Apparatus and method for reconstructing high dynamic range video
A method is provided for reconstructing a high dynamic range (HDR) video from a low dynamic range (LDR) video. The LDR video is captured with dynamic exposure values by a regular camera device to store as an LDR video file. An exposure setting sequence and an LDR video frame sequence are retrieved from the LDR video file, where the exposure setting sequence corresponds to the LDR video frame sequence. The LDR video frame sequence is aligned to generate a compensated frame sequence to merge with the LDR video frame sequence, so as to generate an HDR frame sequence and reconstruct the HDR video.
1. A method of reconstructing high dynamic range (HDR) video from low dynamic range (LDR) video, comprising:
outputting an exposure setting to a camera device to receive an LDR video from the camera device, wherein the camera device captures the LDR video with dynamic exposure values according to the exposure setting;
storing the LDR video as an LDR video file;
retrieving an exposure setting sequence and an LDR video frame sequence from the LDR video file, where the exposure setting sequence corresponds to the LDR video frame sequence;
performing alignment to the LDR video frame sequence to generate a compensated frame sequence; and
merging the LDR video frame sequence with the compensated frame sequence to generate an HDR frame sequence and the HDR video;
wherein performing alignment to the LDR video frame sequence to generate the compensated frame sequence comprises:
performing alignment to first and third frames of three continuous frames of the LDR video frame sequence to generate an aligned frame; and
performing alignment to a middle frame of the three continuous frames of the LDR video frame sequence and the aligned frame to generate a compensated frame of the compensated frame sequence.
2. The method of claim 1 , further comprising:
processing the LDR video frame sequence according to the exposure setting sequence and a camera curve of the camera device.
3. The method of claim 1 , wherein the first and third frames of the three continuous frames are captured with a first exposure value of the dynamic exposure values, and the middle frame of the three continuous frames is captured with a second exposure value of the dynamic exposure values.
4. The method of claim 1 , wherein the first, middle and third frames of the three continuous frames are respectively captured with first, second and third exposure values of the dynamic exposure values, and the middle exposure value is lower or higher than both the first and third exposure values.
5. The method of claim 1 , further comprising:
mapping the HDR frame sequence to the LDR video frame sequence according to display configurations of a display device.
6. An apparatus for reconstructing high dynamic range (HDR) video from low dynamic range (LDR) video for an electronic device, comprising:
a memory device for storing an LDR video with dynamic exposure values as an LDR video file and a program code;
a processing device coupled to the memory device for performing a process of HDR video reconstruction according to an instruction from the program code to generate an HDR video, wherein the process comprises following steps:
retrieving an exposure setting sequence and an LDR video frame sequence from the LDR video file, where the exposure setting sequence corresponds to the LDR video frame sequence;
performing alignment to the LDR video frame sequence to generate a compensated frame sequence; and
merging the LDR video frame sequence with the compensated frame sequence to generate an HDR frame sequence and the HDR video;
wherein performing alignment to the LDR video frame sequence to generate the compensated frame sequence comprises:
performing alignment to first and third frames of three continuous frames of the LDR video frame sequence to generate an aligned frame; and
performing alignment to a middle frame of the three continuous frames of the LDR video frame sequence and the aligned frame to generate a compensated frame of the compensated frame sequence.
7. The apparatus of claim 6 , wherein the electronic device comprises a camera device coupled to the processing device for capturing the LDR video with dynamic exposure values according to an exposure setting.
8. The apparatus of claim 7 , wherein the process further comprises:
outputting the exposure setting to the camera device to receive the LDR video from the camera device.
9. The apparatus of claim 7 , wherein the process further comprises:
processing the LDR video frame sequence according to the exposure setting sequence and a camera curve of the camera device.
10. The apparatus of claim 6 , wherein first and third frames of the three continuous frames are captured with a first exposure value of the dynamic exposure values, and the middle frame of the three continuous frames is captured with a second exposure value of the dynamic exposure values.
11. The apparatus of claim 6 , wherein first, middle and third frames of the three continuous frames are respectively captured with first, second and third exposure values of the dynamic exposure values, and the middle exposure value is lower or higher than both the first and third exposure values.
12. The apparatus of claim 6 , wherein the process further comprises:
mapping the HDR frame sequence to the LDR video frame sequence according to display configurations of a display device of the apparatus.