DIP & GIS Software Systems: An overview

Nirmal Kumar

Two types of data:•Analog: e.g., topo sheet, aerial photo•Digital: e.g., satellite data

Elements of visual imageinterpretation & optical instrumentssuch as stereoscopes

Requires DIP Systems:•Computer hardware•Image processing software

Digital Image Processing System Considerations

SoftwareHardware• CPU• RAM• Display• Storage• Network

• OS• Software Compiler• Image Processing

Software

Expert

CPU: Confused??

Processor Architecture: 32/64 bit•This basically means that theprocessor can process internallyeither 32 bits or 64 bits of data at anyone time.

Processor Clock Speed :•Dictates how fast the processor can process the data(0's and 1's).

• If a processor is having a speed of 2GHz, this meansthat it can process data internally 2 billion times asecond (every clock cycle).

•If the processor is a 32-bit processorrunning at 2GHz then itcan potentially process 32 bits of datasimultaneously, 2 billion times a second !!

CPU:Front Side Bus (FSB):• The front side bus transfers data between the processor and the

computer's other components such as memory, hard drives, etc.• The FSB will have a certain width (measured in bits) which dictates how

many bits can be transferred at any one time.• The FSB also has a clock cycle frequency indicating how fast the data can

be transferred.• For example a processor having a FSB width of 32-bits and

running at 533MHz, can transfer a set of 32-bits of data,533,000,000 times a second.

Instruction Sets:• The type of work a processor carries out is defined by its instructions. All modern

processors have their own instructions built-in for common tasks.CISC (Complex Instruction Set Computer): PCs• More internal instructions, allowing a more diverse set of operations.• Generally slower due to the complexity of the instructions.RISC (Reduced Instruction Set Computer): Work stations• Fewer built-in instructions• Add to the overall speed of the processor due to the simplicity of the instructions

When the processor needs to execute an instruction, it looks firstin its own data registers. If the needed data isn't there, it goes tothe L1 cache (SRAM) and then to the L2 cache (DRAM). If thedata isn't in any cache, the CPU calls out to the main RAM. Itmight not even be there, in which case the system has to retrieveit from the disk.e.g., •All Intel Core i7 processors feature L1, L2, and shared L3 caches. •Before, Intel Core 2 Duo and Quad processors had just an L1 and L2 cache.

Memory:

Processor Clock Speed (GHz) Cores L1 L2 L3

Core i7-990X 3.47 6 384KB 1.5 MB 12 MB

Core i7-975 3.33 4 256 KB 1 MB 8 MB

Storage:

Landsat ETM+

185x170 km scene7 bands8 bit30x30 m resolution

SPOT 3 HRV XS multispectral60x60 km scene3 bands8 bit20x20 m resolution

Mbbandscolumnsrows 271000000

330003000=

××

Mbbandscolumnsrows 2441000000

761665666=

××

Storage Longevity:

14" 15" 17" 19" 21"640x480 BEST GOOD TOO BIG HUGE TERRIBLE800x600 GOOD BEST GOOD TOO BIG HUGE

1024x768 TOO SMALL GOOD BEST GOOD STILL GOOD

1280x1024 TINY TOO SMALL GOOD BEST GOOD

1600x1200 TERRIBLE TINY TOO SMALL GOOD BEST

Display:Resolution:•Most monitors today are capable of changing their displayed resolution under software control

•Maximum resolution that a monitor can display is limited by the size of the monitor and the characteristics of the CRT (cathode-ray tube)

Colour:•4 standard color depths used by monitors: 4-bit(Standard VGA), 8-bit (256-Color Mode), 16-bit(High Color),and 24-bit (True Color).

BIT DEPTH COLOR RESOLUTION1-bit 2 colors2-bit 4 colors3-bit 8 colors4-bit 16 colors5-bit 32 colors6-bit 64 colors7-bit 128 colors8-bit 256 colors16-bit 65,536 colors24-bit 16,777,215 colors

I am having 12 bit

image!!!!!!

Sorry!!!!!Only 24 bit display

Network:

LANWAN

Operating System:

• Single user OS: e.g., MS Window XP (HE), Macintosh OS• Network OS: e.g., Microsoft Windows Server 2003, Microsoft Windows Server

2008, UNIX, Linux, Mac OS X, and Novell NetWare.

Compiler:

A computer software compiler translates instructions programmed in a high levellanguage such as C++ or visual basics in to machine language that the CPU canunderstand.Many DIP softwares provide a toolkit that programmers can use to compile their ownDIP algorithms. e.g., ERDAS, ER Mapper, ENVI

Image Processing Softwares:

Lets Discuss

Important Image Processing Functions:

Preprocessing:• Radiometric correction (for sensor, system, and environmental effects)• Geometric correction (image-to-map, image-to-image)• Sensor specific rectifications• Orthorectification• Projection conversion• Image mosaicking (geo referenced, non-georeferenced)• Masking• Spectral and spatial sub-setting• Layer stacking/ band composite• Data format conversion (BSQ, BIL, BIP)

Display & Enhancement:• Black & white, color-composite display• Density slice, Pseudo colour transform• Magnification, reduction, roam, pan• Transects• Contrast manipulation (linear, nonlinear)• Colour space transformation (RGB to HIS, HLS, HSV)• Image algebra (band ratioing, image differencing, NDVI, SAVI, Kauth-

Thomas, EVI, Tasseled cap etc.)• Spatial filtering (Low pass, high pass, band pass, Adoptive, FFT, etc)• Edge enhancement (Krisch, Laplacian, Sobel, etc)

Display & Enhancement:• Principal components (Forward, inverse, standardized, non-

standardized)• Minimum noise fraction (Forward, inverse, standardized, non-

standardized)• Independent component (Forward, inverse)• Texture Transforms (min-max, texture spectrum, fractal dimension,

occurrence, co-occurrence)• Frequency transforms (Fourier, Walsh, Wavelet, Cosine, etc.)• Digital elevation models (DEMs)• 3-dimensional transformations• Animation• Image compression• Image fusion (HSV, HIS, PC, CN, Gram-Schmidt, Brovey)• Sub-pixel information extraction

Information Extraction• Univariate and multivariate statistical analysis• Supervised classification (Minimum distance, Maximum likelyhood,

Mahalanobis, Parallelepiped, Spectral angle Mapper, SpectralInformation Divergence)

• Decision tree, regression tree, Binary encoding, Support VectorMachine, Neural network, Fuzzy logic classification

• Unsupervised classification• Contextual classification• Incorporation of ancillary data during classification• Radar image processing• Hyper-spectral data analysis• LIDAR data analysis• Subpixel classification

Photogrammetric Information extraction• Soft copy photogrammetry to extract digital elevation models• Soft copy photogramemtry to extract orthophotographs• Soft copy extraction of polarimetric detailsGeographic Information Systems (GIS)• Raster (image) based GIS• Vector (polygon) based GIS (must allow polygon comparison)Integrated Image Processing and GIS• Complete Image Processing Systems• Complete Image Processing Systems and GISUtilities• Network (Internet, local talk, etc.)• Image compression• Import and export of various file formats

Important Image Processing Functions:

Software, HQ special strength

ERDAS (Atlanta, USA: 1979) – vector integration

PCI (Toronto, Canada: 1982) – orthophotos / breadth

ENVI (Boulder, USA: 1991) – hyperspectral

ER Mapper (Perth, Australia:) - image web server…. now part of ERDAS (2007)

TNTMips (USA) - Digitization

Definiens Developer (Trimble, Germany) – Object based classification

Open Source DIP & GIS Softwares:

Key features• Integrated raster and vector design• Import and export of widely used data formats• On-screen and tablet digitizing• Comprehensive set of image processing tools• Orthophoto, image georeferencing, transformation and mosaicing• Advanced modeling and spatial data analysis• 3D visualization with interactive editing for optimal view findings• Rich projection and coordinate system library• Geo-statisitical analyses, with Kriging for improved interpolation• Production and visualization of stereo image pairs• Spatial Multiple Criteria Evaluation• Set of operations on DEMs/DTMs and hydrological processing• Variable Threshold Computation, to help preparing a threshold map

for drainage network extraction• Horton Statistics,to calculate the number of streams, the average stream

length, the average area of catchments for Strahler stream orders• Georeference editors

ILWIS - Remote Sensing and GIS softwareIntegrated Land and Water Information System (ILWIS)

• Commonly referred to as GRASS, this is a free GeographicInformation System (GIS) used for geospatial data managementand analysis, image processing, graphics/maps production, spatialmodeling, and visualization.

• GRASS contains over 350 programs and tools• GRASS uses both an intuitive windows interface as well as

command line syntax for ease of operations.• GRASS is currently used in academic and commercial settings

around the world, as well as by many governmental agencies andenvironmental consulting companies.

Geographic Resources Analysis Support SystemOpen Source DIP & GIS Softwares:

• Quantum GIS (QGIS) is a Geographic Information System (GIS) built for Linux/Unix. • QGIS supports vector, raster, and database formats.

• MapServer is an OpenSource development environment for constructing spatially enabled Internet-web applications.

Open Source DIP & GIS Softwares:

• Coded in the widespreadand powerful C++programming language

• Object oriented systemdesign

• Run on MS-Windows as wellas with Linux.

• > 300 modules for Vector &Raster processing.

• Powerful Geostatisticalmodule.

• Digital terrain analysis• LIDAR data analysis• GUI & Scripting in

Command Line Interpreter

Matlab Programming:• Image Processing Toolbox™ provides a comprehensive set of reference-

standard algorithms and graphical tools for image processing, analysis,visualization, and algorithm development.

• You can perform image enhancement, image deblurring, featuredetection, noise reduction, image segmentation, spatial transformations,and image registration.

• Many functions in the toolbox are multithreaded to take advantage ofmulticore and multiprocessor computers.

Diffs = zeros(rmax, cmax-1); for row = 1:rmax; for col = 1:cmax-1; Diffs(row, col) = Image(row, col+1) - Image(row, col); endendimshow(Diffs, []);

+

___________

Software – proprietary, low cost and free (shareware):

Data sources including online satellite imagery from major suppliers, DEM data plus GIS maps and data of all kinds

Tutorial: Fundamentals of Remote Sensing Canada Centre for Remote Sensinghttp://www.ccrs.nrcan.gc.ca/resource/tutor/fundam/index_e.php The Remote Sensing Tutorialrst.gsfc.nasa.gov/NEODC remote sensing tutorialwww.neodc.rl.ac.uk/tutorials/rstutorial/tutorialhome.htmprofessional tutorials on GIS, Remote Sensing, GIS ...www.spatialhydrology.com/tutorial.html

Information and technical information on standards, best practice, formats, techniques and various publications