 90º or -90º). 下面的两个小图 On the x-axis the viewing angle is plotted. The reflectance show a narrow peak in reflectance at -30º. With a solar zenith angle of 30º, this is the backscatter observation position (looking with the sun at our back). ==At this position we do not see any shadows, and the reflectance has a maximum.==也就是： With a solar zenith angle of 10 degrees a hot-spot at 10 degrees viewing angle in the backward direction is observed. Wavelength的变化，引起的BRF的变化 Towards the periphery边缘 of the circle, the value of BRF gets higher. For the Green and NIR bands, the changes are relatively obvious, while for the red band, the changes are not significant. hot-spot parameter (hspot) 的变小 Moving out of the principal plane, the hot-spot effect becomes less pronounced. In the cross-principal plane no hot-spot can be observed anymore and the BRF is mirrored around nadir viewing. Hot-spot parameter设成0和0.5 A hot-spot parameter of 0 means no hot-spot effect is included in the model and the peak has disappeared. However, the angular dependency (anisotropy) still is visible.
What are major events in the development of XR both theoretical and practical History plato ‘cave victorian 3D link flight simulators Sensorama NASA View System Palmer Luckey,Oculus
IAaPreProcessingModel: module 1-5
Crucial Skill in Education 4Rs reading writing rithemetic researching Researching implies to use what is called the scientific method behavioral research Why the Scientific Method Our modern way of life is largely a creation of science and technology Understanding how people obtain their research results fostering and backing up creative thinking learn about limitations It’s fun Peirce’s Methods of Fixing Beliefs scientific and non-scientific thinking differs Peirce systematically analysed different approaches by distinguishing the method of tenacity, authority, a priori method,and scientific method Empirical Reasoning and scientific method Spatial Presence
Social XR spatial presence social presence self embodiment agency multi-modol non verbal cues The Impact and Vision of Immersive Tech future of human communication: building it responsibly,together Immersive media: Face-to-Face »AR>MR> Agrumented Reality»VR words> 2Dpictures> 3D immersive Applications XR collaboration: Microsoft Mesh Vision Metaverse: Meta’Vision Spatial Computation: Apple Vision pro capacablity Digital Human balance technology and artistry Point clouds,Meshes,NeRF,3D Gaussian Splatting 3D Gaussian Splatting can not measure but see fill the gap Neural Radiance Field deep learning for reconstructing a 3D from sparse 2D image AI based Dynamic scenarios sycohronous cameras limited field fo fview heavy post processing minics reality using custom-caotured Why is it challenging? Generative AL ,LLMs: Computing power and reasoning engine for creation Ethical considerations: Balancing Potention and Responsiblity USERS data privacy and control inclusive accessible safe and secure digital worlds digital human human righte and risks Application transforming lives with impact and responsibility:healthcare , education Life-Like AR -example view remote collaboration tp global expertise Vision for the future of human connection integrated to sensory
Digital Twins: from/for Earth Observation Heigh estimation 3D virtual urban scene reconstruction terrestrial videogrammetry
Sense of Place GEO as a place-based theme Informal Local context Experiential Engagement Geo-visualization Timeline traditional mapping and mapmaking 3D CAD based Virtual Globes Immersion parallax physical reality head-mounted display Embodied Coginition Mind> Body > Environment Two level model of spatial presence Attention allocation spatial situation model self-location possible actions spatial presence From technology to user experience technological affordances(自解释)> immersion application experience Sensing the world Data from multiple sources Immersive Visualization Visualization provides insight> abstract data made visually accessible,communication everything is about cognition> perceiving, understanding , deciding spatial understanding is an important part of place-based cognition> XR is space creator, XR aids cognition, but in practice it can be complex and messy Cognitive Load Theory Intrinsic load germane load> task extraneous load > unnecessary Seductive(有吸引力的) details Design is the key Body-based interactions Isovist the spatial extent visible from a given viewpoint
What is Design Thinking? Design Thinking Process Empathize define ideate prototype test
Recap Animation considerations Inverse-Kinetics Why optimise 3D models for game engine use? Higher polygon counts in the scene can decrease the frame rate
Part 1 Creating Realism XR Realism 3D environment: 3D Assets, Particle Effects, Lighting/Lights, Animations, Texturing/ Materials Material Explained make 3D models look realistic glossiness and reflection Complex material » Layers Classes of Materials Bitmap texture: Old Wall Texture Procedural maps: Procedural Wood Texture General Concepts of Light Maps Diffuse Ambience Specular ![[cd0066a2b1a3020289607c36f3c5771.png]] Combining Types of Materials Diffuse Color Diffuse – Light spread evenly across the surface. there is no black line in your photo no shadow Specular Maps Specular Map Specular Color Map Specular Level Map Glossiness Map affect the specular region of a shiny object Luminance Map brightness of a surface based on the map’s grayscale intensity Opacity Map use grayscale bitmap images to control opacity and transparency reflect Bump Map The different intensities of light and dark tones of the grayscale bitmap