Compute Library
 21.02
CPPDetectionWindowNonMaximaSuppressionKernel.cpp
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2017-2020 Arm Limited.
3  *
4  * SPDX-License-Identifier: MIT
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in all
14  * copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  * SOFTWARE.
23  */
25 
27 
28 #include <algorithm>
29 #include <cmath>
30 
31 using namespace arm_compute;
32 
33 namespace
34 {
35 bool compare_detection_window(const DetectionWindow &lhs, const DetectionWindow &rhs)
36 {
37  if(lhs.idx_class < rhs.idx_class)
38  {
39  return true;
40  }
41  if(rhs.idx_class < lhs.idx_class)
42  {
43  return false;
44  }
45 
46  // idx_classes are equal so compare by score
47  if(lhs.score > rhs.score)
48  {
49  return true;
50  }
51  if(rhs.score > lhs.score)
52  {
53  return false;
54  }
55 
56  return false;
57 }
58 } // namespace
59 
61  : _input_output(nullptr), _min_distance(0.0f)
62 {
63 }
64 
66 {
67  return false;
68 }
69 
71 {
72  ARM_COMPUTE_ERROR_ON(nullptr == input_output);
73 
74  _input_output = input_output;
75  _min_distance = min_distance;
76 
77  IKernel::configure(Window()); // Default 1 iteration window
78 }
79 
81 {
82  ARM_COMPUTE_UNUSED(info);
83  ARM_COMPUTE_UNUSED(window);
86  ARM_COMPUTE_ERROR_ON(_input_output->buffer() == nullptr);
87 
88  const size_t num_candidates = _input_output->num_values();
89  size_t num_detections = 0;
90 
91  // Sort list of candidates by idx_class and then score
92  std::sort(_input_output->buffer(), _input_output->buffer() + num_candidates, compare_detection_window);
93 
94  const float min_distance_pow2 = _min_distance * _min_distance;
95 
96  // Euclidean distance
97  for(size_t i = 0; i < num_candidates; ++i)
98  {
99  if(0.0f != _input_output->at(i).score)
100  {
101  DetectionWindow cur;
102  cur.x = _input_output->at(i).x;
103  cur.y = _input_output->at(i).y;
104  cur.width = _input_output->at(i).width;
105  cur.height = _input_output->at(i).height;
106  cur.idx_class = _input_output->at(i).idx_class;
107  cur.score = _input_output->at(i).score;
108 
109  // Store window
110  _input_output->at(num_detections) = cur;
111 
112  ++num_detections;
113 
114  const float xc = cur.x + cur.width * 0.5f;
115  const float yc = cur.y + cur.height * 0.5f;
116 
117  for(size_t k = i + 1; k < (num_candidates) && (cur.idx_class == _input_output->at(k).idx_class); ++k)
118  {
119  const float xn = _input_output->at(k).x + _input_output->at(k).width * 0.5f;
120  const float yn = _input_output->at(k).y + _input_output->at(k).height * 0.5f;
121 
122  const float dx = std::fabs(xn - xc);
123  const float dy = std::fabs(yn - yc);
124 
125  if(dx < _min_distance && dy < _min_distance)
126  {
127  const float d = dx * dx + dy * dy;
128 
129  if(d < min_distance_pow2)
130  {
131  // Invalidate detection window
132  _input_output->at(k).score = 0.0f;
133  }
134  }
135  }
136  }
137  }
138 
139  _input_output->resize(num_detections);
140 }
const Window & window() const
The maximum window the kernel can be executed on.
Definition: IKernel.cpp:28
uint16_t x
Top-left x coordinate.
Definition: Types.h:592
float score
Confidence value for the detection window.
Definition: Types.h:597
Array of type T.
Definition: IArray.h:40
void resize(size_t num)
Resizes the array to contain "num" elements.
Definition: IArray.h:128
#define ARM_COMPUTE_ERROR_ON(cond)
If the condition is true then an error message is printed and an exception thrown.
Definition: Error.h:466
Copyright (c) 2017-2021 Arm Limited.
void run(const Window &window, const ThreadInfo &info) override
Execute the kernel on the passed window.
bool is_parallelisable() const override
Indicates whether or not the kernel is parallelisable.
#define ARM_COMPUTE_UNUSED(...)
To avoid unused variables warnings.
Definition: Error.h:152
virtual T * buffer() const =0
Pointer to the first element of the array.
size_t num_values() const
Number of values currently stored in the array.
Definition: IArray.h:68
#define ARM_COMPUTE_ERROR_ON_MISMATCHING_WINDOWS(f, w)
Definition: Validate.h:183
uint16_t width
Width of the detection window.
Definition: Types.h:594
void configure(IDetectionWindowArray *input_output, float min_distance)
Initialise the kernel&#39;s input, output and the euclidean minimum distance.
#define ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(k)
Definition: Validate.h:941
uint16_t idx_class
Index of the class.
Definition: Types.h:596
uint16_t height
Height of the detection window.
Definition: Types.h:595
ScaleKernelInfo info(interpolation_policy, default_border_mode, PixelValue(), sampling_policy, false)
Information about executing thread and CPU.
Definition: CPPTypes.h:235
Detection window used for the object detection.
Definition: Types.h:590
uint16_t y
Top-left y coordinate.
Definition: Types.h:593
Describe a multidimensional execution window.
Definition: Window.h:39
virtual T & at(size_t index) const
Reference to the element of the array located at the given index.
Definition: IArray.h:117