NCC Layer Filter Design for Infrared Small Target Detection

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Solution Overview

Problem

Current methods for small target detection on infrared imagery are inefficient in distinguishing targets from clutter and false targets, and existing solutions lack a widely-accepted, off-the-shelf approach for real-time computation, especially in systems with limited data and computational constraints.

Innovation Solution

A machine learning approach using a normalized-cross-correlational (NCC) layer in neural networks for designing a filter bank, which is optimized for FPGA systems through the MAD-NCC layer, avoiding square root operations for real-time computation and minimizing resource use, to enhance target detection and reduce false alarms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional filters (mean, median, top-hat, Gaussian) are used to reduce background clutter, then clutter reduction is achieved, but the ability to differentiate targets from false targets is insufficient

Engineering Contradiction:
Improvebackground clutterVSAvoidtarget differentiation accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent transforms the filter design from fixed heuristic parameters to learned parameters through supervised training. The NCC layer learns optimal filter shapes and characteristics from training data, adapting parameters dynamically to distinguish targets from false targets while reducing clutter.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements supervised training with feedback loops where the neural network learns from labeled training data containing both targets and false targets. The training process provides feedback to adjust filter parameters, enabling the system to differentiate targets from false targets effectively.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If deep CNNs are used for target detection, then detection performance is improved, but the risk of overfitting increases when training data is limited

Engineering Contradiction:
Improvedetection performanceVSAvoidoverfitting risk
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses a normalized cross-correlation layer instead of full deep CNNs, applying partial action by implementing only the essential correlation operation with normalization. This reduced architecture achieves effective detection while requiring fewer training parameters, thereby reducing overfitting risk when training data is limited.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The normalization operation changes the parameter space by standardizing inputs, which regularizes the learning process. This parameter transformation helps prevent overfitting by constraining the effective capacity of the model while maintaining detection performance.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If NCC-based matching is used for target detection, then template matching effectiveness is improved, but filter selection and design become ambiguous

Engineering Contradiction:
Improvetemplate matching effectivenessVSAvoidfilter selection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements self-service by using supervised training to automatically learn optimal filters from data. The system serves itself by generating appropriate filter selections through training, eliminating the need for manual filter design or ambiguous filter selection processes.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If standard NCC layer is implemented for real-time computation, then detection accuracy is improved, but computational complexity increases due to square root operations

Engineering Contradiction:
Improvedetection accuracyVSAvoidreal-time computation speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the computationally expensive square root operation with simpler arithmetic operations (subtraction and division) in the MAD-NCC layer. This substitution uses cheaper computational operations that can be executed faster, enabling real-time processing while maintaining detection accuracy.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

5Measurement precision

If standard NCC layer is used, then normalization is achieved, but resource consumption increases for FPGA implementations

Engineering Contradiction:
Improvenormalization accuracyVSAvoidFPGA resource consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces resource-intensive square root operations with simpler arithmetic operations in the MAD-NCC layer. This substitution uses computationally cheaper operations that consume fewer FPGA resources (LUTs, DSP blocks, memory) while achieving the same normalization objective.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS11775837B2Filter design for small target detection on infrared imagery using normalized-cross-correlation layer in neural networks
Publication Date: 2023.10.03 ASELSAN ELEKTRONIK SANAYI & TICARET ANONIM SIRKETI
  • US11775837B2 patent drawing

AI summary

A filter design method for a small target detection on infrared imagery using a normalized-cross-correlation layer in neural networks, including the steps of: Normalizing inputs and filters of a convolutional neural network, wherein normalizing inputs and filters of the convolutional neural network provides faster convergence in a limited database. Defining a forward function of a normalization layer in the convolutional neural network, wherein the forward function of the normalization layer in the convolutional neural network is used for training a neural network. Defining a derivative function of the normalization layer for a back propagation in a neural network training phase. Training created neural networks with datasets, wherein the datasets consist of target and background views and using trained neural networks in the small target detection.