Frame rate conversion device, image display apparatus, and method of converting frame rate

A moving image device performing a frame rate conversion, the device comprising:

• a signal input terminal to which an image signal is inputted;
• and
• a frame rate conversion unit for generating an interpolated frame using the image signal inputted to the signal input terminal and converting the frame rate of the image signal by inserting the interpolated frame into the image signal, wherein:
• the frame rate conversion unit generates the interpolated frame using a motion vector of the image on four frames, the four frames including a first frame which appeared, with respect to the timing when the interpolated frame is inserted, before the insertion time of the interpolated frame, a second frame appeared before the first frame, a third frame appeared after the insertion time, and a fourth frame appeared after the third frame;
• and
• the frame rate conversion unit generates the interpolated frame by setting the plurality of straight lines passing through the first to fourth frames based on the interpolated pixel in the interpolated frame, obtains, for each of the plurality of the straight lines, a sum of the difference between the pixel on the first frame and the pixel on the second frame located on each straight line, the difference between the pixel on the first frame and the pixel on the third frame located on the straight line, and the difference between the pixel on the third frame and the pixel on the fourth frame located on the straight line, and generates the certain interpolated pixel using the pixel information on the first frame and the third frame located on the straight line whereof the sum of the differences is the smallest.

A moving image device performing a frame rate conversion, the device comprising:

• a signal input terminal to which an image signal is inputted;
• and
• a frame rate conversion unit for generating an interpolated frame using the image signal inputted to the signal input terminal and converting the frame rate of the image signal by inserting the interpolated frame into the image signal, wherein the frame rate conversion unit
• generates the interpolated frame using a motion vector of the image on four frames, the four frames including a first frame which appeared, with respect to the timing when the interpolated frame is inserted, before the insertion time of the interpolated frame, a second frame appeared before the first frame, a third frame appeared after the insertion time, and a fourth frame appeared after the third frame,
• generates the interpolated frame by setting a plurality of straight lines passing through the first to the fourth frames based on a certain interpolated pixel in the interpolated frame,
• obtains, for each of the plurality of the straight lines, a sum of the difference between the pixel on the first frame and the pixel on the second frame located on each straight line, the difference between the pixel on the first frame and the pixel on the third frame located on the straight line, the difference between the pixel on the third frame and the pixel on the fourth frame located on the straight line, and
• uses the straight line whereof the sum of the difference is the smallest as a reference for determining the direction of interpolation and generates the certain interpolated pixel using pixel information of the first frame to the third frame in the determined direction of interpolation.

A moving image device performing a frame rate conversion, the device comprising:

• a signal input terminal to which an image signal is inputted;
• and
• a frame rate conversion unit for generating an interpolated frame using the image signal inputted to the signal input terminal and converting the frame rate of the image signal by inserting the interpolated frame into the image signal,
• wherein the frame rate conversion unit generates the interpolated frame using a motion vector of the image on four frames, the four frames including a first frame which appeared, with respect to the timing when the interpolated frame is inserted, before the insertion time of the interpolated frame, a second frame appeared before the first frame, a third frame appeared after the insertion time, and a fourth frame appeared after the third frame,
• the moving image device further comprising:
• a first frame memory for delaying the image signal by one frame and generating the third frame;
• a second frame memory for delaying an output from the first frame memory by another one frame to generate the first frame;
• a third frame memory for delaying the output from the second frame memory by another one frame to generate the second frame;
• an interpolated frame generating unit for generating the interpolated frame by using the image signal as the fourth frame and using the third frame outputted from the first frame memory, the first frame outputted from the second frame memory, and the second frame outputted from the third frame memory;
• a fourth frame memory for converting the rate of the image outputted from the interpolated frame generating unit;
• and
• a switching unit for switching between the output from the fourth frame memory and the output from the second frame memory periodically.

A moving image device performing a frame rate conversion, the device comprising:

• a signal input terminal to which an image signal is inputted;
• and
• a frame rate conversion unit for generating an interpolated frame using the image signal inputted to the signal input terminal and converting the frame rate of the image signal by inserting the interpolated frame into the image signal,
• wherein the frame rate conversion unit generates the interpolated frame using a motion vector of the image on four frames, the four frames including a first frame which appeared, with respect to the timing when the interpolated frame is inserted, before the insertion time of the interpolated frame, a second frame appeared before the first frame, a third frame appeared after the insertion time, and a fourth frame appeared after the third frame,
• the moving image device further comprising:
• a first frame memory for delaying the image signal by one frame and generating the fourth frame;
• a second frame memory for delaying the output of the first frame memory by another one frame and generating the third frame;
• a third frame memory for delaying the output of the second frame memory by another one frame and generating the first frame;
• a fourth frame memory for delaying the output of the third frame memory by another one frame and generating the second frame;
• an interpolated frame generating unit for generating the interpolated frame using the first to fourth frames outputted from the first to fourth frame memories;
• a fifth frame memory converting the rate of the image outputted from the interpolated frame generating unit;
• and
• a switching unit for switching between the output from the fifth frame memory and the output from the third frame memory periodically.

A method of converting a frame rate, comprising the steps of:

• obtaining four consecutive frames from an inputted image signal;
• generating an interpolated frame using a motion vector of the image on the obtained four frames;
• inserting the interpolated frame between the second and third frames of the obtained four frames to convert the frame rate of the inputted image signal;
• deciding the direction of interpolation for generating the interpolated frame from the consecutive four frames;
• generating the interpolated frame using information on the pixels of the second and third frames located in the fixed direction of interpolation;
• setting a plurality of straight lines passing through the four consecutive frames on the basis of a certain interpolated pixel in the interpolated frame;
• obtaining, for each of the plurality of the straight lines, a sum of the difference between the pixel on the first frame and the pixel on the second frame located on each straight line, the difference between the pixel on the second frame and the pixel on the third frame, the difference between the pixel on the third frame and the pixel on the fourth frame;
• and
• fixing the direction of interpolation based on a straight line whereof the sum value is the smallest.