Learning method, learning device, program, and recording medium

A learning device, comprising:

• a learning data generator configured to generate learning data that contains a composite image, including a computer graphics (CG) model of an object, and contains a training signal of the object;
• an object recognizer configured to recognize information regarding an object included in an input image by neuro computation;
• and
• a learning processor configured to learn a recognition function of the object recognizer,
• wherein the learning processor calculates a gradient of error for each pixel of the composite image, from the composite image and the training signal, by backpropagation,
• wherein the learning data generator generates new learning data on the basis of the gradient of error, and
• wherein the learning processor learns the recognition function by using the new learning data.