在对象检测算法中,非最大抑制(NMS)用于丢弃对象(例如车辆)的额外检测结果。
通常,水平边界框用于对象检测算法,水平 NMS 的 GPU 实现已经存在,但我希望 GPU 实现旋转边界框。
CPU 实现已经完成,但我正在努力使用 CuPy 包将 CPU 版本转换为 GPU 版本。这是我写的代码。在代码部分之后,您可以看到错误。
我的问题是 TypeError 的原因是什么:列表索引必须是整数或切片,而不是 cupy.core.core.ndarray?
from shapely.geometry import Polygon as shpoly
import time
#### CPU implementation
import numpy as np
def polygon_iou(poly1, poly2):
"""
Intersection over union between two shapely polygons.
"""
if not poly1.intersects(poly2): # this test is fast and can accelerate calculation
iou = 0
else:
try:
inter_area = poly1.intersection(poly2).area
union_area = poly1.area + poly2.area - inter_area
iou = float(inter_area) / float(union_area)
except shapely.geos.TopologicalError:
warnings.warn("'shapely.geos.TopologicalError occured, iou set to 0'", UserWarning)
iou = 0
except ZeroDivisionError:
iou = 0
return iou
def polygon_from_array(poly_):
"""
Create a shapely polygon object from gt or dt line.
"""
polygon_points = np.array(poly_).reshape(4, 2)
polygon = shpoly(polygon_points).convex_hull
return polygon
def nms(dets, thresh):
scores = dets[:, 8]
order = scores.argsort()[::-1]
polys = []
areas = []
for i in range(len(dets)):
tm_polygon = polygon_from_array(dets[i,:8])
polys.append(tm_polygon)
keep = []
while order.size > 0:
ovr = []
i = order[0]
keep.append(i)
for j in range(order.size - 1):
iou = polygon_iou(polys[i], polys[order[j + 1]])
ovr.append(iou)
ovr = np.array(ovr)
inds = np.where(ovr <= thresh)[0]
order = order[inds + 1]
return keep
#### GPU implementation
import cupy as cp
def polygon_iou_gpu(poly1, poly2):
"""
Intersection over union between two shapely polygons.
"""
if not poly1.intersects(poly2): # this test is fast and can accelerate calculation
iou = 0
else:
try:
inter_area = poly1.intersection(poly2).area
union_area = poly1.area + poly2.area - inter_area
iou = float(inter_area) / float(union_area)
except shapely.geos.TopologicalError:
warnings.warn("'shapely.geos.TopologicalError occured, iou set to 0'", UserWarning)
iou = 0
except ZeroDivisionError:
iou = 0
return iou
def polygon_from_array_gpu(poly_):
"""
Create a shapely polygon object from gt or dt line.
"""
polygon_points = cp.array(poly_).reshape(4, 2)
polygon = shpoly(polygon_points).convex_hull
return polygon
def nms_gpu(dets, thresh):
scores = dets[:, 8]
order = scores.argsort()[::-1]
polys = []
areas = []
for i in range(len(dets)):
tm_polygon = polygon_from_array_gpu(dets[i,:8])
polys.append(tm_polygon)
keep = []
while order.size > 0:
ovr = []
i = order[0]
keep.append(i)
for j in range(order.size - 1):
iou = polygon_iou_gpu(polys[i], polys[order[j + 1]])
ovr.append(iou)
ovr = np.array(ovr)
inds = np.where(ovr <= thresh)[0]
order = order[inds + 1]
return keep
if __name__ == '__main__':
import random
boxes = np.random.randint(0,100,(1000,8))
scores = np.random.rand(1000, 1)
dets = np.hstack((boxes, scores[:])).astype(np.float32)
thresh = 0.1
start = time.time()
keep = nms(dets, thresh)
print("CPU implementation took: {}".format(time.time() - start))
cp.cuda.Device(1)
dets_gpu = cp.array(dets)
start = time.time()
keep = nms_gpu(dets_gpu, thresh)
print("GPU implementation took: {}".format(time.time() - start))
错误是
CPU 实现占用:0.3672311305999756
回溯(最近一次通话最后):
文件“nms_rotated.py”,第 117 行,在
keep = nms_gpu(dets_gpu, thresh)
文件“nms_rotated.py”,第 97 行,在 nms_gpu 中
iou = polygon_iou_gpu(polys[i], polys[order[j + 1]])
TypeError:列表索引必须是整数或切片,而不是 cupy.core.core.ndarray
更新:13.02.2019 我试过@Yuki Hashimoto 的回答
通过替换iou = polygon_iou_gpu(polys[i], polys[order[j + 1]])
为 iou = polygon_iou_gpu(polys[i.get()], polys[order[j + 1].get()])
. 它不会抛出任何错误,但 GPU 版本比 CPU 版本慢几倍。
通过使用 100000 次随机检测:
CPU implementation took: 47.125494956970215 GPU implementation took: 142.08464860916138