Analysis and Comparison of FPGA-Based Histogram of Oriented Gradients Implementations
Bibliographic record
Abstract
One of the commonly-used feature extraction algorithms in computer vision is the histogram of oriented gradients. Extracting the features from an image using this algorithm requires a large amount of computations. One way to boost the speed is to implement this algorithm on field programmable gate arrays, to benefit from flexible designs such as parallel computing. In this paper, we first, provide a summary of the steps of the histogram of oriented gradients algorithm. We then survey the implementation techniques of the histogram of oriented gradients on field-programmable gate arrays in the past decade. We group the different techniques into four main categories and analyze various enhancement methods in each category. The first group is the optimization of the algorithm computation which involves the steps of input selection, magnitude calculation, orientation and bin assignment, and normalization. The second category is data manipulation techniques which include numerical representation, data flow modification, and memory optimization. The third group contains modified features based on the histogram of oriented gradients and their hardware implementation, and the fourth one is the implementations in hardware-software co-design of the algorithm. We compare the different implementations using a speed metric called pixels per clock cycle, and resource utilization. Finally, we provide design summary tables for efficient implementation with respect to the speed metric, accuracy, and resource utilization.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".