A forage harvester is disclosed. The forage harvester has at least one work assembly for processing harvested material of a crop, which includes grain components. In operation, the harvested material is transported in a harvested material flow along a harvested material transport path through the forage harvester. The forage harvester further includes a corn cracker as a work assembly and a control assembly that includes an optical measuring system. The optical measuring system has a camera for recording image data of the harvested material, with the camera being positioned after the corn cracker. The control assembly, using an image recognition routine, determines image regions assigned to a comminuted grain component in the image data, determines geometric properties of the assigned comminuted grain components based on the image regions, and determines an indicator of a processing quality of the comminuted grain components from the geometric properties.