Identification of QR Code Perspective Distortion Based on Edge Directions and Edge Projections Analysis

Karrach, Ladislav; Pivarčiová, Elena; Božek, Pavol

doi:10.3390/jimaging6070067

Cited by 22 publications

(13 citation statements)

References 26 publications

(29 reference statements)

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“…Slight reductions of the set elongation points might be related to the algorithms exploited for error correction by QR scanners, and to possible damage or deformation compensation of the 2D code pattern. [ 42,43 ] An exemplary behavior of the MW under stretching is also shown in Movie S1 (Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Cryptographic Strain‐Dependent Light Pattern Generators

D’Elia

Pisani

Tredicucci

et al. 2021

Adv Materials Technologies

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Refractive freeform components are becoming increasingly relevant for generating controlled patterns of light, because of their capability to spatially modulate optical signals with high efficiency and low background. However, the use of these devices is still limited by difficulties in manufacturing macroscopic elements with complex, 3D surface reliefs. Here, 3D‐printed and stretchable magic windows generating light patterns by refraction are introduced. The shape and, consequently, the light texture achieved can be changed through controlled device strain. Cryptographic magic windows are demonstrated through exemplary light patterns, including micro‐QR‐codes, that are correctly projected and recognized upon strain gating while remaining cryptic for as‐produced devices. The light pattern of micro‐QR‐codes can also be projected by two coupled magic windows, with one of them acting as the decryption key. Such novel, freeform elements with 3D shape and tailored functionalities is relevant for applications in illumination design, smart labels, anti‐counterfeiting systems, and cryptographic communication.

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Section: Resultsmentioning

confidence: 99%

Cryptographic Strain‐Dependent Light Pattern Generators

D’Elia

Pisani

Tredicucci

et al. 2021

Adv Materials Technologies

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“…(Note: By maximizing the standard deviation in the edge projections, it is also possible to iteratively determine the position of P 4 in case the Data Matrix code is perspective distorted. We introduced this approach for QR Codes in [ 15 ]).…”

Section: The Data Matrix Code Localization Methodsmentioning

confidence: 99%

Comparative Study of Data Matrix Codes Localization and Recognition Methods

Karrach

Pivarčiová

2021

J. Imaging

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We provide a comprehensive and in-depth overview of the various approaches applicable to the recognition of Data Matrix codes in arbitrary images. All presented methods use the typical “L” shaped Finder Pattern to locate the Data Matrix code in the image. Well-known image processing techniques such as edge detection, adaptive thresholding, or connected component labeling are used to identify the Finder Pattern. The recognition rate of the compared methods was tested on a set of images with Data Matrix codes, which is published together with the article. The experimental results show that methods based on adaptive thresholding achieved a better recognition rate than methods based on edge detection.

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“…To improve the accuracy of identifying the positional relationships of markers in the lateral view, we developed a new technique using a quick response (QR) code as a marker. A QR code is a type of matrix barcode (or two-dimensional barcode) invented in 1994 by the Japanese automotive company Denso Wave [ 11 ]. A barcode is a machine-readable optical label that contains information on the item to which it is attached.…”

Section: Introductionmentioning

confidence: 99%

Comparison of 3D Bone Position Estimation Using QR Code and Metal Bead Markers

Ikumi

Yoshii

Iwahashi³

et al. 2023

Diagnostics

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To improve the accuracy of a 3D bone position estimation system that displays 3D images in response to changes in the position of fluoroscopic images, modified markers using quick response (QR) codes were developed. The aims of this study were to assess the accuracy of the estimated bone position on 3D images with reference to QR code markers on fluoroscopic images and to compare its accuracy with metal bead markers. Bone positions were estimated from reference points on a fluoroscopic image compared with those on a 3D image. The positional relationships of QR code and metal bead markers on the fluoroscopic image were compared with those on the 3D image in order to establish whether a 3D image may be drawn by tracking positional changes in radius models. Differences were investigated by comparing the distance between markers on the fluoroscopic image and that on the 3D image, which was projected on the monitor. The error ratio, which was defined as the difference in the measurement between the fluoroscopic and 3D images divided by the fluoroscopic measurement, was compared between QR code and metal bead markers. Error ratios for the QR code markers were 5.0 ± 2.0%, 6.4 ± 7.6%, and 1.0 ± 0.8% in the anterior–posterior view, ulnar side lateral view, and posterior–anterior view, respectively. Error ratios for the metal bead markers were 1.3 ± 1.7%, 13.8 ± 14.5%, and 4.7 ± 5.7% in the anterior–posterior view, ulnar side lateral view, and posterior–anterior view, respectively. The error ratio for the metal bead markers was smaller in the initial position (p < 0.01). However, the error ratios for the QR code markers were smaller in the lateral position and the posterior–anterior position (p < 0.05). In QR code marker tracking, tracking was successful even with discontinuous images. The accuracy of a 3D bone position estimation was increased by using the QR code marker system. QR code marker tracking facilitates real-time comparisons of dynamic changes in preoperative 3D and intraoperative fluoroscopic images.

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Identification of QR Code Perspective Distortion Based on Edge Directions and Edge Projections Analysis

Cited by 22 publications

References 26 publications

Cryptographic Strain‐Dependent Light Pattern Generators

Cryptographic Strain‐Dependent Light Pattern Generators

Comparative Study of Data Matrix Codes Localization and Recognition Methods

Comparison of 3D Bone Position Estimation Using QR Code and Metal Bead Markers

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