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detect header

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This commit is contained in:
Ahmet Inan 2024-04-28 22:50:18 +02:00
parent 97881c770c
commit af06ae6fdc
1 changed files with 66 additions and 1 deletions
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67
app/src/main/java/xdsopl/robot36/Decoder.java
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@ -6,6 +6,8 @@ Copyright 2024 Ahmet Inan <xdsopl@gmail.com>
package xdsopl.robot36;
import android.util.Log;
import java.util.ArrayList;
import java.util.Arrays;
@ -25,15 +27,22 @@ public class Decoder {
private final float[] last5msFrequencyOffsets;
private final float[] last9msFrequencyOffsets;
private final float[] last20msFrequencyOffsets;
private final float[] visCodeBitFreqs;
private final int scanLineReserveSamples;
private final int syncPulseToleranceSamples;
private final int scanLineToleranceSamples;
private final int leaderToneSamples;
private final int leaderBreakSamples;
private final int visCodeBitSamples;
private final int visCodeSamples;
private final Mode rawMode;
private final ArrayList<Mode> syncPulse5msModes;
private final ArrayList<Mode> syncPulse9msModes;
private final ArrayList<Mode> syncPulse20msModes;
public Mode lastMode;
private boolean checkHeader;
private int visCode;
private int curSample;
private int lastSyncPulseIndex;
private int lastScanLineSamples;
@ -49,6 +58,15 @@ public class Decoder {
double scratchBufferSeconds = 1.1;
int scratchBufferSamples = (int) Math.round(scratchBufferSeconds * sampleRate);
scratchBuffer = new float[scratchBufferSamples];
double leaderToneSeconds = 0.3;
leaderToneSamples = (int) Math.round(leaderToneSeconds * sampleRate);
double leaderBreakSeconds = 0.01;
leaderBreakSamples = (int) Math.round(leaderBreakSeconds * sampleRate);
double visCodeBitSeconds = 0.03;
visCodeBitSamples = (int) Math.round(visCodeBitSeconds * sampleRate);
double visCodeSeconds = 0.3;
visCodeSamples = (int) Math.round(visCodeSeconds * sampleRate);
visCodeBitFreqs = new float[10];
int scanLineCount = 4;
last5msScanLines = new int[scanLineCount];
last9msScanLines = new int[scanLineCount];
@ -170,6 +188,47 @@ public class Decoder {
copyScaled(scale);
}
private boolean detectHeader(int syncPulseIndex) {
if (!checkHeader)
return false;
if (syncPulseIndex < 2 * leaderBreakSamples || curSample < syncPulseIndex + leaderToneSamples + visCodeSamples)
return false;
checkHeader = false;
float preBreakFreq = 0;
for (int i = 0; i < leaderBreakSamples; ++i)
preBreakFreq += scanLineBuffer[syncPulseIndex - 2 * leaderBreakSamples + i];
float centerFreq = 1900;
float halfBandWidth = 400;
preBreakFreq = preBreakFreq * halfBandWidth / leaderBreakSamples + centerFreq;
if (preBreakFreq < 1850 || preBreakFreq > 1950)
return false;
float postBreakFreq = 0;
for (int i = 0; i < leaderToneSamples; ++i)
postBreakFreq += scanLineBuffer[syncPulseIndex + i];
postBreakFreq = postBreakFreq * halfBandWidth / leaderToneSamples + centerFreq;
if (postBreakFreq < 1850 || postBreakFreq > 1950)
return false;
Arrays.fill(visCodeBitFreqs, 0);
for (int j = 0; j < 10; ++j)
for (int i = 0; i < visCodeBitSamples; ++i)
visCodeBitFreqs[j] += scanLineBuffer[syncPulseIndex + leaderToneSamples + visCodeBitSamples * j + i];
for (int i = 0; i < 10; ++i)
visCodeBitFreqs[i] = visCodeBitFreqs[i] * halfBandWidth / visCodeBitSamples + centerFreq;
if (visCodeBitFreqs[0] < 1150 || visCodeBitFreqs[0] > 1250 || visCodeBitFreqs[9] < 1150 || visCodeBitFreqs[9] > 1250)
return false;
for (int i = 1; i < 9; ++i)
if (visCodeBitFreqs[i] < 1050 || visCodeBitFreqs[i] > 1150 && visCodeBitFreqs[i] < 1250 || visCodeBitFreqs[i] > 1350)
return false;
visCode = 0;
for (int i = 0; i < 8; ++i)
visCode |= (visCodeBitFreqs[i + 1] < 1200 ? 1 : 0) << i;
boolean check = true;
for (int i = 0; i < 8; ++i)
check ^= (visCode & 1 << i) != 0;
visCode &= 127;
return check;
}
private boolean processSyncPulse(ArrayList<Mode> modes, float[] freqOffs, int[] pulses, int[] lines, int index) {
for (int i = 1; i < lines.length; ++i)
lines[i - 1] = lines[i];
@ -242,11 +301,17 @@ public class Decoder {
case FiveMilliSeconds:
return processSyncPulse(syncPulse5msModes, last5msFrequencyOffsets, last5msSyncPulses, last5msScanLines, syncPulseIndex);
case NineMilliSeconds:
checkHeader = true;
return processSyncPulse(syncPulse9msModes, last9msFrequencyOffsets, last9msSyncPulses, last9msScanLines, syncPulseIndex);
case TwentyMilliSeconds:
return processSyncPulse(syncPulse20msModes, last20msFrequencyOffsets, last20msSyncPulses, last20msScanLines, syncPulseIndex);
default:
return false;
}
} else if (lastSyncPulseIndex >= scanLineReserveSamples && curSample > lastSyncPulseIndex + (lastScanLineSamples * 5) / 4) {
}
if (detectHeader(last9msSyncPulses[last9msSyncPulses.length - 1]))
Log.d("Robot36", "VIS code: " + visCode);
if (lastSyncPulseIndex >= scanLineReserveSamples && curSample > lastSyncPulseIndex + (lastScanLineSamples * 5) / 4) {
copyLines(lastMode.decodeScanLine(pixelBuffer, scratchBuffer, scanLineBuffer, scopeBuffer.width, lastSyncPulseIndex, lastScanLineSamples, lastFrequencyOffset));
lastSyncPulseIndex += lastScanLineSamples;
return true;