the C++ implemententation of LFFD with MNN

I have implemented the LFFD referring to the official python implementation

paper:LFFD: A Light and Fast Face Detector for Edge Devices

official github: LFFD

Also,my ncnn implementation is here

some tips

• You can set the input tensor shape smaller ,since you need to reduce the memory and accelerate the inference.
• You can set the scale_num=8 to use another larger model.
• I just test it on vs2019 PC and the result is correct compared to original implementation,you can use the code to another device such as android、RK3399、and so on.

result show

TODO(you can refer this implementation to do more)

• TensorRT demo: mmxnet model --> onnx-->trt engine
• openvino demo: mxnet model-->onnx-->openvino