Method and apparatus for detecting and removing false contour, method and apparatus for verifying whether pixel in included in contour, and method and apparatus for calculating simplicity

A method for detecting and removing a false contour, comprising:

• verifying whether a pixel of an input video is included in a contour;
• calculating simplicity of the pixel, the calculating comprising calculating a numeric value by accumulating predetermined weighted values according a comparison of the pixel and adjacent pixels in either a longitudinal direction or a diagonal direction;
• determining whether the pixel is included in a false contour based on the simplicity and based on whether the pixel is included in the contour;
• and
• removing the false contour from the input video via smoothing with respect to the false contour,
• wherein the calculating of the simplicity of the pixel comprises:
• verifying whether a difference between the adjacent pixels within an n x n sized pixel group, including the pixel in a center thereof, is less than a predetermined difference;
• measuring a bond strength between the adjacent pixels according to directions of the adjacent pixels when the difference between the adjacent pixels is less than the predetermined difference;
• and
• calculating the simplicity of the pixel based on the bond strength.

A method of determining whether a pixel is included in a contour comprising:

• calculating a gradient of each pixel of an input video;
• verifying whether a linked pixel to the pixel exists, and
• determining whether the pixel is included in the contour based on the gradient and based on whether the linked pixel to the pixel exists;
• wherein the calculating of the gradient of each pixel calculates the gradient using a nonlinear partial differential of an x axis and a nonlinear partial differential of a y axis, which correspond to the pixel, as below:
• |G|=|Gx|+|Gy|, [Equation 7]
• where G indicates the gradient, Gx indicates the nonlinear partial differential of the x axis, and the Gy indicates the nonlinear partial differential of the y axis,
• wherein the nonlinear partial differential of the x axis, and the nonlinear partial differential of the y axis are calculated by applying a gradient mask to a 2×2 sized pixel group, including the pixel in a predetermined location, and the gradient mask includes an x mask and a y mask shown in Equation 8,
• xGMask
• =
• [
• 1
• ,
• -
• 1
• 2
• ,
• -
• 1
• ]
• ,
• ⁢
• yGMask
• =
• [
• -
• 1
• ,
• -
• 2
• 1
• ,
• 2
• ]
• ,
• [
• Equation
• ⁢
• ⁢
• 8
• ]
• where xGMask indicates a matrix expressing the x mask, and yGMask indicates a matrix expressing the y mask.

An apparatus of detecting and removing a false contour comprising one or more processors, comprising:

• a contour verifying unit, controlled by the one or more processors, configured to receive an input video and verify whether a pixel of the input video is included in a contour;
• a simplicity calculation unit, controlled by the one or more processors, configured to calculate simplicity of the pixel, the calculating comprising calculating a numeric value by accumulating predetermined weighted values according a comparison of the pixel and adjacent pixels in either a longitudinal direction or a diagonal direction, the predetermined weighted values being determined prior to receiving the input video;
• a false contour determination unit, controlled by the one or more processors, configured to determine whether the pixel is included in a false contour based on the simplicity and based on whether the pixel is included in the contour;
• and
• a false contour removing unit, controlled by the one or more processors, configured to remove the false contour via smoothing from the input video with respect to the false contour,
• wherein the simplicity calculation unit comprises:
• a pixel difference verifying unit, controlled by the one or more processors, configured to verify whether a difference between adjacent pixels within an n x n sized pixel group, including the pixel in a center thereof, is less than a predetermined difference;
• a bond strength measurement unit, controlled by the one or more processors, configured to measure a bond strength between the adjacent pixels according to directions of the adjacent pixels when the difference between the adjacent pixels is less than the predetermined difference;
• and
• a calculation unit, controlled by the one or more processors, configured to calculate the simplicity of the pixel based on the bond strength.

An apparatus of determining a contour, comprising:

• a gradient calculation unit, controlled by the one or more processors, configured to calculate a gradient of each pixel of an input video;
• a linked pixel verifying unit, controlled by the one or more processors, configured to verify whether a linked pixel of the pixel exists;
• and
• a contour determination unit, controlled by the one or more processors, configured to determine whether the pixel is included in the contour based on the gradient and based on whether the linked pixel exists,
• wherein the gradient calculation unit calculates the gradient using a nonlinear partial differential of an x axis and a nonlinear partial differential of a y axis, which correspond to the pixel, as below:
• |G|=|Gx|+|Gy|, [Equation 9]
• where G indicates the gradient, Gx indicates the nonlinear partial differential of the x axis, and the Gy indicates the nonlinear partial differential of the y axis,
• wherein the nonlinear partial differential of the x axis and the nonlinear partial differential of the y axis are calculated by applying a gradient mask to a 2×2 sized pixel group, including the pixel in a predetermined location, and the gradient mask includes an x mask and a y mask shown in Equation 10,
• xGMask
• =
• [
• 1
• ,
• -
• 1
• 2
• ,
• -
• 1
• ]
• ,
• ⁢
• yGMask
• =
• [
• -
• 1
• ,
• -
• 2
• 1
• ,
• 2
• ]
• ,
• [
• Equation
• ⁢
• ⁢
• 10
• ]
• where xGMask indicates a matrix expressing the x mask, and yGMask indicates a matrix expressing the y mask.