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Building a Visual Search Workflow

Pixeltable image search works in two phases:

  1. Define your workflow structure (once)
  2. Query your image database (anytime)
1

Install Dependencies

pip install pixeltable openai sentence-transformers

Define Your Workflow

Create table.py:

import pixeltable as pxt
from pixeltable.functions.openai import vision
from pixeltable.functions.huggingface import sentence_transformer

# Initialize app structure
pxt.drop_dir("image_search", force=True)
pxt.create_dir("image_search")

# Create images table
img_t = pxt.create_table(
  "image_search.images", 
  {"image": pxt.Image}
)

# Add OpenAI Vision analysis
img_t.add_computed_column(
  image_description=vision(
      prompt="Describe the image. Be specific on the colors you see.",
      image=img_t.image,
      model="gpt-4o-mini",
  )
)

# Configure embedding model
embed_model = sentence_transformer.using(
  model_id="intfloat/e5-large-v2"
)

# Add search capability
img_t.add_embedding_index(
  column="image_description", 
  string_embed=embed_model
)

Use Your Workflow

Create app.py:

import pixeltable as pxt

# Connect to your table
img_t = pxt.get_table("image_search.images")

# Sample image URLs
IMAGE_URL = (
    "https://raw.github.com/pixeltable/pixeltable/release/docs/resources/images/"
)

image_urls = [
    IMAGE_URL + doc for doc in [
        "000000000030.jpg",
        "000000000034.jpg",
        "000000000042.jpg",
    ]
]

# Add images to the database
img_t.insert({"image": url} for url in image_urls)

# Perform search
query_text = "Blue flowers"
sim = img_t.image_description.similarity(query_text)
result = (
    img_t.order_by(sim, asc=False)
    .select(img_t.image, img_t.image_description, similarity=sim)
    .collect()
)

# Print results
for i in result:
    print(f"Image: {i['image']}\n")
    print(f"Image description: {i['image_description']}\n")

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What Makes This Different?

AI Vision

OpenAI Vision generates rich image descriptions automatically:

image_description=vision(
    prompt="Describe the image...",
    image=img_t.image
)

Vector Search

Natural language image search using E5 embeddings:

img_t.add_embedding_index(
    column="image_description",
    string_embed=embed_model
)

Auto-updating

Self-maintaining image database:

img_t.insert([{"image": new_url}])
# Descriptions and embeddings update automatically

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Workflow Components

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Advanced Usage

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Custom Search Functions

Create specialized search functions:

@pxt.query
def search_with_threshold(query: str, min_similarity: float):
    sim = img_t.image_description.similarity(query)
    return (
        img_t.where(sim >= min_similarity)
        .order_by(sim, asc=False)
        .select(
            img_t.image,
            img_t.image_description,
            similarity=sim
        )
    )

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Batch Processing

Process multiple images in batch:

# Bulk image insertion
image_urls = [
    "https://example.com/image1.jpg",
    "https://example.com/image2.jpg",
    "https://example.com/image3.jpg"
]

img_t.insert({"image": url} for url in image_urls)

​
Custom Vision Prompts

Customize the OpenAI Vision analysis:

img_t.add_computed_column(
    detailed_analysis=vision(
        prompt="""Analyze this image in detail:
        1. Main objects and their positions
        2. Color palette
        3. Lighting and atmosphere
        4. Any text or symbols present""",
        image=img_t.image,
        model="gpt-4o-mini",
    )
)

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