Brute-force (Bf) Feature Matcher - 2023.2 English

Vitis Libraries

Release Date
2023-12-20
Version
2023.2 English

Bf matcher takes the descriptor of one feature in first set and is matched with all other features in second set and the closest one is returned.

API Syntax

template <int PU = 1, int MAX_KEYPOINTS = 10000>
void bfMatcher(ap_uint<256> desc_list_q[MAX_KEYPOINTS],
               ap_uint<256> desc_list_t[MAX_KEYPOINTS],
               ap_int<16> match_list[MAX_KEYPOINTS],
               ap_uint<32> num_keypoints_q,
               ap_uint<32> num_keypoints_t,
               float ratio_thresh)

Parameter Descriptions

The following table describes template paramters and arguments of the function.

Table 297 Table brute-force matcher Parameter Description
Parameter Description
PU Parallel units / compute units. Number of parallel matches computed. Default is ‘1’. Increasing this parameter results in lesser compute time, but also consumes more hardware resources.
MAX_KEYPOINTS Maximum keypoints in the query and training feature sets.
desc_list_q Feature descriptor query list of 256-bit type.
desc_list_t Feature descriptor training list of 256-bit type.
match_list Index of corresponding matches for query list in training set.
num_keypoints_q Total number keypoints in the query set. This must not exceed MAX_KEYPOINTS.
num_keypoints_t Total number keypoints in the training set. This must not exceed MAX_KEYPOINTS.
ratio_thresh Ratio threshold for lowe’s test, for strong matches.

Resource Utilization

The following table summarizes the resource utilization of the kernel in different configurations, generated using Vitis 2020.2 tool, for MAX_KEYPOINTS of 10000.

Table 298 Table brute-force matcher Resource Utilization Summary
Operating Mode Operating Frequency (MHz) Utilization Estimate
BRAM_18K DSP_48Es FF LUT
PU = 1 300 162 0 5152 8453
PU = 2 300 176 0 9471 16320
PU = 10 300 176 0 17708 48839

Performance Estimate

The following table summarizes a performance estimate of the kernel in different configurations, as generated using Vitis 2020.2 tool, for MAX_KEYPOINTS of 10000.

Table 299 Table brute-force matcher Function Performance Estimate Summary
Operating Mode Operating Frequency (MHz) Latency Estimate Max (ms)
PU = 1 300 333.4
PU = 2 300 168.6
PU = 10 300 34.285