A system comprising: one or more transmitters to transmit an excitation energy into an object under observation one or more detectors to generate projection space data encoding an energy received by the one or more detectors in response to the transmitted excitation energy into the object under observation a controller to control the one or more transmitters to transmit the excitation energy and the one or more receivers to generate the projection space data and an image reconstructor having at least one processor to receive the projection space data and to process the projection space data by: computing a first quantity characterizing a difference between the projection space data and predicted projection data, wherein the difference between the projection space data and predicted projection data is associated with a projection gain recording, in a data storage device, a first data encoding the difference computing a revised first quantity based on recorded first data from preceding iterations computing an update value using the revised first quantity and reconstructing an object space image representing the object under observation using the update value.一系統,其包含:一或更多個發射器,以發射一激發能量進入被觀察的一物體內;一或更多個偵側器以產生投射空間資料,以將由該一或多個偵測器反應於被發射入被觀察物體內之激發能量而所接收到的一能量加以編碼;一控制器,其控制該一或更多個發射器發射激發能量及該一或更多個偵側器產生該投射空間資料;與一影像重建器,具有至少一處理器以利用以下方式而接收該投射空間資料並處理該投射空間資料:計算表現該投射空間資料與預測投射資料間之差異特徵之一第一量,其中投射空間資料與預測投射資料間之差異係與一投射增益相關聯;於一資料儲存裝置內記錄下將該差異加以編碼之一第一資料;依據來自先前疊代所記錄的第一資料而計算經修改過的第一量;利用修改過第一量而計算一更新值;與重建代表被觀察物體之一物體空間影像。101‧‧‧投射影像獲取102‧‧‧儲存裝置103‧‧‧模擬104‧‧‧投射像素資料編碼物體資訊105‧‧‧影像重建器106‧‧‧物體之重建影像107‧‧‧輸出裝置
