What is the function of quantization in digital imaging?

What is the function of quantization in digital imaging?

• A. Assigns a gray tone to each pixel
• B. Converts X-ray energy to light
• C. Determines the sampling frequency
• D. Stores binary values

Answer: (A)

Quantization in digital imaging is the step that converts a continuous range of image intensities into a finite set of discrete gray levels. After sampling, each pixel’s tonal value is approximated by the nearest quantization level, so a specific gray tone is assigned to that pixel. The number of gray levels—and thus the smoothness of the image—depends on the bit depth (for example, 8-bit depth provides 256 levels). This process is what enables the image to be stored digitally as discrete values. It’s not about converting X-ray energy to light—that’s the detector/scintillator’s job—and it’s not about setting how often we sample the image—that’s the sampling frequency. It also isn’t simply storing binary values, though those quantized levels are eventually encoded into binary form for storage.

Quantization in digital imaging is the step that converts a continuous range of image intensities into a finite set of discrete gray levels. After sampling, each pixel’s tonal value is approximated by the nearest quantization level, so a specific gray tone is assigned to that pixel. The number of gray levels—and thus the smoothness of the image—depends on the bit depth (for example, 8-bit depth provides 256 levels). This process is what enables the image to be stored digitally as discrete values. It’s not about converting X-ray energy to light—that’s the detector/scintillator’s job—and it’s not about setting how often we sample the image—that’s the sampling frequency. It also isn’t simply storing binary values, though those quantized levels are eventually encoded into binary form for storage.