Low-altitude aerial photography for optimum N fertilization of winter wheat on the North China Plain

Previous research has shown that site-specific nitrogen (N) fertilizer recommendations based on an assessment of a soil’s N supply (mineral N testing) and the crop’s N status (sap nitrate analysis) can help to decrease excessive N inputs for winter wheat on the North China Plain. However, the costs to derive such recommendations based on multiple sampling of a single field hamper the use of this approach at the on-farm level. In this study low-altitude aerial true-color photographs were used to examine the relationship between image-derived reflectance values and soil–plant data in an on-station experiment. Treatments comprised a conventional N treatment (typical farmers’ practice), an optimum N treatment (N application based on soil–plant testing) and six treatments without N (one to six cropping seasons without any N fertilizer input). Normalized intensities of the red, green and blue color bands on the photographs were highly correlated with total N concentrations, SPAD readings and stem sap nitrate of winter wheat. The results indicate the potential of aerial photography to determine in combination with on site soil–plant testing the optimum N fertilizer rate for larger fields and to thereby decrease the costs for N need assessments.

Flash Photography Enhancement via Intrinsic Relighting

We enhance photographs shot in dark environments by combining a picture taken with the available light and one taken with the flash. We preserve the ambiance of the original lighting and insert the sharpness from the flash image. We use the bilateral filter to decompose the images into detail and large scale. We reconstruct the image using the large scale of the available lighting and the detail of the flash. We detect and correct flash shadows. This combines the advantages of available illumination and flash photography.

fotografía y métodos históricos : dos textos para un debate = Photography and historical Methodology : two text for a debat.

La presente obra bilingüe (castellano e inglés) a través de sus dos textos pretende servir como punto de partida para el desarrollo de un debate sobre la fotografía y sus relaciones con la historia. El objetivo del libro es establecer puntos de reflexión sobre metodología de la historia frente a las dimensiones culturales, estéticas y tecnológicas del fenómeno fotográfico. Se divide el libro en dos capítulos: 1. De la 'Fotohistoria' a la Historia con la fotografía. 2. Imágenes contaminadas. (La fotografía en la Historia del arte).

How about a visual lecture? : viewers' interpretations of a visual-pedagogical installation challenging family photography. '¿Qué tal una clase visual? : las interpretaciones de los espectadores de una instalación visual-pedagógica que cuestiona la fotografía de familia'.

Resumen basado en el de la publicación

Extraction of tidal channel networks from airborne scanning laser altimetry and aerial photography

The study of the morphodynamics of tidal channel networks is important because of their role in tidal propagation and the evolution of salt-marshes and tidal flats. Channel dimensions range from tens of metres wide and metres deep near the low water mark to only 20-30cm wide and 20cm deep for the smallest channels on the marshes. The conventional method of measuring the networks is cumbersome, involving manual digitising of aerial photographs. This paper describes a semi-automatic knowledge-based network extraction method that is being implemented to work using airborne scanning laser altimetry (and later aerial photography). The channels exhibit a width variation of several orders of magnitude, making an approach based on multi-scale line detection difficult. The processing therefore uses multi-scale edge detection to detect channel edges, then associates adjacent anti-parallel edges together to form channels using a distance-with-destination transform. Breaks in the networks are repaired by extending channel ends in the direction of their ends to join with nearby channels, using domain knowledge that flow paths should proceed downhill and that any network fragment should be joined to a nearby fragment so as to connect eventually to the open sea.

3D face computational photography using PCA spaces

In this paper, we present a 3D face photography system based on a facial expression training dataset, composed of both facial range images (3D geometry) and facial texture (2D photography). The proposed system allows one to obtain a 3D geometry representation of a given face provided as a 2D photography, which undergoes a series of transformations through the texture and geometry spaces estimated. In the training phase of the system, the facial landmarks are obtained by an active shape model (ASM) extracted from the 2D gray-level photography. Principal components analysis (PCA) is then used to represent the face dataset, thus defining an orthonormal basis of texture and another of geometry. In the reconstruction phase, an input is given by a face image to which the ASM is matched. The extracted facial landmarks and the face image are fed to the PCA basis transform, and a 3D version of the 2D input image is built. Experimental tests using a new dataset of 70 facial expressions belonging to ten subjects as training set show rapid reconstructed 3D faces which maintain spatial coherence similar to the human perception, thus corroborating the efficiency and the applicability of the proposed system.

Photography and christian mission: George Brown`s images of the New Britain mission 1875-80

In 1875, Methodist George Brown arrived in the Bismarck Archipelago to establish the New Britain Mission. Based in the Duke of York Islands, Brown's territory covered New Ireland and the Gazelle Peninsula of New Britain. The mission was one of the first to be photographed from its inception. The Australian Museum holds 96 plates from the first five years of the mission. Brown's photographs are a visual record of conditions and peoples of the time. Analysed in relation to Brown's writings they are indicative of the relationships and bonds established through photography both in the mission field and across wider scientific and church audiences. The methodology employed here also challenges the kinds of interpretations of photographs that can arise from visual analyses relying solely on the caption and the posing of the subject.