GAN Training Data Generation for Rare-Event Segmentation
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Solution Overview
Problem
Conventional generative adversarial networks (GANs) fail to generate images of rare or uncommon events, leading to mode drop and poor performance in safety-critical applications like autonomous vehicles, as they are trained with real-world data that underrepresents these events.
Innovation Solution
A method that trains a GAN using a loss function combining F1 loss and a conventional GAN loss to encourage the generation of rare classes, employing a StyleGAN architecture and global pooling to mitigate mode collapse, and generates diverse training datasets for semantic and instance segmentations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional GANs are trained with real-world data, then the training process is simple and follows standard procedures, but rare events and uncommon classes are underrepresented leading to mode drop
Solution Approach 1:
The method performs preliminary action by generating synthetic training data before the main training process. A first GAN is trained offline to generate diverse synthetic images including rare events, which are then used as training data for the second GAN. This preliminary data generation ensures rare modes are represented in the training set without complicating the main training procedure.
Solution Approach 2:
The first GAN acts as an intermediary that bridges the gap between limited real-world data and the need for diverse training samples. It generates synthetic data that mediates the training of the second GAN, allowing rare events to be represented without directly modifying the second GAN's training procedure.
2Reliability
If GANs are trained to generate diverse data, then rare events can be represented, but the training becomes computationally intensive and time-consuming
Solution Approach 1:
The training process is segmented into two distinct phases: first, training a GAN to generate diverse synthetic data, and second, training the target model on this synthetic data. This segmentation allows the computationally intensive diversity generation to be performed once offline, while the main training proceeds efficiently on the prepared dataset.
Solution Approach 2:
The diverse data generation is performed as a preliminary step before the main training. By pre-generating synthetic training samples with rare events, the method avoids the need for time-consuming adaptive training during the main learning process, reducing overall training time.
3Quantity of substance
If more real-world data of rare events is collected, then the training dataset becomes more comprehensive, but data collection becomes impossible for all relevant rare events
Solution Approach 1:
Instead of collecting more real-world data, the method creates copies of common events with modified characteristics to represent rare events. The GAN learns from abundant real-world data and generates synthetic copies that capture rare patterns, making comprehensive dataset creation feasible without physical data collection.
Solution Approach 2:
The method changes parameters of existing data through the GAN's generative process. By modifying latent space representations and conditioning vectors, the GAN transforms common event data into rare event representations, achieving dataset diversity without collecting new physical data.
Data Source
AI summary
A computer-implemented method for training a first machine learning system which is configured to generate an output characterizing a label map of an image. The method includes: providing first and second inputs, the first input characterizing a binary vector characterizing respective presences or absences of classes from a plurality of classes, and the second input characterizing a randomly drawn value; determining, by a first generator, an output based on the first and second inputs, the output characterizing a first label map, wherein the first label map characterizes probabilities for the classes from the plurality of classes; determining a representation of the first label map using a global pooling operation; training the first machine learning system based on a loss function, wherein the loss function characterizes an F1 loss, wherein the F1 loss characterizes a difference between the first input and the representation of the first label map.


