Marking-based portrait relighting

A system, comprising:

• a processing device;
• and
• a computer-readable storage media storing instructions that, responsive to execution by the processing device, cause the processing device to perform operations including:
• receiving user input defining one or more markings input with respect to a portrait image and selecting a skin tone color value associated with a human subject depicted in the portrait image;
• generating, using one or more machine learning models, an albedo representation of the portrait image that captures a skin tone of the human subject based on the skin tone color value;
• and
• generating, using the one or more machine learning models, a relit portrait image by:
• designating the one or more markings as a lighting condition;
• and
• applying the lighting condition to the albedo representation of the portrait image.

A non-transitory computer-readable medium storing executable instructions, which when executed by a processing device, cause the processing device to perform operations comprising:

• receiving a training portrait image;
• generating a shading map of the training portrait image;
• partitioning the shading map into superpixels by performing superpixel segmentation on the shading map;
• selecting a subset of the superpixels as one or more simulated markings drawn on the training portrait image;
• generating, using one or more machine learning models, a relit portrait image by:
• designating the one or more simulated markings as a lighting condition;
• and
• applying the lighting condition to the training portrait image;
• and
• training the one or more machine learning models based on a comparison of the relit portrait image and the training portrait image.