| 摘要 |
PURPOSE:To obtain a subtracted data directly without calculating the subtraction of picture data by reading out a contrast picture by reading light previsously modulated by mask picture information or an electronic line. CONSTITUTION:At first, picture information before the injection of a contrast medium to be a mask picture is stored in a picture memory 10. Then, a two- dimensional analog picture film 1 after the injection of the contrast medium is set up, scanned by beams and stored in a picture memory 11. Synchronously with the scanning of the film 1, the data of a mask picture are read out from the picture memory 10, a signal through a D/A converter 12 and a compensating circuit 13 is guided to a modulator 3 to modulate the optical beam. At that time, the output of a photodetector 5 becomes a picture signal embossed only at a part changed after the injection of the contrast medium and the automatically subtracted data are stored in the picture memory 11. |
