CDIA Scanning Technology 4 — Questions and Answers
Question 1: Which scanning artifact appears as a repetitive pattern of light and dark bands caused by interference between the scanner sampling frequency and the halftone screen frequency of printed images?
- Aliasing
- Moiré pattern (Correct answer)
- Banding
- Ghosting
Correct answer: Moiré pattern
Moiré patterns occur when the scanner's sampling grid interacts with the periodic dot pattern of halftone-printed images, creating an unwanted interference pattern.
Question 2: In a document imaging system, what is the function of an ADF (Automatic Document Feeder)?
- To automatically enhance scanned images
- To automatically feed multiple documents sequentially through the scanner without manual intervention (Correct answer)
- To automatically index scanned documents in the ECM system
- To automatically convert scanned images to PDF format
Correct answer: To automatically feed multiple documents sequentially through the scanner without manual intervention
An ADF is a mechanical attachment that picks and feeds individual sheets from a stack, enabling unattended high-volume scanning operations.
Question 3: What is 'optical density' (OD) as it relates to scanner specifications?
- The number of pixels per inch the scanner can capture
- A measure of a scanner's ability to distinguish detail in very dark or very light areas (Correct answer)
- The speed at which a scanner processes pages
- The thickness of documents the scanner can handle
Correct answer: A measure of a scanner's ability to distinguish detail in very dark or very light areas
Optical density (Dmax) measures the scanner's ability to capture detail across its tonal range, particularly in shadows; higher Dmax values indicate better shadow detail capture.
Question 4: A production scanner consistently produces images with a faint shadow of the previous page visible in the current scan. This is known as:
- Bleed-through
- Ghosting (Correct answer)
- Show-through
- Dropout
Correct answer: Ghosting
Ghosting occurs when residual charge or optical persistence in the scanner's sensor causes a faint echo of a previously scanned image to appear in subsequent scans.
Question 5: Which color model is most commonly used internally by document scanners to capture color information?
- CMYK
- HSL
- RGB (Correct answer)
- YCbCr
Correct answer: RGB
Document scanners use RGB (Red, Green, Blue) as their native color model because it directly corresponds to the sensor's red, green, and blue light-sensitive elements.
Question 6: What is the purpose of using a 'patch code' document in production scanning environments?
- To trigger automatic scanner calibration
- To automatically separate batches or trigger specific processing actions based on a printed barcode pattern (Correct answer)
- To mark documents that need re-scanning
- To indicate the end of a scanning session
Correct answer: To automatically separate batches or trigger specific processing actions based on a printed barcode pattern
Patch codes are specially printed barcode-like patterns inserted between document batches to signal the scanner software to start a new batch or initiate a specific workflow action.
Question 7: When scanning fragile historical documents, which scanning mode minimizes physical stress on the document?
- High-speed ADF mode
- Continuous-feed mode
- Overhead (planetary) scanning mode (Correct answer)
- Flatbed with pressure plate
Correct answer: Overhead (planetary) scanning mode
Overhead planetary scanners capture images without any contact with the document, eliminating the physical stress caused by rollers or pressure plates.
CDIA Scanning Technology 4
Which scanning artifact appears as a repetitive pattern of light and dark bands caused by interference between the scanner sampling frequency and the halftone screen frequency of printed images?