초록 ▼

Infrared and visible light energies are directed through a container onto a CCD camera that is responsive to both the visible and infrared light energy. Crossed polarizers are positioned on opposed sides of the container, and operate on the visible light energy in such a way as to block transmission

Infrared and visible light energies are directed through a container onto a CCD camera that is responsive to both the visible and infrared light energy. Crossed polarizers are positioned on opposed sides of the container, and operate on the visible light energy in such a way as to block transmission of visible light to the camera in the absence of stress variations in the container, which alter polarization of the visible light energy traveling through the container. On the other hand, the polarizers have little or no effect on the infrared light energy, which creates a normally gray intensity of background light at the camera. In this way, incidence of visible light on the camera due to stress variations in the container appears as a bright signal against a normally gray background, while blockage of infrared light due to opaque variations in the container appears as a dark signal against the normally gray background.

대표청구항 ▼

[ I claim:] [1.] A method of inspecting containers for commercial variations that affect optical characteristics of the containers, which comprises the steps of:(a) directing light energy onto a container in such a way that a first wavelength of the light energy is responsive to a first type of comm

[ I claim:] [1.] A method of inspecting containers for commercial variations that affect optical characteristics of the containers, which comprises the steps of:(a) directing light energy onto a container in such a way that a first wavelength of the light energy is responsive to a first type of commercial variation in the container and a second wavelength of the light energy different from said first wavelength is responsive to a second type of commercial variation different from said first type,(b) detecting light energy from the container onto light sensing means, and(c) detecting commercial variations of said first and second types at the container as a function of a comparison between light energies at said first and second wavelengths incident on said light sensing means by forming an image at said light sensing means of light energy at said first wavelength against a background of energy at said second wavelength.