Self-adjusting audio detection of medium jam
A method of indicating a medium misfeed along a medium transport path comprising one or more rollers for conveying the medium along the medium transport path; a microphone for detecting the sound of the conveyed medium and producing a signal representing the sound; a processor for producing sound values from the signal; providing a sensitivity setting responsive to the sound values; and indicating the medium misfeed responsive to the sound values and the sensitivity setting.
1. A method of indicating a medium misfeed along a medium transport path comprising:
(a) one or more rollers for conveying the medium along the medium transport path;
(b) a microphone for detecting the sound of the conveyed medium and producing a signal representing the sound;
(c) a processor for producing sound values from the signal;
(d) providing a sensitivity setting responsive to the sound values;
(e) computing at least one of a moving window sum responsive to the sound values, a high amplitude count responsive to the sound values, a pre roller sum responsive to the sound values, or a post roller sum responsive to the sound values; and
(f) indicating the medium misfeed responsive to the sensitivity setting, moving window sum, high amplitude count, pre roller sum, or post roller sum.
2. A method of indicating a medium misfeed along a medium transport path comprising:
(a) one or more rollers for conveying the medium along the medium transport path;
(b) a microphone for detecting the sound of the conveyed medium and producing a signal representing the sound;
(c) a processor for producing sound values from the signal; and
(i) providing a sensitivity setting responsive to the sound values;
(ii) computing a moving window sum responsive to the sound values;
(iii) computing a high amplitude count responsive to the sound values;
(iv) computing a pre roller sum responsive to the sound values;
(v) computing a post roller sum responsive to the sound values; and
(d) indicating the medium jam responsive to the sensitivity setting, moving window sum, high amplitude count, pre roller sum, or post roller sum.
3. The method of claim 2 wherein (c) (ii) includes computing the sum of sound values using a given window width.
4. The method of claim 2 wherein (c) (iii) includes computing the sum of sound values that are greater than a high amplitude sound threshold value.
5. The method of claim 2 wherein (c) (iv) includes computing a sum of sound values from a region of the medium transport path before one of the rollers.
6. The method of claim 2 wherein (c) (v) includes computing a sum of sound values from a region of the medium transport path after one of the rollers.
7. The method of claim 2 wherein (d) includes indicating a medium jam responsive to a moving window sum threshold value, a high amplitude count threshold value, a pre roller sum threshold value, or a post roller sum threshold value.
8. A method of indicating a medium misfeed along a medium transport path comprising:
(a) one or more rollers for conveying the medium along the medium transport path;
(b) a microphone for detecting the sound of the conveyed medium and producing a signal representing the sound;
(c) a processor for producing sound values from the signal; and
(i) providing a sensitivity setting responsive to the sound values;
(ii) providing frequency values from the sound values;
(iii) computing a frequency extent responsive to the frequency values; and
(iv) computing a frame energy responsive to the frequency values;
(d) indicating the medium jam responsive to the sensitivity setting, frequency extent, or frame extent.
9. The method of claim 8 wherein (c) (iii) includes computing a frequency above a frequency extent threshold value.
10. The method of claim 8 wherein (c) (iv) includes computing the sum of frequency values using a given frame width.
11. The method of claim 8 wherein (d) includes indicating a medium jam responsive to a frequency extent threshold value, or a frame energy threshold value.