SurfSense/surfsense_backend/app/etl_pipeline/parsers/vision_llm.py
DESKTOP-RTLN3BA\$punk c187b04e82 chore: linting
2026-05-15 17:33:44 -07:00

116 lines
4.3 KiB
Python

import asyncio
import base64
import os
from langchain_core.messages import HumanMessage
# Single-shot prompt used by standalone image uploads (.png/.jpg/etc).
# A standalone image IS the document, so we want everything: visual
# content plus any text the model can read off it. The output is
# combined markdown that the chunker treats as the full document body.
_PROMPT = (
"Describe this image in markdown. "
"Transcribe any visible text verbatim. "
"Be concise but complete — let the image content guide the level of detail."
)
# Per-image-in-PDF prompt. Here the image is *inside* a larger
# document, and the ETL service (Docling/Azure DI/LlamaCloud/...) is
# already running OCR over the whole page — including text rendered
# into images. So we explicitly tell the model NOT to transcribe text
# and to focus only on visual interpretation. This avoids paying
# output tokens for OCR content the ETL pipeline already captured.
_DESCRIPTION_PROMPT = (
"Describe what this image visually depicts in concise markdown. "
"Focus on visual content — anatomy, structures, charts, diagrams, "
"spatial relationships, colors, modality (e.g. axial CT, ECG strip, "
"histology slide), and any clinically or structurally relevant "
"findings.\n\n"
"Do NOT transcribe text from the image. Any text in the image "
"(axis labels, annotations, scale bars, lab values, etc.) is "
"already extracted by a separate OCR pipeline; duplicating it "
"here would be redundant. Stick to the visual interpretation."
)
_MAX_IMAGE_BYTES = (
5 * 1024 * 1024
) # 5 MB (Anthropic Claude's limit, the most restrictive)
_INVOKE_TIMEOUT_SECONDS = 120
_EXT_TO_MIME: dict[str, str] = {
".png": "image/png",
".jpg": "image/jpeg",
".jpeg": "image/jpeg",
".gif": "image/gif",
".bmp": "image/bmp",
".tiff": "image/tiff",
".tif": "image/tiff",
".webp": "image/webp",
".svg": "image/svg+xml",
".heic": "image/heic",
".heif": "image/heif",
}
def _image_to_data_url(file_path: str) -> str:
file_size = os.path.getsize(file_path)
if file_size > _MAX_IMAGE_BYTES:
raise ValueError(
f"Image too large for vision LLM ({file_size / (1024 * 1024):.1f} MB, "
f"limit {_MAX_IMAGE_BYTES // (1024 * 1024)} MB): {file_path}"
)
ext = os.path.splitext(file_path)[1].lower()
mime_type = _EXT_TO_MIME.get(ext)
if not mime_type:
raise ValueError(f"Unsupported image extension {ext!r}: {file_path}")
with open(file_path, "rb") as f:
encoded = base64.b64encode(f.read()).decode("ascii")
return f"data:{mime_type};base64,{encoded}"
async def _invoke_vision(llm, prompt: str, data_url: str, filename: str) -> str:
message = HumanMessage(
content=[
{"type": "text", "text": prompt},
{"type": "image_url", "image_url": {"url": data_url}},
]
)
response = await asyncio.wait_for(
llm.ainvoke([message]), timeout=_INVOKE_TIMEOUT_SECONDS
)
text = response.content if hasattr(response, "content") else str(response)
if not text or not text.strip():
raise ValueError(f"Vision LLM returned empty content for {filename}")
return text.strip()
async def parse_with_vision_llm(file_path: str, filename: str, llm) -> str:
"""Single-shot: returns combined markdown for a standalone image upload.
Used when the operator uploads an image file directly (jpg/png/etc).
The image is the document, so the prompt asks for both visual
description and verbatim text in one go.
"""
data_url = _image_to_data_url(file_path)
return await _invoke_vision(llm, _PROMPT, data_url, filename)
async def parse_image_for_description(file_path: str, filename: str, llm) -> str:
"""Visual-description-only call for per-image-in-PDF use.
Used by ``picture_describer`` when an image is embedded inside a
larger document. Returns a markdown description of what the image
visually depicts; deliberately does NOT include text-in-image OCR
because the ETL service (Docling, Azure DI, LlamaCloud, ...) is
already running OCR over the entire page and would duplicate that
text content.
"""
data_url = _image_to_data_url(file_path)
return await _invoke_vision(llm, _DESCRIPTION_PROMPT, data_url, filename)
__all__ = [
"parse_image_for_description",
"parse_with_vision_llm",
]