What is 'Dithering' in digital image processing?
Option C is correct. Dithering creates the optical illusion of broader color depth on low-color displays by arranging patterns of colored pixels to visually blend adjacent shades.
Which filter is non-linear and specifically used to remove impulse noise ('salt-and-pepper noise') while preserving sharp image edges?
Option C is correct. A Median filter replaces each pixel value with the median value of neighboring pixels, effectively removing isolated noise spikes ('salt-and-pepper') without blurring sharp edges like mean filters do.
What does a histogram of a digital image represent?
Option B is correct. An image histogram plots the number of pixels (frequency) at each brightness/color intensity level (typically 0 to 255 in 8-bit images).
Which technique enhances image contrast by spreading out the most frequent intensity values across the full dynamic range?
Option C is correct. Histogram equalization stretches the cumulative density function of image pixel intensities, enhancing overall contrast in low-contrast images.
What component in a flatbed scanner or digital camera converts light photons into proportional electrical signals?
Option A is correct. CCD and CMOS image sensors contain photosensitive diodes that convert incoming photons of light into analog electrical charges.