Classification and Regression Heads
Following the Section 6.2 of the MobileNetV2 paper, SSDlite replaces the regular convolutions used on the original Heads with separable convolutions. Consequently, our implementation introduces new heads that use 3x3 Depthwise convolutions and 1x1 projections. Since all other components of the SSD method remain the same, to create an SSDlite model our implementation initializes the SSDlite head and passes it directly to the SSD constructor.
Backbone Feature Extractor