1. An IR detector system comprising a High Operating Temperature detector array of pixels and a filter for filtering noise from the data generated by the pixel array, the filter comprising a reading portion for reading the array size, a selection portion for selecting the pixel under test and a number of surrounding pixels, a comparison portion for comparing the data representative of selected pixel to each neighbouring pixel and generating a score representative of the condition of the selected pixel data, a counting portion for counting the score of the selected pixel; and an averaging portion for taking a mean average score of each surrounding pixel of the selected pixel such that noise generated by the detector array and included in the image data is substantially removed.