Gesture Recognition Code #include #include #include #include #include "uart.h" FILE uart_str = FDEV_SETUP_STREAM(uart_putchar, uart_getchar, _FDEV_SETUP_RW); #define t1 2 #define t2 1500 #define t2Circle 3000 #define t3 750 #define t4 12000 #define AVG_LEN 200 #define MOVING_LEN 60 #define THRESHOLD 400 #define PAST_LEN 6 #define LOG_LEN 900 volatile char time1; volatile int time2, time3, time4; int mic[AVG_LEN + 1], moving = 0, avg = 0, upper = 0, lower = 0, peakWidth[PAST_LEN], valleyWidth[PAST_LEN], peakSlope[PAST_LEN], peakHeight[PAST_LEN], peakCount = 0, index = 0, begin = 0, isUpper = 0, signalWidth = 0, tPeakWidth = 0, tValleyWidth = 0, tSignalWidth = 0, tPeakSlope = 0, k = 0; char circleMode = 0, tapCircle = 0; ISR (TIMER0_COMPA_vect) { if (time1 > 0) time1--; if (time2 > 0) time2--; if (time3 > 0) time3--; if (time4 > 0) time4--; } void capture() { // Captures the ADC value and calculates two different moving averages. // Moving is a moving average of the past 60 data points. Moving simply // smooths out the sometimes erratic signal from the analog filter. // Avg is a moving average of the past 200 data points. Avg is used to // calculate the hysteresis values upper and lower. mic[index] = ADCH; ADCSRA |= (1 = MOVING_LEN) moving = moving + (mic[index] * 10 / MOVING_LEN) - (mic[index - MOVING_LEN] * 10 / MOVING_LEN); else moving = moving + (mic[index] * 10 / MOVING_LEN) - (mic[AVG_LEN + 1 - MOVING_LEN + index] * 10 / MOVING_LEN); if (index == AVG_LEN) avg = avg + (mic[AVG_LEN] * 10 / AVG_LEN) - (mic[0] * 10 / AVG_LEN); else avg = avg + (mic[index] * 10 / AVG_LEN) - (mic[index + 1] * 10 / AVG_LEN); upper = 12 * avg / 10; lower = 8 * avg / 10; } void extract() { // Extracts features from the incoming signal, such as peak heights, peak // slope, peak width, valley width, signal width, and peak count. This is // done without holding any past data points. Past data points are only // kept for moving averages. // // Peaks count is amplitude independent. This is done by hysteresis of // moving. Whenever moving is greater than upper, a peak is counted only if // moving has been smaller than lower previously isUpper is used to keep // the hysteresis state. if (moving > THRESHOLD) { if (circleMode) time2 = t2Circle; else time2 = t2; if (!isUpper && moving > upper) { isUpper = 1; if (peakCount == 0) tSignalWidth = 0; else valleyWidth[(peakCount - 1) % PAST_LEN] = tValleyWidth; peakCount++; tPeakWidth = 0; tPeakSlope = 0; } } if (isUpper) { if (peakHeight[(peakCount - 1) % PAST_LEN] < moving) { peakHeight[(peakCount - 1) % PAST_LEN] = moving; peakSlope[(peakCount - 1) % PAST_LEN] = tPeakSlope; } if (moving < lower) { isUpper = 0; tValleyWidth = 0; peakWidth[(peakCount - 1) % PAST_LEN] = tPeakWidth; } } } void selector() { // Attempts to map the attributes extracted from the signal to a gesture. int tempWDiff, tempHDiff, antiTap = 0; signalWidth = tSignalWidth; // Often times when starting a gesture, the initial finger placement creates // an unwanted tap with RC decay. The following anti-tap filters out most // unwanted intial taps. if (peakCount > 1 && peakWidth[0] < 200 && peakWidth[1] > 185) { antiTap = 1; peakCount--; } if (peakCount == 1) { if (peakWidth[0 + antiTap] < 200) { tapCircle = 1; time4 = t4; } else if (peakWidth[0 + antiTap] > 230 && peakWidth[0 + antiTap] < 1000) fprintf(stdout, "1 "); } else if (peakCount == 2) { tempHDiff = peakHeight[0] - peakHeight[1]; if (tempHDiff < 0) tempHDiff = -tempHDiff; if (tempHDiff < peakHeight[0] / 10 && peakWidth[0] < 200 && peakWidth[1] < 185) fprintf(stdout, "D "); else if (peakWidth[0 + antiTap] > 220 && peakWidth[1 + antiTap] < 300 && valleyWidth[0 + antiTap] > 250 && peakSlope[1 + antiTap] < 300) fprintf(stdout, "2 "); else if (peakWidth[0 + antiTap] > 220 && peakWidth[1 + antiTap] > 240 && valleyWidth[0 + antiTap] > 250) fprintf(stdout, "3 "); } else if (peakCount == 3) { tempHDiff = peakHeight[0 + antiTap] - peakHeight[1 + antiTap]; if (tempHDiff < 0) tempHDiff = -tempHDiff; if (tempHDiff < peakHeight[0] / 10 && peakWidth[0] < 200 && peakWidth[1] < 185 && peakWidth[2] < 185) fprintf(stdout, "X "); else if (tempHDiff > (2 * peakHeight[0 + antiTap] / 5) && peakWidth[0 + antiTap] > 220 && peakWidth[2 + antiTap] > 240) { tempHDiff = peakHeight[2 + antiTap] - peakHeight[1 + antiTap]; if (tempHDiff < 0) tempHDiff = -tempHDiff; if (tempHDiff > (2 * peakHeight[2 + antiTap] / 5)) fprintf(stdout, "3 "); } } } void reset() { // Resets the all signal characteristic variables for the next // gesture input. for (int i = 0; i < PAST_LEN; i++) { peakHeight[i] = 0; peakWidth[i] = 0; peakSlope[i] = 0; valleyWidth[i] = 0; } circleMode = 0; peakCount = 0; isUpper = 0; } int main() { // Resets variables for the initial gesture. int rPeakCount = 0; for (int i = 0; i < AVG_LEN; i++) mic[i] = 0; time1 = 0; reset(); // Starts Timer0 and Timer0 interrupts for task scheduling. TCCR0A = (1
Posted on: Mon, 24 Jun 2013 17:27:49 +0000