Data Output Format - 3D Instance Segmentation

Details about output format for instance segmentation labels

Labels for 3D instance segmentation can be downloaded as combination of a binary (.dpn) file and a supporting metadata (.json) file per dataset.

The json data present in metadata file is in the below format : { "paint_categories": [ "paint_category_1", "paint_category_2", "paint_category_13, ] }

Here, paint_categories is a list of paint categories configured for the project the dataset belongs to.

The dpn file is a binary file which contains point level information for label cateogry and label id. For a dataset with n number of points, first n bytes of dpn file represent the label category, the next n bytes represent the lower bytes of the label id and the subsequent n bytes represent the higher bytes of the label id the point belongs to.

For example, consider a dataset containing 3 files each with 10,000 points, 11,000 points and 9000 points respectively. Assuming that the point with index 50 in second file of the dataset is annotated as below :

label_category : "paint_category_2" label_id : 1024

For the above scenario, dpn file will contain 90000 bytes ((10,000 + 11,000 + 9000) * 3). The annotation information for the point will be present at 10,050th (10,000 + 50), 40,050th (30,000 + 10,050) and 70,050th (60,000 + 10,050) indexes. The values of bytes at these indexes are as below:

10050 : 2 (1 based index of "paint_category_2" in metadata) 40050 : 0 (1024 % (2^8)) 70050 : 4 (1024 / (2^8)) The value 0 for label category is reserved for unpainted points.