Unity Imaging Collaborative

Images - png-cache.zip

1) We curate a collection of DICOM files that will contribute to a dataset.

2) Each DICOM file is assigned to a dataset class - currently there are two

• 01 - development - training / tuning / internal validation images
• 02 - external validation images

3) Each DICOM file is given a 64 character hexadecimal code, e.g. 4d44413619e0161c5ab795bc1b899f7fb4bd0b2f5ab2efc881ecfc663d3bfb66

4) Each image within a DICOM (typically an individual frame for echo) gets given a number padded to 4 digits, starting from 0000 and going to 9999.

5) These images are extracted from the DICOM file, burnt-in meta-data masked, and saved as a png with their code as a filename - e.g. 01-4d44413619e0161c5ab795bc1b899f7fb4bd0b2f5ab2efc881ecfc663d3bfb66-0000.png

6) The individual images that make up a dataset for a paper are saved in a folder called png-cache, with sub directories for the dataset class (e.g. /01) and then the first two pairs of hexadecimal digits (e.g. /4d/44), i.e. /png-cache/01/4d/44/4d44413619e0161c5ab795bc1b899f7fb4bd0b2f5ab2efc881ecfc663d3bfb66-0000.png

7) This folder is then compressed to form png-cache.zip

Not all files may have an associated label - e.g. all the frames of a video may be included, but only a few of them have expert labels

Labels - labels.zip

These are stored as JSON files. The development dataset (provided as labels-all.json) is divided up into:

• labels-train.json - training
• labels-tune.json - tuning
• labels-ival.json - internal validation

For each image file (which acts as the key), there is a dictionary for every possible label. Each label for an image may have a type of:

• "off": the structure is definitely not in the image - i.e the outputs would be expected to be all zeros
• "blurred": the structure is might be in the image, but there is no label available (either it was too blurry, or no one has tried to label it) - i.e the output would need to be masked from the loss function
• "point": the structure is a single point, with the x and y coordinate from the x and y keys
• "curve": the structure is a curve, repreesnted as a cubic spline, with the x and y coordinates of the control points in the x and y keys

For convenience each of the .json files have an equivalent .txt file with a list of the contained images.