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YOLOv4 on Edge TPU


Prepare int8 tflite​

Supported Operation: https://coral.ai/docs/edgetpu/models-intro/#supported-operations

  • Use YOLOv4-Tiny because YOLOv4 model size is too large.
  • Use relu for activation. YOLOv4-Tiny uses leaky-relu, but this is an unsupported operation on the Edge TPU.
  • Set the desired input_size before converting the model to tflite.

Training​

Ref: https://wiki.loliot.net/docs/lang/python/libraries/yolov4/python-yolov4-training#full-script

Use yolov4-tiny-relu.cfg

Convert to tflite​

  • 2021-02-21
  • OS: Ubuntu 20.04
  • TF: v2.4.1
  • yolov4: v3.1.0

Use yolov4-tiny-relu-tpu.cfg

caution

Don't confuse yolov4-iny-relu.cfg and yolov4-tiny-relu-tpu.cfg

from yolov4.tf import YOLOv4, YOLODataset, save_as_tflite

yolo = YOLOv4()

yolo.config.parse_names("test/coco.names")
yolo.config.parse_cfg("config/yolov4-tiny-relu-tpu.cfg")

yolo.make_model()
yolo.load_weights(
    "/home/hhk7734/NN/yolov4-tiny-relu.weights", weights_type="yolo"
)

dataset = YOLODataset(
    config=yolo.config,
    dataset_list="/home/hhk7734/NN/val2017.txt",
    image_path_prefix="/home/hhk7734/NN/val2017",
    training=False,
)

save_as_tflite(
    model=yolo.model,
    tflite_path="yolov4-tiny-relu-int8.tflite",
    quantization="full_int8",
    dataset=dataset,
)
$ edgetpu_compiler -sa yolov4-tiny-relu-int8.tflite
Edge TPU Compiler version 15.0.340273435

Model compiled successfully in 758 ms.

Input model: yolov4-tiny-relu-int8.tflite
Input size: 5.91MiB
Output model: yolov4-tiny-relu-int8_edgetpu.tflite
Output size: 5.98MiB
On-chip memory used for caching model parameters: 5.83MiB
On-chip memory remaining for caching model parameters: 1.78MiB
Off-chip memory used for streaming uncached model parameters: 0.00B
Number of Edge TPU subgraphs: 2
Total number of operations: 51
Operation log: yolov4-tiny-relu-int8_edgetpu.log

Model successfully compiled but not all operations are supported by the Edge TPU. A percentage of the model will instead run on the CPU, which is slower. If possible, consider updating your model to use only operations supported by the Edge TPU. For details, visit g.co/coral/model-reqs.
Number of operations that will run on Edge TPU: 46
Number of operations that will run on CPU: 5

Operator                       Count      Status

RESIZE_BILINEAR                1          Operation version not supported
DEQUANTIZE                     4          Operation is working on an unsupported data type
CONV_2D                        21         Mapped to Edge TPU
QUANTIZE                       8          Mapped to Edge TPU
PAD                            2          Mapped to Edge TPU
CONCATENATION                  7          Mapped to Edge TPU
LOGISTIC                       2          Mapped to Edge TPU
SPLIT                          3          Mapped to Edge TPU
MAX_POOL_2D                    3          Mapped to Edge TPU
rsync yolov4-tiny-relu-int8_edgetpu.tflite coco.names yolov4-tiny-relu-tpu.cfg \
    mendel@<tpu ip>:~

Run on Edge TPU​

Install the Edge TPU runtime​

Ref: https://coral.ai/docs/accelerator/get-started/#1-install-the-edge-tpu-runtime

Install just the TensorFlow Lite interpreter​

Ref: https://www.tensorflow.org/lite/guide/python#install_just_the_tensorflow_lite_interpreter

Run example script​

edge_yolov4_tiny_video_test.py
import cv2

from yolov4.tflite import YOLOv4

yolo = YOLOv4()

yolo.config.parse_names("coco.names")
yolo.config.parse_cfg("yolov4-tiny-relu-tpu.cfg")

yolo.summary()

yolo.load_tflite("yolov4-tiny-relu-int8_edgetpu.tflite")

yolo.inference(
    "/dev/video1",
    is_image=False,
    cv_apiPreference=cv2.CAP_V4L2,
    cv_frame_size=(640, 480),
    cv_fourcc="YUYV",
)
python3 edge_yolov4_tiny_video_test.py

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