A method comprising: receiving a first version of an image signal at a first resolution; and iteratively creating a second version of the image signal at a second resolution higher than or equal to the first resolution using at least one warped transform and spatially adaptive thresholding, wherein creating a second version of the image signal comprises: selecting sub-frames of a frame in the first version of the image signal, the sub-frame being either regular or adaptive, by minimizing the warped row variance, adaptively selecting the at least one warped transform for a sub-frame selected at each pixel, applying the at least one warped transform to the sub-frame to create transform coefficients, wherein support of the transform basis of the at least one warped transform is warped to match the sub-frame shape, and the sub-frame shape is determined based on measured statistics for each possible shape, performing spatially adaptive thresholding on the transform coefficients by applying at least one spatially adaptive threshold to the transform coefficients, wherein the threshold value adapts such that high-frequency detail in the frame is preserved, applying an inverse transform to threshold coefficients, combining all the processed sub-frames in a weighted fashion to form an output frame of the second version of the signal, and determining whether more iterations are needed. receiving a first version of an image signal at a first resolution; and iteratively creating a second version of the image signal at a second resolution higher than or equal to the first resolution using at least one warped transform and spatially adaptive thresholding, wherein creating a second version of the image signal comprises: selecting sub-frames of a frame in the first version of the image signal, the sub-frame being either regular or adaptive, by minimizing the warped row variance, adaptively selecting the at least one warped transform for a sub-frame selected at each pixel, applying the at least one warped transform to the sub-frame to create transform coefficients, wherein support of the transform basis of the at least one warped transform is warped to match the sub-frame shape, and the sub-frame shape is determined based on measured statistics for each possible shape, performing spatially adaptive thresholding on the transform coefficients by applying at least one spatially adaptive threshold to the transform coefficients, wherein the threshold value adapts such that high-frequency detail in the frame is preserved, applying an inverse transform to threshold coefficients, combining all the processed sub-frames in a weighted fashion to form an output frame of the second version of the signal, and determining whether more iterations are needed. selecting sub-frames of a frame in the first version of the image signal, the sub-frame being either regular or adaptive, by minimizing the warped row variance, adaptively selecting the at least one warped transform for a sub-frame selected at each pixel, applying the at least one warped transform to the sub-frame to create transform coefficients, wherein support of the transform basis of the at least one warped transform is warped to match the sub-frame shape, and the sub-frame shape is determined based on measured statistics for each possible shape, performing spatially adaptive thresholding on the transform coefficients by applying at least one spatially adaptive threshold to the transform coefficients, wherein the threshold value adapts such that high-frequency detail in the frame is preserved, applying an inverse transform to threshold coefficients, combining all the processed sub-frames in a weighted fashion to form an output frame of the second version of the signal, and determining whether more iterations are needed.