diff options
Diffstat (limited to 'Project/RTDSP/enhance.c')
| -rw-r--r-- | Project/RTDSP/enhance.c | 95 |
1 files changed, 48 insertions, 47 deletions
diff --git a/Project/RTDSP/enhance.c b/Project/RTDSP/enhance.c index 8c8cd44..3aae46a 100644 --- a/Project/RTDSP/enhance.c +++ b/Project/RTDSP/enhance.c @@ -80,6 +80,11 @@ DSK6713_AIC23_Config Config = { \ /**********************************************************************/ }; +typedef struct { + float *mag_spec; + float sum; +} MVal; + // Codec handle:- a variable used to identify audio interface DSK6713_AIC23_CodecHandle H_Codec; @@ -89,14 +94,15 @@ float *inwin, *outwin; /* Input and output windows */ float ingain, outgain; /* ADC and DAC gains */ float cpufrac; /* Fraction of CPU time used */ complex *fft_out; /* FFT output */ -complex* noise; +float* noise; volatile int io_ptr=0; /* Input/ouput pointer for circular buffers */ volatile int frame_ptr=0; /* Frame pointer */ -volatile int frame_ctr =0; -volatile float lambda = 0.05; -volatile float alpha = 20; +volatile int frame_ctr = 0; +volatile int m_ptr = 0; +float lambda = 0.05; +float alpha = 20; double avg = 0; -float *M[NUM_M]; +MVal M[NUM_M]; float K; float time_constant = 50E-6; /* Time constant in ms */ /******************************* Function prototypes *******************************/ @@ -137,16 +143,14 @@ void main() ingain=INGAIN; outgain=OUTGAIN; - for (k = 0; k < NUM_M; ++k) - { + for (k = 0; k < NUM_M; ++k) { int i; - M[k].spec = (complex *) calloc(FFTLEN, sizeof(complex)); - M[k].mag_avg = MAX_FLOAT; + M[k].mag_spec = (float *) calloc(FFTLEN, sizeof(float)); for(i = 0; i < FFTLEN; ++i) { - M[k].spec[i].r = MAX_FLOAT; - M[k].spec[i].i = MAX_FLOAT; + M[k].mag_spec[i] = MAX_FLOAT; } - } + M[k].sum = 0; + } // initializing the value to estimate the low pass filter K = exp(- TFRAME / time_constant); @@ -195,40 +199,38 @@ void init_HWI(void) // Spectrum calculations for the new values void write_spectrum(void) { unsigned int k; - avg = 0; + float x_val; + M[m_ptr].sum = 0; for(k = 0; k < FFTLEN; ++k) { - avg += cabs(fft_out[k]); - } - avg /= FFTLEN; - - if(avg < M[0].mag_avg) { - M[0].mag_avg = avg; - for(k = 0; k < FFTLEN; ++k) { - M[0].spec[k] = fft_out[k]; + x_val = cabs(fft_out[k]); + if(M[m_ptr].mag_spec[k] > x_val) { + M[m_ptr].mag_spec[k] = x_val; + M[m_ptr].sum += x_val; + } else { + M[m_ptr].sum += M[m_ptr].mag_spec[k]; } } } void get_noise(void) { - float min_avg = MAX_FLOAT; + float min_sum = M[0].sum; + int min_index = 0, k; - for(k = 0; k < NUM_M; ++k) { - if (M[k].mag_avg < min_avg) { - min_avg = M[k].mag_avg; + for(k = 1; k < NUM_M; ++k) { + if (M[k].sum != 0 && M[k].sum < min_sum) { + min_sum = M[k].sum; min_index = k; } } - - noise = M[min_index].spec; -} + noise = M[min_index].mag_spec; +} /******************************** process_frame() ***********************************/ void process_frame(void) { int k, m; int io_ptr0; - int min_index; float mag_N_X; /* work out fraction of available CPU time used by algorithm */ cpufrac = ((float) (io_ptr & (FRAMEINC - 1)))/FRAMEINC; @@ -256,7 +258,7 @@ void process_frame(void) // Initialise the array fft_out for FFT for (k = 0; k < FFTLEN; ++k) { - fft_out[k] = cmplx(inframe[k], 0.0) + fft_out[k] = cmplx(inframe[k], 0.0); } // Perform the FFT @@ -268,32 +270,31 @@ void process_frame(void) // Set the noise get_noise(); + // alpha*... + if(frame_ctr > MAX_COUNT-1) { + int i; + float x_val; + frame_ctr = 0; + if(++m_ptr == NUM_M) m_ptr = 0; + M[m_ptr].sum = 0; + for(i = 0; i < FFTLEN; ++i) { + x_val = cabs(fft_out[i]); + M[m_ptr].mag_spec[i] = x_val; + M[m_ptr].sum += x_val; + } + } + // max(lambda, |N(w)/g(w)| for (k = 0; k < FFTLEN; ++k) { float g; - mag_N_X = 1 - cabs(noise[k])/cabs(fft_out[k]); + mag_N_X = 1 - alpha * noise[k]/cabs(fft_out[k]); g = mag_N_X > lambda ? mag_N_X : lambda; - fft_out[k] = rmul(fft_out[k], g); + fft_out[k] = rmul(g, fft_out[k]); } // Back into time domain ifft(FFTLEN, fft_out); - // alpha*... - if(frame_ctr > MAX_COUNT-1) { - int i; - frame_ctr = 0; - M[0].spec = M[NUM_M-1].spec; - for(k = NUM_M-1; k > 0; --k) { - M[k] = M[k-1]; - } - M[0].mag_avg = MAX_FLOAT; - for(i = 0; i < FFTLEN; ++i) { - M[0].spec[i].r = MAX_FLOAT; - M[0].spec[i].i = MAX_FLOAT; - } - } - for (k = 0; k < FFTLEN; ++k) { outframe[k] = fft_out[k].r; } |