Detector - Mosaic data augmentation

[AlexeyAB]

Mosaic-data augmentation (like CutMix augmentation): #3114 (comment)

• Mosaic-data mAP increasing: Implement Yolo-LSTM (~+4-9 AP) for detection on Video with high mAP and without blinking issues #3114 (comment)

• comparison MixUp and CutMix: BoF (Bag of Freebies) - Visually Coherent Image Mixup ~+4 AP@[.5, .95] #3272 (comment)

Use:

[net]
mosaic=1

Currently works only if Darknet is compiled with OpenCV.

---

New mosaic:

---

Old mosaic=1 - CLICK ME to view

---

[AlexeyAB]

Implemented.

[Kyuuki93]

Something goes wrong with

[net]
mosaic=1

chart:

cfg file:
yolov3-spp-giou-gs-mos.cfg.txt

without mosaic chart:

[LukeAI]

For me, mosaic gave me -0.4% mAP - don't really know if that's just random fluctuation or it did actually hurt performance a little.

[AlexeyAB]

@LukeAI @Kyuuki93

I improved mosaic=1 for Detector. Try new mosaic.
Two commits: 87f36b7 and 13f064f