Heatmap generation transforms #3328
Description
Is your feature request related to a problem? Please describe.
Heatmap regression is used to address a number of regression problems. In these approaches, the targets are usually converted into heatmaps, which are directly learned using a CNN.
Describe the solution you'd like
Currently, MONAI provides a number of transforms to process/pre-process input images, however a transform for generating heatmaps does not exist. The feature will essentially be a transform that takes as input the original regression labels, their ranges, heatmap size and variances for evaluating Gaussians on a heatmap grid. These will be written into a dictionary item of choice, e.g. key=label
Describe alternatives you've considered
There are some existing implementation of this, e.g. https://github.com/christianpayer/MedicalDataAugmentationTool-HeatmapRegression however they don't provide a generalised/reusable solution to generating heatmaps.
More context
The transform signature may look like as follows:
class GenerateHeatmap(Transform):
def __init__(in_key, out_key, sigmas, step, range):
....
....
def __call__(data):
....
....
return data