All (23422)
Notes (10000)
note
Celebrations
Updated 293d ago
0.0(0)
note
CELEBRITY CULTURE
Updated 587d ago
0.0(0)
note
Izzys phone mishap
Updated 22d ago
0.0(0)
note
CELEBRATION VOCAB
Updated 512d ago
0.0(0)
note
Celebrations Vocab
Updated 406d ago
0.0(0)
note
Spanish celebrations
Updated 509d ago
0.0(0)
note
DURATION OF CELEBRATIONS
Updated 417d ago
0.0(0)
note
Celebrations Vocab
Updated 515d ago
0.0(0)
note
Notes on Celebrated Gymnast
Updated 43d ago
0.0(0)
note
Birthday Celebration Greetings
Updated 29d ago
0.0(0)
note
Notes on Birthday Celebration
Updated 78d ago
0.0(0)
note
Celebrating Holy Communion
Updated 1303d ago
0.0(0)
note
Ageing Celebrity Culture
Updated 147d ago
0.0(0)
note
cerebral
Updated 361d ago
0.0(0)
note
Unit 3 celebrations Spanish
Updated 431d ago
0.0(0)
Flashcards (10000)
flashcards
Intro to Neuro Ch. 6 Book
99
Updated 11m ago
0.0(0)
flashcards
BIO (BOOK 1): Enzymes
40
Updated 1h ago
0.0(0)
flashcards
Intro To Neuro Book Ch. 5
78
Updated 3h ago
0.0(0)
flashcards
Quiz 3 Study Guide – Digital Radiography ⸻ Preprocessing vs Postprocessing • Preprocessing = happens before the image is displayed • Corrects raw data from the detector • Examples: flat-field correction, dead pixel correction • Postprocessing = happens after image acquisition • Adjusts image appearance • Examples: brightness, contrast, edge enhancement ⸻ Postprocessing Domains Spatial Domain • Works with pixel location • Affects detail/resolution • Example: smoothing, edge enhancement Intensity Domain • Works with pixel brightness values • Affects contrast • Example: windowing, LUT Frequency Domain • Works with patterns (frequencies) in the image • Separates noise vs detail • Example: filtering (remove noise or enhance edges) ⸻ Histogram Analysis What the Histogram Represents • Graph of pixel intensity distribution • X-axis = brightness (black → white) • Y-axis = number of pixels ⸻ Types of Histogram Analysis • Type 1 • Simple exams (extremities) • Single peak • Type 2 • Two main tissue types (chest) • Two peaks • Type 3 • Complex anatomy (abdomen) • Multiple peaks • Neural (AI-based) • Uses pattern recognition instead of fixed shapes ⸻ Construction of Histogram 1. Image acquired 2. Exposure field recognized 3. Pixels analyzed 4. Histogram created from pixel values ⸻ Histogram Analysis Errors • Wrong body part selected • Collimation too wide/narrow • Artifacts (prosthetics, shielding) • Multiple exposures on one plate 👉 Leads to incorrect brightness/contrast ⸻ Look-Up Table (LUT) • Converts pixel values → visible grayscale • Controls contrast and brightness appearance • Different LUTs = different exam types ⸻ Dynamic Range Compression (DRC) • Reduces wide exposure range into visible range • Helps see both dark & light areas ⚠️ Effects: • Can reduce contrast • Can hide pathology if overused ⸻ Smoothing • Reduces noise • Makes image look softer • ↓ spatial resolution ⸻ Edge Enhancement • Increases sharpness • Highlights borders • Can increase noise/artifacts ⸻ SNR vs CNR • SNR (Signal-to-Noise Ratio) • Signal vs background noise • Higher = cleaner image • CNR (Contrast-to-Noise Ratio) • Difference between structures vs noise • Higher = better visibility of anatomy ⸻ Dose Creep & Exposure Index (EI) • Dose creep • Gradual increase in exposure over time • Happens because images still look good even at higher dose • Exposure Index (EI) • Indicates how much radiation reached detector • Used to monitor proper exposure ⸻ Segmentation • Identifies area of interest • Removes background from analysis • Important for accurate histogram ⸻ Grid Line Suppression • Removes visible grid lines digitally • Prevents moiré patterns ⸻ Kernels • Mathematical filters applied to image • Types: • Smooth (reduce noise) • Sharp (increase detail) ⸻ Postprocessing Controls (Tech Can Adjust) • Window level (brightness) • Window width (contrast) • Magnification • Edge enhancement • Smoothing ⸻ Sequence of Preprocessing Events 1. Exposure detection 2. Analog → digital conversion 3. Flat-field correction 4. Dead pixel correction 5. Exposure field recognition 6. Histogram creation 7
44
Updated 5h ago
0.0(0)
flashcards
Test 2 Current Events
52
Updated 5h ago
0.0(0)
flashcards
Day 3 Evening (135-147)
22
Updated 7h ago
0.0(0)
flashcards
Social psych 3 book
35
Updated 10h ago
0.0(0)
Users (3422)