The invention provides a projection
light source brightness output method. The projection
light source brightness output method comprises the following steps: obtaining a ratio of a first maximum
gray level value of the N frame of image to a second maximum
gray level value of the N+M frame of image in real time to obtain an adjustment coefficient, performing weighting calculation on the N+M frame of
image signal according to the adjustment coefficient, judging whether the number of
gray level values of base colors reaching to a preset gray level value in the N+M frame of
image signal after the weighting calculation is equal to a preset threshold, if so, adjusting the projection
light source brightness to a set value, and if not, adjusting the projection light source brightness to 1 / G of the original one. According to the projection light source brightness output method provided by the invention, the projection light source brightness can be dynamically adjusted, so that a projection light source is not always in a high-load working state, a certain energy saving effect can be realized, the service life of the light source is prolonged, and the output stability of projection images is ensured at the same time.