fix(pdf-inspector): recover borderless region tables

napi/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@firecrawl/pdf-inspector",
-  "version": "1.9.1",
+  "version": "1.9.2",
   "description": "Fast PDF classification and text extraction. Detect text-based vs scanned PDFs, extract text by region with quality checks. Native Rust performance via napi-rs.",
   "main": "index.js",
   "types": "index.d.ts",

src/lib.rs

@@ -881,6 +881,11 @@ pub fn extract_tables_in_regions_mem(
             {
                 candidates.push(candidate);
             }
+            if let Some(table) = tables::try_build_table_from_columns(&matched, page_1idx) {
+                if let Some(candidate) = evaluate(TableCandidateSource::Column, &table) {
+                    candidates.push(candidate);
+                }
+            }
 
             match select_table_candidate(&candidates) {
                 Some(candidate) => page_results.push(RegionText {
@@ -3752,6 +3757,7 @@ enum TableCandidateSource {
     Rect,
     Line,
     Heuristic,
+    Column,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -3786,8 +3792,10 @@ fn select_table_candidate(candidates: &[TableCandidate]) -> Option<&TableCandida
     // serving a tidy-looking fragment.
     if first.issue == Some(TableCandidateIssue::LineRowUndercount) {
         return candidates.iter().find(|candidate| {
-            candidate.source == TableCandidateSource::Heuristic
+            matches!(
-                && candidate.issue.is_none()
+                candidate.source,
+                TableCandidateSource::Heuristic | TableCandidateSource::Column
+            ) && candidate.issue.is_none()
                 && candidate.shape.cols * 10 >= first.shape.cols * 13
         });
     }
@@ -3805,14 +3813,27 @@ fn select_table_candidate(candidates: &[TableCandidate]) -> Option<&TableCandida
         TableCandidateSource::Rect | TableCandidateSource::Line
     ) {
         if let Some(heuristic) = candidates.iter().find(|candidate| {
-            candidate.source == TableCandidateSource::Heuristic
+            matches!(
-                && candidate.issue.is_none()
+                candidate.source,
+                TableCandidateSource::Heuristic | TableCandidateSource::Column
+            ) && candidate.issue.is_none()
                 && heuristic_substantially_better(candidate.shape, accepted.shape)
         }) {
             accepted = heuristic;
         }
     }
 
+    if accepted.source == TableCandidateSource::Heuristic {
+        if let Some(column) = candidates.iter().find(|candidate| {
+            candidate.source == TableCandidateSource::Column
+                && candidate.issue.is_none()
+                && candidate.shape.cols >= accepted.shape.cols
+                && candidate.shape.rows > accepted.shape.rows
+        }) {
+            accepted = column;
+        }
+    }
+
     Some(accepted)
 }
 
@@ -4314,7 +4335,9 @@ fn looks_like_partial_table_ex(markdown: &str, layout_assisted: bool) -> bool {
                         cell.trim().is_empty() && header_empty_indices.contains(&idx)
                     })
                     && layout_assisted_empty_header_has_dense_body(markdown, n_cols);
-                if !sparse_row_shares_header_spacer {
+                let sparse_row_is_section_label = layout_assisted
+                    && layout_assisted_sparse_section_row_is_ok(data_inner, markdown, n_cols);
+                if !sparse_row_shares_header_spacer && !sparse_row_is_section_label {
                     return true;
                 }
             }
@@ -4406,6 +4429,26 @@ fn layout_assisted_empty_header_has_dense_body(markdown: &str, n_cols: usize) ->
         && filled_cells * 100 >= total_cells * 45
 }
 
+fn layout_assisted_sparse_section_row_is_ok(row: &[&str], markdown: &str, n_cols: usize) -> bool {
+    let labels: Vec<&str> = row
+        .iter()
+        .map(|cell| cell.trim())
+        .filter(|cell| !cell.is_empty())
+        .collect();
+    if labels.len() != 1 {
+        return false;
+    }
+    let label = labels[0];
+    if label.len() > 40 || !label.chars().any(|ch| ch.is_alphabetic()) {
+        return false;
+    }
+    if label.ends_with('.') || label.ends_with('!') || label.ends_with('?') || label.ends_with(':')
+    {
+        return false;
+    }
+    layout_assisted_empty_header_has_dense_body(markdown, n_cols)
+}
+
 fn markdown_table_body_is_dense(markdown: &str) -> bool {
     let rows = markdown_pipe_rows(markdown);
     let data_rows: Vec<&Vec<&str>> = rows
@@ -4787,6 +4830,16 @@ mod table_candidate_selection_tests {
         assert_eq!(selected.source, TableCandidateSource::Heuristic);
     }
 
+    #[test]
+    fn prefers_clean_column_fallback_when_it_recovers_more_rows() {
+        let candidates = vec![
+            candidate(TableCandidateSource::Heuristic, 6, 5, None),
+            candidate(TableCandidateSource::Column, 7, 5, None),
+        ];
+        let selected = select_table_candidate(&candidates).unwrap();
+        assert_eq!(selected.source, TableCandidateSource::Column);
+    }
+
     #[test]
     fn line_candidate_collapsing_captured_y_clusters_is_suspicious() {
         let long = "value value value value value value value value value value value value";
@@ -5091,6 +5144,24 @@ mod looks_like_partial_table_tests {
         );
     }
 
+    #[test]
+    fn sparse_section_row_passes_when_layout_assisted_body_is_dense() {
+        let md = "|Properties|Conditions|Method|Typical values|Units|\n\
+                  |---|---|---|---|---|\n\
+                  |Rheology|||||\n\
+                  |Melt Flow Rate|230 C/2.16 kg|ASTM D1238|3.0|g/10 min|\n\
+                  |Tensile Stress at Yield|50 mm/min|ASTM D638|31|MPa|\n\
+                  |Elongation at Yield|50 mm/min|ASTM D638|8|%|";
+        assert!(
+            looks_like_partial_table(md),
+            "strict mode rejects the sparse first row"
+        );
+        assert!(
+            !looks_like_partial_table_ex(md, true),
+            "layout-assisted should allow a short section label above dense table rows"
+        );
+    }
+
     #[test]
     fn paragraph_still_rejected_when_layout_assisted() {
         // Paragraph detection is not relaxed — it's a genuine extraction issue.

src/tables/format.rs

@@ -208,6 +208,24 @@ fn looks_like_compact_entry_label(cell: &str) -> bool {
     (1..=6).contains(&words)
 }
 
+fn looks_like_plain_section_label(cell: &str) -> bool {
+    let trimmed = cell.trim();
+    if trimmed.len() < 4 || trimmed.len() > 40 {
+        return false;
+    }
+    if trimmed.ends_with(['.', ',', ';', ':']) || trimmed.contains(|ch: char| ch.is_ascii_digit()) {
+        return false;
+    }
+    if trimmed.len() <= 4 && trimmed.chars().all(|ch| !ch.is_lowercase()) {
+        return false;
+    }
+    trimmed
+        .chars()
+        .all(|ch| ch.is_alphabetic() || ch.is_whitespace() || matches!(ch, '&' | '/' | '-'))
+        && starts_with_uppercase_alpha(trimmed)
+        && (1..=4).contains(&alpha_word_count(trimmed))
+}
+
 fn ends_like_incomplete_phrase(cell: &str) -> bool {
     let lower = cell.trim_end().to_ascii_lowercase();
     lower.ends_with(" and")
@@ -305,6 +323,10 @@ fn clean_table_cells(cells: &[Vec<String>]) -> (Vec<Vec<String>>, Vec<String>) {
             .and_then(|r| r.first())
             .map(|c| c.trim())
             .unwrap_or("");
+        let header_filled = cleaned
+            .first()
+            .map(|r| r.iter().filter(|c| !c.trim().is_empty()).count())
+            .unwrap_or(num_cols);
         let looks_like_spanning_first_column_row = first_cell.is_empty()
             && row.len() >= 4
             && non_first_cells.len() == row.len().saturating_sub(1)
@@ -328,6 +350,10 @@ fn clean_table_cells(cells: &[Vec<String>]) -> (Vec<Vec<String>>, Vec<String>) {
             && non_first_cells
                 .iter()
                 .any(|cell| looks_like_compact_entry_label(cell));
+        let looks_like_section_label_row = !first_cell.is_empty()
+            && filled_cells == 1
+            && header_filled >= 3
+            && looks_like_plain_section_label(first_cell);
         // Classic continuation: first cell empty, content in other cells
         let is_classic_continuation = first_cell.is_empty()
             && !non_first_cells.is_empty()
@@ -344,10 +370,6 @@ fn clean_table_cells(cells: &[Vec<String>]) -> (Vec<Vec<String>>, Vec<String>) {
             .last()
             .map(|r| r.iter().filter(|c| !c.trim().is_empty()).count())
             .unwrap_or(0);
-        let header_filled = cleaned
-            .first()
-            .map(|r| r.iter().filter(|c| !c.trim().is_empty()).count())
-            .unwrap_or(num_cols);
         // Merge when the row has significantly fewer filled cells than header.
         // For wide tables (5+ cols), require ≤50% of header cells.
         // For narrow tables (2-4 cols), require fewer than header cells.
@@ -369,6 +391,7 @@ fn clean_table_cells(cells: &[Vec<String>]) -> (Vec<Vec<String>>, Vec<String>) {
             && !looks_like_spanning_first_column_row
             && !looks_like_hierarchical_subrow
             && !looks_like_new_first_column_entry
+            && !looks_like_section_label_row
             && !is_short_subheader;
 
         let is_continuation = is_classic_continuation || is_wrapped_continuation;
@@ -514,6 +537,44 @@ mod tests {
         assert!(cleaned[1][1].contains("continued text here"));
     }
 
+    #[test]
+    fn test_clean_table_cells_first_column_section_label_not_merged() {
+        let cells = vec![
+            vec![
+                "Properties".into(),
+                "Conditions".into(),
+                "Method".into(),
+                "Typical values".into(),
+                "Units".into(),
+            ],
+            vec![
+                "Melt Flow Rate".into(),
+                "230 C/2.16 kg".into(),
+                "ASTM D1238".into(),
+                "3.0".into(),
+                "g/10 min".into(),
+            ],
+            vec![
+                "Mechanical".into(),
+                "".into(),
+                "".into(),
+                "".into(),
+                "".into(),
+            ],
+            vec![
+                "Tensile Stress at Yield".into(),
+                "50 mm/min".into(),
+                "ASTM D638".into(),
+                "31".into(),
+                "MPa".into(),
+            ],
+        ];
+        let (cleaned, _) = clean_table_cells(&cells);
+
+        assert_eq!(cleaned.len(), 4);
+        assert_eq!(cleaned[2][0], "Mechanical");
+    }
+
     #[test]
     fn test_clean_table_cells_short_subheader_not_merged() {
         let cells = vec![

src/tables/mod.rs

@@ -460,6 +460,7 @@ pub(crate) fn try_build_table_from_columns(items: &[TextItem], page: u32) -> Opt
             item_indices.push(item_idx);
         }
     }
+    merge_superscript_marker_rows(&mut row_ys, &mut cells);
 
     // Validate: need reasonable fill rate
     let total_cells = row_ys.len() * columns.len();
@@ -547,6 +548,60 @@ pub(crate) fn try_build_table_from_columns(items: &[TextItem], page: u32) -> Opt
     Some(Table::new(col_xs, row_ys, cells, item_indices))
 }
 
+fn merge_superscript_marker_rows(row_ys: &mut Vec<f32>, cells: &mut Vec<Vec<String>>) {
+    let mut row_idx = 0;
+    while row_idx < cells.len() {
+        let non_empty: Vec<(usize, String)> = cells[row_idx]
+            .iter()
+            .enumerate()
+            .filter_map(|(col_idx, cell)| {
+                let trimmed = cell.trim();
+                (!trimmed.is_empty()).then_some((col_idx, trimmed.to_string()))
+            })
+            .collect();
+
+        if non_empty.len() != 1 || !is_superscript_marker_cell(&non_empty[0].1) {
+            row_idx += 1;
+            continue;
+        }
+
+        let (marker_col, marker) = &non_empty[0];
+        let prev =
+            (row_idx > 0).then(|| (row_idx - 1, (row_ys[row_idx - 1] - row_ys[row_idx]).abs()));
+        let next = (row_idx + 1 < cells.len())
+            .then(|| (row_idx + 1, (row_ys[row_idx] - row_ys[row_idx + 1]).abs()));
+        let target = [prev, next]
+            .into_iter()
+            .flatten()
+            .filter(|(_, gap)| *gap <= 10.0)
+            .min_by(|(_, gap_a), (_, gap_b)| gap_a.total_cmp(gap_b))
+            .map(|(idx, _)| idx);
+
+        let Some(target_idx) = target else {
+            row_idx += 1;
+            continue;
+        };
+
+        let target_cell = &mut cells[target_idx][*marker_col];
+        if target_cell.trim().is_empty() {
+            *target_cell = marker.to_string();
+        } else {
+            target_cell.push_str(marker);
+        }
+        cells.remove(row_idx);
+        row_ys.remove(row_idx);
+    }
+}
+
+fn is_superscript_marker_cell(value: &str) -> bool {
+    let trimmed = value.trim();
+    !trimmed.is_empty()
+        && trimmed.chars().count() <= 2
+        && trimmed
+            .chars()
+            .all(|ch| matches!(ch, '*' | '#' | 'o' | 'O' | '°' | 'º' | '†' | '‡'))
+}
+
 /// What kind of structure a detected `Table` represents. Classification is
 /// computed once at construction so consumers don't have to re-analyze the
 /// cells (and stay consistent across detection backends).
@@ -689,6 +744,69 @@ mod tests {
         assert!(md.contains("|Cell 1|"));
     }
 
+    #[test]
+    fn test_merge_superscript_marker_rows() {
+        let mut rows = vec![506.0, 500.0, 480.0];
+        let mut cells = vec![
+            vec!["".into(), "".into(), "*".into()],
+            vec!["Name".into(), "Method".into(), "Typical values".into()],
+            vec!["Flow".into(), "ASTM D1238".into(), "3.0".into()],
+        ];
+
+        merge_superscript_marker_rows(&mut rows, &mut cells);
+
+        assert_eq!(rows, vec![500.0, 480.0]);
+        assert_eq!(cells[0][2], "Typical values*");
+    }
+
+    #[test]
+    fn test_column_builder_handles_borderless_specs_table() {
+        let items = vec![
+            make_char("*", 458.1, 544.2, 8.0, 4.4),
+            make_char("Properties", 36.0, 538.6, 12.0, 53.1),
+            make_char("Conditions", 195.8, 538.6, 12.0, 55.0),
+            make_char("Method", 297.2, 538.6, 12.0, 39.4),
+            make_char("Typical values", 384.1, 538.6, 12.0, 74.0),
+            make_char("Units", 510.6, 538.6, 8.0, 17.9),
+            make_char("Rheology", 36.0, 508.3, 10.0, 40.6),
+            make_char("o", 209.8, 492.5, 6.5, 3.5),
+            make_char("Melt Flow Rate", 36.0, 488.0, 10.0, 65.2),
+            make_char("230 ", 190.4, 488.0, 10.0, 19.4),
+            make_char("C/2.16 kg", 213.3, 488.0, 10.0, 42.8),
+            make_char("ASTM D1238", 288.4, 488.0, 10.0, 56.8),
+            make_char("3.0 ", 416.4, 488.0, 10.0, 16.9),
+            make_char("g/10 min", 504.1, 488.0, 10.0, 39.5),
+            make_char("Mechanical", 36.0, 451.5, 10.0, 48.3),
+            make_char("Tensile Stress at Yield", 36.0, 431.3, 10.0, 96.7),
+            make_char("50 mm/min", 197.9, 431.3, 10.0, 50.8),
+            make_char("ASTM D638", 291.2, 431.3, 10.0, 51.3),
+            make_char("31 ", 417.9, 431.3, 10.0, 13.9),
+            make_char("MPa", 514.7, 431.3, 10.0, 18.4),
+            make_char("Elongation at Yield", 36.0, 403.0, 10.0, 82.2),
+            make_char("50 mm/min", 197.9, 403.0, 10.0, 50.8),
+            make_char("ASTM D638", 291.2, 403.0, 10.0, 51.3),
+            make_char("8 ", 420.6, 403.0, 10.0, 8.5),
+            make_char("%", 519.1, 403.0, 10.0, 9.7),
+            make_char("Flexural Modulus", 36.0, 374.6, 10.0, 74.0),
+            make_char("ASTM D790", 291.2, 374.6, 10.0, 51.3),
+            make_char("1400", 412.4, 374.6, 10.0, 21.8),
+            make_char("MPa", 514.7, 374.6, 10.0, 18.4),
+        ];
+
+        let table = try_build_table_from_columns(&items, 1).unwrap();
+        let md = table_to_markdown(&table);
+
+        assert!(
+            md.contains("|Properties|Conditions|Method|Typical values*|Units|"),
+            "{md}"
+        );
+        assert!(md.contains("|Mechanical|||||"), "{md}");
+        assert!(
+            md.contains("|Flexural Modulus||ASTM D790|1400|MPa|"),
+            "{md}"
+        );
+    }
+
     #[test]
     fn test_body_font_table_detected() {
         let items = vec![