Abstract: A detection system for detecting an optical signal from a luminescent material applied to or incorporated within an object (S) comprises: at least one light source (11) which generates light, as excitation light, for illuminating at least a region (IS) of the object (S); at least one detector (21) which detects light, as collection light, from the object (S) when illuminated by the excitation light and provides an output signal having a signal intensity in response to an intensity of the collection light; and a controller (31) which is adapted to control the output signal to have a signal intensity within a predetermined range or at substantially a constant value, or post-process the output signal to extract the output signal at a signal intensity within a predetermined range or at substantially a constant value.