Patent GB-1460433-A (GB)
Title: Huntingdon instruments image analysis apparatus
IPC: G06V10/98
Filed: 1973-04-06
Abstract: 1460433 Cathode-ray tube circuits NUTRITIONAL RESEARCH UNIT Ltd [trading as HUNTINGDON INSTRUMENTS] 3 April 1974 [6 April 1973] 16664/73 Heading H4T In apparatus for analysing a video image produced on the screen of a cathode-ray tubealightpen, manually movable over the screen indicates an area of interest, the X-Y co-ordinates of the pen motion are stored and from the latter, a gating signal is formed which is employed to gate-out the video signals representative of the display in such area for subsequent analysis by any known means. The invention is described in connection with the analysis of (the image of), e.g. a single white cell in a blood sample, the cytoplasm of a cell and in automatic tracking in the analysis of histological sections. As shown, a television camera 4, optically coupled to a microscope 1, produces video signals representative of a specimen carried by the microscope stage 3. The latter is movable in X-Y co-ordinate directions by means of a stepping motor supplied from a drive amplifier 24 and the optical magnification of the microscope may be changed by automatic means 2 supplied from a drive circuit 22. The video signal output of the camera is supplied to a display amplifier 6 controlling the display on a cathode-ray tube (T.V. monitor) 7 and is also supplied to a "detector" 16 to which the gating signal is also supplied to gate out the required video signals. The scanning of the camera 4 and of the display tube 7 is controlled by means 9 supplied with clock pulses from a generator 8 the means 9 being also connected to an interface 12 which receives the output signal from the light pen 11. The interface output is supplied to an X-Y coordinate store 10 (also supplied with clock pulses) which stores the X-Y co-ordinates of successive points on the path of the pen as it is moved over the screen of tube 7 to indicate an area of interest, an output from the store being fed to the display amplifier 6 so that a visible trace of the movement of the pen is produced on the screen of tube 7. This output is also supplied to movable contact 15 of switch 13 and in the position shown, the "A" position, is fed to a gating signal generator 19 the output of which is supplied via movable contact 14 to the "detector" 16 (which may or may not have a set threshold level) to gate out the required video signals. In the tracking mode of operation switch 13 is operated to its "B" position, a low optical magnification is set and stage 3 is manually moved to locate a field of interest. Light pen 11 is then employed to indicate a succession of points of interest (which may be randomly distributed) on the screen of tube 7 and by applying a suitable signal to terminal 20, the operator then sets the magnification at which the analysis of the indicated points of interest is required to be made. The input at terminal 20 is also supplied to a second gating signal generator 21 which supplies a gating signal of "size" appropriate to the selected magnification and this is effective via contact 17B to produce the required gating action in detector 16. In this mode of operation the co-ordinate store 10 supplies (via contact 18B) the co-ordinate of the first indicated point to an X-Y co-ordinate generator 23 the output of which is fed to an X-Y drive amplifier 24 controlling the stepping motor drive for the specimen holding microscope stage 3 which is driven to position the selected point in the centre of the field of view. The display (and analysis) of each selected point of interest is effected in this manner in the order determined by the T.V. raster scan i.e. starting in the top left-hand corner and finishing in the bottom right hand corner.