4. An information processing apparatus according to claim 1 , wherein the at least one processor is further configured to: output success/failure information showing whether extraction of token points that conform to the extraction criterion succeeded, and adjust a value of a gradient of the criterion line based on the success/failure information.
4. An information processing apparatus according to claim 1 , wherein the at least one processor is further configured to: output success/failure information showing whether extraction of token points that conform to the extraction criterion succeeded, and adjust a value of a gradient of the criterion line based on the success/failure information. 9. An information processing apparatus according to claim 4 , wherein the at least one processor is further configured to adjust the value of the gradient of the criterion line when the success/failure information shows that extraction has succeeded consecutively for at least a certain number of times or more or when the success/failure information shows that extraction has failed consecutively for at least a certain number of times, to adjust the value of the gradient of the criterion line.