[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-09-04 (世界標準時間)。"],[],[],null,["# Downloading, preprocessing, and uploading the COCO dataset\n==========================================================\n\nCOCO is a large-scale object detection, segmentation, and captioning dataset.\nMachine learning models that use the COCO dataset include:\n\n- Mask-RCNN\n- Retinanet\n- ShapeMask\n\nBefore you can train a model on a Cloud TPU, you must prepare the training\ndata.\n\nThis document describes how to prepare the [COCO](http://cocodataset.org) dataset for\nmodels that run on Cloud TPU. The COCO dataset can only be prepared after you\nhave created a Compute Engine VM. The script used to prepare the data,\n`download_and_preprocess_coco.sh`,\nis installed on the VM and must be run on the VM.\n\nAfter preparing the data by running the `download_and_preprocess_coco.sh`\nscript, you can bring up the Cloud TPU and run the training.\n\nTo fully download and preprocess and upload the COCO dataset to a\nCloud Storage bucket takes approximately 2 hours.\n\n1. In your [Cloud Shell](https://console.cloud.google.com/), configure `gcloud` with your project\n ID.\n\n ```bash\n export PROJECT_ID=project-id\n gcloud config set project ${PROJECT_ID}\n ```\n2. In your [Cloud Shell](https://console.cloud.google.com/),\n create a Cloud Storage bucket using the following command:\n\n **Note:** In the following command, replace \u003cvar translate=\"no\"\u003ebucket-name\u003c/var\u003e with the name you want to assign to your bucket. \n\n ```bash\n gcloud storage buckets create gs://bucket-name --project=${PROJECT_ID} --location=us-central2\n ```\n3. Create a Compute Engine VM to download and preprocess the dataset. For more\n information, see\n [Create and start a Compute Engine instance](/compute/docs/instances/create-start-instance).\n\n ```bash\n $ gcloud compute instances create vm-name \\\n --zone=us-central2-b \\\n --image-family=ubuntu-2204-lts \\\n --image-project=ubuntu-os-cloud \\\n --machine-type=n1-standard-16 \\\n --boot-disk-size=300GB \\\n --scopes=https://www.googleapis.com/auth/cloud-platform\n ```\n4. Connect to the Compute Engine VM using SSH:\n\n ```bash\n $ gcloud compute ssh vm-name --zone=us-central2-b\n ```\n\n When you connect to the VM, your shell prompt changes from\n `username@projectname` to `username@vm-name`.\n5. Set up two variables, one for the storage bucket you\n created earlier and one for the directory that holds\n the training data (`DATA_DIR`) on the storage bucket.\n\n ```bash\n (vm)$ export STORAGE_BUCKET=gs://bucket-name\n ``` \n\n ```bash\n (vm)$ export DATA_DIR=${STORAGE_BUCKET}/coco\n ```\n6. Install the packages needed to pre-process the data.\n\n ```bash\n (vm)$ sudo apt-get update && \\\n sudo apt-get install python3-pip && \\\n sudo apt-get install -y python3-tk && \\\n pip3 install --user Cython matplotlib opencv-python-headless pyyaml Pillow numpy absl-py tensorflow && \\\n pip3 install --user \"git+https://github.com/cocodataset/cocoapi#egg=pycocotools&subdirectory=PythonAPI\" && \\\n pip3 install protobuf==3.19.0 tensorflow==2.11.0 numpy==1.26.4\n ```\n7. Run the `download_and_preprocess_coco.sh` script to convert\n the COCO dataset into a set of TFRecord files (`*.tfrecord`) that the training\n application expects.\n\n ```bash\n (vm)$ git clone https://github.com/tensorflow/tpu.git\n (vm)$ sudo -E bash tpu/tools/datasets/download_and_preprocess_coco.sh ./data/dir/coco\n ```\n\n This installs the required libraries and then runs the preprocessing\n script. It outputs `*.tfrecord` files in your local data directory.\n The COCO download and conversion script takes approximately one hour to complete.\n8. Copy the data to your Cloud Storage bucket.\n\n After you convert the data into the TFRecord format, copy the data from local storage\n to your Cloud Storage bucket using the gcloud CLI. You must\n also copy the annotation files. These files help validate the model's\n performance.\n\n\n ```bash\n (vm)$ gcloud storage cp ./data/dir/coco/*.tfrecord ${DATA_DIR}\n (vm)$ gcloud storage cp ./data/dir/coco/raw-data/annotations/*.json ${DATA_DIR}\n ```\n\n \u003cbr /\u003e\n\nClean up\n--------\n\nFollow these steps to clean up your Compute Engine and Cloud Storage resources.\n\n1. Disconnect from the Compute Engine VM:\n\n ```bash\n (vm)$ exit\n ```\n2. Delete your Compute Engine VM:\n\n ```bash\n $ gcloud compute instances delete vm-name \\\n --zone=us-central2-b\n ```\n3. Delete your Cloud Storage bucket and its contents:\n\n ```bash\n $ gcloud storage rm -r gs://bucket-name\n $ gcloud storage buckets delete gs://bucket-name\n ```"]]
