To finetune the model, we have prepared a run script for you, which can run as follows:
This will finetune the pre-trained BLIP large model into a new model that can be used for captioning.
Deep Dive
Now let’s take a closer look at the script and see what it does.
python -m torch.distributed.run --nproc_per_node=8 train.py --cfg-path lavis/projects/blip/train/caption_coco_large_ft.yaml
As can be seen, the script simply calls the train.py
with PyTorch distributed training enabled.
The --cfg-path
argument specifies the runtime config file to use. The config file is a YAML file that specifies the training parameters, shown as follows:
1 # Copyright (c) 2022, salesforce.com, inc.
2 # All rights reserved.
3 # SPDX-License-Identifier: BSD-3-Clause
4 # For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
5
6model:
7 arch: blip_caption
8
9 model_type: large_coco
10 load_finetuned: False
11
12datasets:
13 coco_caption: # name of the dataset builder
14 vis_processor:
15 train:
16 name: "blip_image_train"
17 eval:
18 name: "blip_image_eval"
19 text_processor:
20 train:
21 name: "blip_caption"
22 prompt: "a picture of "
23 eval:
24 name: "blip_caption"
25
26run:
27 task: captioning
28 # optimizer
29 lr_sched: "linear_warmup_cosine_lr"
30 init_lr: 2e-6
31 min_lr: 0
32 weight_decay: 0.05
33 max_epoch: 5
34 batch_size_train: 16
35 batch_size_eval: 64
36 num_workers: 4
37
38 max_len: 20
39 min_len: 5
40 num_beams: 3
41
42 seed: 42
43 output_dir: "output/BLIP/Caption_coco"
44
45 amp: False
46 resume_ckpt_path: null
47
48 evaluate: False
49 train_splits: ["train"]
50 valid_splits: ["val"]
51 test_splits: ["test"]
52
53 device: "cuda"
54 world_size: 1
55 dist_url: "env://"
56 distributed: True
- The runtime config file is divided into 3 sections:
model
: specifies the model architecture and type to use.
data
: specifies the dataset to use.
run
: specifies the runner arguments, such as tasks, optimizer, learning rate scheduler, etc.
We describe each section in detail below.
Model configurations
1model:
2 arch: blip_caption
3
4 model_type: large_coco
5 load_finetuned: False
The arch
argument specifies the model architecture to use. In this case, we use the blip_caption
architecture.
You can find available architectures by inspecting the model_zoo
.
Once the architecture is specified, the runner will look for the model class registered with the name and try to instantiate a model instance.
In this case BlipCaption
is the model registered with the name blip_caption
.
The registry maintains a mapping from the name string to the model class.
This allows the runner to find the model class dynamically based on the name string from the config file.
The following segment in lavis/models/blip_models/blip_caption.py
shows how BlipCaption
is registered with the name string blip_caption
:
1@registry.register_model("blip_caption")
2class BlipCaption(BlipBase):
3 """
4 BLIP captioning model.
5
6 Supported model types:
7 - base_coco: fine-tuned BLIP base model on COCO caption dataset (Karparthy split).
8 - large_coco: fine-tuned BLIP large model on COCO caption dataset (Karparthy split).
9
10 Usage:
11 >>> from lavis.models import load_model
12 >>> model = load_model("blip_caption", "base_coco")
13 >>> model = load_model("blip_caption", "large_coco")
14 """
15
16 PRETRAINED_MODEL_CONFIG_DICT = {
17 "base_coco": "configs/models/blip_caption_base_coco.yaml",
18 "large_coco": "configs/models/blip_caption_large_coco.yaml",
19 }
One same model architecture may be pre-trained or finetuned on different datasets or have different model configurations.
For example, BlipCaption
have:
Therefore, we also need to specify model_type
. Here we use large_coco
.
And we set load_finetuned
to False
to indicate that we are finetuning the model from the pre-trained weights.
If load_finetuned
set to True
as by default, the model will load finetuned weights on coco captioning.
Given the model architecture and type, the library will then look for the default model config for large_coco
in lavis/models/blip_models/blip_caption.py
.
As can be seen in the above code snippet, the corresponding config path is stored in BlipCaption.PRETRAINED_MODEL_CONFIG_DICT
.
Then the library will load lavis/configs/models/blip_caption_large_coco.yaml
as the configuration to build the model.
Priority of Configs: Note that the priority of the run config is higher than the default model config, meaning that arguments in the run config will override the default model config.
For example, in the default model config, load_finetuned
is set to True
by default, while in the run config, we set it to False
and finetuning from the pre-trained weights only.
Dataset configurations
The second section of the config file specifies the dataset(s) to use.
1datasets:
2 coco_caption: # name of the dataset builder
3 vis_processor:
4 train:
5 name: "blip_image_train"
6 eval:
7 name: "blip_image_eval"
8 text_processor:
9 train:
10 name: "blip_caption"
11 prompt: "a picture of "
12 eval:
13 name: "blip_caption"
We associate each dataset with a vis_processor
and a text_processor
, responsible for processing the visual and textual input respectively.
Here we again use the registry mechanism to dynamically load the processor class based on the name string.
For example, blip_image_train
is the name string for the BlipImageTrainProcessor
class, which is registered in lavis/processors/blip_processors.py
.
Similarly, the dataset name string is also registered in the registry, pointing to a dataset builder COCOCapBuilder
class.
By default, the builder will load the default dataset configuration as in DATASET_CONFIG_DICT
. You may also add new dataset types by adding new entries to the dictionary.
The dataset configuration used here is:
1datasets:
2 coco_caption: # name of the dataset builder
3 dataset_card: dataset_card/coco_caption.md
4 # data_dir: ${env.data_dir}/datasets
5 data_type: images # [images|videos|features]
6
7 build_info:
8 # Be careful not to append minus sign (-) before split to avoid itemizing
9 annotations:
10 train:
11 url: https://storage.googleapis.com/sfr-vision-language-research/datasets/coco_karpathy_train.json
12 md5: aa31ac474cf6250ebb81d18348a07ed8
13 storage: coco/annotations/coco_karpathy_train.json
14 val:
15 url: https://storage.googleapis.com/sfr-vision-language-research/datasets/coco_karpathy_val.json
16 md5: b273847456ef5580e33713b1f7de52a0
17 storage: coco/annotations/coco_karpathy_val.json
18 test:
19 url: https://storage.googleapis.com/sfr-vision-language-research/datasets/coco_karpathy_test.json
20 md5: 3ff34b0ef2db02d01c37399f6a2a6cd1
21 storage: coco/annotations/coco_karpathy_test.json
22 images:
23 storage: coco/images/
In this configuration file, we specify the dataset name and mainly its building information.
The build information is divided into two parts: annotation
and images
. The annotation files will be automatically downloaded upon loading the dataset for the first time.
The images
part specifies the image root directory. This is a relative path to the cache directory, which is cache
by default. If you have a local copy of the dataset, you can specify the path to the local copy by
overwriting the images
part in the runtime config file. For example, you may alter the run config as below to use your local dataset copy:
datasets:
coco_caption: # name of the dataset builder
vis_processor:
train:
name: "blip_image_train"
eval:
name: "blip_image_eval"
text_processor:
train:
name: "blip_caption"
prompt: "a picture of "
eval:
name: "blip_caption"
images:
YOUR_LOCAL_IMAGE_ROOT_DIR
LAVIS supports using multiple datasets for training. See an example in lavis/projects/blip/train/pretrain_14m.yaml
.
Runner configurations
The last section of the config file specifies the arguments for the runner, shown below:
1run:
2 task: captioning
3 # optimizer
4 lr_sched: "linear_warmup_cosine_lr"
5 init_lr: 2e-6
6 min_lr: 0
7 weight_decay: 0.05
8 max_epoch: 5
9 batch_size_train: 16
10 batch_size_eval: 64
11 num_workers: 4
12
13 max_len: 20
14 min_len: 5
15 num_beams: 3
16
17 seed: 42
18 output_dir: "output/BLIP/Caption_coco"
19
20 amp: False
21 resume_ckpt_path: null
22
23 evaluate: False
24 train_splits: ["train"]
25 valid_splits: ["val"]
26 test_splits: ["test"]
27
28 device: "cuda"
29 world_size: 1
30 dist_url: "env://"
31 distributed: True
- Here we specify runner-related arguments, including
task-specific arguments, such as task
, max_len
, min_len
, etc.
learning rate schedulers, optimizer;
distributed training settings;
logging and checkpointing settings.