Merge pull request #8022 from takagi/cusignal-pulse_compression

Add `cupyx.signal.pulse_compression` from cuSignal's non SciPy-compat API

cupyx/signal/__init__.py

@@ -0,0 +1 @@
+from cupyx.signal.radartools import pulse_compression  # NOQA

cupyx/signal/radartools/__init__.py

@@ -0,0 +1 @@
+from cupyx.signal.radartools._radartools import pulse_compression  # NOQA

cupyx/signal/radartools/_radartools.py

@@ -0,0 +1,85 @@
+"""
+Some of the functions defined here were ported directly from CuSignal under
+terms of the MIT license, under the following notice:
+
+Copyright (c) 2019-2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+import cupy as cp
+from cupyx.scipy.signal import windows
+
+
+def pulse_compression(x, template, normalize=False, window=None, nfft=None):
+    """
+    Pulse Compression is used to increase the range resolution and SNR
+    by performing matched filtering of the transmitted pulse (template)
+    with the received signal (x)
+
+    Parameters
+    ----------
+    x : ndarray
+        Received signal, assume 2D array with [num_pulses, sample_per_pulse]
+
+    template : ndarray
+        Transmitted signal, assume 1D array
+
+    normalize : bool
+        Normalize transmitted signal
+
+    window : array_like, callable, string, float, or tuple, optional
+        Specifies the window applied to the signal in the Fourier
+        domain.
+
+    nfft : int, size of FFT for pulse compression. Default is number of
+        samples per pulse
+
+    Returns
+    -------
+    compressedIQ : ndarray
+        Pulse compressed output
+    """
+    [num_pulses, samples_per_pulse] = x.shape
+
+    if nfft is None:
+        nfft = samples_per_pulse
+
+    if window is not None:
+        Nx = len(template)
+        if callable(window):
+            W = window(cp.fft.fftfreq(Nx))
+        elif isinstance(window, cp.ndarray):
+            if window.shape != (Nx,):
+                raise ValueError("window must have the same length as data")
+            W = window
+        else:
+            W = windows.get_window(window, Nx, False)
+
+        template = cp.multiply(template, W)
+
+    if normalize is True:
+        template = cp.divide(template, cp.linalg.norm(template))
+
+    fft_x = cp.fft.fft(x, nfft)
+    fft_template = cp.conj(
+        cp.tile(cp.fft.fft(template, nfft), (num_pulses, 1)))
+    compressedIQ = cp.fft.ifft(cp.multiply(fft_x, fft_template), nfft)
+
+    return compressedIQ

docs/source/reference/ext.rst

@@ -16,6 +16,17 @@ CuPy-specific functions are placed under ``cupyx`` namespace.
    cupyx.zeros_pinned
    cupyx.zeros_like_pinned
 
+non-SciPy compat Signal API
+---------------------------
+
+The functions under `cupyx.signal` are non-SciPy compat signal API ported from cuSignal 
+through the courtesy of Nvidia cuSignal team.
+
+.. autosummary::
+   :toctree: generated/
+
+   cupyx.signal.pulse_compression
+
 Profiling utilities
 -------------------
 

tests/cupyx_tests/signal_tests/radartools_tests/test_radartools.py

@@ -0,0 +1,21 @@
+import pytest
+
+import cupy
+from cupyx import signal
+
+
+class TestPulseCompression:
+
+    @pytest.mark.parametrize('dtype', [cupy.float32, cupy.float64])
+    def test_pulse_compression(self, dtype):
+        num_pulses = 128
+        num_samples_per_pulse = 9000
+        template_length = 1000
+
+        shape = num_pulses, num_samples_per_pulse
+        x = cupy.random.randn(*shape, dtype=dtype) + \
+            1j * cupy.random.rand(*shape, dtype=dtype)
+        template = cupy.random.randn(template_length, dtype=dtype) + \
+            1j * cupy.random.randn(template_length, dtype=dtype)
+
+        signal.pulse_compression(x, template, normalize=True, window='hamming')