Abstract: A method for detecting at least one pseudo-3D bounding box based on a CNN capable of converting modes according to conditions of objects in an image is provided. The method includes steps of: a learning device (a) instructing a pooling layer to generate a pooled feature map corresponding to a 2D bounding box, and instructing a type-classifying layer to determine whether objects in the pooled feature map are truncated or non-truncated; (b) instructing FC layers to generate box pattern information corresponding to the pseudo-3D bounding box; (c) instructing classification layers to generate orientation class information on the objects, and regression layers to generate regression information on coordinates of the pseudo-3D bounding box; and (d) backpropagating class losses and regression losses generated from FC loss layers. Through the method, rendering of truncated objects can be performed while virtual driving, and this is useful for mobile devices and also for military purpose.