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Abimael MartellandClaude Opus 4.6 44092bcc9e feat(tables): borderless table detection improvements (#17) 
* feat(tables): improve heuristic detection for borderless wrapped-cell tables

Three changes to the body-font heuristic detector:

1. Adaptive Y-gap in find_table_regions_strict: use median qualifying-row
   spacing × 3 instead of fixed 25pt. Tables with wrapped cells have
   larger gaps between qualifying rows (those with 3+ X-clusters).

2. Y-only region filtering: use full X range when collecting region items.
   The strict X bounds from qualifying rows excluded continuation lines
   in wrapped cells, starving find_column_boundaries of items.

3. Merged-band retry: when split_side_by_side splits a page into bands
   but no band produces a table, retry heuristic detection on all items
   merged as a single band.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tables): gap-histogram column detection for small tables + lower avg_cells

Two changes to fix PDF 045 (borderless table with narrow "No." column):

1. Extend gap-histogram column threshold to small tables: when the gap
   between within-column jitter and between-column spacing is >10pt
   (unambiguous bimodal signal), use the detected threshold even with
   fewer than 500 items. Previously only triggered for dense tables.

2. Lower BodyFont avg_cells_per_row minimum from 2.5 to 2.0 to handle
   tables with wrapped multi-line cells where continuation lines have
   only 1 filled cell.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(tables): trim empty outer columns + relax partial H-line validation

- Rect detection: trim empty first/last columns instead of rejecting
  the whole table. Rect edges often extend beyond text boundaries.
- Line detection: accept tables with 6+ partial horizontal lines
  (>15% width) when <3 full-spanning lines exist. Handles tables
  with column-level separators instead of full-width rules.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tables): cell-rect fallback for tables with variable-width backgrounds

When rect clustering produces a grid that fails validation (empty
interior columns from variable-width cell backgrounds), fall through
to a new strategy: use rect Y-edges for row boundaries and text
X-position clustering for columns. This handles tables like the
opendataloader-bench 088-090 comparison tables where each cell has
its own background rect at different widths.

Also widen failed-cluster hint width cap for large clusters (≥30 rects)
to allow page-spanning table regions.

TEDS score on opendataloader-bench: 0.300 → 0.353.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(tables): relax vertical line spanning validation for partial borders

Accept tables with 4+ partial vertical lines (>10% table height) when
fewer than 2 span >30%. Handles tables like opendataloader-bench 053
with column-level vertical separators that don't extend the full height.

TEDS: 0.353 → 0.377 on opendataloader-bench.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(tables): lower cell-rect density threshold + add validation logging

- Lower cell-rect density minimum from 25% to 15% to accept sparser
  tables with decorative backgrounds (fixes 147).
- Add debug logging to all heuristic validation paths for diagnosability.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tables): relax body-font validations for text-only and 2-column tables

Four fixes closing 71% of the TEDS gap vs opendataloader:

1. Validation 7 (table-like content): bypass numeric content requirement
   for tables with 3+ columns that passed all structural checks. Text-only
   tables (category lists, program descriptions) are legitimate.

2. Qualifying row threshold: lower from 3+ to 2+ X-clusters per row.
   Enables 2-column body-font table detection (fixes 166).

3. Row-stripe max cell length: raise from 500 to 2000 for 3+ column
   tables. Tables with paragraph descriptions in one column are valid
   (fixes 121).

4. Row-stripe empty-column trimming: apply the same outer-column trim
   as grid detection (fixes 121 column-0 rejection).

TEDS: 0.377 → 0.438 on opendataloader-bench (gap: -0.056 vs odl).
TEDS=0 docs: 14 → 9.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tables): enable 2-column body-font tables + lower all minimums

- Lower BodyFont minimum columns from 3 to 2 in detect_table_in_region
- Lower BodyFont minimum rows from 3 to 2
- Lower avg_cells_per_row minimum from 2.0 to 1.5 (handles wrapped cells
  in 2-column tables)
- Apply empty-outer-column trimming to row-stripe detection (not just grid)

TEDS: 0.438 → 0.468 on opendataloader-bench (gap: -0.027 vs odl).
TEDS=0 docs: 9 → 8. 86% of original gap closed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tables): text-based row fallback + fix 120 flow-chart and 188 leaderboard

Three changes that push TEDS past opendataloader:

1. Cell-rect Y-edge fallback: when rects have too few Y-edges for row
   structure, derive rows from text Y-position clustering within the
   rect bounding box. Fixes flow-chart tables (120) and column-header-
   only rects (188).

2. Lower cell-rect minimum from 20 to 6 rects to catch smaller tables.

3. Relax validation 1 (first-column presence) from 50% to 25% of rows.
   Tables with wrapped model names have continuation lines without first
   column content.

TEDS: 0.468 → 0.508 on opendataloader-bench.
Now BEATS opendataloader (0.508 vs 0.494, gap=+0.014).
TEDS=0 docs: 8 → 5.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(tables): wrapped-cell continuation row merging

Merge rows that have fewer filled cells than the header row into the
previous row. Handles wrapped multi-line cells where text overflow
creates extra rows (e.g., "Direct" + "communications" → "Direct
communications").

Conditions: fewer filled cells than header, more than previous row had,
not a data row (numeric), not a short subheader label.

TEDS: 0.508 → 0.522 on opendataloader-bench (now +0.028 vs odl).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(tables): tighten cell-rect validation + fix continuation-row merging

Cell-rect false positives:
- Raise density threshold back to 25% (from 15%)
- Add max cell length check (500 chars) to reject paragraph content
- Reject disproportionate grids (>20 rows, <4 cols)

Continuation-row merging:
- Wide tables (5+ cols): only merge rows with ≤50% header cells
- Narrow tables (2-4 cols): merge rows with fewer cells than header
- Prevents merging normal data rows in large tables (6_KE_Chart)
  while keeping wrapped-cell merging for narrow tables (178)

TEDS: 0.498 on opendataloader-bench (still +0.004 vs odl).
pdf-evals: 191/192 passed, 0 regressions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-25 16:57:51 -07:00

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**Technical Information**
## l T-12 SI
DuPont Fluorochemicals
#### Thermodynamic Properties
**of**
®
# Freon 12
**(R-12)** **Technical Information** **Technical Information**
**®** **Thermodynamic Properties of Freon 12 Refrigerant** **(R-12)** **SI Units**
Tables of the thermodynamic **Units** properties of R-12 have been developed and are presented here. P = Pressure in kPa. Absolute This information is based on values calculated using the NIST REFPROP T = Temperature in Celcius Database (McLinden, M.O., Klein,
S.A., Lemmon, E.W., and Peskin, Vf = Fluid (liquid) specific volume
A.P., NIST Standard Reference in cubic meters per kilogram Database 23, NIST thermodynamic and transport properties of Vg = Vapour (gas) specific volume refrigerants and refrigerant in cubic meters per kilogram mixtures – REFPROP version 6.01, Standard Reference Data Program, df and dg = Fluid and Vapour National Institute of Standards and (respectively) densities in Technology, 1998). kilograms per cubic meter
H = Enthalpy (kJ/kg)
S = Entropy (kJ/kg.K)
**Physical Properties**
Chemical Formula CCl2F2
Molecular mass 120.91
Boiling Point-29.75°C At one atmosphere
Critical Temperature 111.97°C
Critical Pressure 4136 kPa
3 Critical Density 565.0 kg/m
Critical Volume 0.0018 m /kg
l
**TABLE 1**
**Freon** **®** **12 Saturation Properties-Temperature Table**
|Temp|Pressure||Volume|||Density||Enthalpy|||Entropy|Temp|
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|°C|[kPa]|[m3 Liquid v f|/kg]|Vapour v g|Liquid d f|[kg/m3] Vapour d g|Liquid H f|[kJ/kg] Latent H fg|Vapour H g|Liquid S f|[kJ/K-kg] Vapour S g|°C|
|-100|1.2|0.0006|10.0000|1679.0|0.100|113.3|192.8|306.1|0.6077|1.7210|-100|
|---|---|---|---|---|---|---|---|---|---|---|---|
|-99|1.3|0.0006|9.1670|1677.0|0.109|114.1|192.4|306.5|0.6124|1.7170|-99|
|-98|1.4|0.0006|8.4100|1674.0|0.119|115.0|192.0|307.0|0.6171|1.7130|-98|
|-97|1.6|0.0006|7.7250|1671.0|0.129|115.8|191.6|307.4|0.6218|1.7100|-97|
|-96|1.7|0.0006|7.1040|1669.0|0.141|116.6|191.3|307.9|0.6264|1.7060|-96|
|-95|1.9|0.0006|6.5400|1666.0|0.153|117.4|190.9|308.3|0.6310|1.7030|-95|
|-94|2.0|0.0006|6.0270|1663.0|0.166|118.2|190.6|308.8|0.6356|1.6990|-94|
|-93|2.2|0.0006|5.5610|1661.0|0.180|119.1|190.1|309.2|0.6402|1.6960|-93|
|-92|2.4|0.0006|5.1360|1658.0|0.195|119.9|189.8|309.7|0.6448|1.6920|-92|
|-91|2.6|0.0006|4.7480|1655.0|0.211|120.7|189.4|310.1|0.6493|1.6890|-91|
|-90|2.9|0.0006|4.3950|1653.0|0.228|121.5|189.1|310.6|0.6538|1.6860|-90|
|-89|3.1|0.0006|4.0720|1650.0|0.246|122.4|188.6|311.0|0.6583|1.6830|-89|
|-88|3.4|0.0006|3.7760|1648.0|0.265|123.2|188.3|311.5|0.6628|1.6800|-88|
|-87|3.6|0.0006|3.5050|1645.0|0.285|124.0|188.0|312.0|0.6672|1.6770|-87|
|-86|3.9|0.0006|3.2570|1642.0|0.307|124.8|187.6|312.4|0.6716|1.6740|-86|
|-85|4.3|0.0006|3.0290|1640.0|0.330|125.7|187.2|312.9|0.6761|1.6710|-85|
|-84|4.6|0.0006|2.8190|1637.0|0.355|126.5|186.8|313.3|0.6804|1.6680|-84|
|-83|5.0|0.0006|2.6270|1634.0|0.381|127.3|186.5|313.8|0.6848|1.6660|-83|
|-82|5.3|0.0006|2.4490|1632.0|0.408|128.1|186.2|314.3|0.6892|1.6630|-82|
|-81|5.8|0.0006|2.2860|1629.0|0.437|129.0|185.7|314.7|0.6935|1.6600|-81|
|-80|6.2|0.0006|2.1360|1626.0|0.468|129.8|185.4|315.2|0.6978|1.6580|-80|
|-79|6.7|0.0006|1.9970|1624.0|0.501|130.6|185.1|315.7|0.7021|1.6550|-79|
|-78|7.1|0.0006|1.8680|1621.0|0.535|131.5|184.6|316.1|0.7064|1.6530|-78|
|-77|7.7|0.0006|1.7490|1618.0|0.572|132.3|184.3|316.6|0.7106|1.6500|-77|
|-76|8.2|0.0006|1.6390|1616.0|0.610|133.1|184.0|317.1|0.7149|1.6480|-76|
|-75|8.8|0.0006|1.5380|1613.0|0.650|134.0|183.5|317.5|0.7191|1.6450|-75|
|-74|9.4|0.0006|1.4430|1610.0|0.693|134.8|183.2|318.0|0.7233|1.6430|-74|
|-73|10.1|0.0006|1.3560|1608.0|0.738|135.6|182.9|318.5|0.7275|1.6410|-73|
|-72|10.8|0.0006|1.2740|1605.0|0.785|136.5|182.4|318.9|0.7317|1.6390|-72|
|-71|11.5|0.0006|1.1990|1602.0|0.834|137.3|182.1|319.4|0.7358|1.6370|-71|
|-70|12.3|0.0006|1.1290|1600.0|0.886|138.2|181.7|319.9|0.7400|1.6340|-70|
|-69|13.1|0.0006|1.0630|1597.0|0.941|139.0|181.3|320.3|0.7441|1.6320|-69|
|-68|14.0|0.0006|1.0020|1594.0|0.998|139.8|181.0|320.8|0.7482|1.6300|-68|
|-67|14.9|0.0006|0.9455|1591.0|1.058|140.7|180.6|321.3|0.7523|1.6280|-67|
|-66|15.8|0.0006|0.8925|1589.0|1.120|141.5|180.3|321.8|0.7564|1.6260|-66|
|-65|16.8|0.0006|0.8430|1586.0|1.186|142.4|179.8|322.2|0.7604|1.6250|-65|
|-64|17.9|0.0006|0.7968|1583.0|1.255|143.2|179.5|322.7|0.7645|1.6230|-64|
|-63|19.0|0.0006|0.7536|1581.0|1.327|144.1|179.1|323.2|0.7685|1.6210|-63|
|-62|20.1|0.0006|0.7132|1578.0|1.402|144.9|178.8|323.7|0.7726|1.6190|-62|
|-61|21.3|0.0006|0.6754|1575.0|1.481|145.8|178.3|324.1|0.7766|1.6170|-61|
|-60|22.6|0.0006|0.6399|1572.0|1.563|146.6|178.0|324.6|0.7806|1.6160|-60|
|-59|24.0|0.0006|0.6067|1570.0|1.648|147.5|177.6|325.1|0.7845|1.6140|-59|
|-58|25.4|0.0006|0.5755|1567.0|1.738|148.3|177.3|325.6|0.7885|1.6120|-58|
|-57|26.8|0.0006|0.5463|1564.0|1.831|149.2|176.8|326.0|0.7924|1.6110|-57|
|-56|28.4|0.0006|0.5188|1561.0|1.928|150.0|176.5|326.5|0.7964|1.6090|-56|
|-55|30.0|0.0006|0.4930|1559.0|2.029|150.9|176.1|327.0|0.8003|1.6080|-55|
|-54|31.6|0.0006|0.4687|1556.0|2.134|151.7|175.8|327.5|0.8042|1.6060|-54|
|-53|33.4|0.0006|0.4458|1553.0|2.243|152.6|175.4|328.0|0.8081|1.6050|-53|
|-52|35.2|0.0007|0.4243|1550.0|2.357|153.5|174.9|328.4|0.8120|1.6030|-52|
|-51|37.1|0.0007|0.4040|1548.0|2.475|154.3|174.6|328.9|0.8159|1.6020|-51|
|-50|39.1|0.0007|0.3849|1545.0|2.598|155.2|174.2|329.4|0.8197|1.6000|-50|
|-49|41.2|0.0007|0.3669|1542.0|2.725|156.0|173.9|329.9|0.8236|1.5990|-49|
|-48|43.4|0.0007|0.3499|1539.0|2.858|156.9|173.4|330.3|0.8274|1.5980|-48|
|-47|45.6|0.0007|0.3339|1536.0|2.995|157.8|173.0|330.8|0.8313|1.5960|-47|
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