Interpret prediction results from image object detection models

After requesting a prediction, Vertex AI returns results based on yourmodel's objective. AutoML image object detection prediction responsesreturn all objects found in an image. Each found object has an annotation (labeland normalized bounding box) with a corresponding confidence score. The boundingbox is written as:

"bboxes": [ [xMin, xMax, yMin, yMax], ...]

WherexMin, xMax are the minimum and maximum x values and yMin, yMax are the minimum and maximum y values respectively.

Example batch prediction output

Batch AutoML image object detection prediction responses are stored as JSON Lines files in Cloud Storage buckets. Each line of the JSON Lines file contains all objects found in a single image file. Each found object has an annotation (label and normalized bounding box) with a corresponding confidence score.

Note: Zero coordinate values omitted. When the API detects a coordinate ("x" or "y") value of 0,that coordinate is omitted in the JSON response. Thus, a response with a bounding poly around the entire image would be
[{},{"x": 1,"y": 1}]. For more information, see
Method: projects.locations.models.predict.

Note: The following JSON Lines example includes line breaks for readability. In your JSON Lines files, line breaks are included only after each each JSON object.

Important: Bounding boxes are specified as:

"bboxes": [ [xMin, xMax, yMin, yMax], ...]

WherexMin andxMax are the minimum and maximum x values and yMin andyMax are the minimum and maximum y values respectively.

{  "instance": {"content": "gs://bucket/image.jpg", "mimeType": "image/jpeg"},  "prediction": {    "ids": [1, 2],    "displayNames": ["cat", "dog"],    "bboxes":  [      [0.1, 0.2, 0.3, 0.4],      [0.2, 0.3, 0.4, 0.5]    ],    "confidences": [0.7, 0.5]  }}

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Last updated 2025-11-24 UTC.