OCR with Go

Lightning Talk feita na GopherCon Brasil 2018 falando um pouco sobre um side project para extrair informações da Nota Fiscal Paulistana usando OCR e expondo os dados em uma API escrita em Go.

Images:
- Tesseract [ http://marvelcinematicuniverse.wikia.com ]
- Thanos [ http://hdqwalls.com ]
- NF de exemplo [ https://br.pinterest.com/pin/161496336618265839/?lp=true ]

Transcript

1. OCR with Go GopherCon Brazil 2018 Marco Singer
4. Optical character recognition Optical character recognition (also optical character reader, OCR) is the mechanical or electronic conversion of images of typed, handwritten or printed text into machine-encoded text, whether from a scanned document, a photo of a document, a scene-photo (for example the text on signs and billboards in a landscape photo) or from subtitle text superimposed on an image (for example from a television broadcast) - Wikipedia
8. package main import ( "fmt" "github.com/otiai10/gosseract" ) func main() { client := gosseract.NewClient() defer client.Close() client.SetImage("path/to/image.png") text, _ := client.Text() fmt.Println(text) // Hello, World! }
10. 87 OCR binary
13. 87 OCR binary API
16. { "source": "path/to/document", "labels": [ { "name": "Número da Nota", "x": 1900, "y": 260, "h": 30, "w": 450 }, { "name": "Razão Social", "x": 250, "y": 590, "h": 45, "w": 1040 }, ] } payload.json
17. curl -d @payload.json http://localhost/detect
18. func DetectDocumentText(source string) (*vtypes.TextAnnotation, error) { ctx := context.Background() client, _ := vision.NewImageAnnotatorClient(ctx) defer client.Close() return client.DetectDocumentText( ctx, vision.NewImageFromURI(source), nil, ) }
19. func DetectDocumentText(source string) (*vtypes.TextAnnotation, error) { ctx := context.Background() client, _ := vision.NewImageAnnotatorClient(ctx) defer client.Close() return client.DetectDocumentText( ctx, vision.NewImageFromURI(source), nil, ) }
20. for _, page := range ta.Pages { for _, block := range page.Blocks { for _, label := range labels { for _, paragraph := range block.Paragraphs { for _, words := range paragraph.Words { for _, symbols := range w.Symbols {
21. for _, page := range ta.Pages { for _, block := range page.Blocks { for _, label := range labels { for _, paragraph := range block.Paragraphs { for _, words := range paragraph.Words { for _, symbols := range w.Symbols {
22. { "source": "path/to/document", "labels": [ { "name": "Número da Nota", "x": 1900, "y": 260, "h": 30, "w": 450, "text": "00000086", "confidence": 0.99, }, { "name": "Razão Social", "x": 250, "y": 590, "h": 45, "w": 1040, "text": "PayPal do Brasil Serviços de Pagamento LTDA", "confidence": 0.97, }, ] }
23. { "source": "path/to/document", "labels": [ { "name": "Número da Nota", "x": 1900, "y": 260, "h": 30, "w": 450, "text": "00000086", "confidence": 0.99, }, { "name": "Razão Social", "x": 250, "y": 590, "h": 45, "w": 1040, "text": "PayPal do Brasil Serviços de Pagamento LTDA", "confidence": 0.97, }, ] }
24. Templates
25. { "source": "path/to/document", "labels": [ { "name": "Número da Nota", "x": 1900, "y": 260, "h": 30, "w": 450 }, { "name": "Razão Social", "x": 250, "y": 590, "h": 45, "w": 1040 }, ] } payload.json
26. { "source": "path/to/document", "template": "nf_sp" } payload.json
27. { "source": "path/to/document", "labels": [ { "name": "Número da Nota", "x": 1900, "y": 260, "h": 30, "w": 450, "text": "00000086", "confidence": 0.99, }, { "name": "Razão Social", "x": 250, "y": 590, "h": 45, "w": 1040, "text": "PayPal do Brasil Serviços de Pagamento LTDA", "confidence": 0.97, }, ] } curl -d @payload.json http://localhost/detect
28. ~ 3.75s Call Google Vision API
29. ~ 204µs Detect labels
30. Goals • Accept other formats (e.g. PDFs) • Create new templates • Scale support • Extract data as table (e.g. product's list)
31. Links - https://github.com/tesseract-ocr/tesseract - https://cloud.google.com/vision - https://github.com/otiai10/gosseract - https://godoc.org/cloud.google.com/go/vision/apiv1
32. Thanks! @mahsinger github.com/marcosinger linkedin.com/in/marcosinger msinger@87labs.com