VisionAPIExample01.cs

//
// 以下のusing を追加しておく。
//
//  using GCP.VisionAPI.Sample.Services;
//  using Google.Cloud.Vision.V1;
//
Image image                 = Image.FromFile(fileName);
ImageAnnotatorClient client = ImageAnnotatorClient.Create();

// ここで解析結果を取得する。
TextAnnotation response = client.DetectDocumentText(image);
Block[] blocks          = response.Pages.SelectMany(x => x.Blocks).ToArray();
Paragraph[] paragraphs  = blocks.SelectMany(x => x.Paragraphs).ToArray();
Word[] words            = paragraphs.SelectMany(x => x.Words).ToArray();
Symbol[] symbols        = words.SelectMany(x => x.Symbols).ToArray();
string[] textList       = symbols.Select(x => x.Text).ToArray();