Jakob Wennberg
3f255ea201
Extract shared vision/document analysis logic into lib/ai (vision-client, document-analyzer, image preprocessing, validation helpers), simplifying invoice-analyzer, receipt-analyzer, and document classifier. Add migration 046 for journal entry reversal/correction link columns (reversed_by_id, reverses_id, correction_of_id) required by storno service. Update extension components and shared UI. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
44 lines
1.0 KiB
TypeScript
44 lines
1.0 KiB
TypeScript
/**
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* Image Preprocessing for OCR
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*
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* SERVER-ONLY: Uses sharp for image processing.
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*
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* Preprocesses receipt/invoice images before sending to Claude Vision.
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* Targets faded thermal prints with low contrast — the primary source
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* of garbled OCR output.
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*/
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import 'server-only'
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import sharp from 'sharp'
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/**
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* Preprocess an image for better OCR accuracy.
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* Converts to grayscale, normalizes contrast, and sharpens.
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* Returns base64-encoded JPEG.
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*
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* For PDFs: returns input unchanged (sharp doesn't handle PDFs).
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*/
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export async function preprocessImage(
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base64: string,
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mimeType: string
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): Promise<{ base64: string; mimeType: string }> {
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// PDFs are not image files — return as-is
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if (mimeType === 'application/pdf') {
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return { base64, mimeType }
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}
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const buffer = Buffer.from(base64, 'base64')
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const processed = await sharp(buffer)
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.grayscale()
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.normalize()
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.sharpen({ sigma: 1.5 })
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.jpeg({ quality: 90 })
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.toBuffer()
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return {
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base64: processed.toString('base64'),
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mimeType: 'image/jpeg',
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}
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}
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