(US5068522-A)      The arrangement (100) determines the position of the energy centre (o') of the image (S') of a luminous object by barycentric calculation within a window surrounding the image (S') and covering plXpc elements of a charge-transfer matrix (120). The arrangement has a first mode of operation, during which on the one hand the matrix (120) is read by grouping the N1 lines m-by-m (m is less than p1) in the output register, whereas on the other hand, the output register is emptied by grouping, in the read ' arrangement of the matrix (120),1 (1 is less than pc) consecutive elements from the output register, so as to determine the brightest zone m x 1 of the matrix defining the approximate position of the image (S') on the matrix.    During a second mode of operation, the matrix (120) is first read, by grouping the lines n-by-n (n is less than p1), thereafter, line by line in a zone of k lines (k is less than p1) located around the brightest zone and finally, by again grouping the lines n-by-n until all the N1 lines have been used up.    USE -   Solar view finders. @(5pp)@    (EP384527-B1)      A method of determining the direction of the energy centre of a luminous object by means of a lens forming an image of said luminous object on a photo-sensitive detector, said photo-sensitive detector being a charge-transfer matrix without memory having N1 lines and Nc columns with an output register of Nc elements, in which method the position of the energy centre of the image of the luminous object is determined by barycentric calculation within a window surrounding said image and covering plxpc elements of the matrix, said method being characterised in that: in a first mode of operation, denoted the search mode, said matrix is read by grouping the Nl lines m-by-m (m less than pl) in the output register, whereas the output register is emptied by grouping l (l less than pc) consecutive elements of the output register in the read arrangement of the matrix, in order to determine the brightest area mxl of the matrix defining the approximate position of the image on the matrix, in a second mode of operation, denoted the measuring mode, which follows the search mode, the matrix is first read by grouping the lies n-by-n (n greater than pl), thereafter fine by line in an area of k lines (k greater than pl) located around said brightest area, and finally by again grouping the lines n-by-n until all the Nl lines have been used up.