This paper presents the design and implementation of an encoder and decoder of a colored barcode with high data density and storage capacity and freedom in shape. The approximately three times higher data density compared to conventional 2D matrix codes such as DataMatrix, QR or Aztec code is achieved by the use of eight colors and enables new applications, especially in the endconsumer market as well as in IT security. The challenges associated with the use of the color channel in printing with conventional office printers and recording by smartdevices under typical scenarios are addressed. The flexibility in the barcode shape is achieved by combining a primary and several secondary symbols according to a given scheme and give the necessary freedom for various applications. The presented code stores colors redundantly in a color palette as a reference in order to provide high robustness. JAB code, Just Another Barcode, has been specified, implemented, tested and is avaiable in github and www.jabcode.org under the license LGPL 2.1. JAB code is currently in the standardization process at the International Organization for Standardization ISO.
Using Natural Steganography (NS), a cover raw image acquired at sensitivity ISO1 is transformed into a stego image whose statistical distribution is similar to a cover image acquired at sensitivity ISO2 > ISO1. This paper proposes such an embedding scheme for color sensors in the JPEG domain, extending thus the prior art proposed for the pixel domain and the JPEG domain for monochrome sensors. We first show that color sensors generate strong intra-block and inter-block dependencies between DCT coefficients and that theses dependencies are due to the demosaicking step in the development process. Capturing theses dependencies using an empirical covariance matrix, we propose a pseudo-embedding algorithm on greyscale JPEG images which uses up to four sub-lattices and 64 lattices to embed information while preserving the estimated correlations among DCT coefficients. We then compute an approximation of the average embedding rate w.r.t. the JPEG quality factor and evaluate the empirical security of the proposed scheme for linear and non-linear demosaicing schemes. Our experiments show that we can achieve high capacity (around 2 bit per nzAC) with a high empirical security (PE ≃ 30% using DCTR at QF 95).