Non-Destructive Optical Document Highlighter & AI Engine
Hardware-software system for non-destructive physical text document highlighting, OCR extraction, and AI processing.
The Problem
Physical highlighting permanently marks books, library archives, and legal documents, while digital notes remain disconnected from the physical source material.
Designed an optical capture workflow that isolates color-coded digital highlights without altering physical paper, pairing computer vision segmentation with text extraction.
The System & Architecture
Optical sensor capture workflow feeding an OpenCV image processing pipeline with HSV thresholding, contour detection, OCR bounding box extraction, and structured note sync.
Optical Highlight & Extraction Pipeline
Optical Sensor
Physical Page Capture
OpenCV Pipeline
HSV Segmentation
OCR Engine
Text Bounding Boxes
Structured Notes
Categorized Sync
My Engineering Work
- Formulated adaptive HSV color filtering thresholds to reliably detect transparent highlighter tints across varying illumination
- Engineered spatial bounding box merging algorithm to reconstruct multiline paragraphs from fragmented character contours
- Authored and submitted formal patent specification with the Indian Patent Office (Application No. 202511052205)
def extract_highlighted_regions(image_bgr, lower_hsv, upper_hsv):
hsv = cv2.cvtColor(image_bgr, cv2.COLOR_BGR2HSV)
mask = cv2.inRange(hsv, lower_hsv, upper_hsv)
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (5, 5))
cleaned = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)
contours, _ = cv2.findContours(cleaned, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
return [cv2.boundingRect(c) for c in contours if cv2.contourArea(c) > 100]Decisions & Trade-offs
Challenge: Ambient room lighting variations and page curvature causing false-positive color segmentation
Solution: Applied adaptive histogram equalization and dynamic white balancing prior to color space conversion
Validation & Limitations
- Filed Indian Patent Application No. 202511052205 (Inventor)
- Verified high-accuracy OCR extraction across standard printed academic typography
- Performance degrades on handwritten cursive scripts and heavily creased physical paper
- Physical hardware rig requires consistent document positioning for optimal focal calibration
Evidence & Verification
Verify the implementation directly via source code, commit history, and setup documentation:
Ref: Indian Patent Application No. 202511052205; academic specifications and OpenCV prototype benchmarks