US 12,300,009 B2
Method for detecting holographic elements on documents in a video stream
Vladimir Viktorovich Arlazarov, Moscow (RU); Leisan Ildarovna Koliaskina, Ufa (RU); Dmitry Petrovich Nikolaev, Moscow (RU); Dmitry Valerevich Polevoy, Moscow (RU); Daniil Vyacheslavovich Tropin, Moscow (RU); and Sergey Aleksandrovich Usilin, Moscow (RU)
Assigned to Smart Engines Service, LLC, Moscow (RU)
Filed by Smart Engines Service, LLC, Moscow (RU)
Filed on Sep. 9, 2022, as Appl. No. 17/941,981.
Claims priority of application No. RU2021121819 (RU), filed on Jul. 22, 2021.
Prior Publication US 2023/0085858 A1, Mar. 23, 2023
Int. Cl. G06V 30/14 (2022.01); G06V 30/18 (2022.01)
CPC G06V 30/1448 (2022.01) [G06V 30/18105 (2022.01)] 2 Claims
OG exemplary drawing
 
1. A method for detecting security holograms on documents in a video stream, the method comprising:
localizing a document in the video stream;
normalizing a document image of the localized document while the document image is projected into a rectangle with a known size, wherein the normalized document image is color-corrected to be resistant to changes in lighting and automatic white balancing;
calculating a chromaticity vector for each pixel of the normalized document image, wherein the modulus of the chromaticity vector is equal to a saturation of the pixel and the angle of the chromaticity vector is equal to a hue of the pixel;
updating saturation and hue values for each pixel of the normalized document image, the brightness value of which does not exceed a specified threshold, wherein the updated saturation and hue values include: (i) the maximum saturation value of all processed images of the document and (ii) the average value of the chromaticity vectors of all processed images of the document;
generating a new image using pixels having updated saturation and hue values;
filtering the new image using binarization; and
finding connectivity components in the filtered image and filtering the connectivity components in accordance with a priori knowledge about a shape of holograms of the document.