Mailpiece Thickness Measurement Using FIFO Register Filtering
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Solution Overview
Problem
Existing mail handling systems face challenges in accurately determining the thickness of mailpieces due to non-uniform thickness and measurement defects caused by jolts and rebounds, leading to errors in postage calculation.
Innovation Solution
A method that measures the maximum thickness of a mailpiece while it is moving, using a FIFO register to record successive measurements, determine the difference between maximum and minimum values, and compare it with a predetermined threshold to ignore deviant values, thereby determining the accurate thickness unaffected by jolts or rebounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If successive thickness measurements are taken as the mailpiece advances, then the problem of non-uniform thickness is addressed, but the mean value does not reflect the real thickness and causes errors in postage determination
Solution Approach 1:
The patent applies preliminary action by recording multiple successive thickness measurements in a FIFO register before determining the final thickness value. This allows the system to collect N measurements (where N is typically 8-32) and then process them to find the maximum value that falls within the acceptable variation range, ensuring accurate postage determination before the mailpiece leaves the measurement zone.
2Measurement precision
If the maximum value of thickness is used instead of the mean value, then the real thickness is better reflected, but jolts and rebounds from the measuring device contact cause measurement defects
Solution Approach 1:
The patent applies partial action by taking N successive measurements (where N > 1) and then selecting only the maximum value that falls within the acceptable variation range (delta). This partial selection process filters out measurements affected by jolts and rebounds, as these typically produce outlier values that exceed the predetermined threshold delta, thereby ensuring measurement consistency while still capturing the real thickness.
3Measurement precision
If a threshold value is used to filter deviant measurements, then measurement accuracy is improved, but the complexity of the measurement process increases
Solution Approach 1:
The patent applies parameter changes by introducing a predetermined threshold parameter (delta) that represents the maximum acceptable thickness variation. This single parameter simplifies the filtering process - the system only needs to compare each measurement against this threshold and select the maximum value within range. The threshold is typically calculated based on the mailpiece length and acceptable variation percentage, making the process straightforward despite the multiple measurements taken.
Data Source
AI summary
A method of measuring the maximum thickness of a mailpiece while it is moving through a mail-handling machine. The method includes: acquiring a thickness measurement; recording the measured value in a register; determining a maximum value and a minimum value of the register; determining a difference between said maximum value and minimum value, and comparing the difference with a predetermined threshold value; and if the difference is less than the threshold value, and if the maximum value is greater than a current maximum thickness value, taking the maximum value as the new current maximum thickness value for the mailpiece.