Method and apparatus for stroboscopic video inspection of an asynchronous event
First Claim
1. Apparatus for synchronizing high intensity short duration illumination of a substantially predictable asynchronous event in real-time with image acquisition by a video camera having an image sensor and a synchronization generator circuit which generates periodic scan pulses which trigger an image acquisition scan of the image sensor, comprising:
- means for selectively disabling the periodic scan pulses and for generating a prefresh scan pulse for triggering an image acquisition scan of the image sensor a first predetermined time period prior to the substantially predictable event thereby preconditioning the image sensor and disabling image acquisition scan until occurrence of the substantially predictable event; and
means for triggering an image acquisition scan of the image sensor subsequent to the first predetermined time period to generate image data corresponding to the substantially predictable event.
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Abstract
Apparatus and method particularly suitable for use with the closed loop color to color registration system of a commercial web printing apparatus utilizes a CCD camera having an image sensor and a synchronization generator circuit which generates periodic scan pulses which trigger the image acquisition scan of the image sensor. A predetermined time prior to triggering of a strobe a prefresh pulse is generated in order to trigger a complete scan of the image sensor prior to firing the strobe. A predetermined time period subsequent to the firing of the strobe a scan triggering pulse is generated to trigger an image acquisition scan of the image sensor. This results in highly stable and reliable acquisition of a low noise image of for example, a registration mark on a printed web which may then be processed by a registration control system.
43 Citations
21 Claims
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1. Apparatus for synchronizing high intensity short duration illumination of a substantially predictable asynchronous event in real-time with image acquisition by a video camera having an image sensor and a synchronization generator circuit which generates periodic scan pulses which trigger an image acquisition scan of the image sensor, comprising:
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means for selectively disabling the periodic scan pulses and for generating a prefresh scan pulse for triggering an image acquisition scan of the image sensor a first predetermined time period prior to the substantially predictable event thereby preconditioning the image sensor and disabling image acquisition scan until occurrence of the substantially predictable event; and means for triggering an image acquisition scan of the image sensor subsequent to the first predetermined time period to generate image data corresponding to the substantially predictable event. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for synchronizing image acquisition by a video camera to high intensity short duration illumination of a substantially predictable asynchronous event in real time wherein the video camera includes an image sensor, the method comprising the steps of;
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generating periodic refresh pulses to periodically trigger an image acquisition scan of the image sensor; disabling the refresh pulses and generating a prefresh pulse a first predetermined time period prior to the substantially predictable event for triggering an image acquisition scan of the image sensor a first predetermined time period prior to the substantially predictable event thereby preconditioning the image sensor and disabling image acquisition scan until occurrence of the substantially predictable event; and generating an image acquisition pulse for triggering an image acquisition scan of the image sensor a second predetermined time period subsequent to the first predetermined time period to generate image information responsive to the substantially predictable event. - View Dependent Claims (15, 16, 17, 18)
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19. Apparatus for synchronizing high intensity short duration illumination of a substantially predictable recurring asynchronous event in real-time with image acquisition by a video camera, comprising:
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a video camera having an image sensor and a synchronization generator circuit which generates periodic scan pulses which trigger image acquisition scans of the image sensor; means for disabling the periodic scan pulses; illumination means for providing high intensity, short duration illumination to illuminate the substantially predictable event; means for activating the illumination means in response to the substantially predictable event including means for pre-charging to enable said activation; means for triggering an image acquisition scan of the image sensor in response to activation of the illumination means to generate image data corresponding to the substantially predictable event; means for disabling the means for pre-charging for a first predetermined period subsequent to the activation of the illumination means. - View Dependent Claims (20, 21)
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Specification