A difficult history of light. About metaphysical ideas of “light writing” formulated before the birth of photography

The reflections presented in this article are devoted to Junko Theresa Mikuriya’s book, A History of Light. The Idea of Photography. It is a unique view on the search for pre-photographic origins of photography in the field of philosophical writings ranging from Plato, through the neoplatonic philosopher Jamblich’s enquiry, to the texts by Philotheus of Batos and by an early Renaissance philosopher, Marsilio Ficino. When thinking about metaphysics present in (moving and still) images, one should not forget about the metaphysics of the image itself. The idea of photography – regardless of whether we are witnessing a fundamental change in an ontological transition from an analogue to a digital form of image recording – obliges us to discuss the “history of light”, as this is what Mikuriya does. While locating the discussed concepts in the context of the history and theory of photography, as well as the archaeology of media, the author of this essay engages in a dialogue with Mikuriya and polemically discusses many of her hypotheses. Key concepts such as chalepon, photagogia, triton genos, phôteinographeisthai are analysed in order to indicate inspiring moments in the Mikuriya’s reflections, but also a kind of interpretive abuse in the process of reading and analysing philosophical texts addressing the issues of light.

Raspberry Pi-based mobile system of the pupil size evaluation

The article considers development of a human pupil measuring system on the Raspberry platform. The system is aimed at evaluating the variations of the human pupil diameter or area in the process of watching test images or video recordings. To reduce the interference from the eye surface the camera uses a band-stop color glass filter PS 13. In order to increase the pupil image contrast, IR LED backlighting of the eye is implemented. To provide the mobility of the system, battery power of the single-board computer was used while the registered image and the measurement results were transmitted via a Wi-Fi channel. The video camera and the single-board computer Raspberry Pi 4 with the battery bay are attached to the head-mounted flexible belt. The article gives the operation duration evaluation of the battery-supplied system. During the first stage of image processing, binarization by the threshold was performed. The threshold is determined by the image brightness histogram. Since the study is focused on relative variations of the pupil size, the pupil diameter or area values in pixels were chosen as informative parameters. The image recording and processing frequency in the system equalled 25 Hz that provides accurate recording of the pupil variations.

Study on Distortion Compensation of Underwater Archaeological Images Acquired through a Fisheye Lens and Practical Suggestions for Underwater Photography - A Case of Taean Mado Shipwreck No. 1 and No. 2 -

Underwater archaeology relies heavily on photography and video image recording during surveillances and excavations like ordinary archaeological studies on land. All underwater images suffer poor image quality and distortions due to poor visibility, low contrast and blur, caused by differences in refractive indices of water and air, properties of selected lenses and shapes of viewports. In the Yellow Sea (between mainland China and the Korean peninsula), the visibility underwater is far less than 1 m, typically in the range of 30 cm to 50 cm, on even a clear day, due to very high turbidity. For photographing 1 m x 1 m grids underwater, a very wide view angle (180o) fisheye lens with an 8 mm focal length is intentionally used despite unwanted severe barrel-shaped image distortion, even with a dome port camera housing. It is very difficult to map wide underwater archaeological excavation sites by combining severely distorted images. Development of practical compensation methods for distorted underwater images acquired through the fisheye lens is strongly desired. In this study, the source of image distortion in underwater photography is investigated. We have identified the source of image distortion as the mismatching, in optical axis and focal points, between dome port housing and fisheye lens. A practical image distortion compensation method, using customized image processing software, was explored and verified using archived underwater excavation images for effectiveness in underwater archaeological applications. To minimize unusable area due to severe distortion after distortion compensation, practical underwater photography guidelines are suggested.

Photogram: The Art of Recording Shapes in Photography as Media for Enhaching Creativity in Children's Communication

Photogram is a technique that produces images without using a camera as an image recording aid. However, it makes more use of sunlight and chemicals as recording materials. The photos from this photogram are in the form of a silhouette or an outline of the object being recorded. Considering the dangers of chemicals for children, using natural dyes is friendlier to them. Therefore, the process of conveying messages through photographs by children can run well. This study aims to analyze the 4P elements (Personal, Process, Press, Product) of photogram's work as an enhancer of creativity in children's communication. This study uses a descriptive qualitative approach which will elaborate the data by describing them into sentences. The technique of collecting data is in the form of observing photogram works, documenting the work and looking for references through literature study. The photographic works produced by the children will be studied in terms of creativity by describing the 4P elements. Apart from that through the photographic works produced by these children, it can be concluded that creativity arises because of one's own interaction with the environment which is then processed and supported by the people around them and the environment so that it becomes creative photogram work. It is also intended that photogram can become an alternative media in honing children's creativity in communicating with their environment.

ANALISIS KECUKUPAN RUANG TERBUKA HIJAU (RTH) KOTA BATAM

Batam City is an industrial city and has a total area of 1,570.35 km2 with a land area of 715 km2. Following the economic development and increasing population, the green open space in Batam City is decreasing. The purpose of this research was to analyze the adequacy of Batam’s green open space based on the criteria of Law No. 26 of 2007 concerning Spatial Planning and Minister of Public Works Regulation No. 5 of 2008 concerning Guidelines and Utilization of Green Open Space. This research was conducted with a spatial analysis method based on land cover information from the interpretation of Landsat 8 OLI image recording on 05-06-2018. Based on the results showed that Batam’s green open space is still 221.400 ha or 32.05% from land area. It means, Batam City’s open space is still sufficient at least 30% according to Law No. 26 of 2007 and Minister of Public Works Regulation No. 5 of 2008. The largest type of land cover in green open space is secondary dry land forest, covering 79.200 ha (11.45%). Keyword : Batam City, analysis, green open space.

Novel Twofold Use of Photographic Technique for Simultaneous Flow Boiling Image Recording and Void Fraction Computation in a Mini-Channel Experiment

The paper presents a novel twofold use of the photographic technique for flow boiling heat transfer investigation in the horizontal mini-channel. The dedicated measurement system was constructed to record basic thermal and flow parameters, i.e., boiling liquid inlet and outlet temperatures and pressures, and also temperatures inside the heating block to calculate heat flux going into the liquid. A high-speed video camera equipped with synchronous movement system was applied to combine the recording of two-phase flow images with simultaneous local void fraction measurements both based on the same photographic data set. The data were collected, managed, and refined with the scripts developed in the MathWorks Matlab 2019b environment. The synchronous use of two intelligent techniques in the scripts, i.e., the background subtraction technique and the statistical analysis of individual pictures allowed obtaining reliable experimental results. The proposed method of the void fraction determination ensures high measurement accuracy.

EXPERIMENTAL ASSESSMENT OF THE EFFECT OF EXPOSURE LEVEL ON THE RESOLUTION OF A DIGITAL PHOTOGRAPHIC SYSTEM

While photographing in a wide range of brightness within the frame, the exposure devices must provide exposure control for each elementary area of ​​the frame, i.e., provide local exposure control. Cameras which equipped by well-known exposure devices with local exposure control is used a multiplicative, additive or multifunction method of image recording. Using of the multiplicative method leads to energy losses in the optical channel, which requires correction of the exposure control parameters. Using of the additive method makes it possible to reduce the effective shutter speed, but reduces the contrast of small images. The multiplicative method of image registration allows to suppress low-informative low-frequency components of the spectrum of the input signal, providing less losses from the image blur according to the multiplicative method and less losses from reducing the contrast of images of small parts according to the additive method. Comparative evaluation of cameras’ effectiveness which are equipped by exposure devices with local exposure control, which are based on different methods of image registration, is convenient to assess the criterion of "resolution averaged over the frame field". According to the developed methodology of evaluating the effectiveness of this type of cameras, the averaged field resolution can be calculated in several ways, each of which assumes a preliminary calculation or obtaining the dependence of resolution from exposure (resolvometric characteristics of the camera). The methodology of experimental determination of the resolvometric characteristic of a photographic image recorder equipped by exposure devices of local exposure control is proposed. This methodology is illustrated by the example of measuring the resolvometric characteristics of the digital camera nex-6 for different external conditions. The good convergence of results of theoretical and experimental researches is shown. The proposed methodology can be used in studies of the impact of the process of the multifunction method of image recording on the photographing efficiency. Keywords: image; resolution; measure; camera

Multi-Device Piezoelectric Direct Discharge for Large Area Plasma Treatment

The piezoelectric cold plasma generators (PCPG) allow for production of the piezoelectric direct discharge (PDD), which is a kind of cold atmospheric pressure plasma (APP). The subjects of this study are different arrays of PCPGs for large-area treatment of planar substrates. Two limiting factors are crucial for design of such arrays: (i) the parasitic coupling between PCPGs resulting in minimum allowed distance between devices, and (ii) the homogeneity of large area treatment, requiring an overlap of the activation zones resulting from each PCPG. The first limitation is investigated by the use of electric measurements. The minimum distance for operation of 4 cm between two PCPGs is determined by measurement of the energy coupling from an active PCPG to a passive one. The capacitive probe is used to evaluate the interference between signals generated by two neighboring PCPGs. The second limitation is examined by activation image recording (AIR). Two application examples illustrate the compromising these two limiting factors: the treatment of large area planar substrates by PCPG array, and the pretreatment of silicon wafers with an array of PCPG driven dielectric barrier discharges (DBD).