Method of generating motion vectors of images of a video sequence

A method of filtering an image of an input video sequence, the method comprising:

• defining horizontal and vertical weighing functions with values over pixels belonging to a first portion of the image being larger than values over pixels outside the first portion of said image;
• computing horizontal and vertical characteristic curves of the image and of a preceding image in the sequence;
• determining a horizontal global displacement between the two images that minimizes a weighted average, calculated using the horizontal weighing function, of an absolute value of a difference between taps of the horizontal characteristic curve of the current image and of a translated replica of the horizontal characteristic curve of the preceding image in the sequence;
• determining a vertical global displacement between the two images that minimizes a weighted average, calculated using the vertical weighing function, of an absolute value of a difference between taps of the vertical characteristic curve of the current image and of a translated replica of the vertical characteristic curve of the preceding imagein the sequence;
• and
• generating a filtered output image by filtering out the horizontal and vertical global displacements from the current image.

A method of filtering an image of an input video sequence, the method comprising:

• computing horizontal and vertical characteristic curves of the image and of a preceding image in the sequence, then generating corresponding high-pass replicas thereof using a high-pass filter;
• calculating a horizontal global displacement between the two images that minimizes an average of an absolute value of a difference between taps of the horizontal high-pass replica characteristic curve of the current image and of a translated replica of the high-pass replica horizontal characteristic curve of the preceding image in the sequence;
• calculating a vertical global displacement between the two images that minimizes an average of an absolute value of a difference between taps of the vertical high-pass replica characteristic curve of the current image and of a translated replica of the vertical high-pass replica characteristic curve of the preceding image in the sequence;
• and
• generating a filtered output image by filtering out the horizontal and vertical global displacements from the current image.

A method of filtering an image of an input video sequence, comprising:

• computing horizontal and vertical characteristic curves of the image and of a preceding image in the sequence, then generating corresponding band-pass replicas thereof using a Butterworth IIR band-pass filter;
• calculating a horizontal global displacement between the two images that minimizes an average of an absolute value of a difference between taps of the horizontal band-pass replica characteristic curve of the current image and of a translated replica of the horizontal band-pass replica characteristic curve of the proceding image in the sequence;
• calculating a vertical global displacement between the two images that minimizes an average of an absolute value of a difference between taps of the vertical band-pass replica characteristic curve of the current image and of a translated replica of the vertical band-pass replica characteristic curve of the preceding image in the sequence;
• and
• generating a filtered output image by filtering out the horizontal and vertical global displacements from the current image.

A method of filtering an image of an input video sequence, comprising the steps of:

• computing horizontal and vertical characteristic curves of the image and of a preceding image in the sequence, then generating corresponding high-pass replicas thereof;
• calculating a horizontal global displacement between the two images that minimizes an average of an absolute value of a difference between taps of the horizontal high-pass replica characteristic curve of the current image and of a translated replica of the horizontal high-pass replica characteristic curve of the proceding image in the sequence;
• calculating a vertical global displacement between the two images that minimizes an average of an absolute value of a difference between taps of the vertical high-pass replica characteristic curve of the current image and of a translated replica of the vertical high-pass replica characteristic curve of the preceding image in the sequence;
• and
• generating a filtered output image by filtering out the horizontal and vertical global displacements from the current image.

A system to process digital images, comprising:

• a Bayer sensor configured to generate Bayer pattern images of captured scenes;
• a curve generator configured to generate characteristic curves of the Bayer pattern images;
• a memory storing the Bayer pattern images and the respective characteristic curves;
• and
• a digital signal processor configured to generate absolute global motion vectors based on the Bayer images and the respective characteristic curves.

A computer readable memory medium comprising contents that cause a computing device to implement a method of processing a digital image, the method including:

• defining horizontal and vertical weighing functions with values over pixels belonging to a first portion of the image being larger than values over pixels outside the first portion of the image;
• computing horizontal and vertical characteristic curves of the image and of a preceding image in the video sequence;
• determining a horizontal global displacement between the two images that minimizes a weighted average, calculated using the horizontal weighing function, of an absolute value of a difference between taps of the horizontal characteristic curve of the current image and of a translated replica of the horizontal characteristic curve of the preceding image in the sequence;
• determining a vertical global displacement between the two images that minimizes a weighted average, calculated using the vertical weighing function, of an absolute value of a difference between taps of the vertical characteristic curve of the current image and of a translated replica of the vertical characteristic curve of the preceding image in the sequence;
• aligning the image with the preceding image in the sequence and calculating relative motion vectors between the aligned images;
• and
• generating the signals representing absolute motion vectors between the images as a vector sum of the relative motion vectors and the horizontal and vertical global displacement.

A method of generating signals representing absolute motion vectors of an image of a video sequence, the method comprising:

• defining horizontal and vertical weighing functions with values over pixels belonging to a first portion of the image being larger than values over pixels outside the first portion of the image;
• computing horizontal and vertical characteristic curves of the image and of a preceding image in the video sequence;
• determining a horizontal global displacement between the two images that minimizes a weighted average, calculated using the horizontal weighing function, of an absolute value of a difference between taps of the horizontal characteristic curve of the current image and of a translated replica of the characteristic curve of the preceding image in the sequence;
• determining a vertical global displacement between the two images that minimizes a weighted average, calculated using the vertical weighing function, of an absolute value of a difference between taps of the horizontal characteristic curve of the current image and of a translated replica of the characteristic curve of the preceding image in the sequence;
• aligning the image with the preceding image in the sequence and calculating relative motion vectors between the aligned images;
• and
• generating the signals representing absolute motion vectors between the images as a vector sum of the relative motion vectors and the horizontal and vertical global displacement.