An information processing method includes: measuring profile data of deposited material that is a plurality of particles, the profile data including distance data to the deposited material or image data of the deposited material; detecting each of the plurality of particles based on the profile data; calculating an index based on the profile data; and extracting particles in a surface layer among the deposited material, based on results of the detecting for each of the plurality of particles and the index calculated based on the profile data.

The present invention relates to a method for the production of sponge iron from iron ore, comprising the steps of: charging iron ore into a direct reduction shaft (1); introducing a hydrogen-rich process gas into the direct reduction shaft (1) in order to reduce the iron ore and produce sponge iron; wherein the step of introducing the hydrogen-rich process gas comprises the steps of: conducting a reduction gas comprising at least 80 vol. % hydrogen gas through a first gas line (5) from a hydrogen gas source (4, 21) to the reduction shaft (1), and heating the reduction gas in said first gas line (5) to a first temperature T1. The method further comprises the steps of adding carbon dioxide gas to the reduction gas, upstream or downstream a point along the first gas line (5) at which the reduction gas is heated, and adding oxygen gas to the heated reduction gas to form said hydrogen-rich process gas, and introducing the hydrogen-rich process gas is into the shaft (1).