Image Processing Flashcards

Which color space is most commonly used in document imaging for representing grayscale documents?

Answer: 8-bit grayscale

8-bit grayscale provides 256 shades of gray and is the standard representation for monochrome document imaging.

What does the term 'despeckle' refer to in document image processing?

Answer: Removing isolated noise pixels

Despeckle filtering removes isolated noise pixels (salt-and-pepper noise) that appear as random black or white dots on scanned documents.

Which image format uses lossless compression and supports transparency, making it suitable for logos in document workflows?

Answer: PNG

PNG uses lossless compression and supports alpha channel transparency, making it ideal for logos and graphics in document workflows.

In document scanning, what is 'halftone detection' used for?

Answer: Identifying printed photographs or screened images for appropriate compression

Halftone detection identifies regions containing photographic or screened content so that appropriate compression (e.g., JPEG) is applied instead of bitonal compression.

What is the primary purpose of adaptive thresholding in document binarization?

Answer: Adjusting the threshold locally based on surrounding pixel values

Adaptive thresholding calculates a local threshold for each pixel region, handling uneven illumination and background variation better than a single global threshold.

Which scanning artifact occurs when light bleeds through from the reverse side of a thin document page?

Answer: Show-through (bleed-through)

Show-through or bleed-through occurs when text or images on the reverse side of thin paper are faintly visible on the scanned side.

What does a histogram equalization operation do to a document image?

Answer: Redistributes pixel intensity values to improve contrast

Histogram equalization redistributes the intensity values across the full range to enhance overall contrast and detail visibility.