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    Optical reader exposure control apparatus comprising illumination level detection circuitry
    1.
    发明授权
    Optical reader exposure control apparatus comprising illumination level detection circuitry 失效
    光读取器曝光控制装置，包括照明级检测电路

    公开(公告)号：US06254003B1

    公开(公告)日：2001-07-03

    申请号：US09099604

    申请日：1998-06-18

    申请人： John A. Pettinelli ,  Dennis McEnery

    发明人： John A. Pettinelli ,  Dennis McEnery

    IPC分类号： G06K714

    CPC分类号： G06K7/10584 ,  G06K7/10752 ,  G06K7/10851

    摘要： An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the illumination level at the image sensor. A window detecting circuit samples the illumination signal during a predetermined part of each scan to determine whether the illumination signal is within the window, has exited the window, or has re-entered the window. Exposure control circuitry uses the output of the window detecting circuit to control which of a plurality of the subdivisions of the exposure control range of the image sensor will be used. Changes in exposure time are made only between adjacent subdivisions of the exposure control range. Together with a predetermined hysteresis between the exit and re-entry thresholds of the window, the latter changes stabilize the operation of the reader by reducing exposure control “hunting”.

    摘要翻译： 一种用于光学读取器的曝光控制装置，例如利用光敏图像传感器的条形码阅读器。 照明信号发生电路产生具有根据图像传感器的照度的变化的幅度的照明信号。 窗口检测电路在每次扫描的预定部分期间对照明信号进行采样，以确定照明信号是否在窗口内，已经退出窗口，或已经重新进入窗口。 曝光控制电路使用窗口检测电路的输出来控制将使用图像传感器的曝光控制范围的多个细分中的哪一个。 曝光时间的变化仅在曝光控制范围的相邻细分之间进行。 与窗口的出口和重入阈值之间的预定滞后一起，后者通过减少曝光控制“搜索”来改变读者的操作。

    Exposure control apparatus for use with optical readers
    6.
    发明授权
    Exposure control apparatus for use with optical readers 失效
    用于光学读取器的曝光控制装置

    公开(公告)号：US5831254A

    公开(公告)日：1998-11-03

    申请号：US574386

    申请日：1995-12-18

    申请人： Thomas W. Karpen ,  Dennis W. McEnery ,  Robert C. Gardiner ,  John A. Pettinelli

    发明人： Thomas W. Karpen ,  Dennis W. McEnery ,  Robert C. Gardiner ,  John A. Pettinelli

    IPC分类号： G06K7/10

    CPC分类号： G06K7/10851 ,  G06K7/10584 ,  G06K7/10752

    摘要： An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the time averaged value of the illumination level at the image sensor. A window detecting circuit periodically samples the illumination signal to determine if that signal is or is not within a window of acceptability. Exposure period determining circuitry uses the output of the window detecting circuit to upwardly or downwardly adjust the value of a control variable as necessary to cause the illumination signal to approach, enter and remain within the window of acceptability.

    摘要翻译： 一种用于光学读取器的曝光控制装置，例如利用光敏图像传感器的条形码阅读器。 照明信号发生电路产生具有根据图像传感器的照度级的时间平均值变化的幅度的照明信号。 窗口检测电路周期性地对照明信号进行采样，以确定该信号是否在不可接受的窗口内。 曝光周期确定电路使用窗口检测电路的输出来向上或向下调整控制变量的值，以使照明信号接近，进入并保持在可接受窗口内。