An imaging system for providing a three-dimensional surface representation of an animal, the imaging system comprising: a camera; an imaging chamber comprising a set of walls enclosing an interior cavity (44; 201); a stage (58; 204) configured to support the animal within the interior cavity, wherein the stage is movable to a plurality of positions in the interior cavity at different distances from the camera, each of the plurality of positions being within a field of view of the camera; a structured light source (420; 170) configured to produce structured light comprising a set of lines at each of the plurality of positions of the stage for transmission onto the stage alone to produce a reference pattern without the animal and onto the animal while the animal rests on the stage, wherein interception of the structured light by the animal generates structured light surface information for the animal, wherein the camera is arranged to capture the structured light surface information and wherein the structured light source is configured to vary a spacing between the set of lines; and a processor configured to: produce a three-dimensional surface representation of at least a portion of the animal using the reference pattern and the structured light surface information at the plurality of positions of the stage; and use the three-dimensional surface representation of at least a portion of the animal to reconstruct a location, a brightness, and a size of a light source within the animal; characterized in that the processor is further configured to control the structured light source to vary the spacing between the set of lines. a camera; an imaging chamber comprising a set of walls enclosing an interior cavity (44; 201); a stage (58; 204) configured to support the animal within the interior cavity, wherein the stage is movable to a plurality of positions in the interior cavity at different distances from the camera, each of the plurality of positions being within a field of view of the camera; a structured light source (420; 170) configured to produce structured light comprising a set of lines at each of the plurality of positions of the stage for transmission onto the stage alone to produce a reference pattern without the animal and onto the animal while the animal rests on the stage, wherein interception of the structured light by the animal generates structured light surface information for the animal, wherein the camera is arranged to capture the structured light surface information and wherein the structured light source is configured to vary a spacing between the set of lines; and a processor configured to: produce a three-dimensional surface representation of at least a portion of the animal using the reference pattern and the structured light surface information at the plurality of positions of the stage; and use the three-dimensional surface representation of at least a portion of the animal to reconstruct a location, a brightness, and a size of a light source within the animal; characterized in that the processor is further configured to control the structured light source to vary the spacing between the set of lines. produce a three-dimensional surface representation of at least a portion of the animal using the reference pattern and the structured light surface information at the plurality of positions of the stage; and use the three-dimensional surface representation of at least a portion of the animal to reconstruct a location, a brightness, and a size of a light source within the animal; characterized in that the processor is further configured to control the structured light source to vary the spacing between the set of lines.