Add Simple peak detection.

Dubrzr · Dubrzr · commit 2773cd1417a7 · 2017-06-26T15:56:29.000Z
diff --git a/tests/test_processing.py b/tests/test_processing.py
@@ -39,3 +39,15 @@ def test_3(self):
         assert x.shape[0] == sig.shape[0]
         assert numpy.min(x) >= lb
         assert numpy.max(x) <= ub
+
+    def test_4(self):
+        x = []
+        hp, sp = wfdb.processing.find_peaks(x)
+        assert hp.shape == (0,)
+        assert sp.shape == (0,)
+
+    def test_5(self):
+        x = [0, 2, 1, 0, -10, -15, -15, -15, 9, 8, 0, 0, 1, 2, 10]
+        hp, sp = wfdb.processing.find_peaks(x)
+        assert numpy.array_equal(hp, [1, 8])
+        assert numpy.array_equal(sp, [6, 10])
diff --git a/wfdb/processing/__init__.py b/wfdb/processing/__init__.py
@@ -1 +1,2 @@
 from .basic import resample_ann, resample_sig, resample_singlechan, resample_multichan, normalize
+from .peaks import find_peaks
diff --git a/wfdb/processing/peaks.py b/wfdb/processing/peaks.py
@@ -0,0 +1,38 @@
+import numpy
+
+
+def find_peaks(x):
+    # Definitions:
+    # * Hard peak: a peak that is either /\ or \/
+    # * Soft peak: a peak that is either /-*\ or \-*/ (In that cas we define the middle of it as the peak)
+
+    # Returns two numpy arrays:
+    # * hard_peaks contains the indexes of the Hard peaks
+    # * soft_peaks contains the indexes of the Soft peaks
+
+    if len(x) == 0:
+        return numpy.empty([0]), numpy.empty([0])
+
+    tmp = x[1:]
+    tmp = numpy.append(tmp, [x[-1]])
+    tmp = x-tmp
+    tmp[numpy.where(tmp>0)] = +1
+    tmp[numpy.where(tmp==0)] = 0
+    tmp[numpy.where(tmp<0)] = -1
+    tmp2 = tmp[1:]
+    tmp2 = numpy.append(tmp2, [0])
+    tmp = tmp-tmp2
+    hard_peaks = numpy.where(numpy.logical_or(tmp==-2,tmp==+2))[0]+1
+    soft_peaks = []
+    for iv in numpy.where(numpy.logical_or(tmp==-1,tmp==+1))[0]:
+        t = tmp[iv]
+        i = iv+1
+        while True:
+            if i==len(tmp) or tmp[i] == -t or tmp[i] == -2 or tmp[i] == 2:
+                break
+            if tmp[i] == t:
+                soft_peaks.append(int(iv+(i-iv)/2))
+                break
+            i += 1
+    soft_peaks = numpy.asarray(soft_peaks)+1
+    return hard_peaks, soft_peaks

Original file line number	Diff line number	Diff line change
`@@ -1 +1,2 @@`
`1`	`1`	`from .basic import resample_ann, resample_sig, resample_singlechan, resample_multichan, normalize`
	`2`	`+from .peaks import find_peaks`