A surveillance system comprising: a lighting system comprising a plurality of lighting apparatuses including one or more lights; a surveillance imaging device arranged to capture image data of a monitored area illuminated by one or more of the lighting apparatuses; and a control system comprising: an image processor arranged to receive the image data from the surveillance imaging device, wherein the image data comprises a plurality of frames, and wherein the image processor is arranged to analyse each frame of the image data to obtain an image quality parameter for each frame; wherein the image processor is arranged to receive information on a selection of a portion of the image data of each frame, and wherein the image processor is arranged to obtain the image quality parameter for each frame based only on the selected portion of the image data; a controller arranged to determine a difference between a value of the image quality parameter for a current frame and a reference value of the image quality parameter, wherein if said difference is greater than a threshold value the controller is arranged to repeat a process of: sending to the lighting system control information for controlling a lighting parameter of at least one of the plurality of lighting apparatuses so as to change illumination of the selected portion; and determining a new difference between a value of the image quality parameter for a new current frame and the reference value of the image quality parameter; wherein the process is repeated until said new difference is less than or equal to the threshold value. a lighting system comprising a plurality of lighting apparatuses including one or more lights; a surveillance imaging device arranged to capture image data of a monitored area illuminated by one or more of the lighting apparatuses; and a control system comprising: an image processor arranged to receive the image data from the surveillance imaging device, wherein the image data comprises a plurality of frames, and wherein the image processor is arranged to analyse each frame of the image data to obtain an image quality parameter for each frame; wherein the image processor is arranged to receive information on a selection of a portion of the image data of each frame, and wherein the image processor is arranged to obtain the image quality parameter for each frame based only on the selected portion of the image data; a controller arranged to determine a difference between a value of the image quality parameter for a current frame and a reference value of the image quality parameter, wherein if said difference is greater than a threshold value the controller is arranged to repeat a process of: sending to the lighting system control information for controlling a lighting parameter of at least one of the plurality of lighting apparatuses so as to change illumination of the selected portion; and determining a new difference between a value of the image quality parameter for a new current frame and the reference value of the image quality parameter; wherein the process is repeated until said new difference is less than or equal to the threshold value. an image processor arranged to receive the image data from the surveillance imaging device, wherein the image data comprises a plurality of frames, and wherein the image processor is arranged to analyse each frame of the image data to obtain an image quality parameter for each frame; wherein the image processor is arranged to receive information on a selection of a portion of the image data of each frame, and wherein the image processor is arranged to obtain the image quality parameter for each frame based only on the selected portion of the image data; wherein the image processor is arranged to analyse each frame of the image data to obtain an image quality parameter for each frame; wherein the image processor is arranged to receive information on a selection of a portion of the image data of each frame, and wherein the image processor is arranged to obtain the image quality parameter for each frame based only on the selected portion of the image data; a controller arranged to determine a difference between a value of the image quality parameter for a current frame and a reference value of the image quality parameter, wherein if said difference is greater than a threshold value the controller is arranged to repeat a process of: sending to the lighting system control information for controlling a lighting parameter of at least one of the plurality of lighting apparatuses so as to change illumination of the selected portion; and determining a new difference between a value of the image quality parameter for a new current frame and the reference value of the image quality parameter; wherein the process is repeated until said new difference is less than or equal to the threshold value. sending to the lighting system control information for controlling a lighting parameter of at least one of the plurality of lighting apparatuses so as to change illumination of the selected portion; and determining a new difference between a value of the image quality parameter for a new current frame and the reference value of the image quality parameter; wherein the process is repeated until said new difference is less than or equal to the threshold value.