MUSTARD

A structured repackaging of badrivishalk/MUSTARD that surfaces the OTSL annotations and language metadata as proper dataset columns.

MUSTARD (Multilingual Scanned and Scene Table Structure Recognition Dataset) contains 1,429 table images across 13 languages, annotated with OTSL (Optimized Table Structure Language) sequences for table structure recognition. Introduced by the SPRINT paper (ICDAR 2024).

This is an evaluation-only benchmark (test split only, no train).

Why this version

The original upload uses imagefolder format, which means the OTSL annotations in merged.txt are not exposed as columns in the dataset viewer or via load_dataset. Loading it returns only {"image": ...} with no annotation access.

This version gives you:

{
  "image_id":    "indic/assamese/1",         # stable identifier
  "image":       <PIL Image>,
  "width":       2210,
  "height":      1394,
  "language":    "assamese",                 # 13 values
  "script_type": "indic",                    # "indic" or "scenetext"
  "has_lines":   True,                       # scenetext: whether grid lines visible
  "otsl":        "FFFLFFFNUUFFUUUN...",
  "n_rows":      10,
  "n_cols":      7,
}

Schema

Field	Type	Description
image_id	string	Stable path-derived identifier (e.g. indic/assamese/1, scenetext/chinese_lines/1)
image	Image	Table image (PNG)
width	int32	Image width in pixels
height	int32	Image height in pixels
language	string	One of 13 languages (see table below)
script_type	string	"indic" for printed/scanned Indic-script tables; "scenetext" for scene-text tables
has_lines	bool	For scenetext: whether the table has visible grid lines. Always True for indic.
otsl	string	OTSL annotation sequence (see format below)
n_rows	int32	Number of table rows decoded from OTSL
n_cols	int32	Number of table columns decoded from OTSL (max row width)

Language distribution

Language	Script type	Count
assamese	indic	101
bengali	indic	100
chinese	indic + scenetext	207
english	scenetext	109
gujarati	indic	101
hindi	indic	101
kannada	indic	101
malayalam	indic	102
oriya	indic	101
punjabi	indic	102
tamil	indic	100
telugu	indic	102
urdu	indic	102
Total		1,429

Scenetext subset: 111 with visible grid lines (has_lines=True), 103 without (has_lines=False).

OTSL format

OTSL (Optimized Table Structure Language) encodes table structure as a flat token sequence. Rows are delimited by N; within each row, each character is one cell:

Token	Meaning
F	Regular cell (no span)
L	Cell spanning left (continuation of the cell immediately to its left)
U	Cell spanning up (continuation of the cell directly above)
E	Cell spanning both left and up (interior merge corner)
X	Empty/non-data cell

Example: FFLNFFN = a 2-row, 3-column table where row 1 has a merged cell in columns 2-3 (F F L) and row 2 is all regular cells (F F).

Decode OTSL to an HTML table

def otsl_to_html(otsl: str) -> str:
    rows = [r for r in otsl.split("N") if r]
    n_cols = max(len(r) for r in rows)

    # First pass: compute colspan/rowspan
    grid = [[None] * n_cols for _ in range(len(rows))]
    spans = {}

    for r, row in enumerate(rows):
        for c, tok in enumerate(row):
            if tok == "F":
                spans[(r, c)] = [1, 1]
                grid[r][c] = (r, c)
            elif tok == "L":
                origin = grid[r][c - 1]
                spans[origin][1] += 1
                grid[r][c] = origin
            elif tok == "U":
                origin = grid[r - 1][c]
                spans[origin][0] += 1
                grid[r][c] = origin
            elif tok == "E":
                origin = grid[r - 1][c - 1]
                grid[r][c] = origin

    # Second pass: emit HTML
    html = ["<table>"]
    for r, row in enumerate(rows):
        html.append("  <tr>")
        for c in range(len(row)):
            if grid[r][c] == (r, c):
                rs, cs = spans[(r, c)]
                attrs = ""
                if rs > 1:
                    attrs += f' rowspan="{rs}"'
                if cs > 1:
                    attrs += f' colspan="{cs}"'
                html.append(f"    <td{attrs}></td>")
        html.append("  </tr>")
    html.append("</table>")
    return "\n".join(html)

Usage

from datasets import load_dataset

ds = load_dataset("rootsautomation/MUSTARD", split="test")

# Filter to a single language
hindi = ds.filter(lambda x: x["language"] == "hindi")

# Filter to scenetext with lines
scene_lines = ds.filter(lambda x: x["script_type"] == "scenetext" and x["has_lines"])

# Access a sample
row = ds[0]
print(row["language"], row["n_rows"], "x", row["n_cols"])
row["image"].show()

License

MIT. Source data curated by the IIT Bombay LEAP OCR Team. See badrivishalk/MUSTARD for the original release.

Citation

@inproceedings{sprint2024,
  title     = {SPRINT: Script-agnostic Structure Recognition in Tables},
  booktitle = {Document Analysis and Recognition -- ICDAR 2024},
  year      = {2024},
  note      = {arXiv:2503.11932}
}