  Streaming keyword spotting is a widely used solution for activating voice
assistants. Deep Neural Networks with Hidden Markov Model (DNN-HMM) based
methods have proven to be efficient and widely adopted in this space, primarily
because of the ability to detect and identify the start and end of the wake-up
word at low compute cost. However, such hybrid systems suffer from loss metric
mismatch when the DNN and HMM are trained independently. Sequence
discriminative training cannot fully mitigate the loss-metric mismatch due to
the inherent Markovian style of the operation. We propose an low footprint CNN
model, called HEiMDaL, to detect and localize keywords in streaming conditions.
We introduce an alignment-based classification loss to detect the occurrence of
the keyword along with an offset loss to predict the start of the keyword.
HEiMDaL shows 73% reduction in detection metrics along with equivalent
localization accuracy and with the same memory footprint as existing DNN-HMM
style models for a given wake-word.
