ENVI40新功能介绍！！

1. ENVI4.0总揽

ENVI4.0是继IDL6.0推出的改进版本。此次版本改进界面风格和菜单的逻辑结构没有太大的变化，但是在功能有了一些显著的增强。其中，对航片、IKONOS以及Quickbrid数据的正射纠正工具的出现，突破了ENVI在工程应用方面的市场瓶颈，成为遥感软件中性价比最高产品。同时，ENVI4.0还就其他方面做了相应改进，此次信息发布，只是节选了突出点，目前，ENVI4.0正处于发布前的测试阶段，相信很快就会与大家见面。

  2. 正射工具

ENVI 4.0 New Ortho Tools:
IKONOS、QuickBird and SPOT
Uses RPC sensor model provided with certain IKONOS and QuickBird data products Required Data:
 Image to orthorectify
 RPCs in known format
 Single elevation value, or DEM
Geoid height (from data provider)

  3. 决策树分类

一、什么是决策树?    A type of multistage classifier.
   A series of decisions used to determine the correct category for each pixel.    Decisions are based on any available characteristic of the dataset.  
  Each decision divides the data into one of two possible groups.  
  No one decision performs the complete classification.  
 Input can be one image or a stack of different images.

二、决策树工具的功能特点：
   Implements decision trees generated outside of  ENVI  
  Input can be images in different projections, pixel sizes    
Can use as exploration tool to find areas with specific characteristics  
 Trees can be edited, pruned, and applied to multiple datasets  
 Many variables can be calculated on the fly as the decision tree executes:
 slope, aspect, NDVI, principal components, MNF transforms, mean, standard deviation, minimum or maximum, tasseled cap transforms and more

4. 等高线标签

 New option in contour dialog
  Labels Calculated automatically from underlying image
  Toggle labels on or off  
When converting contours to vectors,can export labels and elevation values to attributes

  5. 大气校正

Calculating Emissivity and Temperature  
 ENVI has tools to separate temperature from emissivity information in corrected thermal data.  
 Reference Channel Emissivity    
Emissivity Normalization  
 Alpha Residuals    
Requires atmospheric correction first
  6. 全新的融合算法

New Pan Sharpening 2 New Types:  
   Gram-Schmidt Spectral Sharpening  
   PC Spectral Sharpening Fuse high spatial resolution panchromatic images with low spatial resolution spectral images
 Doesn’t lose spectral information from images

 7. 矢量编辑工具
 Non-adjacent attribute cells
 Save selected to new layer
 Query attrobutes from attribute table itself

  8. 新的显示输出选项

 Out contents of Zoom window only
 Output Image window with dynamic overlay on

really?

的确比envi3.5好用，有些功能方便多了。