In a recent work, we introduced some topological notions for grayscale images based on a cross-section topology. In particular, the notion of destructible point, which corresponds to the classical notion of simple point, allows us to build operators that simplify a grayscale image while preserving its topology. In this paper, we introduce new notions and operators in the framework of the cross-...

In image recognition it is often assumed the method used to convert color images to grayscale has little impact on recognition performance. We compare thirteen different grayscale algorithms with four types of image descriptors and demonstrate that this assumption is wrong: not all color-to-grayscale algorithms work equally well, even when using descriptors that are robust to changes in illumin...

Grayscale skeletonization offers an interesting alternative to traditional skeletonization following a binarization. It is well known that parallel algorithms for skeletonization outperform sequential ones in terms of quality of results, yet no general and well defined framework has been proposed until now for parallel grayscale thinning. We introduce in this paper a parallel thinning algorithm...

Considered as topographic reliefs, grayscale images can be decomposed into a number of peaks that can be stored in the data structure of a tree. This decomposition is called the peak analysis of grayscale images in this paper. Its mathematical definition and its fast algorithm based on the watershed transform are both presented. Due to its intuitive definition, there is a wide range of applicat...

We propose a novel approach to automatically produce multiple colorized versions of a grayscale image. Our method results from the observation that the task of automated colorization is relatively easy given a low-resolution version of the color image. We first train a conditional PixelCNN to generate a low resolution color for a given grayscale image. Then, given the generated low-resolution c...

Thinning is an important task in many image processing applications, including remote sensing, photogrammetry, optical character recognition, and medical imaging. In this study, we compare the performance of thinning algorithms on parallel hardware. Grayscale thinning involves a substantial amount of computation per pixel, and may be accelerated in several ways: algorithmic improvements, code o...

The Congruent Matching Cells (CMC) method for ballistics identification was invented at the National Institute of Standards and Technology (NIST). The CMC method is based on the correlation of pairs of small correlation cells instead of the correlation of entire images. Four identification parameters - T CCF, T θ, T x and T y are proposed for identifying correlated cell pairs originating from t...

In this paper, we introduce the use of microscale schlieren technique to measure mixing inhomogeneity in a microfluidic device. The microscale schlieren system is constructed from a Hoffman modulation contrast microscope, which provides easy access to the rear focal plane of the objective lens, by removing the slit plate and replacing the modulator with a knife-edge. The working principle of mi...

Color intensity projections (CIP) have been shown to improve the visualisation of greyscale angiography images by combining greyscale images into a single color image. A key property of the combined CIP image is the encoding of the arrival time information from greyscale images into the hue of the color in the CIP image. A few minor improvements to the calculation of the CIP image are introduce...

Digital and analogue printing methods are studied for reconstructing a Mayan decorative relief from the ancient temple of Jaguars. Height maps, image files encoding height information as intensity values, were produced in commercial editing software early 20th century photographic records. Physical was generated different materials through processes including casting embossing photo exposed pol...