# Presentation: 530022

## Digital Resource Acquisition

- John Mootz, APFO
- Charlotte Vanderbilt, APFO

- 12/12/2007

## Why move to digital?

- Multi-Spectral
- Panchromatic
- Natural color
- Near Color IR

- USDA Planning Briefing

- 12/12/2007

## Why move to digital? (Con’t)

- Increase in dynamic range (12-bit)
- More shadow detail
- 8-bit only contains 6.25% of 12-bit values
- Some benefit with 8-bit deliverable

**12-bit: 4,096 values**

**8-bit: 256 values**

- USDA Planning Briefing

- 12/12/2007

## Why move to digital? (Con’t)

- Sharper images
- First generation (no scanning)
- No dust, lint, or scratches
- Better geometric resolution
- Simple AT process
- Limited control requirement
- Requires IMU/Airborne GPS systems

- USDA Planning Briefing

- 12/12/2007

## Why stay with film?

- Storage needs for digital products
- No film to “fall back to”
- No cheap contact prints
- Inkjet vs “photographic” prints
- Slight increase in cost for stereo
- Difference should be eliminated soon
- Min difference when creating ortho

**NO SIGNIFICANT SCHEDULE BENEFIT**

- USDA Planning Briefing

- 12/12/2007

## Elimination of Small Businesses

- Digital cameras are _very_ expensive
- ADS40: ~$1.2M
- DMC: ~$800k
- DSS: $300-350k
- Having a single camera adds risk
- Camera cost is only a small element
- Software, storage, IT equipment, etc

- USDA Planning Briefing

- 12/12/2007

## Types of Digital Cameras

- Small format cameras
- do not meet resolution or geometric accuracy requirements
- Medium format cameras
- Small collection area (footprint)
- Most cannot capture multi-spectral
- Large format “mapping” cameras
- Push-broom sensor
- Frame based sensor

**Applanix DSS 422**

**Nikon D40**

**Intergraph DMC**

- USDA Planning Briefing

- 12/12/2007

## Small format Camera

- Bayer pattern

- USDA Planning Briefing

- 12/12/2007

## Push-broom sensor

- Minimizes “building lean” in flight direction
- Heavily dependent on GPS/IMU

- USDA Planning Briefing

- 12/12/2007

## Push-broom sensor (Con’t)

- USDA Planning Briefing

- 12/12/2007

## Push-broom sensor (Con’t)

- Level 1 (Rectified)

- Level 0 (Raw data)

- USDA Planning Briefing

- 12/12/2007

## Frame-based sensor

- Same workflow as film-based
- Typically uses multiple heads and is pan sharpen

**Multiple high resolution CCD heads (4 pan and  4 color)**

- USDA Planning Briefing

- 12/12/2007

## Multiple Head Cameras

**4 pan sensors are mosaick using tie points**
**Combined with “color” sensors**

- USDA Planning Briefing

- 12/12/2007

## Pan-sharpening

**Mosaick the 4 pan**
**Registration the 4 MS**
**Upsample color**
**Co-register pan to G channel**
**RGB -> HSV**
**Replace V channel with pan**
**HSV -> RGB**

- 3)

- USDA Planning Briefing

- 12/12/2007

## Radiometric Sensitivity

- Ideal bands for remote sensing applications should be narrow and non-overlapping, whereas the requirement for high quality true-colour images dictates broad, overlapping bands.

- USDA Planning Briefing

- 12/12/2007

## What is the requirements?

- Ground Resolution
- End product
- Data format
- Metadata and other products
- Storage
- Inspection

- USDA Planning Briefing

- 12/12/2007

## Ground Resolution

- Digital imagery uses GSD
- To compare to traditional film scale, we need to consider scanning resolution:

-     _Scale_            _25 micron_
- 	1:7,920	8 in	(20cm)
- 	1:12,000	1 ft	(30cm)
- 	1:15,840	1.3 ft	(40cm)
- 	1:24,000	2 ft	(60cm)

- USDA Planning Briefing

- 12/12/2007

## Western ID

**3 foot**

**1 foot**

- USDA Planning Briefing

- 12/12/2007

## End Product

- Footprint?
- Original camera footprint
- USGS quarter-quad
- Level of Georeferencing?
- None
- Single point
- “Rubber sheeted”
- Full ortho

- USDA Planning Briefing

- 12/12/2007

## End Product (Con’t)

- Mosaick?
- Radiometric Balanced?
- Coverage?
- Stereo pairs
- 3D viewing requires AT solution

- USDA Planning Briefing

- 12/12/2007

## Metadata and Other products

- AT solution
- Viewing software dependant
- Raw imagery for remote sensing
- Not “geoprocessed” or “radiometrically corrected”
- GPS and IMU data
- Multiple formats

- USDA Planning Briefing

- 12/12/2007

## Storage

- Who will be responsible for storage
- APFO has storage film
- Public access via...?

- USDA Planning Briefing

- 12/12/2007

## Inspection

- New inspection process will need to be established
- No current specification for products
- Stereo pairs
- AT solutions
- GPS/IMU data

- USDA Planning Briefing

- 12/12/2007

## Resource Ortho Issues

- Accurate ortho comes from an accurate digital elevation model
- Pixel resolution for imagery is only as good as the quality and accuracy of the terrain model and local control points (geodetic network)
- Bottom line:
- NED may not be accurate enough
- Ground control is going to add cost

- USDA Planning Briefing

- 12/12/2007