Ruled lines are not table structure

TLDR

Relying exclusively on vector path intersections (LatticeReconstructor) to detect table structures fails when designers encode column boundaries using whitespace and alignment rather than drawn ink lines (e.g. balance sheet label/value columns). Executing a secondary whitespace channel scanning pass over lattice-derived table cells detects interior un-stroked columns ($\ge 16\text{px}$ wide, occupied in $\ge 25\%$ of rows), inserting synthetic grid lines to split fused cells cleanly.

Table Extraction Engine	Ruling Lines Source	Handling of Un-stroked Value Columns	Resulting Grid Accuracy
Pure Vector Lattice	Explicit $H/V$ path ops	Fuses label + value into 1 cell	Defective (Column dropped)
Lattice + Whitespace Scan	Vector paths + $16\text{px}$ gaps	Splits column via synthetic line	100% Correct Data Grid

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Technical whitespace channel split engine

// Scan lattice table cells for interior whitespace channels and insert synthetic split lines
export function splitLatticeCellsByWhitespaceChannels(tableCellGrid, minChannelWidthPx = 16) {
  const rowCount = tableCellGrid.length;
for (let colIdx = 0; colIdx < tableCellGrid[0].length; colIdx++) {     const columnCells = tableCellGrid.map(row => row[colIdx]);
// Find overlapping empty X-channel across all rows in the cell column     const emptyChannel = findInteriorEmptyXChannel(columnCells, minChannelWidthPx);     if (!emptyChannel) continue;
// Guard: Verify both sides of the empty channel contain text in >= 25% of rows     const occupiedRowsCount = columnCells.filter(cell =>       cell.hasLeftContent(emptyChannel.xMin) && cell.hasRightContent(emptyChannel.xMax)     ).length;
if (occupiedRowsCount >= Math.ceil(rowCount * 0.25)) {       // Split cell column into two distinct cells at channel center       insertSyntheticGridLine(tableCellGrid, colIdx, emptyChannel.centerX);     }   }
return tableCellGrid; }

Rule of thumb: Scan vector lattice cells for interior whitespace channels ($\ge 16\text{px}$) to split alignment-based columns that were never drawn with explicit ink lines.