US 12,322,072 B2
Method and apparatus for noise reduction
Joris Soons, Mortsel (BE); and Pieter Vuylsteke, Mortsel (BE)
Assigned to Agfa NV, Mortsel (BE)
Appl. No. 17/767,597
Filed by AGFA NV, Mortsel (BE)
PCT Filed Oct. 8, 2020, PCT No. PCT/EP2020/078231
§ 371(c)(1), (2) Date Apr. 8, 2022,
PCT Pub. No. WO2021/069557, PCT Pub. Date Apr. 15, 2021.
Claims priority of application No. 19202349 (EP), filed on Oct. 10, 2019.
Prior Publication US 2023/0133074 A1, May 4, 2023
Int. Cl. G06T 5/70 (2024.01)
CPC G06T 5/70 (2024.01) [G06T 2207/20012 (2013.01); G06T 2207/20016 (2013.01); G06T 2207/20192 (2013.01); G06T 2207/30004 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A computer-implemented method for enhancing contrast to noise ratio in an electronic representation of an original image represented by an array of pixel values by processing said image, said processing comprising the steps of:
a) decomposing said digital image into a set of detail images at multiple resolution levels and a residual image at a resolution level lower than said multiple resolution levels,
b) processing the detail images,
c) computing a processed image by applying a reconstruction algorithm to the residual image and the processed detail images, said reconstruction algorithm being such that if it were applied to the residual image and the detail images without processing, then said digital image or a close approximation thereof would be obtained,
d) calculating a local variance value for at least one detail image pixel within a neighborhood of said detail image pixel;
e) enhancing or suppressing at least one detail image pixel as a function of said local variance value and said detail image pixel value,
characterized in that:
said local variance value is a calculated local variance of translation differences of said detail image pixel, and said translation differences being a measurement of elementary contrast of said detail image pixel of an approximation image.