| 摘要 |
PURPOSE:To conduct trimming with easy operation without complicated constitution by controlling a light spot scanning so as to set a scanning region by the light spot scanning and allow the light spot to be scanned in the scanning region in an image pickup device scanning a photo film or the like by the light spot and transducing it into a picture signal. CONSTITUTION:In decreasing a scanning region 14 on fluorescent screen 2 of a cathode ray tube 1 less than the size of an object 4, the scanning region of a light spot projected on the object 4 is decreased, it means that only a part of the object 4 is scanned and the trimming or zooming is conducted. In order to change the scanning region on the cathode ray tube 1, deflection signals Sai, Sbi deflecting the electron beam of the cathode ray tube 1 have only to be changed. That is, the scanning region on the cathode ray tube 1 is changed by changing the amplitude of the deflection signals Sa1, Sb1 at a standard operating state and a bias. In order to keep the aspect ratio of the screen to a constant value at the trimming, the ratio of the amplitude of the deflection signal at the standard scanning to the deflection signal at trimming is to be made constant. |
