Using TDI camera with nonzero viewing angles for surface inspection

Jari Miettinen, Xu Zelin, Heikki J. Ailisto

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    2 Citations (Scopus)


    A variety of time delay and integration (TDI) arrays have been developed. The TDI image sensor offers significant improvement in performance over a linear CCD-sensor with respect to sensitivity. This is particularly significant in low level operations since the exposure time is increased by a factor which is equal to the number of the TDI stages in the sensor. Typically, the use of a TDI camera is restricted to cases where the surface is viewed from the direction of the surface normal. This is because the TDI-camera sensor has to be parallel to the viewed surface plane, in order to avoid a decrease of image quality due to varying magnification. However, in certain visual inspection applications it would be advantageous to use non-zero viewing angles. Three different solutions were tested and analyzes: a commercial shifting lens, standard lenses with an extension structure to support the lens in the shifting position and a commercial shifting and tilting lens. The results indicate that the TDI-camera can be used with viewing angles up to 30 degrees from the surface normal,which has been found to be the optimal viewing angle in some visual inspection applications.

    Original languageEnglish
    Title of host publicationMachine Vision Applications, Architectures, and Systems Integration V
    PublisherInternational Society for Optics and Photonics SPIE
    Number of pages8
    Publication statusPublished - 1 Dec 1996
    MoE publication typeA4 Article in a conference publication
    EventMachine Vision Applications, Architectures, and Systems Integration V - Boston, MA, United States
    Duration: 18 Nov 199618 Nov 1996

    Publication series

    SeriesProceedings of SPIE


    ConferenceMachine Vision Applications, Architectures, and Systems Integration V
    Country/TerritoryUnited States
    CityBoston, MA


    • TDI-camera
    • Visual inspection


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