---
title: "VertexAIImageCaptioner"
id: vertexaiimagecaptioner
slug: "/vertexaiimagecaptioner"
description: "`VertexAIImageCaptioner` enables text generation using Google Vertex AI `imagetext` generative model."
---

# VertexAIImageCaptioner

`VertexAIImageCaptioner` enables text generation using Google Vertex AI `imagetext` generative model.

<div className="key-value-table">

|  |  |
| --- | --- |
| **Mandatory run variables** | `image`: A [`ByteStream`](../../concepts/data-classes.mdx#bytestream)  object storing an image               |
| **Output variables**        | `captions`: A list of strings generated by the model                                            |
| **API reference**           | [Google Vertex](/reference/integrations-google-vertex)                                                 |
| **GitHub link**             | https://github.com/deepset-ai/haystack-core-integrations/tree/main/integrations/google_vertex |

</div>

### Parameters Overview

`VertexAIImageCaptioner` uses Google Cloud Application Default Credentials (ADCs) for authentication. For more information on how to set up ADCs, see the [official documentation](https://cloud.google.com/docs/authentication/provide-credentials-adc).

Keep in mind that it’s essential to use an account that has access to a project authorized to use Google Vertex AI endpoints.

You can find your project ID in the [GCP resource manager](https://console.cloud.google.com/cloud-resource-manager) or locally by running `gcloud projects list` in your terminal. For more info on the gcloud CLI, see its [official documentation](https://cloud.google.com/cli).

## Usage

You need to install `google-vertex-haystack` package to use the  `VertexAIImageCaptioner`:

```shell
pip install google-vertex-haystack
```

### On its own

Basic usage:

```python
import requests

from haystack.dataclasses.byte_stream import ByteStream
from haystack_integrations.components.generators.google_vertex import VertexAIImageCaptioner

captioner = VertexAIImageCaptioner()

image = ByteStream(data=requests.get("https://raw.githubusercontent.com/silvanocerza/robots/main/robot1.jpg").content)
result = captioner.run(image=image)

for caption in result["captions"]:
    print(caption)

>>> two gold robots are standing next to each other in the desert
```

You can also set the caption language and the number of results:

```python
import requests

from haystack.dataclasses.byte_stream import ByteStream
from haystack_integrations.components.generators.google_vertex import VertexAIImageCaptioner

captioner = VertexAIImageCaptioner(
	number_of_results=3, # Can't be greater than 3
	language="it",
)

image = ByteStream(data=requests.get("https://raw.githubusercontent.com/silvanocerza/robots/main/robot1.jpg").content)
result = captioner.run(image=image)

for caption in result["captions"]:
    print(caption)

>>> due robot dorati sono in piedi uno accanto all'altro in un deserto
>>> un c3p0 e un r2d2 stanno in piedi uno accanto all'altro in un deserto
>>> due robot dorati sono in piedi uno accanto all'altro
```