Vision Callbacks¶
Useful callbacks for vision models
Confused Logit¶
Shows how the input would have to change to move the prediction from one logit to the other
Example outputs:

class
pl_bolts.callbacks.vision.confused_logit.
ConfusedLogitCallback
(top_k, projection_factor=3, min_logit_value=5.0, logging_batch_interval=20, max_logit_difference=0.1)[source] Bases:
pytorch_lightning.Callback
Takes the logit predictions of a model and when the probabilities of two classes are very close, the model doesn’t have high certainty that it should pick one vs the other class.
This callback shows how the input would have to change to swing the model from one label prediction to the other.
In this case, the network predicts a 5… but gives almost equal probability to an 8. The images show what about the original 5 would have to change to make it more like a 5 or more like an 8.
For each confused logit the confused images are generated by taking the gradient from a logit wrt an input for the top two closest logits.
Example:
from pl_bolts.callbacks.vision import ConfusedLogitCallback trainer = Trainer(callbacks=[ConfusedLogitCallback()])
Note
Whenever called, this model will look for
self.last_batch
andself.last_logits
in the LightningModule.Note
This callback supports tensorboard only right now.
Authored by:
Alfredo Canziani
 Parameters
projection_factor¶ (
int
) – How much to multiply the input image to make it look more like this logit labelmin_logit_value¶ (
float
) – Only consider logit values above this thresholdlogging_batch_interval¶ (
int
) – How frequently to inspect/potentially plot somethingmax_logit_difference¶ (
float
) – When the top 2 logits are within this threshold we consider them confused
Tensorboard Image Generator¶
Generates images from a generative model and plots to tensorboard

class
pl_bolts.callbacks.vision.image_generation.
TensorboardGenerativeModelImageSampler
(num_samples=3, nrow=8, padding=2, normalize=False, norm_range=None, scale_each=False, pad_value=0)[source] Bases:
pytorch_lightning.Callback
Generates images and logs to tensorboard. Your model must implement the
forward
function for generationRequirements:
# model must have img_dim arg model.img_dim = (1, 28, 28) # model forward must work for sampling z = torch.rand(batch_size, latent_dim) img_samples = your_model(z)
Example:
from pl_bolts.callbacks import TensorboardGenerativeModelImageSampler trainer = Trainer(callbacks=[TensorboardGenerativeModelImageSampler()])
 Parameters
num_samples¶ (
int
) – Number of images displayed in the grid. Default:3
.nrow¶ (
int
) – Number of images displayed in each row of the grid. The final grid size is(B / nrow, nrow)
. Default:8
.normalize¶ (
bool
) – IfTrue
, shift the image to the range (0, 1), by the min and max values specified byrange
. Default:False
.norm_range¶ (
Optional
[Tuple
[int
,int
]]) – Tuple (min, max) where min and max are numbers, then these numbers are used to normalize the image. By default, min and max are computed from the tensor.scale_each¶ (
bool
) – IfTrue
, scale each image in the batch of images separately rather than the (min, max) over all images. Default:False
.