Abstract: A device and method for reading optical marks are disclosed. The device, an optical mark reader (OMR) has an array of photo sensors with light-emitting diodes (LEDs), which are driven by digital-to-analog converters (DACs), which are in turn controlled by a microcontroller. When calibrating the OMR, the sensors read a white card, and the microcontroller adjust the DACs so that the outputs of all sensors are at a voltage close to the saturation points of the photo-transistors in the sensors so that the maximum useable ranges of the sensors are utilized. The sensors then read one or more patterns of known grayscales and their response voltages are recorded. The microcontroller generates an array of voltage values as a function of grayscale for each sensor and store the values in a memory device. When reading an optical marks, the sensor output voltage in response to a mark is looked up in the table of voltages values stored in the memory device to determine the grayscale of the mark.

Abstract: An optical mark reader includes a housing formed by a base and an upper housing assembly. A scanner is associated with the upper housing assembly for performing scanning operations on cards that are input into the housing. The base and the upper housing are detachably connected to each other by a quick connect/disconnect fastening system which permits easy access to the lens of the scanner, whereby the lens can be cleaned as needed. In addition, the housing includes a unique card path defined, in part, by a pair of guide walls on the base. The card path includes an inlet that is tapered both vertically and horizontally make insertion of cards into the housing easier. Further, a single, offset drive wheel is used to transport cards through the housing.

Abstract: An optical mark reader includes a housing formed by a base and an upper housing assembly. A scanner is associated with the upper housing assembly for performing scanning operations on cards that are input into the housing. The base and the upper housing are detachably connected to each other by a quick connect/disconnect fastening system which permits easy access to the lens of the scanner, whereby the lens can be cleaned as needed. In addition, the housing includes a unique card path defined, in part, by a pair of guide walls on the base. The card path includes an inlet that is tapered both vertically and horizontally make insertion of cards into the housing easier. Further, a single, offset drive wheel is used to transport cards through the housing.

Abstract: A device and method for reading optical marks are disclosed. The device, an optical mark reader (OMR) has an array of photo sensors with light-emitting diodes (LEDs), which are driven by digital-to-analog converters (DACs), which are in turn controlled by a microcontroller. When calibrating the OMR, the sensors read a white card, and the microcontroller adjust the DACs so that the outputs of all sensors are at a voltage close to the saturation points of the photo-transistors in the sensors so that the maximum useable ranges of the sensors are utilized. The sensors then read one or more patterns of known grayscales and their response voltages are recorded. The microcontroller generates an array of voltage values as a function of grayscale for each sensor and store the values in a memory device. When reading an optical marks, the sensor output voltage in response to a mark is looked up in the table of voltages values stored in the memory device to determine the grayscale of the mark.

Abstract: This invention is directed to an optical mark sensing device known as a mark read scanner for reading marks on a form. This scanner is a stand-alone device that has an internal micro-controller with the controlling software therein. An external personal computer is not required to operate the scanner in its intended manner. "Graphic switches" are printed on the form to define the characteristics of a form to be scanned. The expense of replacing the internal program of a scanner when a user requests a variation of a test form that had not been pre-programmed into the original specifications of the scanner is eliminated.