Processing apparatus, image pickup apparatus, image pickup system, and processing method

A processing apparatus configured to combine a plurality of images based on a plurality of object images formed on an imaging plane of an image sensor by a plurality of lens units and to generate a combined image, the processing apparatus comprising:

• at least one processor or circuit configured to execute a plurality of tasks including:
• an acquisition task configured to acquire information on a center position of each of the plurality of object images on the imaging plane, information on a correspondence relationship between the center position and positions of the plurality of images in the combined image, and conversion information for converting a first coordinate system in the imaging plane into a second coordinate system in the combined image, the conversion information being generated based on a correction function for correcting the plurality of object images;
• and
• a processing task configured to generate the combined image using the conversion information.