When verifying a display system, which tool should be used to determine if it meets a specified contrast ratio?

When verifying a display system's contrast ratio, a spot photometer is the most appropriate tool to use. This device measures the intensity of light emitted from a particular point on the screen. By taking readings of both the brightest and darkest areas of the display, the spot photometer allows you to quantify the light levels and, in turn, calculate the contrast ratio.

The contrast ratio is a critical performance metric that indicates the difference in luminance between the brightest white and the darkest black that a display can produce. Using a spot photometer enables precise measurements of these luminance values, which is essential for tasks such as calibrating the display and ensuring it performs within the desired specifications.

Other tools mentioned serve different purposes: a multi-meter is typically used for measuring electrical parameters, a histogram visualizes data distributions but does not provide direct luminance readings, and a lux meter measures illuminance but does not isolate the peak brightness and black levels necessary for contrast ratio calculations. Therefore, the spot photometer is the tool specifically designed to assess contrast ratios accurately.