example_processing_peak_interpolation.c
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1 // Copyright (c) Acconeer AB, 2022-2023
2 // All rights reserved
3 // This file is subject to the terms and conditions defined in the file
4 // 'LICENSES/license_acconeer.txt', (BSD 3-Clause License) which is part
5 // of this source code package.
6
7 #include <assert.h>
8 #include <stdbool.h>
9 #include <stdint.h>
10 #include <stdio.h>
11
12 #include "acc_config.h"
13 #include "acc_definitions_a121.h"
14 #include "acc_hal_definitions_a121.h"
15 #include "acc_hal_integration_a121.h"
16 #include "acc_integration_log.h"
17 #include "acc_rss_a121.h"
18 #include "acc_version.h"
19
20 #include "acc_control_helper.h"
21 #include "acc_processing_helpers.h"
22
23
24 #define SENSOR_ID (1U)
25
26 static void update_configuration(acc_config_t *config);
27
28
29 /** \example example_processing_peak_interpolation.c
30 * @brief example_processing_peak_interpolation.c
31 * This program shows how to apply a distance filter and how to interpolate the
32 * position of the peak to improve distance accuracy.
33 *
34 * The distance filter is applied to the IQ data and will reduce noise and smooth out
35 * the the amplitude of the radar eacho peaks. The smoothing is important for the
36 * next step where we estimate the acctual position of the peak, i.e the position
37 * of the peak that we would have gotten if we had used an shorter distance between
38 * the measurement steps.
39 */
40
41 int acconeer_main(int argc, char *argv[]);
42
43
44 int acconeer_main(int argc, char *argv[])
45 {
46 (void)argc;
47 (void)argv;
48
49 acc_control_helper_t control_helper_state = {0};
50
51 const uint32_t peak_width_points = 104; // Approximate peak width for profile 3
52
53 printf("Acconeer software version %s \n", acc_version_get());
54
55 const acc_hal_a121_t *hal = acc_hal_rss_integration_get_implementation();
56
57 if (!acc_rss_hal_register(hal))
58 {
59 return EXIT_FAILURE;
60 }
61
62 bool status_ok = acc_control_helper_create(&control_helper_state, SENSOR_ID);
63
64 if (!status_ok)
65 {
66 printf("acc_control_helper_create ()failed \n");
67 return EXIT_FAILURE;
68 }
69
70 update_configuration(control_helper_state.config);
71
72 status_ok = acc_control_helper_activate(&control_helper_state);
73
74 if (!status_ok)
75 {
76 printf("acc_control_helper_activate ()failed\n");
77 acc_control_helper_destroy(&control_helper_state);
78 return EXIT_FAILURE;
79 }
80
81 uint32_t sweep_data_length = control_helper_state.proc_meta.sweep_data_length;
82 uint32_t filter_length = acc_processing_helper_get_filter_length(peak_width_points,
83 acc_config_step_length_get(control_helper_state.config));
84
85 acc_vector_iq_t *current_sweep_iq = acc_vector_iq_alloc(sweep_data_length);
86 acc_vector_iq_t *filtered_sweep_iq = acc_vector_iq_alloc(sweep_data_length);
87
88 acc_vector_float_t *filter_vector = acc_vector_float_alloc(filter_length);
89 acc_vector_float_t *filtered_sweep_amplitude = acc_vector_float_alloc(sweep_data_length);
90
91 bool mem_ok = (current_sweep_iq != NULL) && (filtered_sweep_iq != NULL) &&
92 (filter_vector != NULL) && (filtered_sweep_amplitude != NULL);
93 if (!mem_ok)
94 {
95 printf("Memory allocation for vectors failed\n");
96 goto clean_up;
97 }
98
99 acc_vector_float_create_depth_filter_vector(filter_vector);
100
101 uint32_t iterations = 50U;
102 for (uint32_t i = 0U; i < iterations; i++)
103 {
104 if (!acc_control_helper_get_next(&control_helper_state))
105 {
106 printf("acc_control_helper_get_next() failed\n");
107 break;
108 }
109
110 acc_get_iq_sweep_vector(&control_helper_state, current_sweep_iq);
111
112 // Apply distance filter to smooth out the amplitude of the radar signal and
113 // reduce noise. Note that phase enhancement should be enabled when applying
114 // the distance filter on an IQ data vector.
115 acc_vector_iq_apply_filter(current_sweep_iq, filter_vector, filtered_sweep_iq);
116
117 // Find the index of the element with the highest amplitude. We skip the first and last
118 // element of the vector in the search as we would make an of bounds read in the next step
119 // if the max value was found in the first or last element.
120 acc_vector_iq_amplitude(filtered_sweep_iq, filtered_sweep_amplitude);
121
122 uint32_t max_peak_index = acc_vector_float_argmax_skip_edges(filtered_sweep_amplitude, 1);
123
124 // We know that the distance between steps is constant, so it is enough to
125 // use only the peak amplitude and the amplitudes before and after the peak to
126 // estimate the location of the peak relative to the location of the max value.
127 float peak_offset = acc_processing_helper_interpolate_peak_position(filtered_sweep_amplitude->data[max_peak_index - 1],
128 filtered_sweep_amplitude->data[max_peak_index],
129 filtered_sweep_amplitude->data[max_peak_index + 1]);
130
131 // Calculate the distance to the start of the measuring range and the distance between
132 // measurement steps.
133 float start = acc_processing_points_to_meter(acc_config_start_point_get(control_helper_state.config));
134 float step_length = acc_processing_points_to_meter(acc_config_step_length_get(control_helper_state.config));
135
136 // Make the final calculation of the distance to the reflecting object using the index of the
137 // value with the higest amplitude and the interpolated peak offset.
138 float distance = start + (max_peak_index + peak_offset) * step_length;
139
140 printf("Interpolated distance: %d mm\n", (int)(distance * 1000 + .5f));
141 }
142
143 clean_up:
144 acc_control_helper_destroy(&control_helper_state);
145
146 acc_vector_iq_free(current_sweep_iq);
147 acc_vector_iq_free(filtered_sweep_iq);
148 acc_vector_float_free(filter_vector);
149 acc_vector_float_free(filtered_sweep_amplitude);
150
151 printf("Application finished OK\n");
152
153 return EXIT_SUCCESS;
154 }
155
156
157 static void update_configuration(acc_config_t *config)
158 {
159 int32_t start_point = 100; // start at approx 100*2.5 mm ~= 250 mm
160 uint16_t step_length = 8; // 8 * 2.5 mm ~= 20 mm between each step
161 uint16_t num_points = 50; // range length ~= 250 mm + 50*20 mm ~= 1250 mm
162
163 acc_config_start_point_set(config, start_point);
164 acc_config_num_points_set(config, num_points);
165 acc_config_step_length_set(config, step_length);
166 acc_config_profile_set(config, ACC_CONFIG_PROFILE_3);
167 acc_config_hwaas_set(config, 200);
168 // The processing in this example assumes that sweeps_per_frame = 1
169 acc_config_sweeps_per_frame_set(config, 1);
170 acc_config_frame_rate_set(config, 5.0f);
171 acc_config_phase_enhancement_set(config, true);
172 acc_config_prf_set(config, ACC_CONFIG_PRF_13_0_MHZ);
173 }
acc_config_start_point_set
void acc_config_start_point_set(acc_config_t *config, int32_t start_point)
Set the starting point of the sweep.
acc_control_helper_create
bool acc_control_helper_create(acc_control_helper_t *radar, acc_sensor_id_t sensor_id)
Create a helper instance.
Definition: acc_control_helper.c:41
acc_rss_a121.h
acc_vector_float_free
void acc_vector_float_free(acc_vector_float_t *vector)
Free storage of data elements in a float vector.
Definition: acc_processing_helpers.c:85
acc_vector_iq_free
void acc_vector_iq_free(acc_vector_iq_t *vector)
Free storage of data elements in an IQ vector.
Definition: acc_processing_helpers.c:73
acc_control_helper_t::config
acc_config_t * config
Definition: acc_control_helper.h:25
acc_version.h
acc_config_profile_set
void acc_config_profile_set(acc_config_t *config, acc_config_profile_t profile)
Set a profile.
acc_config_sweeps_per_frame_set
void acc_config_sweeps_per_frame_set(acc_config_t *config, uint16_t sweeps)
Set sweeps per frame.
acc_vector_float_argmax_skip_edges
uint32_t acc_vector_float_argmax_skip_edges(acc_vector_float_t *vector_a, uint32_t elements_to_skip)
Index of element with maximum value in a float vector disregarding edge elements.
Definition: acc_processing_helpers.c:375
acc_vector_float_t::data
float * data
Definition: acc_processing_helpers.h:36
acc_processing_helper_get_filter_length
uint32_t acc_processing_helper_get_filter_length(uint32_t peak_width_points, uint32_t step_length)
Calculate filter vector length.
Definition: acc_processing_helpers.c:166
acc_control_helper_destroy
void acc_control_helper_destroy(acc_control_helper_t *radar)
Destroy a helper instance.
Definition: acc_control_helper.c:50
acc_hal_rss_integration_get_implementation
const acc_hal_a121_t * acc_hal_rss_integration_get_implementation(void)
Get hal implementation reference.
Definition: acc_hal_integration_stm32cube_xm.c:166
acc_vector_iq_t
Definition: acc_processing_helpers.h:27
acc_config_frame_rate_set
void acc_config_frame_rate_set(acc_config_t *config, float frame_rate)
Set the frame rate.
acc_config_start_point_get
int32_t acc_config_start_point_get(const acc_config_t *config)
Get the starting point of the sweep.
acc_hal_a121_t
Definition: acc_hal_definitions_a121.h:82
acc_control_helper_t::proc_meta
acc_processing_metadata_t proc_meta
Definition: acc_control_helper.h:32
acc_rss_hal_register
bool acc_rss_hal_register(const acc_hal_a121_t *hal)
Register an integration.
acc_vector_iq_apply_filter
void acc_vector_iq_apply_filter(const acc_vector_iq_t *vector_a, acc_vector_float_t *filter_vector, acc_vector_iq_t *vector_out)
Apply a FIR filter to an IQ vector.
Definition: acc_processing_helpers.c:203
acc_vector_iq_amplitude
void acc_vector_iq_amplitude(const acc_vector_iq_t *vector_a, acc_vector_float_t *vector_out)
Amplitude of an IQ vector.
Definition: acc_processing_helpers.c:305
ACC_CONFIG_PRF_13_0_MHZ
@ ACC_CONFIG_PRF_13_0_MHZ
Definition: acc_definitions_a121.h:110
acc_config_hwaas_set
void acc_config_hwaas_set(acc_config_t *config, uint16_t hwaas)
Set the hardware accelerated average samples (HWAAS)
acc_processing_metadata_t::sweep_data_length
uint16_t sweep_data_length
Definition: acc_processing.h:41
acc_control_helper.h
acc_hal_integration_a121.h
acc_version_get
const char * acc_version_get(void)
Get the version of the Acconeer software.
acc_config_t
struct acc_config acc_config_t
Definition: acc_config.h:26
printf
#define printf
Definition: printf.h:60
acc_config_step_length_get
uint16_t acc_config_step_length_get(const acc_config_t *config)
Get the step length in a sweep.
acc_processing_points_to_meter
float acc_processing_points_to_meter(int32_t points)
Convert a distance or step length in points to meter.
acc_config_step_length_set
void acc_config_step_length_set(acc_config_t *config, uint16_t step_length)
Set the step length in a sweep.
acc_config_num_points_set
void acc_config_num_points_set(acc_config_t *config, uint16_t num_points)
Set the number of data points to measure.
acc_hal_definitions_a121.h
acconeer_main
int acconeer_main(int argc, char *argv[])
Assembly test example.
Definition: example_processing_peak_interpolation.c:44
SENSOR_ID
#define SENSOR_ID
Definition: example_processing_peak_interpolation.c:24
acc_vector_float_create_depth_filter_vector
void acc_vector_float_create_depth_filter_vector(acc_vector_float_t *vector_out)
Create a distance filter vector.
Definition: acc_processing_helpers.c:172
acc_processing_helpers.h
acc_config_phase_enhancement_set
void acc_config_phase_enhancement_set(acc_config_t *config, bool enable)
Enable or disable phase enhancement.
update_configuration
static void update_configuration(acc_config_t *config)
Definition: example_processing_peak_interpolation.c:157
acc_vector_float_t
Definition: acc_processing_helpers.h:33
acc_integration_log.h
acc_vector_iq_alloc
acc_vector_iq_t * acc_vector_iq_alloc(uint32_t data_length)
Allocate storage for an IQ vector.
Definition: acc_processing_helpers.c:27
acc_vector_float_alloc
acc_vector_float_t * acc_vector_float_alloc(uint32_t data_length)
Allocate storage for a float vector.
Definition: acc_processing_helpers.c:50
acc_control_helper_t
Definition: acc_control_helper.h:23
acc_control_helper_activate
bool acc_control_helper_activate(acc_control_helper_t *radar)
Activate the sensor.
Definition: acc_control_helper.c:81
acc_config_prf_set
void acc_config_prf_set(acc_config_t *config, acc_config_prf_t prf)
Set Pulse Repetition Frequency.
acc_config.h
ACC_CONFIG_PROFILE_3
@ ACC_CONFIG_PROFILE_3
Definition: acc_definitions_a121.h:44
acc_control_helper_get_next
bool acc_control_helper_get_next(acc_control_helper_t *radar)
Perform a radar measurement and wait for the result.
Definition: acc_control_helper.c:157
acc_get_iq_sweep_vector
void acc_get_iq_sweep_vector(const acc_control_helper_t *control_helper_state, acc_vector_iq_t *vector_out)
Converts a newly captured IQ frame with one sweep to an IQ vector.
Definition: acc_processing_helpers.c:138
acc_processing_helper_interpolate_peak_position
float acc_processing_helper_interpolate_peak_position(float y1, float y2, float y3)
Interpolate peak position.
Definition: acc_processing_helpers.c:395
acc_definitions_a121.h