feat(ocr): Word-based image deskew for Ground Truth pipeline
Begradigt schiefe Scans vor der OCR-Extraktion anhand der linksbuendigen
Wortanfaenge der Vokabelspalte. Tesseract liefert achsenparallele Boxen,
die bei ~2-3 Grad Schraege in Nachbarzeilen bluten — der Deskew behebt das.
- Neue Funktion deskew_image_by_word_alignment() in cv_vocab_pipeline.py
- Deskew-Integration im extract-with-boxes Endpoint (vor OCR)
- Neuer GET Endpoint /deskewed-image/{page} fuer begradigtes Seitenbild
- Frontend: GroundTruthPanel wechselt nach Extraktion auf deskewed Image
- ~1s Overhead durch schnellen Tesseract-Pass auf halbiertem Bild
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
@@ -111,6 +111,9 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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const [imageNatural, setImageNatural] = useState({ w: 0, h: 0 })
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const [showSummary, setShowSummary] = useState(false)
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const [savedMessage, setSavedMessage] = useState<string | null>(null)
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const [isFullscreen, setIsFullscreen] = useState(false)
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const [imageUrl, setImageUrl] = useState(pageImageUrl)
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const [deskewAngle, setDeskewAngle] = useState<number | null>(null)
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// Editable fields for current entry
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const [editEn, setEditEn] = useState('')
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@@ -120,13 +123,19 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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const panelRef = useRef<HTMLDivElement>(null)
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const enInputRef = useRef<HTMLInputElement>(null)
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// Reset image URL when page changes
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useEffect(() => {
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setImageUrl(pageImageUrl)
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setDeskewAngle(null)
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}, [pageImageUrl])
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// Load natural image dimensions
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useEffect(() => {
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if (!pageImageUrl) return
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if (!imageUrl) return
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const img = new Image()
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img.onload = () => setImageNatural({ w: img.naturalWidth, h: img.naturalHeight })
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img.src = pageImageUrl
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}, [pageImageUrl])
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img.src = imageUrl
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}, [imageUrl])
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// Sync edit fields when current entry changes
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useEffect(() => {
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@@ -157,6 +166,12 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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const loaded: GTEntry[] = (data.entries || []).map((e: GTEntry) => ({ ...e, status: 'pending' as const }))
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setEntries(loaded)
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setCurrentIndex(0)
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// Switch to deskewed image if available
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if (data.deskewed) {
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setImageUrl(`${KLAUSUR_API}/api/v1/vocab/sessions/${sessionId}/deskewed-image/${selectedPage}`)
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setDeskewAngle(data.deskew_angle)
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}
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} catch (err) {
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setError(err instanceof Error ? err.message : 'Extraction failed')
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} finally {
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@@ -225,9 +240,15 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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// ---------- Keyboard shortcuts ----------
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useEffect(() => {
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const handler = (e: KeyboardEvent) => {
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if (e.key === 'Escape' && isFullscreen) {
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e.preventDefault()
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setIsFullscreen(false)
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return
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}
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if (entries.length === 0 || showSummary) return
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const handler = (e: KeyboardEvent) => {
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// Don't capture when typing in inputs
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const tag = (e.target as HTMLElement)?.tagName
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const isInput = tag === 'INPUT' || tag === 'TEXTAREA'
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@@ -251,7 +272,7 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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window.addEventListener('keydown', handler)
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return () => window.removeEventListener('keydown', handler)
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}, [entries.length, showSummary, confirmEntry, skipEntry, goTo, currentIndex])
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}, [entries.length, showSummary, isFullscreen, confirmEntry, skipEntry, goTo, currentIndex])
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// ---------- Computed ----------
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@@ -298,8 +319,27 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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if (showSummary) {
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return (
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<div className="bg-white rounded-xl border border-slate-200 p-6" ref={panelRef}>
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<h3 className="text-lg font-semibold text-slate-900 mb-4">Zusammenfassung</h3>
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<div className={`bg-white rounded-xl border border-slate-200 p-6 ${
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isFullscreen ? 'fixed inset-0 z-50 overflow-auto m-0 rounded-none' : ''
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}`} ref={panelRef}>
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<div className="flex items-center justify-between mb-4">
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<h3 className="text-lg font-semibold text-slate-900">Zusammenfassung</h3>
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<button
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onClick={() => setIsFullscreen(!isFullscreen)}
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className="p-1.5 rounded-lg hover:bg-slate-100 text-slate-500 hover:text-slate-700 transition-colors"
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title={isFullscreen ? 'Vollbild verlassen (Esc)' : 'Vollbild'}
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>
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{isFullscreen ? (
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<svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor">
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<path strokeLinecap="round" strokeLinejoin="round" d="M9 9V4.5M9 9H4.5M9 9 3.75 3.75M9 15v4.5M9 15H4.5M9 15l-5.25 5.25M15 9h4.5M15 9V4.5M15 9l5.25-5.25M15 15h4.5M15 15v4.5m0-4.5 5.25 5.25" />
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</svg>
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) : (
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<svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor">
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<path strokeLinecap="round" strokeLinejoin="round" d="M3.75 3.75v4.5m0-4.5h4.5m-4.5 0L9 9M3.75 20.25v-4.5m0 4.5h4.5m-4.5 0L9 15M20.25 3.75h-4.5m4.5 0v4.5m0-4.5L15 9m5.25 11.25h-4.5m4.5 0v-4.5m0 4.5L15 15" />
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</svg>
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)}
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</button>
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</div>
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<div className="grid grid-cols-3 gap-4 mb-6">
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<div className="bg-green-50 border border-green-200 rounded-lg p-4 text-center">
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<div className="text-2xl font-bold text-green-700">{confirmedCount}</div>
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@@ -385,22 +425,47 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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// ---------- Render: Main Review UI ----------
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return (
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<div className="bg-white rounded-xl border border-slate-200 overflow-hidden" ref={panelRef}>
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{/* Progress bar */}
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<div className="h-1.5 bg-slate-100">
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<div className={`bg-white rounded-xl border border-slate-200 overflow-hidden ${
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isFullscreen ? 'fixed inset-0 z-50 overflow-auto m-0 rounded-none bg-white' : ''
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}`} ref={panelRef}>
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{/* Header with progress + fullscreen toggle */}
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<div className="flex items-center gap-2 px-4 pt-2">
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<div className="flex-1 h-1.5 bg-slate-100 rounded-full">
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<div
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className="h-full bg-teal-500 transition-all duration-300"
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className="h-full bg-teal-500 transition-all duration-300 rounded-full"
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style={{ width: `${progress}%` }}
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/>
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</div>
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<span className="text-xs text-slate-400 whitespace-nowrap">{currentIndex + 1}/{entries.length}</span>
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{deskewAngle !== null && (
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<span className="text-xs text-teal-600 whitespace-nowrap" title="Bild wurde begradigt">
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{deskewAngle.toFixed(1)}°
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</span>
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)}
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<button
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onClick={() => setIsFullscreen(!isFullscreen)}
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className="p-1.5 rounded-lg hover:bg-slate-100 text-slate-500 hover:text-slate-700 transition-colors"
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title={isFullscreen ? 'Vollbild verlassen (Esc)' : 'Vollbild'}
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>
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{isFullscreen ? (
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<svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor">
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<path strokeLinecap="round" strokeLinejoin="round" d="M9 9V4.5M9 9H4.5M9 9 3.75 3.75M9 15v4.5M9 15H4.5M9 15l-5.25 5.25M15 9h4.5M15 9V4.5M15 9l5.25-5.25M15 15h4.5M15 15v4.5m0-4.5 5.25 5.25" />
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</svg>
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) : (
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<svg className="w-4 h-4" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor">
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<path strokeLinecap="round" strokeLinejoin="round" d="M3.75 3.75v4.5m0-4.5h4.5m-4.5 0L9 9M3.75 20.25v-4.5m0 4.5h4.5m-4.5 0L9 15M20.25 3.75h-4.5m4.5 0v4.5m0-4.5L15 9m5.25 11.25h-4.5m4.5 0v-4.5m0 4.5L15 15" />
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</svg>
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)}
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</button>
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</div>
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<div className="flex flex-col lg:flex-row">
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<div className={`flex flex-col ${isFullscreen ? 'lg:flex-row h-[calc(100vh-3rem)]' : 'lg:flex-row'}`}>
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{/* Left: Page image with SVG overlay (2/3) */}
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<div className="lg:w-2/3 p-4">
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<div className={`${isFullscreen ? 'lg:w-2/3 p-4 overflow-y-auto h-full' : 'lg:w-2/3 p-4'}`}>
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<div className="relative bg-slate-50 rounded-lg overflow-hidden">
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{pageImageUrl && (
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{imageUrl && (
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<img
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src={pageImageUrl}
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src={imageUrl}
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alt={`Seite ${selectedPage + 1}`}
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className="w-full"
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draggable={false}
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@@ -451,13 +516,13 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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</div>
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{/* Right: Crops + Edit fields (1/3) */}
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<div className="lg:w-1/3 border-l border-slate-200 p-4 space-y-4">
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<div className={`lg:w-1/3 border-l border-slate-200 p-4 space-y-4 ${isFullscreen ? 'overflow-y-auto h-full' : ''}`}>
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{currentEntry && (
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<>
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{/* Row crop */}
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{imageNatural.w > 0 && (
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<ImageCrop
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imageUrl={pageImageUrl}
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imageUrl={imageUrl}
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bbox={currentEntry.bbox}
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naturalWidth={imageNatural.w}
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naturalHeight={imageNatural.h}
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@@ -470,7 +535,7 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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<div className="grid grid-cols-3 gap-2">
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{currentEntry.bbox_en.w > 0 && (
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<ImageCrop
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imageUrl={pageImageUrl}
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imageUrl={imageUrl}
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bbox={currentEntry.bbox_en}
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naturalWidth={imageNatural.w}
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naturalHeight={imageNatural.h}
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@@ -480,7 +545,7 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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)}
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{currentEntry.bbox_de.w > 0 && (
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<ImageCrop
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imageUrl={pageImageUrl}
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imageUrl={imageUrl}
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bbox={currentEntry.bbox_de}
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naturalWidth={imageNatural.w}
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naturalHeight={imageNatural.h}
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@@ -490,7 +555,7 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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)}
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{currentEntry.bbox_ex.w > 0 && (
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<ImageCrop
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imageUrl={pageImageUrl}
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imageUrl={imageUrl}
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bbox={currentEntry.bbox_ex}
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naturalWidth={imageNatural.w}
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naturalHeight={imageNatural.h}
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@@ -590,7 +655,7 @@ export function GroundTruthPanel({ sessionId, selectedPage, pageImageUrl }: Grou
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{/* Keyboard hints */}
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<div className="text-xs text-slate-400 text-center border-t border-slate-100 pt-2">
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Enter = Bestaetigen · Tab = Ueberspringen · ←→ = Navigieren
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Enter = Bestaetigen · Tab = Ueberspringen · ←→ = Navigieren{isFullscreen ? ' \u00B7 Esc = Vollbild verlassen' : ''}
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</div>
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</>
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)}
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@@ -193,6 +193,127 @@ def deskew_image(img: np.ndarray) -> Tuple[np.ndarray, float]:
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return corrected, median_angle
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def deskew_image_by_word_alignment(
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image_data: bytes,
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lang: str = "eng+deu",
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downscale_factor: float = 0.5,
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) -> Tuple[bytes, float]:
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"""Correct rotation by fitting a line through left-most word starts per text line.
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More robust than Hough-based deskew for vocabulary worksheets where text lines
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have consistent left-alignment. Runs a quick Tesseract pass on a downscaled
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copy to find word positions, computes the dominant left-edge column, fits a
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line through those points and rotates the full-resolution image.
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Args:
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image_data: Raw image bytes (PNG/JPEG).
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lang: Tesseract language string for the quick pass.
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downscale_factor: Shrink factor for the quick Tesseract pass (0.5 = 50%).
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Returns:
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Tuple of (rotated image as PNG bytes, detected angle in degrees).
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"""
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if not CV2_AVAILABLE or not TESSERACT_AVAILABLE:
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return image_data, 0.0
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# 1. Decode image
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img_array = np.frombuffer(image_data, dtype=np.uint8)
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img = cv2.imdecode(img_array, cv2.IMREAD_COLOR)
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if img is None:
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logger.warning("deskew_by_word_alignment: could not decode image")
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return image_data, 0.0
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orig_h, orig_w = img.shape[:2]
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# 2. Downscale for fast Tesseract pass
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small_w = int(orig_w * downscale_factor)
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small_h = int(orig_h * downscale_factor)
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small = cv2.resize(img, (small_w, small_h), interpolation=cv2.INTER_AREA)
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# 3. Quick Tesseract — word-level positions
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pil_small = Image.fromarray(cv2.cvtColor(small, cv2.COLOR_BGR2RGB))
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try:
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data = pytesseract.image_to_data(
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pil_small, lang=lang, config="--psm 6 --oem 3",
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output_type=pytesseract.Output.DICT,
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)
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except Exception as e:
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logger.warning(f"deskew_by_word_alignment: Tesseract failed: {e}")
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return image_data, 0.0
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# 4. Per text-line, find the left-most word start
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# Group by (block_num, par_num, line_num)
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from collections import defaultdict
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line_groups: Dict[tuple, list] = defaultdict(list)
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for i in range(len(data["text"])):
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text = (data["text"][i] or "").strip()
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conf = int(data["conf"][i])
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if not text or conf < 20:
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continue
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key = (data["block_num"][i], data["par_num"][i], data["line_num"][i])
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line_groups[key].append(i)
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if len(line_groups) < 5:
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logger.info(f"deskew_by_word_alignment: only {len(line_groups)} lines, skipping")
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return image_data, 0.0
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# For each line, pick the word with smallest 'left' → compute (left_x, center_y)
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# Scale back to original resolution
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scale = 1.0 / downscale_factor
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points = [] # list of (x, y) in original-image coords
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for key, indices in line_groups.items():
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best_idx = min(indices, key=lambda i: data["left"][i])
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lx = data["left"][best_idx] * scale
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top = data["top"][best_idx] * scale
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h = data["height"][best_idx] * scale
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cy = top + h / 2.0
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points.append((lx, cy))
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# 5. Find dominant left-edge column + compute angle
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xs = np.array([p[0] for p in points])
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ys = np.array([p[1] for p in points])
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median_x = float(np.median(xs))
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tolerance = orig_w * 0.03 # 3% of image width
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mask = np.abs(xs - median_x) <= tolerance
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filtered_xs = xs[mask]
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filtered_ys = ys[mask]
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if len(filtered_xs) < 5:
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logger.info(f"deskew_by_word_alignment: only {len(filtered_xs)} aligned points after filter, skipping")
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return image_data, 0.0
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# polyfit: x = a*y + b → a = dx/dy → angle = arctan(a)
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coeffs = np.polyfit(filtered_ys, filtered_xs, 1)
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slope = coeffs[0] # dx/dy
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angle_rad = np.arctan(slope)
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angle_deg = float(np.degrees(angle_rad))
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# Clamp to ±5°
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angle_deg = max(-5.0, min(5.0, angle_deg))
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logger.info(f"deskew_by_word_alignment: detected {angle_deg:.2f}° from {len(filtered_xs)} points "
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f"(total lines: {len(line_groups)})")
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if abs(angle_deg) < 0.05:
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return image_data, 0.0
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# 6. Rotate full-res image
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center = (orig_w // 2, orig_h // 2)
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M = cv2.getRotationMatrix2D(center, angle_deg, 1.0)
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rotated = cv2.warpAffine(img, M, (orig_w, orig_h),
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flags=cv2.INTER_LINEAR,
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borderMode=cv2.BORDER_REPLICATE)
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# Encode back to PNG
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success, png_buf = cv2.imencode(".png", rotated)
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if not success:
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logger.warning("deskew_by_word_alignment: PNG encoding failed")
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return image_data, 0.0
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return png_buf.tobytes(), angle_deg
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# =============================================================================
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# Stage 3: Dewarp (Book Curvature) — Pass-Through for now
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# =============================================================================
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@@ -2134,7 +2134,22 @@ async def extract_with_boxes(session_id: str, page_number: int):
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# Convert page to hires image
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image_data = await convert_pdf_page_to_image(pdf_data, page_number, thumbnail=False)
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# Extract entries with boxes
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# Deskew image before OCR
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deskew_angle = 0.0
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try:
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from cv_vocab_pipeline import deskew_image_by_word_alignment, CV2_AVAILABLE
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if CV2_AVAILABLE:
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image_data, deskew_angle = deskew_image_by_word_alignment(image_data)
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logger.info(f"Deskew: {deskew_angle:.2f}° for page {page_number}")
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except Exception as e:
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logger.warning(f"Deskew failed for page {page_number}: {e}")
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# Cache deskewed image in session for later serving
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if "deskewed_images" not in session:
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session["deskewed_images"] = {}
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session["deskewed_images"][str(page_number)] = image_data
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# Extract entries with boxes (now on deskewed image)
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result = await extract_entries_with_boxes(image_data)
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# Cache in session
|
||||
@@ -2148,9 +2163,35 @@ async def extract_with_boxes(session_id: str, page_number: int):
|
||||
"entry_count": len(result["entries"]),
|
||||
"image_width": result["image_width"],
|
||||
"image_height": result["image_height"],
|
||||
"deskew_angle": round(deskew_angle, 2),
|
||||
"deskewed": abs(deskew_angle) > 0.05,
|
||||
}
|
||||
|
||||
|
||||
@router.get("/sessions/{session_id}/deskewed-image/{page_number}")
|
||||
async def get_deskewed_image(session_id: str, page_number: int):
|
||||
"""Return the deskewed page image as PNG.
|
||||
|
||||
Falls back to the original hires image if no deskewed version is cached.
|
||||
"""
|
||||
if session_id not in _sessions:
|
||||
raise HTTPException(status_code=404, detail="Session not found")
|
||||
|
||||
session = _sessions[session_id]
|
||||
deskewed = session.get("deskewed_images", {}).get(str(page_number))
|
||||
|
||||
if deskewed:
|
||||
return StreamingResponse(io.BytesIO(deskewed), media_type="image/png")
|
||||
|
||||
# Fallback: render original hires image
|
||||
pdf_data = session.get("pdf_data")
|
||||
if not pdf_data:
|
||||
raise HTTPException(status_code=400, detail="No PDF uploaded for this session")
|
||||
|
||||
image_data = await convert_pdf_page_to_image(pdf_data, page_number, thumbnail=False)
|
||||
return StreamingResponse(io.BytesIO(image_data), media_type="image/png")
|
||||
|
||||
|
||||
@router.post("/sessions/{session_id}/ground-truth/{page_number}")
|
||||
async def save_ground_truth(session_id: str, page_number: int, data: dict = Body(...)):
|
||||
"""Save ground truth labels for a page.
|
||||
|
||||
Reference in New Issue
Block a user