Keural Mid VLM — Bilingual (EN / KO)

Developed by MKD Co., Ltd. · Encoder: keural-vision-encoder-mid · Code: github.com/mkd-hika/Keural-VLM-Mid-level

A bilingual vision-language model built on Keural Mid, a 183.6M-parameter vision encoder trained from random initialization — not a CLIP, ViT or DINO derivative.

This repository contains the trained bridge only: a projector and LoRA adapters, 37 MB total. The encoder and decoder load from their own repositories.

Measured vision contribution

A vision-language model can post respectable scores while barely using the image — "what colour is the banana?" is answerable from language priors alone. Every benchmark below was therefore run twice: once normally, once with the visual tokens removed and everything else held constant.

The delta is the encoder's contribution. It is the one number a language model cannot manufacture.

Benchmark	With image	Blind	Δ
POPE accuracy · n=2,000	70.50%	44.55%	+25.95
POPE F1 · n=2,000	70.59%	23.46%	+47.13
VQAv2 strict · n=5,000	53.04%	39.83%	+13.21
VQAv2 lenient · n=5,000	53.58%	40.27%	+13.31
MME total, 14 categories · n=2,374	1258.9	812.0	+446.9
MMBench · n=4,377	60.20%	—	—
Held-out perplexity · KO / EN	2.15 / 2.99	—	—

Two figures qualify the headline numbers and are reported because they are what a careful reader will check:

POPE yes-ratio is 0.492 against a gold ratio of 0.500. The model discriminates on object existence rather than defaulting to one answer. A model replying "yes" indiscriminately scores ~50% accuracy while being useless, so accuracy without the yes-ratio is uninterpretable.

The blind VQAv2 score of 39.83% lands where language-prior performance is expected. That the baseline behaves as theory predicts is corroborating evidence that the measurement itself is sound.

Composition

Component	Source	Trained here	Size
Vision encoder	`keural-vision-encoder-mid`	frozen	700 MB
Decoder	`Qwen/Qwen2.5-7B-Instruct`	frozen	15 GB
LevelAwareProjector	this repo	8.9M	17 MB
LoRA adapters · r=16 α=32	this repo	5.0M	20 MB

14.0M trainable parameters against 7.8B frozen. The encoder is never fine-tuned at any learning rate, so every result above is attributable to the Stage 1 representation plus a trained bridge.

Usage

import torch, torchvision.transforms as T
from PIL import Image
from transformers import AutoModel, AutoModelForCausalLM, AutoTokenizer
from peft import PeftModel
from huggingface_hub import hf_hub_download
from alignment.projectors import LevelAwareProjector   # github.com/mkd-hika/Keural-VLM-Mid-level

DT = torch.bfloat16
REPO = "mkd-hika/keural-mid-vlm-bilingual"

vision = AutoModel.from_pretrained(
    "mkd-hika/keural-vision-encoder-mid", trust_remote_code=True, dtype=DT).cuda().eval()

tok = AutoTokenizer.from_pretrained("Qwen/Qwen2.5-7B-Instruct")
llm = AutoModelForCausalLM.from_pretrained(
    "Qwen/Qwen2.5-7B-Instruct", dtype=DT, device_map="auto")
llm = PeftModel.from_pretrained(llm, REPO).eval()

proj = LevelAwareProjector(encoder_dim=768, llm_dim=3584, hidden_dim=2048).cuda().to(DT)
proj.load_state_dict(torch.load(hf_hub_download(REPO, "projector.pt")))
proj.eval()

tf = T.Compose([T.Resize((512, 512)), T.ToTensor(),
                T.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])])

@torch.no_grad()
def ask(image_path: str, question: str) -> str:
    px  = tf(Image.open(image_path).convert("RGB")).unsqueeze(0).cuda().to(DT)
    vis = proj(vision(px, token_budget=512))                    # (1, 512, 3584)
    emb = llm.get_input_embeddings()
    ids = tok.apply_chat_template([{"role": "user", "content": question}],
                                  tokenize=True, add_generation_prompt=True,
                                  return_tensors="pt").to(vis.device)
    inp = torch.cat([vis, emb(ids).to(DT)], dim=1)
    out = llm.generate(
        inputs_embeds=inp,
        attention_mask=torch.ones(inp.shape[:2], dtype=torch.long, device=vis.device),
        max_new_tokens=128, do_sample=False, pad_token_id=tok.pad_token_id)
    return tok.decode(out[0], skip_special_tokens=True)

ask("photo.jpg", "What is in this image?")
ask("photo.jpg", "이 이미지에 무엇이 있나요?")

Inference must run at 512×512 with a 512-token budget. Both are what Stage 2 trained at, neither is auto-detected, and a mismatch degrades output silently with no error raised.

Training

Phase	Objective	Data	Records	Steps	LR	Held-out ppl
2a	Projector alignment	LLaVA-Pretrain	557,128	5,000	5e-4	31.81 → 17.30 (EN)
2b	Supervised instruction tuning	LLaVA-Instruct-150K	156,712	8,000	2e-5	3.22 → 2.90 (EN)
2b	Bilingual SFT	Merged EN/KO	603,255	12,000	2e-5	2.90 → 2.14 (KO)

2× NVIDIA H200 · DistributedDataParallel · bfloat16 · effective batch 64 · seed 42. Label masking supervises assistant turns only, so the model learns to answer rather than to reproduce the question.

On the bilingual mixture. It is 60% Korean / 40% English, rebalanced from an original 70/30 in response to a measured failure rather than a hunch. The English-only model scored 1.73% strict against 48.60% lenient on VQAv2 — a 47-point divergence caused by answer format, not perception. Asked "Is this rice noodle soup?" with gold answer "yes", it replied "Yes, this is a bowl of rice noodle soup", which exact-match scoring credits as zero. The mixture carried only verbose conversational data and no English short-answer supervision. Adding 84,590 short-answer records raised strict accuracy to 53.04%, and strict and lenient now agree to within 0.54 points.

Scope and limitations

Long-form generation fabricates detail. Asked for a detailed description the model invents plausible objects that are not present. Short answers are substantially more reliable, so answer length functions as a reliability control rather than a stylistic one.
Text recognition is partial. No OCR data was used in training. The model scores 110.0 on the MME OCR category against a blind 50.0 and reads large, high-contrast signage, but not documents or small text.
Output is sensitive to prompt phrasing. On POPE, the instruction "Answer yes or no only" — absent from training — collapsed the yes-ratio to 0.050, while the trained phrasing gave 0.492. Prompts resembling the training format behave materially differently from those that do not.
The encoder bounds everything downstream. At 37.2% zero-shot ImageNet it is undertrained relative to CLIP ViT-L/14 (~75%), and its Stage 1 loss was still declining when the run ended.
Single images only. No temporal modelling.

Citation

@misc{keural_mid_vlm_2026,
  title  = {Keural Mid VLM: A Bilingual Vision-Language Model on an
            Adaptive-Tokenization Encoder},
  author = {Barki, Hika},
  year   = {2026},
  url    = {https://huggingface.co/mkd-hika/keural-mid-vlm-bilingual},
  note   = {MKD Co., Ltd.}
}

License — Proprietary, MKD Co., Ltd. Qwen2.5-7B-Instruct (Apache-2.0) is used as the decoder and is not redistributed here.