Which image analysis step is used to help determine the useful signal by evaluating the distribution of pixel intensities?

• A. Histogram analysis
• B. Edge detection
• C. Spatial smoothing
• D. Color space conversion

Answer: (A)

Evaluating how pixel intensities are distributed helps reveal what part of the image carries meaningful information versus noise. This is captured by histogram analysis, which plots how many pixels have each possible brightness level. By inspecting the histogram, you can gauge exposure and contrast and see how the signal spans the available dynamic range. A histogram stretched across a wide range with clear peaks often indicates useful signal across brightness levels, while clipping at the dark or bright ends signals loss of detail. The other options serve different aims: edge detection looks for sharp changes to outline features, smoothing reduces noise but doesn’t summarize overall intensity distribution, and color space conversion changes how colors are represented rather than directly assessing the distribution of intensities for signal content.