Abstract: A video level measuring apparatus for use in conjunction with setup and maintenance of an imaging system, such as an X-ray imaging system, is configured for first and second modes of operation. In the first mode of operation, a measure signal indicative of the average video level of the portion of an input video signal produced by the imaging system within an operator positionable and sizable window area is formed and converted to a numeric displays and an augmented video signal is presented as an output video signal in which the window area of the corresponding image has a video level which is increased by a uniform adjustable amount. In the second mode of operations, a test pattern video signal corresponding to an operator positionable and sizable window of uniform operator adjustable brightness against a black background is presented as the output video signal applied to a monitor.