Method relating to three dimensional measurement of objects
First Claim
1. A method for the three dimensional measurement of an object to be conveyed through, or moved relative to, a measurement frame containing a plurality of transmitter elements for calculating the cubical or circumscribed volume of the object by means of incremental measurements of height, width and length of the object wherein an opposite receiver element which only detects light during the time period when the transmitter element is active is provided for each transmitter element in the measurement frame, the transmitter and receiver elements being mounted in arrays on modules with a number of the elements in each transmitter and receiver module, at least one module being present in each of two measurement directions, and an external signal which is a function of the movement of the object relative to the measurement frame being compared with data signals derived from the receiver elements for calculating said volume, said data signals being derived on a basis of shadow images on the receiver elements caused by the object, comprising the steps of:
- determining for each individual receiver element or groups of receiver elements a threshold level forming criteria for determining whether the receiver element is illuminated or not;
activating the modules, which are arranged in series, by input of a start signal in the first of the modules, which signal is caused to be shifted along the interconnected modules so that at least one element is activated at a time, the start signal causing registration of a module end when it reaches the end of each module, causing registration of an end of each module array when it reaches the end of each module array for the respective measurement direction, and causing registration of the non-presence of subsequent modules in the form of a last module-signal, when it reaches an end of the interconnected module arrays;
feeding all control and data signals for the transmitter part and for the receiver part from one module to the next through tthe transmitter modules and receiver modules, respectively; and
controlling said transmitter part and receiver part from a computer in which said volume is also calculated.
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Abstract
A method for three dimensional measurement of objects being conveyed through or moved relative to a measurement frame for, by incremental measurements of height, width and length of the object to calculate cubical and circumscribed volume of the object. Each transmitter/receiver element pair of the measurement frame is calibrated by controlling the amount of the light emitted from the transmitter and the threshold level of the receiver, such that the signal/noise ratio of the receiver lies above a specific limit, simultaneously with the illumination time being kept the shortest possible. By incremental measurements at least one pair consisting of transmitter element and directly opposite receiver element in the measurement frame is activated at time, and an external signal being a function of the movement of the object relative to the measurement frame is compared with the registered signals from the receiver elements for calculation of the volumes. The measurement frame is constructed in the form of horizontal and vertical transmitter- and receiver modules consisting of the transmitter elements and receiver element respectively. A computer is connected to the measurement frame for calibration of the respective transmitter- and receiver elements of the measurement frame and for calculation of the volumes being derived as a result of shadow images of the object on the receiver elements. A display is associated with the computer for display of the volume magnitude of the object. Utilization for e.g. calculation of freight charges of objects.
107 Citations
19 Claims
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1. A method for the three dimensional measurement of an object to be conveyed through, or moved relative to, a measurement frame containing a plurality of transmitter elements for calculating the cubical or circumscribed volume of the object by means of incremental measurements of height, width and length of the object wherein an opposite receiver element which only detects light during the time period when the transmitter element is active is provided for each transmitter element in the measurement frame, the transmitter and receiver elements being mounted in arrays on modules with a number of the elements in each transmitter and receiver module, at least one module being present in each of two measurement directions, and an external signal which is a function of the movement of the object relative to the measurement frame being compared with data signals derived from the receiver elements for calculating said volume, said data signals being derived on a basis of shadow images on the receiver elements caused by the object, comprising the steps of:
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determining for each individual receiver element or groups of receiver elements a threshold level forming criteria for determining whether the receiver element is illuminated or not; activating the modules, which are arranged in series, by input of a start signal in the first of the modules, which signal is caused to be shifted along the interconnected modules so that at least one element is activated at a time, the start signal causing registration of a module end when it reaches the end of each module, causing registration of an end of each module array when it reaches the end of each module array for the respective measurement direction, and causing registration of the non-presence of subsequent modules in the form of a last module-signal, when it reaches an end of the interconnected module arrays; feeding all control and data signals for the transmitter part and for the receiver part from one module to the next through tthe transmitter modules and receiver modules, respectively; and controlling said transmitter part and receiver part from a computer in which said volume is also calculated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification