EP-3197050-B1 - METHOD FOR CONTROLLING OPERATION OF MOVING AVERAGE FILTER

Inventors

• PARK, JO-DONG

Dates

Publication Date

20260506

Application Date

20161213

Claims (3)

1. A method for controlling the operation of a moving average filter to block a noise, wherein the moving average filter is adapted to generate filter output values as a real time average value by applying a moving average filter value, the moving average filter value corresponding to a number of averaged input values; the method comprising: (a) setting (S410) a first stability reference value and a corresponding first moving average filter value; (b) inputting (S420) measurement data; and (c) calculating (S430) a first moving average value for the measurement data by applying a basic moving average filter value; (d) comparing (S440) the first moving average value to the first stability reference value; and (e) when the first moving average value is equal to or larger than the first stability reference value, calculating (S450) a second moving average value for the measurement data by applying the first moving average filter value corresponding to the set first stability reference value, characterized by setting a second stability reference value and a corresponding second moving average filter value, wherein the second stability reference value is different from the first stability reference value and the second moving average filter value is different from the first moving average filter value, depending on the second moving average value with respect to the second stability reference value, calculating a third moving average value by applying the second moving average filter value.
2. The method according to claim 1, wherein the stability reference value and a sampling interval set in the step (a) are automatically set according to the filtering environments including the current noise situations.
3. The method according to claim 1, wherein the step (e) returns to the step (c) if the second moving average value is maintained below the first stability reference value for more than a specified reference time.

Description

BACKGROUND 1. Technical Field The present invention relates to a method for controlling the operation of a moving average filter, which is capable of optimizing the ability to cope with a surge noise through reasonable control of a tracking speed with respect to a change in an input value. 2. Description of the Related Art Information, which is continuously changed with time, such as sound, light, temperature, pressure, position and the like, can be converted into an analog electrical signal (voltage or current) by means of a transducer or a sensor. An electronic circuit configured to deliver the information by amplifying, detecting and converting a voltage, current, frequency or the like of the analog electrical signal obtained thus is referred to as an analog circuit. Such an analog circuit may contain a noise. As a randomly-varying external signal, the noise is generated by random heat vibration of particles such as atoms. The noise is mainly generated due to use of poorly designed parts, repeated radiation of a signal for remote transmission, introduction of an external electric signal, etc. Such a noise may decrease a level of an original signal by decreasing a irregular change in the signal. If a random external noise is added to an analog signal, it is difficult to distinguish from the original signal. This problem may be solved by a separate circuit or algorithm adapted to cope with such a difficulty. A noise filter is often used to block a noise. WO01/25731 discloses a background art example of using a moving average filter to block noise. Other examples of moving average filters and noise blocking applications are disclosed in JP H0371713 A, US 6012 031 A, and EP 1 739 513. As a kind of the noise filter, a moving average filter has a trade-off relationship between a response speed and a noise blocking performance. That is, a higher response speed of the moving average filter provides a lower noise blocking performance thereof. Therefore, in order to increase the noise blocking performance, it is necessary to decrease the response speed. Accordingly, the present invention suggests a novel algorithm which is capable of efficiently controlling a response speed and a noise blocking performance of a moving average filter. SUMMARY The present invention has been made to overcome the above problems and it is an aspect of the present invention to provide a method for controlling the operation of a moving average filter, which is capable of optimizing the ability to cope with a surge noise through reasonable control of a tracking speed with respect to a change in an input value. The present invention is not limited to the above aspect and other aspects of the present invention will be clearly understood by those skilled in the art from the following description. The above and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings. It should be understood that the objects and advantages of the present invention can be realized by features and combinations thereof set forth in the claims. A method according to the invention is defined in claim 1. In some embodiment, the stability reference value set in the step (a) may include two or more different reference values, and two or more different sampling intervals corresponding the two or more different reference values are set. In some embodiment, the stability reference value and the sampling interval set in the step (a) may be automatically set according to the filtering environments including the current noise situations. In some embodiment, the step (d) may return to the step (c) if the second moving average is maintained below the stability reference value for more than a specified reference time. According to the present invention, it is possible to efficiently change a response speed and a noise blocking performance of a moving average filter to cope with a change in input conditions. In addition, according to the present invention, it is possible to provide a moving average filter capable of providing both of a high response speed and an improved noise blocking performance. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a conceptual view for explaining the meaning of a moving average and a process of calculating the moving average.Figs 2A to 3B are graphs for explaining a process of operation of a conventional moving average filter.Fig. 4 is a flow chart for explaining a method for controlling the operation of a moving average filter according to one embodiment of the present invention.Figs 5A and 5B are graphs for explaining a process of operation of the moving average filter according to one embodiment of the present invention.Figs 6A and 6B are graphs for explaining a response speed of the moving average filter to which an embodiment of the present invention is applied. DETAILED DESCRIPTION The above objec