CDIA Image Capture & Processing Techniques 2 — Questions and Answers
Question 1: Which scanner technology uses a single row of photosensitive elements to capture an entire page width in one pass?
- CCD linear array
- CIS (Contact Image Sensor) (Correct answer)
- Drum scanner photomultiplier
- CMOS area array
Correct answer: CIS (Contact Image Sensor)
CIS sensors use a single row of photodetectors spanning the full document width, making them compact and energy-efficient for flatbed and sheet-fed scanners.
Question 2: What is the primary purpose of adaptive thresholding during document binarization?
- To increase scanning speed
- To handle uneven illumination and varying background tones across a document (Correct answer)
- To reduce file size by converting to grayscale first
- To detect document orientation automatically
Correct answer: To handle uneven illumination and varying background tones across a document
Adaptive thresholding applies locally computed threshold values to compensate for lighting gradients, shadow, and paper color variations across the document.
Question 3: In document scanning, what does the term 'optical density range' (Dmax) refer to?
- The maximum number of dots per inch a scanner can resolve
- The darkest tone a scanner can distinguish from pure black
- The maximum range between the lightest and darkest tones a scanner can capture (Correct answer)
- The physical distance between scan head and document platen
Correct answer: The maximum range between the lightest and darkest tones a scanner can capture
Optical density range (Dmax) defines the scanner's dynamic range — the span from maximum white to maximum black it can accurately distinguish.
Question 4: Which image processing technique is used to straighten a document that was fed at a slight angle during scanning?
- Despeckle
- Deskew (Correct answer)
- Descreen
- Dilation
Correct answer: Deskew
Deskew algorithms detect the skew angle of text lines or document borders and rotate the image to align content horizontally or vertically.
Question 5: What is the function of a descreen filter when scanning printed materials?
- Removing noise from the scan sensor
- Eliminating the halftone dot pattern from commercially printed documents (Correct answer)
- Adjusting color balance to match the original
- Converting color images to black and white
Correct answer: Eliminating the halftone dot pattern from commercially printed documents
Descreen filters apply blur or frequency-domain techniques to remove the halftone grid pattern that appears when scanning offset-printed originals.
Question 6: In high-volume production scanning, what does 'imprinting' or 'endorsing' refer to?
- Digitally adding a watermark post-scan
- Physically printing a mark on the document during the scan pass to show it was processed (Correct answer)
- Embedding metadata into the image file header
- Adding a digital signature to the scanned PDF
Correct answer: Physically printing a mark on the document during the scan pass to show it was processed
Imprinters/endorsers are hardware units integrated into production scanners that stamp a batch number, date, or sequence onto the physical document as it passes through.
Question 7: Which color model is most commonly used for scanned document images intended for print reproduction?
- RGB
- HSV
- CMYK (Correct answer)
- YCbCr
Correct answer: CMYK
CMYK (Cyan, Magenta, Yellow, Key/Black) is the standard color model for print output, making it the appropriate choice when scanned documents will be reproduced on press.
CDIA Image Capture & Processing Techniques 2
Which scanner technology uses a single row of photosensitive elements to capture an entire page width in one pass?