diff options
Diffstat (limited to 'pyecsca/align.py')
| -rw-r--r-- | pyecsca/align.py | 52 |
1 files changed, 39 insertions, 13 deletions
diff --git a/pyecsca/align.py b/pyecsca/align.py index 1c4b891..ff586ab 100644 --- a/pyecsca/align.py +++ b/pyecsca/align.py @@ -63,6 +63,7 @@ def align_correlation(reference: Trace, *traces: Trace, correlation = np.correlate(trace_part, reference_part, "same") max_correlation_offset = correlation.argmax(axis=0) max_correlation = correlation[max_correlation_offset] + del trace_part if max_correlation < min_correlation: return False, 0 left_space = min(max_offset, reference_offset) @@ -103,25 +104,26 @@ def align_peaks(reference: Trace, *traces: Trace, @public -def align_sad(reference: Trace, *traces: Trace, - reference_offset: int, reference_length: int, max_offset: int) -> List[Trace]: +def align_offset(reference: Trace, *traces: Trace, + reference_offset: int, reference_length: int, max_offset: int, + dist_func: Callable[[np.ndarray, np.ndarray], float], max_dist: float = float("inf")) -> List[Trace]: """ - Align `traces` to the reference `trace` so that the Sum Of Absolute Differences between the - reference trace window from `reference_offset` of `reference_length` and the trace being aligned - within `max_offset` of the reference window is maximized. + Align `traces` to the reference `trace` so that the value of the `dist_func` is minimized + between the reference trace window from `reference_offset` of `reference_length` and the trace + being aligned within `max_offset` of the reference window. :param reference: :param traces: :param reference_offset: :param reference_length: :param max_offset: + :param dist_func: :return: """ reference_part = reference.samples[reference_offset: reference_offset + reference_length] - def align_func(trace): length = len(trace.samples) - best_sad = 0 + best_distance = 0 best_offset = 0 for offset in range(-max_offset, max_offset): start = reference_offset + offset @@ -129,17 +131,41 @@ def align_sad(reference: Trace, *traces: Trace, if start < 0 or stop >= length: continue trace_part = trace.samples[start:stop] - # todo: add other distance functions here - sad = np.sum(np.abs(reference_part - trace_part)) - if sad > best_sad: - best_sad = sad + distance = dist_func(reference_part, trace_part) + if distance < best_distance: + best_distance = distance best_offset = offset - return True, best_offset - + if best_distance < max_dist: + return True, best_offset + else: + return False, 0 return align_reference(reference, *traces, align_func=align_func) @public +def align_sad(reference: Trace, *traces: Trace, + reference_offset: int, reference_length: int, max_offset: int) -> List[Trace]: + """ + Align `traces` to the reference `trace` so that the Sum Of Absolute Differences between the + reference trace window from `reference_offset` of `reference_length` and the trace being aligned + within `max_offset` of the reference window is maximized. + + :param reference: + :param traces: + :param reference_offset: + :param reference_length: + :param max_offset: + :return: + """ + def sad(reference_part, trace_part): + return float(np.sum(np.abs(reference_part - trace_part))) + + return align_offset(reference, *traces, + reference_offset=reference_offset, reference_length=reference_length, + max_offset=max_offset, dist_func=sad) + + +@public def align_dtw_scale(reference: Trace, *traces: Trace, radius: int = 1, fast: bool = True) -> List[Trace]: """ |