虚拟现实环境下的远程教育和智能评估系统（十一）

视频帧画面知识点区域划分

知识点区域精确分割技术:

在深度学习检测模型结果基础上使用基于交并比（IoU）阈值的目标合并算法，合并过度重合目标区域面积，实现知识点区域精确分割

多模态知识点内容匹配策略:

图像：利用GPT-4模型的多模态处理能力，将视频帧中的图像与预设的知识点语义注解进行匹配 文本：使用Sentence Transformer模型对视频帧中提取的文本内容进行深度语义编码，将其嵌入向量与知识点数据库中的语义向量进行比较。通过计算语义相似度，精确匹配相关知识点，实现高效的文本内容到知识点的映射；

自此，可以使视频帧画面的各部分都有对应的知识点；

import os
import re
from sentence_transformers import SentenceTransformer, util
from test_gpt import detection_gpt

# 初始化Sentence Transformer模型
model = SentenceTransformer('all-MiniLM-L6-v2')

def get_embedding(text):
    return model.encode(text, convert_to_tensor=True)

def semantic_similarity(text1, text2):
    embedding1 = get_embedding(text1)
    embedding2 = get_embedding(text2)
    return util.pytorch_cos_sim(embedding1, embedding2).item()

def parse_knowledge_content(content):
    knowledge_points = []
    kp_blocks = content.strip().split("\n\n")
    for block in kp_blocks:
        lines = block.split("\n")
        kp_dict = {}
        for line in lines:
            key, value = line.split(":", 1)
            kp_dict[key.strip()] = value.strip()
        knowledge_points.append(kp_dict)
    return knowledge_points

def read_knowledge_file(timestamp, json_folder_path):
    knowledge_file_path = os.path.join(json_folder_path, f"{timestamp}.txt")
    try:
        with open(knowledge_file_path, 'r') as file:
            content = file.read()
        return parse_knowledge_content(content)
    except FileNotFoundError:
        return "Knowledge file not found"
    except Exception as e:
        return str(e)

def parse_merge_text(file_path):
    with open(file_path, 'r') as file:
        content = file.read()
    timestamps = re.split(r'Timestamp: (\d+)', content)[1:]
    timestamp_data = {timestamps[i]: timestamps[i+1] for i in range(0, len(timestamps), 2)}
    return timestamp_data

def kp_match_data(merge_text_path, json_folder_path, object_frames_folder, output_path):
    data = parse_merge_text(merge_text_path)
    output_data = []
    
    for timestamp, contents in data.items():
        knowledge_content = read_knowledge_file(timestamp, json_folder_path)
        knowledge_txt_path = os.path.join("json_files", f"{timestamp}.txt")
        if isinstance(knowledge_content, str):
            output_data.append(f"Timestamp: {timestamp}\n{contents}\n{knowledge_content}\n")
            continue
        try:
            with open(knowledge_txt_path, 'r', encoding='utf-8') as file:
                knowledge_txt = file.read()
        except FileNotFoundError:
            print(f"Knowledge file not found for timestamp {timestamp}")
            continue    

        contents_processed = contents
        detection_matches = re.findall(r'(Detection \d+): \((\d+, \d+, \d+, \d+)\)', contents)
        for match in detection_matches:
            detection_label, detection_data = match
            detection_number = detection_label.split(' ')[1].lower()  # e.g., 'detection1'
            detection_image_path = os.path.join(object_frames_folder, f"{timestamp}_detection{detection_number}.jpg")
            kp_id = detection_gpt(detection_image_path, knowledge_txt)
            contents_processed = contents_processed.replace(detection_label, f"{detection_label} (Knowledge_pdoint_id: {kp_id})")
        
        ocr_texts = re.findall(r'OCR \d+: \(\d+, \d+, \d+, \d+\) (.+)', contents)
        for ocr_text in ocr_texts:
            best_match = None
            best_score = -float('inf')
            for kp in knowledge_content:
                score = semantic_similarity(ocr_text, kp['Original_text'])

                if score > best_score:
                    best_match = kp
                    best_score = score
            if best_match:
                contents_processed = contents_processed.replace(
                    ocr_text, 
                    f"(Knowledge_point_id: {best_match['Knowledge_point_id']}) {ocr_text}"
                )
        output_data.append(f"Timestamp: {timestamp}\n{contents_processed}\n")

    with open(output_path, 'w', encoding='utf-8') as file:
        file.write("\n".join(output_data))

OCR得到的音频文本以及YOLO得到的detection区域对应知识点匹配：

下一步即是匹配三方数据：语音文本知识点、帧知识点区域、实时注视点位置