AI图片识别文字

AI Optical character recognition

AI
R
Python
Author

Tony D

Published

April 21, 2025

with Gemini 2.5 online/InternVL3 offline

Using Gemini 2.5 online

Code
from google import genai
import keyring
from PIL import Image
import torchvision.transforms as T
from torchvision.transforms.functional import InterpolationMode
import sys
import pickle
import math
import numpy as np
import torch
Code
client = genai.Client(api_key=keyring.get_password("system", "google_ai_api_key"))

list model

Code
print("List of models:\n")
for m in client.models.list():
    for action in m.supported_actions:
       # if action == "generateContent":
            print(m.name+" "+ action)

English Extract

Code
image = Image.open("images/english.jpg")

response_gemini_en = client.models.generate_content(
    model="gemini-2.5-pro-exp-03-25",
    contents=[image, "Extract text from image"])
Code
print(response_gemini_en.text)
Write slowly and take the time
to make sure each letter
is the perfect shape

chinese Extract

Code
image = Image.open("images/chinese.png")

response_gemini = client.models.generate_content(
    model="gemini-2.5-pro-exp-03-25",
    contents=[image, "提取图上的文字"])
Code
print(response_gemini.text)
放养

把我不羁的灵魂
放养在可可西里的草原上,
藏雪狐活泼没人爱人
我与它捉迷藏

把我不羁的灵魂,
放养在撒哈拉沙漠上,
看生命在贫瘠的土地上,
依然欣欣向荣地生长

把我不羁的灵魂
放养在昏黄遗迹的小岛
坐上星期五的木筏
勇敢地乘风破浪

把我不羁的灵魂
放养在天涯海角
就让我自由地去流浪。

Using InternVL3 1B model offline

https://huggingface.co/OpenGVLab/InternVL3-8B-hf

If using better model will increase accuracy

Code
print(sys.version)
Code
pip install --upgrade transformers
pip install einops timm
pip install -U bitsandbytes
Code
import os
os.system('pip show transformers')
Code
import torch
from transformers import AutoTokenizer, AutoModel,pipeline
path = "OpenGVLab/InternVL3-1B"

model = AutoModel.from_pretrained(path,torch_dtype=torch.bfloat16,trust_remote_code=True).eval()

tokenizer = AutoTokenizer.from_pretrained(path, trust_remote_code=True)
Code
generation_config = dict(max_new_tokens=1024, do_sample=True)

testing

Code
question = 'Hello, who are you?'
response, history = model.chat(tokenizer, None, question, generation_config, history=None, return_history=True)
print(f'User: {question}\nAssistant: {response}')

single-image single-round conversation (单图单轮对话)

Code
IMAGENET_MEAN = (0.485, 0.456, 0.406)
IMAGENET_STD = (0.229, 0.224, 0.225)

def build_transform(input_size):
    MEAN, STD = IMAGENET_MEAN, IMAGENET_STD
    transform = T.Compose([
        T.Lambda(lambda img: img.convert('RGB') if img.mode != 'RGB' else img),
        T.Resize((input_size, input_size), interpolation=InterpolationMode.BICUBIC),
        T.ToTensor(),
        T.Normalize(mean=MEAN, std=STD)
    ])
    return transform

def find_closest_aspect_ratio(aspect_ratio, target_ratios, width, height, image_size):
    best_ratio_diff = float('inf')
    best_ratio = (1, 1)
    area = width * height
    for ratio in target_ratios:
        target_aspect_ratio = ratio[0] / ratio[1]
        ratio_diff = abs(aspect_ratio - target_aspect_ratio)
        if ratio_diff < best_ratio_diff:
            best_ratio_diff = ratio_diff
            best_ratio = ratio
        elif ratio_diff == best_ratio_diff:
            if area > 0.5 * image_size * image_size * ratio[0] * ratio[1]:
                best_ratio = ratio
    return best_ratio

def dynamic_preprocess(image, min_num=1, max_num=12, image_size=448, use_thumbnail=False):
    orig_width, orig_height = image.size
    aspect_ratio = orig_width / orig_height

    # calculate the existing image aspect ratio
    target_ratios = set(
        (i, j) for n in range(min_num, max_num + 1) for i in range(1, n + 1) for j in range(1, n + 1) if
        i * j <= max_num and i * j >= min_num)
    target_ratios = sorted(target_ratios, key=lambda x: x[0] * x[1])

    # find the closest aspect ratio to the target
    target_aspect_ratio = find_closest_aspect_ratio(
        aspect_ratio, target_ratios, orig_width, orig_height, image_size)

    # calculate the target width and height
    target_width = image_size * target_aspect_ratio[0]
    target_height = image_size * target_aspect_ratio[1]
    blocks = target_aspect_ratio[0] * target_aspect_ratio[1]

    # resize the image
    resized_img = image.resize((target_width, target_height))
    processed_images = []
    for i in range(blocks):
        box = (
            (i % (target_width // image_size)) * image_size,
            (i // (target_width // image_size)) * image_size,
            ((i % (target_width // image_size)) + 1) * image_size,
            ((i // (target_width // image_size)) + 1) * image_size
        )
        # split the image
        split_img = resized_img.crop(box)
        processed_images.append(split_img)
    assert len(processed_images) == blocks
    if use_thumbnail and len(processed_images) != 1:
        thumbnail_img = image.resize((image_size, image_size))
        processed_images.append(thumbnail_img)
    return processed_images

def load_image(image_file, input_size=448, max_num=12):
    image = Image.open(image_file).convert('RGB')
    transform = build_transform(input_size=input_size)
    images = dynamic_preprocess(image, image_size=input_size, use_thumbnail=True, max_num=max_num)
    pixel_values = [transform(image) for image in images]
    pixel_values = torch.stack(pixel_values)
    return pixel_values

def split_model(model_name):
    device_map = {}
    world_size = torch.cuda.device_count()
    config = AutoConfig.from_pretrained(model_path, trust_remote_code=True)
    num_layers = config.llm_config.num_hidden_layers
    # Since the first GPU will be used for ViT, treat it as half a GPU.
    num_layers_per_gpu = math.ceil(num_layers / (world_size - 0.5))
    num_layers_per_gpu = [num_layers_per_gpu] * world_size
    num_layers_per_gpu[0] = math.ceil(num_layers_per_gpu[0] * 0.5)
    layer_cnt = 0
    for i, num_layer in enumerate(num_layers_per_gpu):
        for j in range(num_layer):
            device_map[f'language_model.model.layers.{layer_cnt}'] = i
            layer_cnt += 1
    device_map['vision_model'] = 0
    device_map['mlp1'] = 0
    device_map['language_model.model.tok_embeddings'] = 0
    device_map['language_model.model.embed_tokens'] = 0
    device_map['language_model.output'] = 0
    device_map['language_model.model.norm'] = 0
    device_map['language_model.model.rotary_emb'] = 0
    device_map['language_model.lm_head'] = 0
    device_map[f'language_model.model.layers.{num_layers - 1}'] = 0

    return device_map

English Extract

Code
pixel_values = load_image('images/english.jpg').to(torch.bfloat16)
question = '<image>\nPlease Extract text from image'
response_en = model.chat(tokenizer, pixel_values, question, generation_config)
Code
print(response_en)
Write slowly and take the time to make sure each letter is the perfect shape

Chinese Extract

Code
pixel_values = load_image('images/chinese.png').to(torch.bfloat16)

question = '<image>\n提取图上的文字'
response = model.chat(tokenizer, pixel_values, question, generation_config)
Code
print(response)
放养  
把我不羁的灵魂  
放在了鄂西西里的草原上,  
藏雪狐活发爱人  
我与它捉迷藏  
把我不羁的灵魂  
放在撒哈拉沙漠上,  
看生命在贫瘠的土地上,  
依然欣欣欣荣地生长  
把我不羁的灵魂  
放在鲁滨逊的小岛上  
坐上星期五的木筏  
勇敢地乘风破浪  

把我不羁的灵魂  
放养在天涯海角  
让我自由地去流浪。