1. Chapt 29 Viewing the Digital Image
Photometric Quantities
Hard/Soft Copy
Active Matrix Liquid Crystal Display
Pre/postprocessing digital image
PACS

2. Photometric Quantities
Response of the eye
Photopic
Scotopic

3. Luminous flux Total intensity of light from a source
Measured in “luminous flux in LUMENS

4. Illuminance Intensity of light incident on a surface
Goes back to measure of “candle light” on a single square foot of surface

5. Luminance intensity
Amount of light emitted by a light source (viewbox is a good example)

6. Luminance
Measure of the BRIGHTNESS of a source (like in a digital display)
Measured in candela per meter squared = NIT

7. Cosine Law
Relate to inverse square law and the amount of radiation at varied distance
Same for light at GREATER distances like the CR vs periphery of the beam (pathagoras theory)

8. Hard-soft copy Hard = radiograph on film
Soft = Viewing on a cathode ray tube (computer/T.V. monitor)

9. Active Matrix Liquid Crystal Display
Instead of using a “cathode ray tube” (TV tube type) viewing system, the active matrix, pixel by pixel, viewing monitor is used
Spatial resolution improves with larger matrix (pixels) displays

10. Preprocessing the image
YOU can program the computer with what YOU want the image to look like
i.e. do we want a hand with a dynamic range of 2?
Perhaps a CXR with a dynamic range of 60?
Show what scale of contrast and shades of gray to display

11. Postprocessing Annotation
Window and leveling (expand or shrink the shades of grays)

12. PACS
Aaron – tell your thing!