| 摘要 |
PURPOSE:To improve judging accuracy for a defective container, by forming the image on a wall surface of a hermetically sealed container on a photoelectric transducer screen of an image pickup device as a secondary image, and checking the internal pressure based on irregularity rate of said secondary image. CONSTITUTION:An internal pressure checking apparatus is constituted by the following devices: a light projector 102 which projects plane shaped luminous flux 102a on a wall surface 101 of a hermetically sealed container 100; an image pickup device 104, which encloses a photoelectric transducer screen 105 and forms an image 103 on the wall surface 101 of the screen 105; a image memory device 114; an operating device 115; and the like. The reference value of the irregularity of a secondary image 106 corresponding to the irregularity of the wall surface 101 is set at a specified value. The hermetically sealed container 100 is placed on a conveyer 117 and the luminous flux 102a is projected by the light projector 102. Then the secondary image 106 is projected on the screen 105, and the image signal 113 is stored in an image memory 114. The irregularity value of the secondary image 106 corresponding to the irregularity of the wall surface 101 is computed by the operating device 115 and compared with the reference value. Thus the internal pressure is determined. |
