DETERMINING NATIVE RESOLUTIONS OF VIDEO SEQUENCES

摘要

In one embodiment of the present invention, a native resolution analyzer generates a log-magnitude spectrum that elucidates sampling operations that have been performed on a scene. In operation, the native resolution analyzer performs a transform operation of a color component associated with a frame included in the scene to generate a frame spectrum. The native resolution analyzer then normalizes the magnitudes associated with the frame spectrum and logarithmically scales the normalized magnitudes to create a log-magnitude frame spectrum. This two dimensional log-magnitude frame spectrum serves as a frequency signature for the frame. More specifically, patterns in the log-magnitude spectrum reflect re-sampling operations, such as a down-sampling and subsequent up-sampling, that may have been performed on the frame. By analyzing the log-magnitude spectrum, discrepancies between the display resolution of the scene and the lowest resolution with which the scene has been processed may be detected in an automated fashion.

主权项

1. A computer-implemented method for determining a native resolution of a scene within a video sequence, the method comprising:
determining a low frequency region included in a first log-magnitude spectrum associated with the scene; computing an energy density ratio based on the low frequency region; and if the energy density ratio exceeds a predetermined energy density threshold, then computing the native resolution of the scene based on the dimensions of the low frequency region; or if the energy density ratio does not exceed the predetermined energy density threshold, then equating the native resolution of the scene to a display resolution of the scene.