Patent ID: 6992303

Claim:
A method for scanning an area ( 11 ) for emitters of electromagnetic radiation ( 15 ) by means of a scanner head ( 9 ) including an electromagnetic radiation detecting means ( 19 ) and control means ( 25 ), wherein said control means ( 25 ) is arranged: to control the movement of said scanner head ( 9 ): to control the gain of said electromagnetic radiation detecting means ( 19 ); to record in a memory ( 27 ) if the radiation ( 3 ″) emitted by a detected emitter ( 15 ) of electromagnetic radiation and detected by electromagnetic radiation detecting means ( 19 ) exceeds a certain intensity; and, to record in a memory ( 27 ) the position of lines scanned by said scanner head ( 9 ) which contain a detected emitter of electromagnetic radiation ( 15 ) which emits radiation of an intensity which exceeds said certain intensity, wherein said method comprises the steps of: setting the gain of said electromagnetic radiation detecting means ( 19 ) to a high value; scanning first line by line the whole of said area for emitters of electromagnetic radiation; recording the position and intensity of electromagnetic radiation emitted from detected emitters of electromagnetic radiation ( 15 ); setting the gain of said electromagnetic radiation detecting means ( 19 ) to a lower value; rescanning only lines or pixels in said area ( 11 ) in which a detected emitter of electromagnetic radiation ( 15 ) emitted electromagnetic radiation ( 3 ″) of an intensity greater than said certain intensity; and recording the position and intensity of electromagnetic radiation emitted from detected emitters of electromagnetic radiation ( 15 ).