add new old fourier

rfg_adc_plotter/gui/pyqtgraph_backend.py

@@ -205,6 +205,7 @@ def run_pyqtgraph(args) -> None:
     bg_compute_cb = QtWidgets.QCheckBox("расчет фона")
     bg_subtract_cb = QtWidgets.QCheckBox("вычет фона")
     fft_bg_subtract_cb = QtWidgets.QCheckBox("FFT вычет фона")
+    fft_symmetric_cb = QtWidgets.QCheckBox("симм. IFFT")
     peak_search_cb = QtWidgets.QCheckBox("поиск пиков")
     calib_group = QtWidgets.QGroupBox("Калибровка")
     calib_group_layout = QtWidgets.QVBoxLayout(calib_group)
@@ -239,6 +240,7 @@ def run_pyqtgraph(args) -> None:
     settings_layout.addWidget(bg_compute_cb)
     settings_layout.addWidget(bg_subtract_cb)
     settings_layout.addWidget(fft_bg_subtract_cb)
+    settings_layout.addWidget(fft_symmetric_cb)
     settings_layout.addWidget(peak_search_cb)
 
     status = pg.LabelItem(justify="left")
@@ -248,6 +250,7 @@ def run_pyqtgraph(args) -> None:
     bg_compute_enabled = True
     bg_subtract_enabled = False
     fft_bg_subtract_enabled = False
+    fft_symmetric_enabled = True
     status_note = ""
     status_dirty = True
     fixed_ylim: Optional[Tuple[float, float]] = None
@@ -441,11 +444,26 @@ def run_pyqtgraph(args) -> None:
             fft_bg_subtract_enabled = False
         runtime.mark_dirty()
 
+    def set_fft_symmetric_enabled() -> None:
+        nonlocal fft_symmetric_enabled
+        try:
+            fft_symmetric_enabled = bool(fft_symmetric_cb.isChecked())
+        except Exception:
+            fft_symmetric_enabled = True
+        runtime.ring.set_symmetric_fft_enabled(fft_symmetric_enabled)
+        runtime.current_distances = runtime.ring.distance_axis
+        runtime.current_fft_db = None
+        set_status_note("IFFT: симметричный" if fft_symmetric_enabled else "IFFT: обычный")
+        update_physical_axes()
+        runtime.mark_dirty()
+
     try:
         bg_compute_cb.setChecked(True)
+        fft_symmetric_cb.setChecked(True)
     except Exception:
         pass
     set_bg_compute_enabled()
+    set_fft_symmetric_enabled()
 
     try:
         calib_cb.stateChanged.connect(lambda _v: set_calib_enabled())
@@ -455,6 +473,7 @@ def run_pyqtgraph(args) -> None:
         bg_compute_cb.stateChanged.connect(lambda _v: set_bg_compute_enabled())
         bg_subtract_cb.stateChanged.connect(lambda _v: set_bg_subtract_enabled())
         fft_bg_subtract_cb.stateChanged.connect(lambda _v: set_fft_bg_subtract_enabled())
+        fft_symmetric_cb.stateChanged.connect(lambda _v: set_fft_symmetric_enabled())
     except Exception:
         pass
 
@@ -745,7 +764,12 @@ def run_pyqtgraph(args) -> None:
             distance_axis = runtime.current_distances if runtime.current_distances is not None else runtime.ring.distance_axis
             if sweep_for_fft is not None and sweep_for_fft.size > 0 and distance_axis is not None:
                 if runtime.current_fft_db is None or runtime.current_fft_db.size != distance_axis.size or runtime.plot_dirty:
-                    runtime.current_fft_db = compute_fft_row(sweep_for_fft, runtime.current_freqs, distance_axis.size)
+                    runtime.current_fft_db = compute_fft_row(
+                        sweep_for_fft,
+                        runtime.current_freqs,
+                        distance_axis.size,
+                        symmetric=fft_symmetric_enabled,
+                    )
                 fft_vals = runtime.current_fft_db
                 xs_fft = distance_axis[: fft_vals.size]
                 if fft_bg_subtract_enabled and bg_fft_for_line is not None:

rfg_adc_plotter/processing/fft.py

@@ -6,7 +6,7 @@ from typing import Optional, Tuple
 
 import numpy as np
 
-from rfg_adc_plotter.constants import C_M_S, FFT_LEN
+from rfg_adc_plotter.constants import C_M_S, FFT_LEN, SWEEP_FREQ_MAX_GHZ, SWEEP_FREQ_MIN_GHZ
 
 
 def prepare_fft_segment(
@@ -48,6 +48,45 @@ def prepare_fft_segment(
     return resampled, take_fft
 
 
+def build_symmetric_ifft_spectrum(
+    sweep: np.ndarray,
+    freqs: Optional[np.ndarray],
+    fft_len: int = FFT_LEN,
+) -> Optional[np.ndarray]:
+    """Build a centered symmetric spectrum over [-f_max, f_max] for IFFT."""
+    if fft_len <= 0:
+        return None
+
+    freq_axis = np.linspace(-SWEEP_FREQ_MAX_GHZ, SWEEP_FREQ_MAX_GHZ, int(fft_len), dtype=np.float64)
+    neg_idx_all = np.flatnonzero(freq_axis <= (-SWEEP_FREQ_MIN_GHZ))
+    pos_idx_all = np.flatnonzero(freq_axis >= SWEEP_FREQ_MIN_GHZ)
+    band_len = int(min(neg_idx_all.size, pos_idx_all.size))
+    if band_len <= 1:
+        return None
+
+    neg_idx = neg_idx_all[:band_len]
+    pos_idx = pos_idx_all[-band_len:]
+    prepared = prepare_fft_segment(sweep, freqs, fft_len=band_len)
+    if prepared is None:
+        return None
+
+    fft_seg, take_fft = prepared
+    if take_fft != band_len:
+        fft_seg = np.asarray(fft_seg[:band_len], dtype=np.float32)
+        if fft_seg.size < band_len:
+            padded = np.zeros((band_len,), dtype=np.float32)
+            padded[: fft_seg.size] = fft_seg
+            fft_seg = padded
+
+    window = np.hanning(band_len).astype(np.float32)
+    band = np.nan_to_num(fft_seg, nan=0.0).astype(np.float32, copy=False) * window
+
+    spectrum = np.zeros((int(fft_len),), dtype=np.float32)
+    spectrum[pos_idx] = band
+    spectrum[neg_idx] = band[::-1]
+    return spectrum
+
+
 def fft_mag_to_db(mag: np.ndarray) -> np.ndarray:
     """Convert magnitude to dB with safe zero handling."""
     mag_arr = np.asarray(mag, dtype=np.float32)
@@ -55,15 +94,11 @@ def fft_mag_to_db(mag: np.ndarray) -> np.ndarray:
     return (20.0 * np.log10(safe_mag + 1e-9)).astype(np.float32, copy=False)
 
 
-def compute_fft_mag_row(
+def _compute_fft_mag_row_direct(
     sweep: np.ndarray,
     freqs: Optional[np.ndarray],
     bins: int,
 ) -> np.ndarray:
-    """Compute a linear FFT magnitude row."""
-    if bins <= 0:
-        return np.zeros((0,), dtype=np.float32)
-
     prepared = prepare_fft_segment(sweep, freqs, fft_len=FFT_LEN)
     if prepared is None:
         return np.full((bins,), np.nan, dtype=np.float32)
@@ -79,27 +114,55 @@ def compute_fft_mag_row(
     return mag
 
 
+def compute_fft_mag_row(
+    sweep: np.ndarray,
+    freqs: Optional[np.ndarray],
+    bins: int,
+    *,
+    symmetric: bool = True,
+) -> np.ndarray:
+    """Compute a linear FFT magnitude row."""
+    if bins <= 0:
+        return np.zeros((0,), dtype=np.float32)
+
+    if not symmetric:
+        return _compute_fft_mag_row_direct(sweep, freqs, bins)
+
+    spectrum_centered = build_symmetric_ifft_spectrum(sweep, freqs, fft_len=FFT_LEN)
+    if spectrum_centered is None:
+        return np.full((bins,), np.nan, dtype=np.float32)
+
+    spec = np.fft.ifft(np.fft.ifftshift(spectrum_centered))
+    mag = np.abs(spec).astype(np.float32)
+    if mag.shape[0] != bins:
+        mag = mag[:bins]
+    return mag
+
+
 def compute_fft_row(
     sweep: np.ndarray,
     freqs: Optional[np.ndarray],
     bins: int,
+    *,
+    symmetric: bool = True,
 ) -> np.ndarray:
     """Compute a dB FFT row."""
-    return fft_mag_to_db(compute_fft_mag_row(sweep, freqs, bins))
+    return fft_mag_to_db(compute_fft_mag_row(sweep, freqs, bins, symmetric=symmetric))
 
 
-def compute_distance_axis(freqs: Optional[np.ndarray], bins: int) -> np.ndarray:
+def compute_distance_axis(freqs: Optional[np.ndarray], bins: int, *, symmetric: bool = True) -> np.ndarray:
     """Compute the one-way distance axis for IFFT output."""
     if bins <= 0:
         return np.zeros((0,), dtype=np.float64)
+    if symmetric:
+        df_ghz = (2.0 * float(SWEEP_FREQ_MAX_GHZ)) / max(1, FFT_LEN - 1)
+    else:
         if freqs is None:
             return np.arange(bins, dtype=np.float64)
-
         freq_arr = np.asarray(freqs, dtype=np.float64)
         finite = freq_arr[np.isfinite(freq_arr)]
         if finite.size < 2:
             return np.arange(bins, dtype=np.float64)
-
         df_ghz = float((finite[-1] - finite[0]) / max(1, finite.size - 1))
     df_hz = abs(df_ghz) * 1e9
     if not np.isfinite(df_hz) or df_hz <= 0.0:

rfg_adc_plotter/state/ring_buffer.py

@@ -17,6 +17,7 @@ class RingBuffer:
     def __init__(self, max_sweeps: int):
         self.max_sweeps = int(max_sweeps)
         self.fft_bins = FFT_LEN // 2 + 1
+        self.fft_symmetric = True
         self.width = 0
         self.head = 0
         self.ring: Optional[np.ndarray] = None
@@ -25,6 +26,7 @@ class RingBuffer:
         self.x_shared: Optional[np.ndarray] = None
         self.distance_axis: Optional[np.ndarray] = None
         self.last_fft_db: Optional[np.ndarray] = None
+        self.last_freqs: Optional[np.ndarray] = None
         self.y_min_fft: Optional[float] = None
         self.y_max_fft: Optional[float] = None
 
@@ -61,6 +63,50 @@ class RingBuffer:
             changed = True
         return changed
 
+    def set_symmetric_fft_enabled(self, enabled: bool) -> bool:
+        """Switch FFT mode and rebuild cached FFT rows from stored sweeps."""
+        enabled_bool = bool(enabled)
+        if enabled_bool == self.fft_symmetric:
+            return False
+
+        self.fft_symmetric = enabled_bool
+        self.y_min_fft = None
+        self.y_max_fft = None
+
+        if self.ring is None or self.ring_fft is None:
+            return True
+
+        self.ring_fft.fill(np.nan)
+        for row_idx in range(self.ring.shape[0]):
+            sweep_row = self.ring[row_idx]
+            if not np.any(np.isfinite(sweep_row)):
+                continue
+            fft_mag = compute_fft_mag_row(
+                sweep_row,
+                self.last_freqs,
+                self.fft_bins,
+                symmetric=self.fft_symmetric,
+            )
+            self.ring_fft[row_idx, :] = fft_mag
+
+        if self.last_freqs is not None:
+            self.distance_axis = compute_distance_axis(
+                self.last_freqs,
+                self.fft_bins,
+                symmetric=self.fft_symmetric,
+            )
+
+        last_idx = (self.head - 1) % self.max_sweeps
+        if self.ring_fft.shape[0] > 0:
+            last_fft = self.ring_fft[last_idx]
+            self.last_fft_db = fft_mag_to_db(last_fft)
+            finite = self.ring_fft[np.isfinite(self.ring_fft)]
+            if finite.size > 0:
+                finite_db = fft_mag_to_db(finite.astype(np.float32, copy=False))
+                self.y_min_fft = float(np.nanmin(finite_db))
+                self.y_max_fft = float(np.nanmax(finite_db))
+        return True
+
     def push(self, sweep: np.ndarray, freqs: Optional[np.ndarray] = None) -> None:
         """Push a processed sweep and refresh raw/FFT buffers."""
         if sweep is None or sweep.size == 0:
@@ -74,8 +120,10 @@ class RingBuffer:
         row[:take] = np.asarray(sweep[:take], dtype=np.float32)
         self.ring[self.head, :] = row
         self.ring_time[self.head] = time.time()
+        if freqs is not None:
+            self.last_freqs = np.asarray(freqs, dtype=np.float64).copy()
 
-        fft_mag = compute_fft_mag_row(sweep, freqs, self.fft_bins)
+        fft_mag = compute_fft_mag_row(sweep, freqs, self.fft_bins, symmetric=self.fft_symmetric)
         self.ring_fft[self.head, :] = fft_mag
         self.last_fft_db = fft_mag_to_db(fft_mag)
 
@@ -85,7 +133,7 @@ class RingBuffer:
             self.y_min_fft = fr_min if self.y_min_fft is None else min(self.y_min_fft, fr_min)
             self.y_max_fft = fr_max if self.y_max_fft is None else max(self.y_max_fft, fr_max)
 
-        self.distance_axis = compute_distance_axis(freqs, self.fft_bins)
+        self.distance_axis = compute_distance_axis(freqs, self.fft_bins, symmetric=self.fft_symmetric)
         self.head = (self.head + 1) % self.max_sweeps
 
     def get_display_raw(self) -> np.ndarray:

tests/test_processing.py

@@ -5,6 +5,7 @@ import tempfile
 import numpy as np
 import unittest
 
+from rfg_adc_plotter.constants import FFT_LEN, SWEEP_FREQ_MAX_GHZ, SWEEP_FREQ_MIN_GHZ
 from rfg_adc_plotter.processing.calibration import (
     build_calib_envelope,
     calibrate_freqs,
@@ -12,7 +13,12 @@ from rfg_adc_plotter.processing.calibration import (
     recalculate_calibration_c,
     save_calib_envelope,
 )
-from rfg_adc_plotter.processing.fft import compute_distance_axis, compute_fft_mag_row, compute_fft_row
+from rfg_adc_plotter.processing.fft import (
+    build_symmetric_ifft_spectrum,
+    compute_distance_axis,
+    compute_fft_mag_row,
+    compute_fft_row,
+)
 from rfg_adc_plotter.processing.normalization import (
     build_calib_envelopes,
     normalize_by_calib,
@@ -94,6 +100,23 @@ class ProcessingTests(unittest.TestCase):
         self.assertEqual(axis.shape, (513,))
         self.assertTrue(np.all(np.diff(axis) >= 0.0))
 
+    def test_symmetric_ifft_spectrum_has_zero_gap_and_mirrored_band(self):
+        sweep = np.linspace(1.0, 2.0, 128, dtype=np.float32)
+        freqs = np.linspace(SWEEP_FREQ_MIN_GHZ, SWEEP_FREQ_MAX_GHZ, 128, dtype=np.float64)
+        spectrum = build_symmetric_ifft_spectrum(sweep, freqs, fft_len=FFT_LEN)
+
+        self.assertIsNotNone(spectrum)
+        freq_axis = np.linspace(-SWEEP_FREQ_MAX_GHZ, SWEEP_FREQ_MAX_GHZ, FFT_LEN, dtype=np.float64)
+        neg_idx_all = np.flatnonzero(freq_axis <= (-SWEEP_FREQ_MIN_GHZ))
+        pos_idx_all = np.flatnonzero(freq_axis >= SWEEP_FREQ_MIN_GHZ)
+        band_len = int(min(neg_idx_all.size, pos_idx_all.size))
+        neg_idx = neg_idx_all[:band_len]
+        pos_idx = pos_idx_all[-band_len:]
+        zero_mask = (freq_axis > (-SWEEP_FREQ_MIN_GHZ)) & (freq_axis < SWEEP_FREQ_MIN_GHZ)
+
+        self.assertTrue(np.allclose(spectrum[zero_mask], 0.0))
+        self.assertTrue(np.allclose(spectrum[neg_idx], spectrum[pos_idx][::-1]))
+
     def test_peak_helpers_find_reference_and_peak_boxes(self):
         xs = np.linspace(0.0, 10.0, 200)
         ys = np.exp(-((xs - 5.0) ** 2) / 0.4) * 10.0 + 1.0

tests/test_ring_buffer.py

@@ -39,6 +39,23 @@ class RingBufferTests(unittest.TestCase):
         self.assertIsNotNone(ring.last_fft_db)
         self.assertEqual(ring.last_fft_db.shape, (ring.fft_bins,))
 
+    def test_ring_buffer_can_switch_fft_mode_and_rebuild_fft_rows(self):
+        ring = RingBuffer(max_sweeps=2)
+        sweep = np.linspace(0.0, 1.0, 64, dtype=np.float32)
+        freqs = np.linspace(3.3, 14.3, 64, dtype=np.float64)
+        ring.push(sweep, freqs)
+        fft_before = ring.last_fft_db.copy()
+        axis_before = ring.distance_axis.copy()
+
+        changed = ring.set_symmetric_fft_enabled(False)
+
+        self.assertTrue(changed)
+        self.assertFalse(ring.fft_symmetric)
+        self.assertEqual(ring.get_display_raw().shape[1], 2)
+        self.assertEqual(ring.last_fft_db.shape, fft_before.shape)
+        self.assertFalse(np.allclose(ring.last_fft_db, fft_before))
+        self.assertFalse(np.allclose(ring.distance_axis, axis_before))
+
 
 if __name__ == "__main__":
     unittest.main()