LightOnOCR 3 4B for LM-Kit
This repository holds LightOnOCR-3-4B packaged for LM-Kit.NET, LM-Kit's on-device AI SDK for .NET, and for LM-Kit One.
| File | Content |
|---|---|
lightonocr-3-4b-Q4_K_M.lmk | The model and its vision projector, both quantized to Q4_K_M, in one archive. This is the file LM-Kit downloads. |
lightonocr-3-4b-F16.gguf | The language model at full precision (F16). |
lightonocr-3-4b-mmproj-F16.gguf | The vision projector at full precision (F16). |
About LightOnOCR 3
LightOnOCR 3 is LightOn's third generation of end-to-end OCR models. It comes in three sizes:
| LM-Kit model ID | Architecture | Notes |
|---|---|---|
lightonocr-3:0.8b | Qwen3.5 vision-language | The fastest size |
lightonocr-3:1b | LightOnOCR 2 (Pixtral vision encoder, Qwen3 decoder) | A drop-in upgrade for LightOnOCR 2 deployments |
lightonocr-3:4b | Qwen3.5 vision-language | The most accurate size |
The models have two modes:
- Transcription: the page is returned as clean Markdown in natural reading order, with tables in HTML and formulas in LaTeX.
- Grounding: every block of the page is returned with a label (title, text, list, table, formula, caption, header, footer, page number, footnote, image, chart, ...) and a bounding box. Images get a short description, and charts become an HTML table of their data points.
LM-Kit maps both modes onto VlmOcr intents, so you never write a prompt:
VlmOcrIntent | Mode | Result |
|---|---|---|
Markdown, PlainText | Transcription | The page text |
OcrWithCoordinates | Grounding | The page's text blocks, each with its bounding box in source image pixels and its layout category |
LayoutAnalysis | Grounding | Every block, figures included, with its category; the JSON payload in VlmOcrResult.NormalizedText |
TableRecognition, FormulaRecognition, ChartRecognition | Grounding | The page's tables, formulas or chart data tables |
Pages are fed at the resolution the models were trained on (a 2048 px longest edge at ImageDetail.High).
Usage
using LMKit.Document.Conversion;
using LMKit.Extraction.Ocr;
using LMKit.Model;
LM model = LM.LoadFromModelID("lightonocr-3:4b");
// Document to Markdown.
var converter = new DocumentToMarkdown(model);
string markdown = converter.Convert("report.pdf").Markdown;
// Layout analysis: positioned, categorized blocks.
var ocr = new VlmOcr(model, VlmOcrIntent.LayoutAnalysis);
var result = ocr.Run(new LMKit.Data.Attachment("page.png"));
foreach (var element in result.PageElement.TextElements)
{
Console.WriteLine($"{element.Category} at ({element.Left:0}, {element.Top:0}): {element.Text}");
}
License
The model weights are released by LightOn under the Apache License 2.0. See the original model card for training details and the authors' evaluation.