103 lines
4.1 KiB
Go
103 lines
4.1 KiB
Go
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// Copyright 2016 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/*
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Package vision provides a client for the Google Cloud Vision API.
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Google Cloud Vision allows easy integration of vision detection features
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into developer applications, including image labeling, face and landmark
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detection, optical character recognition (OCR), and tagging of explicit
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content. For more information about Cloud Vision, read the Google Cloud Vision API
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Documentation at https://cloud.google.com/vision/docs.
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Note: This package is in beta. Some backwards-incompatible changes may occur.
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Creating Images
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The Cloud Vision API supports a variety of image file formats, including JPEG,
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PNG8, PNG24, Animated GIF (first frame only), and RAW. See
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https://cloud.google.com/vision/docs/image-best-practices#image_types for the
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complete list of formats. Be aware that Cloud Vision sets upper limits on file
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size as well as on the total combined size of all images in a request. Reducing
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your file size can significantly improve throughput; however, be careful not to
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reduce image quality in the process. See
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https://cloud.google.com/vision/docs/image-best-practices#image_sizing for
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current file size limits.
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Creating an Image instance does not perform an API request.
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Use NewImageFromReader to obtain an image from any io.Reader, such as an open file:
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f, err := os.Open("path/to/image.jpg")
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if err != nil { ... }
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defer f.Close()
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img, err := vision.NewImageFromReader(f)
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if err != nil { ... }
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Use NewImageFromURI to refer to an image in Google Cloud Storage or a public URL:
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img := vision.NewImageFromURI("gs://my-bucket/my-image.png")
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Annotating Images
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Client.Annotate is the most general method in the package. It can run multiple
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detections on multiple images with a single API call.
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To describe the detections you want to perform on an image, create an
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AnnotateRequest and specify the maximum number of results to return for each
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detection of interest. The exceptions are safe search and image properties,
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where a boolean is used instead.
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resultSlice, err := client.Annotate(ctx, &vision.AnnotateRequest{
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Image: img,
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MaxLogos: 5,
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MaxTexts: 100,
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SafeSearch: true,
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})
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if err != nil { ... }
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You can pass as many AnnotateRequests as desired to client.Annotate. The return
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value is a slice of an Annotations. Each Annotations value may contain an Error
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along with one or more successful results. The failed detections will have a nil annotation.
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result := resultSlice[0]
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if result.Error != nil { ... } // some detections failed
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for _, logo := range result.Logos { ... }
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for _, text := range result.Texts { ... }
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if result.SafeSearch != nil { ... }
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Other methods on Client run a single detection on a single image. For instance,
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Client.DetectFaces will run face detection on the provided Image. These methods
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return a single annotation of the appropriate type (for example, DetectFaces
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returns a FaceAnnotation). The error return value incorporates both API call
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errors and the detection errors stored in Annotations.Error, simplifying your
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logic.
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faces, err := client.DetectFaces(ctx, 10) // maximum of 10 faces
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if err != nil { ... }
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Here faces is a slice of FaceAnnotations. The Face field of each FaceAnnotation
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provides easy access to the positions of facial features:
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fmt.Println(faces[0].Face.Nose.Tip)
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fmt.Println(faces[0].Face.Eyes.Left.Pupil)
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Authentication
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See examples of authorization and authentication at
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https://godoc.org/cloud.google.com/go#pkg-examples.
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*/
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package vision // import "cloud.google.com/go/vision"
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