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head related transfer function

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git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@13997 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
henry 2004-11-20 14:41:51 +00:00
parent a17f2fa7b4
commit 1f478a1173
5 changed files with 902 additions and 1 deletions
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4
DOCS/man/en/mplayer.1
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@ -3063,6 +3063,10 @@ cutoff: cutoff frequency (0.0-1.0), default set depending upon filter length
.REss
.IPs sweep[=speed]
sine sweep
.IPs hrtf
.br
Head-related transfer function: Converts multichannel audio to
2 channel output for headphones, preserving the spatiality of the sound.
.IPs channels[=nch]
Change the number of channels to nch output channels.
If the number of output channels is bigger than the number of input channels

5
libaf/Makefile
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@ -2,7 +2,10 @@ include ../config.mak
LIBNAME = libaf.a
SRCS=af.c af_mp.c af_dummy.c af_delay.c af_channels.c af_format.c af_resample.c window.c filter.c af_volume.c af_equalizer.c af_tools.c af_comp.c af_gate.c af_pan.c af_surround.c af_sub.c af_export.c af_volnorm.c af_extrastereo.c af_lavcresample.c af_sweep.c
SRCS=af.c af_mp.c af_dummy.c af_delay.c af_channels.c af_format.c af_resample.c \
window.c filter.c af_volume.c af_equalizer.c af_tools.c af_comp.c af_gate.c \
af_pan.c af_surround.c af_sub.c af_export.c af_volnorm.c af_extrastereo.c \
af_lavcresample.c af_sweep.c af_hrtf.c
OBJS=$(SRCS:.c=.o)

2
libaf/af.c
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@ -27,6 +27,7 @@ extern af_info_t af_info_volnorm;
extern af_info_t af_info_extrastereo;
extern af_info_t af_info_lavcresample;
extern af_info_t af_info_sweep;
extern af_info_t af_info_hrtf;
static af_info_t* filter_list[]={
&af_info_dummy,
@ -50,6 +51,7 @@ static af_info_t* filter_list[]={
&af_info_lavcresample,
#endif
&af_info_sweep,
&af_info_hrtf,
NULL
};

416
libaf/af_hrtf.c Normal file
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@ -0,0 +1,416 @@
/* Experimental audio filter that mixes 5.1 and 5.1 with matrix
encoded rear channels into headphone signal using FIR filtering
with HRTF.
*/
//#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <inttypes.h>
#include <math.h>
#include "af.h"
#include "dsp.h"
/* HRTF filter coefficients and adjustable parameters */
#include "af_hrtf.h"
typedef struct af_hrtf_s {
/* Lengths */
int dlbuflen, hrflen, basslen;
/* L, C, R, Ls, Rs channels */
float *lf, *rf, *lr, *rr, *cf, *cr;
float *cf_ir, *af_ir, *of_ir, *ar_ir, *or_ir, *cr_ir;
int cf_o, af_o, of_o, ar_o, or_o, cr_o;
/* Bass */
float *ba_l, *ba_r;
float *ba_ir;
/* Whether to matrix decode the rear center channel */
int matrix_mode;
/* Full wave rectified amplitude used to steer the active matrix
decoding of center rear channel */
float lr_fwr, rr_fwr;
/* Cyclic position on the ring buffer */
int cyc_pos;
} af_hrtf_t;
/* Convolution on a ring buffer
* nx: length of the ring buffer
* nk: length of the convolution kernel
* sx: ring buffer
* sk: convolution kernel
* offset: offset on the ring buffer, can be
*/
static float conv(const int nx, const int nk, float *sx, float *sk,
const int offset)
{
/* k = reminder of offset / nx */
int k = offset >= 0 ? offset % nx : nx + (offset % nx);
if(nk + k <= nx)
return fir(nk, sx + k, sk);
else
return fir(nk + k - nx, sx, sk + nx - k) +
fir(nx - k, sx + k, sk);
}
/* Detect when the impulse response starts (significantly) */
int pulse_detect(float *sx)
{
/* nmax must be the reference impulse response length (128) minus
s->hrflen */
const int nmax = 128 - HRTFFILTLEN;
const float thresh = IRTHRESH;
int i;
for(i = 0; i < nmax; i++)
if(fabs(sx[i]) > thresh)
return i;
return 0;
}
inline void update_ch(af_hrtf_t *s, short *in, const int k)
{
/* Update the full wave rectified total amplutude */
s->lr_fwr += abs(in[2]) - fabs(s->lr[k]);
s->rr_fwr += abs(in[3]) - fabs(s->rr[k]);
s->lf[k] = in[0];
s->cf[k] = in[4];
s->rf[k] = in[1];
s->lr[k] = in[2];
s->rr[k] = in[3];
s->ba_l[k] = in[0] + in[4] + in[2];
s->ba_r[k] = in[4] + in[1] + in[3];
}
inline void matrix_decode_cr(af_hrtf_t *s, short *in, const int k)
{
/* Active matrix decoding of the center rear channel, 1 in the
denominator is to prevent singularity */
float lr_agc = in[2] * (s->lr_fwr + s->rr_fwr) /
(1 + s->lr_fwr + s->lr_fwr);
float rr_agc = in[3] * (s->lr_fwr + s->rr_fwr) /
(1 + s->rr_fwr + s->rr_fwr);
s->cr[k] = (lr_agc + rr_agc) * M_SQRT1_2;
}
/* Initialization and runtime control */
static int control(struct af_instance_s *af, int cmd, void* arg)
{
af_hrtf_t *s = af->setup;
char mode;
switch(cmd) {
case AF_CONTROL_REINIT:
af->data->rate = ((af_data_t*)arg)->rate;
if(af->data->rate != 48000) {
af_msg(AF_MSG_ERROR,
"[hrtf] ERROR: Sampling rate is not 48000 Hz (%d)!\n",
af->data->rate);
return AF_ERROR;
}
af->data->nch = ((af_data_t*)arg)->nch;
if(af->data->nch < 5) {
af_msg(AF_MSG_ERROR,
"[hrtf] ERROR: Insufficient channels (%d < 5).\n",
af->data->nch);
return AF_ERROR;
}
af->data->format = AF_FORMAT_SI | AF_FORMAT_NE;
af->data->bps = 2;
return AF_OK;
case AF_CONTROL_COMMAND_LINE:
sscanf((char*)arg, "%c", &mode);
switch(mode) {
case 'm':
s->matrix_mode = 1;
break;
case '0':
s->matrix_mode = 0;
break;
default:
af_msg(AF_MSG_ERROR,
"[hrtf] Mode is neither 'm', nor '0' (%c).\n",
mode);
return AF_ERROR;
}
return AF_OK;
}
af_msg(AF_MSG_INFO,
"[hrtf] Using HRTF to mix %s discrete surround into "
"L, R channels\n", s->matrix_mode ? "5" : "5+1");
if(s->matrix_mode)
af_msg(AF_MSG_INFO,
"[hrtf] Using active matrix to decode rear center "
"channel\n");
return AF_UNKNOWN;
}
/* Deallocate memory */
static void uninit(struct af_instance_s *af)
{
if(af->setup) {
af_hrtf_t *s = af->setup;
if(s->lf)
free(s->lf);
if(s->rf)
free(s->rf);
if(s->lr)
free(s->lr);
if(s->rr)
free(s->rr);
if(s->cf)
free(s->cf);
if(s->cr)
free(s->cr);
if(s->ba_l)
free(s->ba_l);
if(s->ba_r)
free(s->ba_r);
if(s->ba_ir)
free(s->ba_ir);
free(af->setup);
}
if(af->data)
free(af->data);
}
/* Filter data through filter
Two "tricks" are used to compensate the "color" of the KEMAR data:
1. The KEMAR data is refiltered to ensure that the front L, R channels
on the same side of the ear are equalized (especially in the high
frequencies).
2. A bass compensation is introduced to ensure that 0-200 Hz are not
damped (without any real 3D acoustical image, however).
*/
static af_data_t* play(struct af_instance_s *af, af_data_t *data)
{
af_hrtf_t *s = af->setup;
short *in = data->audio; // Input audio data
short *out = NULL; // Output audio data
short *end = in + data->len / sizeof(short); // Loop end
float common, left, right, diff, left_b, right_b;
const int dblen = s->dlbuflen, hlen = s->hrflen, blen = s->basslen;
if(AF_OK != RESIZE_LOCAL_BUFFER(af, data))
return NULL;
out = af->data->audio;
/* MPlayer's 5 channel layout (notation for the variable):
*
* 0: L (LF), 1: R (RF), 2: Ls (LR), 3: Rs (RR), 4: C (CF), matrix
* encoded: Cs (CR)
*
* or: L = left, C = center, R = right, F = front, R = rear
*
* Filter notation:
*
* CF
* OF AF
* Ear->
* OR AR
* CR
*
* or: C = center, A = same side, O = opposite, F = front, R = rear
*/
while(in < end) {
const int k = s->cyc_pos;
update_ch(s, in, k);
/* Simulate a 7.5 ms -20 dB echo of the center channel in the
front channels (like reflection from a room wall) - a kind of
psycho-acoustically "cheating" to focus the center front
channel, which is normally hard to be perceived as front */
s->lf[k] += CFECHOAMPL * s->cf[(k + CFECHODELAY) % s->dlbuflen];
s->rf[k] += CFECHOAMPL * s->cf[(k + CFECHODELAY) % s->dlbuflen];
/* Mixer filter matrix */
common = conv(dblen, hlen, s->cf, s->cf_ir, k + s->cf_o);
if(s->matrix_mode) {
/* In matrix decoding mode, the rear channel gain must be
renormalized, as there is an additional channel. */
matrix_decode_cr(s, in, k);
common +=
conv(dblen, hlen, s->cr, s->cr_ir, k + s->cr_o) *
M1_76DB;
left =
( conv(dblen, hlen, s->lf, s->af_ir, k + s->af_o) +
conv(dblen, hlen, s->rf, s->of_ir, k + s->of_o) +
(conv(dblen, hlen, s->lr, s->ar_ir, k + s->ar_o) +
conv(dblen, hlen, s->rr, s->or_ir, k + s->or_o)) *
M1_76DB + common);
right =
( conv(dblen, hlen, s->rf, s->af_ir, k + s->af_o) +
conv(dblen, hlen, s->lf, s->of_ir, k + s->of_o) +
(conv(dblen, hlen, s->rr, s->ar_ir, k + s->ar_o) +
conv(dblen, hlen, s->lr, s->or_ir, k + s->or_o)) *
M1_76DB + common);
}
else {
left =
( conv(dblen, hlen, s->lf, s->af_ir, k + s->af_o) +
conv(dblen, hlen, s->rf, s->of_ir, k + s->of_o) +
conv(dblen, hlen, s->lr, s->ar_ir, k + s->ar_o) +
conv(dblen, hlen, s->rr, s->or_ir, k + s->or_o) +
common);
right =
( conv(dblen, hlen, s->rf, s->af_ir, k + s->af_o) +
conv(dblen, hlen, s->lf, s->of_ir, k + s->of_o) +
conv(dblen, hlen, s->rr, s->ar_ir, k + s->ar_o) +
conv(dblen, hlen, s->lr, s->or_ir, k + s->or_o) +
common);
}
/* Bass compensation for the lower frequency cut of the HRTF. A
cross talk of the left and right channel is introduced to
match the directional characteristics of higher frequencies.
The bass will not have any real 3D perception, but that is
OK. */
left_b = conv(dblen, blen, s->ba_l, s->ba_ir, k);
right_b = conv(dblen, blen, s->ba_r, s->ba_ir, k);
left += (1 - BASSCROSS) * left_b + BASSCROSS * right_b;
right += (1 - BASSCROSS) * right_b + BASSCROSS * left_b;
/* Also mix the LFE channel (if available) */
if(af->data->nch >= 6) {
left += out[5] * M3_01DB;
right += out[5] * M3_01DB;
}
/* Amplitude renormalization. */
left *= AMPLNORM;
right *= AMPLNORM;
/* "Cheating": linear stereo expansion to amplify the 3D
perception. Note: Too much will destroy the acoustic space
and may even result in headaches. */
diff = STEXPAND2 * (left - right);
out[0] = (int16_t)(left + diff);
out[1] = (int16_t)(right - diff);
/* The remaining channels are not needed any more */
out[2] = out[3] = out[4] = 0;
if(af->data->nch >= 6)
out[5] = 0;
/* Next sample... */
in = &in[data->nch];
out = &out[af->data->nch];
(s->cyc_pos)--;
if(s->cyc_pos < 0)
s->cyc_pos += dblen;
}
/* Set output data */
data->audio = af->data->audio;
data->len = (data->len * af->mul.n) / af->mul.d;
data->nch = af->data->nch;
return data;
}
static int allocate(af_hrtf_t *s)
{
if ((s->lf = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->rf = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->lr = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->rr = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->cf = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->cr = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->ba_l = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
if ((s->ba_r = malloc(s->dlbuflen * sizeof(float))) == NULL) return -1;
return 0;
}
/* Allocate memory and set function pointers */
static int open(af_instance_t* af)
{
int i;
af_hrtf_t *s;
float fc;
af_msg(AF_MSG_INFO,
"[hrtf] Head related impulse response (HRIR) derived from KEMAR measurement\n"
"[hrtf] data by Bill Gardner <billg@media.mit.edu>\n"
"[hrtf] and Keith Martin <kdm@media.mit.edu>.\n"
"[hrtf] This data is Copyright 1994 by the MIT Media Laboratory. It is\n"
"[hrtf] provided free with no restrictions on use, provided the authors are\n"
"[hrtf] cited when the data is used in any research or commercial application.\n"
"[hrtf] URL: http://sound.media.mit.edu/KEMAR.html\n");
af->control = control;
af->uninit = uninit;
af->play = play;
af->mul.n = 1;
af->mul.d = 1;
af->data = calloc(1, sizeof(af_data_t));
af->setup = calloc(1, sizeof(af_hrtf_t));
if((af->data == NULL) || (af->setup == NULL))
return AF_ERROR;
s = af->setup;
s->dlbuflen = DELAYBUFLEN;
s->hrflen = HRTFFILTLEN;
s->basslen = BASSFILTLEN;
s->cyc_pos = s->dlbuflen - 1;
s->matrix_mode = 1;
if (allocate(s) != 0) {
af_msg(AF_MSG_ERROR, "[hrtf] Memory allocation error.\n");
return AF_ERROR;
}
for(i = 0; i < s->dlbuflen; i++)
s->lf[i] = s->rf[i] = s->lr[i] = s->rr[i] = s->cf[i] =
s->cr[i] = 0;
s->lr_fwr =
s->rr_fwr = 0;
s->cf_ir = cf_filt + (s->cf_o = pulse_detect(cf_filt));
s->af_ir = af_filt + (s->af_o = pulse_detect(af_filt));
s->of_ir = of_filt + (s->of_o = pulse_detect(of_filt));
s->ar_ir = ar_filt + (s->ar_o = pulse_detect(ar_filt));
s->or_ir = or_filt + (s->or_o = pulse_detect(or_filt));
s->cr_ir = cr_filt + (s->cr_o = pulse_detect(cr_filt));
if((s->ba_ir = malloc(s->basslen * sizeof(float))) == NULL) {
af_msg(AF_MSG_ERROR, "[hrtf] Memory allocation error.\n");
return AF_ERROR;
}
fc = 2.0 * BASSFILTFREQ / (float)af->data->rate;
if(design_fir(s->basslen, s->ba_ir, &fc, LP | KAISER, 4 * M_PI) ==
-1) {
af_msg(AF_MSG_ERROR, "[hrtf] Unable to design low-pass "
"filter.\n");
return AF_ERROR;
}
for(i = 0; i < s->basslen; i++)
s->ba_ir[i] *= BASSGAIN;
return AF_OK;
}
/* Description of this filter */
af_info_t af_info_hrtf = {
"HRTF Headphone",
"hrtf",
"ylai",
"",
AF_FLAGS_REENTRANT,
open
};

476
libaf/af_hrtf.h Normal file
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@ -0,0 +1,476 @@
/* Amplitude scaling factors */
#define M17_0DB 0.1414213562
#define M6_99DB 0.4472135955
#define M4_77DB 0.5773502692
#define M3_01DB 0.7071067812
#define M1_76DB 0.8164965809
#define DELAYBUFLEN 1024 /* Length of the delay buffer */
#define HRTFFILTLEN 64 /* HRTF filter length */
#define IRTHRESH 0.001 /* Impulse response pruning thresh. */
#define AMPLNORM M6_99DB /* Overall amplitude renormalization */
#define BASSFILTFREQ 180 /* Bass compensation filter cut (Hz) */
#define BASSFILTLEN 193 /* Bass compensation filter length */
#define BASSGAIN M4_77DB /* Bass compensation gain */
#define BASSCROSS 0.35 /* Bass cross talk */
#define CFECHODELAY 360 /* Center front echo delay (samples) */
#define CFECHOAMPL M17_0DB /* Center front echo amplitude */
#define STEXPAND2 0.07 /* Stereo expansion / 2 */
/* Head related impulse response (HRIR) derived from KEMAR measurement
data by Bill Gardner <billg@media.mit.edu> and Keith Martin
<kdm@media.mit.edu>:
"This data is Copyright 1994 by the MIT Media Laboratory. It is
provided free with no restrictions on use, provided the authors are
cited when the data is used in any research or commercial
application."
URL: http://sound.media.mit.edu/KEMAR.html
*/
/* EQUALIZED KEMAR HRIR
How to generate these data:
1. You need the MIT Media Lab's KEMAR data, read it into an software
capable of signal/time series analysis (like Mathematica, Matlab,
...)
2. Construct an equalizing FIR inverse filter by calculating the
transfer function of the front, same side impulse response, then
take 1 over the absolute magnitude.
3. Cut the poles in the inverse filter's transfer function
specification by limiting the amplification to 2.5 (note, this
number assumes that you have correct signal processing
normalization of the Fourier transform).
4. Design the FIR inverse filter by calculating the inverse Fourier
transform, then chopping the coefficients down to a reasonable
number (N = 15 is used here), apply the Kaiser-Bessel window (alpha
= 2 is used here). Note the objective is remove the color bias
only (as if you are using an equalizer), _not_ to do a full inverse
filtering. (Note: beta = pi*alpha in other notation.)
For N = 15, alpha = 2, you should get the following impulse
response:
0.001001558668605168, 0.00698457265741865, 0.040453643039829436,
0.012230541722147855, -0.11939760844854072, 0.16468099899755967,
-0.30297563073747436, 1.3140211791355982, -0.30297563073747436,
0.16468099899755967, -0.11939760844854072, 0.012230541722147855,
0.040453643039829436, 0.00698457265741865, 0.001001558668605168
5. Linearly convolve all KEMAR HRIR with this inverse filter.
6. Resample from 44.1 kHz sampling frequency to 48 kHz.
*/
/* Center front (-5 degree) - not 0 degree in order to create a clear
front image from a finite distance */
float cf_filt[128] = {
-0.00008638082319075036, 0.0003198059946385229,
-0.0005010631339162132, 0.0011424741331126876,
-0.001584220794688753, 0.001742715363246275,
-0.0011080796626780694, 0.0001651829990860167,
0.005235028337314985, 0.0035223828473357776,
0.010057681388431303, -0.033469432129545514,
0.013391253316233523, 0.004858462839827063,
0.08172161220103627, 0.26158596134500023,
-0.12420314583323326, -0.14298458356097565,
0.14421897280453896, -0.1635792507629016,
-0.02187136722480014, 0.2426863044711817,
0.07229814207917194, 0.0942742651913879,
0.29856830878076834, 0.2944146162057754,
-0.12122157003421209, -0.19640092165631157,
0.11623836502034968, -0.05794027397995521,
-0.34313138341973776, -0.19487516249168105,
0.010118993953802401, -0.09460218797710966,
-0.16761521117359582, 0.004154461610153861,
0.052768641758969316, -0.00041823982226147407,
0.021634960445143514, 0.07562793486871108,
0.08895407129506479, 0.039857755093416214,
0.044257936180422945, 0.061557584906101664,
0.015547268541895703, -0.023908191934932484,
0.009498030443468223, 0.03816269003221337,
-0.009820500607303615, -0.042003975527908084,
-0.03335447117311547, -0.029294510859746596,
-0.05212623136198511, -0.073427547153205,
-0.061190797824958836, -0.04620925059966413,
-0.04204619420702159, -0.02331915902615157,
0.00211481411477094, 0.00852563995740107,
0.008766809731743399, 0.008666632180812078,
0.018279202191625352, 0.02924332751289675,
0.022293148257836494, 0.012362146008584188,
0.008572582458807008, 0.006491370763597344,
-0.0019366944997535774, -0.006318669309634434,
-0.006457921690218669, -0.015050265524669974,
-0.02110660282616213, -0.017027809096377904,
-0.01651052305334348, -0.022770064150046673,
-0.01999875754219472, -0.012294792027337775,
-0.011506057031057188, -0.011448970577312903,
-0.004823572302580925, 0.0022451134042777883,
0.004145473526859826, 0.005629030064546135,
0.008588029213398785, 0.010092048834844231,
0.007182013245552008, 0.0014600979508720656,
-0.0038314646272511756, -0.003443901997881347,
-0.0029483418254804047, -0.007609357112679647,
-0.006518368948030822, -0.004495803701497202,
-0.007109113004849672, -0.008346237278084265,
-0.005560847336252453, -0.002993453167553188,
-0.005122897816824269, -0.004389782626604215,
-0.0010912633695218108, -0.0019712029474458835,
-0.005870162265802235, -0.005626159534954128,
-0.00027254977910844407, 0.0013794425431633785,
-0.0005919083190430062, -0.0007861203545416682,
-0.0007049560240893946, -0.0032720188494468868,
-0.004460645567968504, -0.0032018528193571696,
-0.0030579229375062105, -0.003593998902656612,
-0.0038032977997776445, -0.004613776010454773,
-0.0059796549143736845, -0.00420126194319768,
-0.0012374419948287222, 0.0008572699213050608,
0.0021490971020081094, 0.00047295283198381995,
-0.0009670277915884887, -0.001354440866080231,
-0.002962902746547851, -0.00533935813338141,
-0.005469203016468759, -0.004355784273189485
};
/* Front, same side (30 degree) */
float af_filt[128] = {
-0.004140580614755493, 0.005790934614385445,
0.003318916682081112, 0.014257145544366063,
0.007328442487127339, -0.06550381777876194,
0.03502225818161845, -0.013090579770708259,
0.2517776798694195, 0.420770489950659,
-0.3418854608834852, -0.24371032493696737,
0.04901356150030018, -0.1778083521632833,
0.26448004245714163, 0.23245199964546834,
0.033053145803936305, 0.46811222821062415,
0.5359265986255611, -0.011912195468533787,
-0.39763432601411647, -0.034482864386898314,
0.029445398240649626, -0.3850940407863262,
-0.3272328478175581, -0.14701421403616477,
-0.08522137400169517, -0.14936851633336035,
-0.09432605283433723, 0.0991200405937827,
0.011075012089917331, -0.0051036489980274685,
0.0933903289749412, 0.1344189369609565,
0.10507466913017807, 0.04240159324684365,
0.06559270110638656, 0.026984119875617524,
-0.03359846103238096, -0.018000197099174275,
0.042031818548178244, 0.03849039666888434,
-0.02450829674011345, -0.03407882403088576,
-0.029230189282961977, -0.046964865291761734,
-0.09458258700116245, -0.1527349330901158,
-0.15411577687826097, -0.08761679790956928,
-0.033623549089171874, -0.007204768531481949,
0.008273425020444852, 0.021368717994908505,
0.04366608267875025, 0.05660907333076205,
0.06775726495503939, 0.05621881735271431,
0.03576231950669927, 0.02500825834889175,
0.015423811076054601, 0.007903258334503761,
-0.0053873014137761945, -0.006987955469434698,
-0.012027972007598602, -0.025228281243816594,
-0.026225091797257318, -0.023809293997344882,
-0.03250172017712295, -0.03195696301067249,
-0.01784813952189948, -0.01663267233760342,
-0.016184530450468065, -0.011659883749357463,
-0.0035378511240219163, -0.0005485800790443406,
0.0018432660108168625, 0.011634844139907534,
0.018333603402051105, 0.020447379185133056,
0.00850783664147828, 0.0004694148911037838,
-0.0017047130409786676, -0.0022409152834483997,
-0.000860472174892845, -0.004111075059198666,
-0.003527843382056666, -0.009640160874903018,
-0.01750044574231376, -0.015613389403672443,
-0.010790028120953001, -0.0095313499955768,
-0.007469721416726809, -0.0019186578145117315,
-0.00014977322572890802, -0.0029803838028179728,
-0.006520567233727221, 0.000035015132033882596,
0.009245098100543752, 0.009896930052308656,
0.008316744929565786, 0.004575207140193997,
-0.0000647420103997081, -0.004502916832871627,
-0.004225962213251224, -0.002886014126381486,
-0.006416834142585976, -0.007156609995423569,
-0.008840274447579472, -0.01441763751386817,
-0.015435817484659574, -0.00924487254924743,
-0.0021571721940235205, 0.0028540722992305453,
0.00273577475088536, -0.000788412365513805,
-0.0032650029728365907, -0.003880217646231338,
-0.0035302087299613778, -0.0038531436176586246,
-0.0011921632190514074, -0.0020722967099011938,
-0.004985351145629344, -0.0042375588844648735,
-0.003030360463006021, -0.0014161075428041471,
-0.0005083025643192044, 0.00035096963769606926
};
/* Front, opposite (-30 degree) */
float of_filt[128] = {
-0.000013472538374193126, -0.00008048061877079751,
0.000043927265781258155, -0.000017931700794858892,
-0.000034774602476112886, -0.00009576223008735474,
0.0001557797638630691, -0.00018742885883751094,
0.00026512448626705716, -0.0001451040203319678,
-0.00008263233117758043, 0.0006486245853639179,
-0.0010631408451846698, 0.0026571994100746143,
0.0014179177997092787, 0.0062326502956616256,
-0.008194149324545333, -0.006568029415878379,
0.009538759710818582, 0.012309193558632693,
0.12336638055838955, 0.046164307101829005,
-0.10228706407884815, 0.04047687260345798,
-0.00296595313977046, -0.07057949208414134,
0.08172114840714612, 0.08736490764127891,
0.05105250431333021, 0.11627179512747428,
0.20717888490340705, 0.09375052213570291,
-0.09784374168330194, -0.010493571845901443,
0.053131894303891716, -0.10157443971694806,
-0.16264032634244974, -0.05402369511361273,
-0.0274403608654217, -0.09860277022495063,
-0.06841875821090282, -0.004434574400066223,
-0.0005222661652743502, -0.006231881259827263,
0.014410397820340159, 0.04885649512730243,
0.04361962569042684, 0.03399214029009391,
0.04961073933475931, 0.04067325604132289,
0.007850647519227257, 0.004564440466905299,
0.02257107958021618, 0.008183791928884486,
-0.014913479343180557, -0.018685938460856224,
-0.01745737397226911, -0.02327177054233603,
-0.03723048632685227, -0.044739390162299685,
-0.042651220125613766, -0.03730017561004743,
-0.029039465434276192, -0.01885087458914294,
-0.01207127752277769, -0.006779800724164512,
-0.001930416967444157, 0.000029454577995528385,
0.0013822760965755472, 0.0014799128583230202,
0.0002068200609199832, 0.0022254295286201083,
0.005143858159434566, 0.0018580542060917013,
-0.0019426046325146259, -0.0014464042108543495,
-0.0034430083560735582, -0.009692758426099499,
-0.011840035292593485, -0.010716508855893968,
-0.012939889036853034, -0.0121846427935653,
-0.006198503315630782, -0.0023186723099380305,
-0.002679872498314837, -0.003086020446226295,
-0.0015709623347698936, -0.0008147490468332398,
-0.0012384575726770983, -0.0005212877089109362,
0.0017707578744906142, 0.001324932723905786,
-0.0017023653780617696, -0.0045108927752919425,
-0.005422155613096912, -0.0039489323837623835,
-0.005295995750506547, -0.00629706566356189,
-0.004685732198036754, -0.0048076735568143,
-0.005978864279217503, -0.005928999306332966,
-0.004187703549017582, -0.003213999896976475,
-0.0028068699816073414, -0.0010889703907593833,
0.0003276714243495386, -0.0013015007040186994,
-0.003208050402434782, -0.0025115319088208545,
-0.0013787553006401076, -0.0018279087370218635,
-0.0025904836507747754, -0.002071221947222004,
-0.0026424212922485594, -0.0039837031817577,
-0.0041635566057380965, -0.004355223489150822,
-0.004350395332709937, -0.0036693292471930263,
-0.003386384394185026, -0.003972568655001128,
-0.004332336840023821, -0.002648767912111827,
-0.001384410080218114, -0.0011353792711849466,
-0.0013726264946164232, -0.0020075119315034313
};
/* Rear, same side (135 degree) */
float ar_filt[128] = {
0.004573315040810066, 0.0013592578059426913,
0.01553271930902704, -0.0002356117224941317,
-0.05746098219774702, 0.03430688963370445,
0.00808371687447385, 0.21893535841158596,
0.2984357591724814, -0.3302799746504719,
-0.3194029149806245, 0.21633225051331056,
0.24371260938097083, -0.08843705549751085,
0.03939684701343366, 0.45386926431114494,
0.07599118140753386, -0.18114706160474578,
0.285640624686038, 0.4049515236666218,
-0.05347890222071792, -0.31464359045319074,
-0.1033502246468194, -0.04553593949283157,
-0.1880747731157464, -0.13629090230626037,
-0.10435789106123239, -0.19818232801888755,
-0.16701805476330397, -0.022793111199284,
0.058049696762683685, 0.007048321372693906,
-0.002966419183225961, 0.10140569697797763,
0.11648999956673124, 0.05218347182779882,
0.028427001212735392, 0.04151900310166159,
-0.0006960604221423734, -0.05898623212226975,
-0.03801934531173312, -0.029306970535287986,
-0.04549125782835908, -0.0599222718506552,
-0.058299618975430116, -0.03765579129720727,
-0.03559302657499581, -0.020647901025903054,
-0.005720957338744348, -0.0041915732688915545,
-0.0011470880098346143, 0.008737404798553,
0.023444168098121512, 0.024204226042172663,
0.01894897166475026, 0.020807655257479588,
0.021570431128040954, 0.006800556178576289,
-0.009000089216921362, -0.010969824547067934,
-0.0033653428332822374, -0.012676936164668659,
-0.026739938673413587, -0.023427869194287573,
-0.023302007105117244, -0.023647155590533712,
-0.021289317515613106, -0.009120487305069884,
0.0009251551667728967, 0.00004285344125653763,
-0.00009042365479456271, 0.00022573242339446494,
0.00720168491586098, 0.007111875505402431,
0.003186514817683482, 0.00810087718334745,
0.012619557025922575, 0.007854726400013397,
-0.0024013592881066267, -0.001452457473161119,
-0.0025535188366093945, -0.012428911627809337,
-0.013729251536694145, -0.0070099675146427344,
-0.007165284278706593, -0.01639289295622301,
-0.015831795079778305, -0.007305768485523729,
-0.003608863157004021, -0.0032640528878698084,
0.0030901263998481944, 0.00749497566124848,
0.002515185532327241, 0.00004840875738621367,
0.0017596043486043966, 0.0046229941553338144,
0.0034259167322926096, 0.003707347634186093,
0.0035584806528586328, -0.0019078936035275198,
-0.006057343815214898, -0.0069262470468817,
-0.004345020728618624, -0.004177623355574794,
-0.005373506556122508, -0.006624933928893836,
-0.008679541408588839, -0.010718719681595322,
-0.011392246979594496, -0.007893917064389902,
-0.0027572935365832536, -0.00006064707149834412,
-0.0012512537319656323, -0.0024501501002409786,
-0.0022106788572895998, -0.00234124933370301,
-0.0008953445167066823, 0.0005393670625637734,
-0.00033175600142209297, -0.004023994309351289,
-0.008655472335784443, -0.009899957354849682,
-0.008664952919996412, -0.00553483124503576,
-0.003735336089277662, -0.002754824348643885,
-0.0026884314856593368, -0.004084181815125924
};
/* Rear, opposite (-135 degree) */
float or_filt[128] = {
0.0001220944028243897, -0.000021785381808441314,
5.823057988603169e-6, -0.00001217768176447613,
-0.00006123604397345513, 5.574117262531134e-6,
-0.00004935331914366778, 1.1771577934768211e-6,
-0.000059236211621095756, 9.503536190497286e-6,
-0.0001494445696103564, 0.00012248858284145305,
-0.0000963975321456313, 6.017905197665205e-6,
0.00003353395360402643, -0.0001931511015359506,
0.0005113536523931485, -0.0005676652619386114,
0.0012057159755477467, 0.0009370492250339692,
0.004596472288877981, -0.0018831773384237068,
-0.008208535225621212, 0.0038178646400751056,
0.008726517739105965, 0.06664363898418262,
0.06788684221502142, -0.04492315162807267,
-0.04019906311255255, 0.026203059677375153,
0.013678129114847544, -0.014334962223993527,
0.010141709596167392, 0.11559131576945537,
0.1586402064538425, 0.059975334707967023,
0.004671725963777715, 0.031498678282775874,
0.014338626006524587, -0.014749719448472231,
-0.02055508237941379, -0.05407690143992048,
-0.07767559836886143, -0.05029091786216801,
-0.030808335706574427, -0.03401958135442541,
-0.030520368430288967, -0.014168302104259355,
0.011907621259989802, 0.014286081013069,
0.006377467879613449, 0.018546823568277478,
0.028297012771618273, 0.025222339408338186,
0.021931611353415138, 0.019708894333646355,
0.01729258494072014, 0.017468204169564034,
0.009729094845051928, -0.002976992018531901,
-0.00956986166277019, -0.016125733548332074,
-0.02934094241442545, -0.04133767871051455,
-0.043536981145416466, -0.0385966307108608,
-0.02784453599342459, -0.018995135307247116,
-0.012849534096536747, -0.004437491064613308,
0.00028385411598204655, 0.003776874988516643,
0.008069432041547833, 0.008764754183751848,
0.008020908861878062, 0.006830351461360802,
0.002218330884267235, -0.0020478725582339444,
-0.003997428121462543, -0.007066287373515421,
-0.00940847412544698, -0.010938998446237963,
-0.011775483016151306, -0.011391103919484287,
-0.010586061195163017, -0.009842793078929053,
-0.007753202010139829, -0.00569213732353025,
-0.006506783349722073, -0.005346134281903736,
-0.003913089814898934, -0.0036091443854759727,
-0.0020328564301266287, 0.00017932870773467683,
0.0032779786679056357, 0.003969695813293966,
0.0020339334412434987, -0.00011345940675415259,
-0.0018344103399567666, -0.003556764701666365,
-0.004263523639408391, -0.002940568582022133,
-0.0034341188272627556, -0.006023399920020824,
-0.0077456903203677865, -0.007912219312377842,
-0.00625202770436523, -0.00530785086116117,
-0.005569722659634311, -0.004664448462594344,
-0.0037747773914077747, -0.004175649656985592,
-0.004659601521384289, -0.005008602967819641,
-0.004730625079902729, -0.0034039554356604146,
-0.0017110333873406587, -0.0006091938771510242,
-0.0016051679050678297, -0.003312864664007262,
-0.004505512715977288, -0.004152222189861692,
-0.003218596419678823, -0.0027277806209877343,
-0.001715005444317267, -0.0012589960071233749,
-0.001852908777923165, -0.002540339553144362
};
/* Center rear (180 degree) */
float cr_filt[128] = {
-0.00005989110716536726, -0.00022790291829128702,
0.0002659166098971966, -0.0003774772716776257,
0.0004540309551867803, -0.000420238187386368,
0.00025518536450885686, 0.00028285526288953955,
-0.001016391007574093, 0.0028634984299063795,
0.0021574799687976045, 0.01035121276682072,
-0.010481720917298163, -0.013197198495899292,
0.0031928225328717195, 0.02903137843618603,
0.1632429772511569, 0.1047487989875262,
-0.10464685060623742, -0.09260196288035998,
-0.007514241993554443, 0.013596249226741712,
-0.019876166508450258, 0.1255626123599804,
0.3648170359521724, 0.19458249753223478,
-0.04434070930031298, 0.046582528121935265,
0.09484427347230277, -0.03137795311969644,
-0.10297437925363695, -0.09351091015917065,
-0.1129521092162064, -0.14925322995658827,
-0.1231466295584665, -0.06356719756705227,
-0.05442277895126282, -0.07568433015661316,
-0.023314932828602003, 0.04260950721318558,
0.02249026315598923, 0.02048195669571197,
0.05651342117268278, 0.05885038917623213,
0.03797102097397795, 0.011767394419953451,
0.00560502503429481, 0.005051125343961189,
-0.012925933188033823, -0.023918884651306566,
-0.013251659441678816, -0.010694772488866284,
-0.03080486448617846, -0.03661278237783158,
-0.0379227303416262, -0.042189005718490775,
-0.026595666344596286, -0.009759025956801257,
-0.002064986663513004, -0.002420117028098389,
-0.006629991977552491, 0.004619970897631026,
0.019450642967537877, 0.0173521119057514,
0.017641425439988062, 0.02270029598048491,
0.018976431925275348, 0.009299852902290885,
-0.001695039371619912, -0.00675162574265618,
-0.009380968871003034, -0.011208396125485165,
-0.01308640049201482, -0.0165636375633249,
-0.022004099870933345, -0.025173458684139286,
-0.016918759559175375, -0.00865150653575917,
-0.006999929082792643, -0.005454830010518988,
-0.0021129521131095317, 0.00018717090054046307,
-0.0002864344788569993, 0.0017615225381095569,
0.006985907557802283, 0.010577308310476465,
0.006466104789306027, -0.0014988738575948326,
-0.0039669755229277195, -0.0065156971200080235,
-0.009343206924192169, -0.0076430644693577495,
-0.004395214976600924, -0.003052735340422483,
-0.007019103043066595, -0.00974109267696527,
-0.007968015032797376, -0.007801513845528344,
-0.007535748903681969, -0.003543341967287925,
0.0015083125553729722, 0.0023345972556147025,
-0.0010043623069557037, -0.0025295765105203746,
-0.0023701840891643634, -0.0005908186035024362,
0.0029826252289082847, 0.004829048542117764,
0.004488360022902081, 0.00002643748103005408,
-0.0042100779212597295, -0.006170600558114495,
-0.007267149164680168, -0.006825522903494639,
-0.006899834372739123, -0.0073493916110062675,
-0.009554351265163382, -0.011790297433830197,
-0.010645796603734424, -0.0064661575394022106,
-0.002026743466524137, -0.0004337034584909932,
-0.0011172647031654614, -0.0017947816283674731,
-0.00255615052036616, -0.0017721562881944813,
-0.0002379619297227554, 0.0007130120121089036
};