Analysis of the problems of acquisition of digital photographs intended to determine the required dimensional accuracy of the product

Abstract

In this paper, some of the problems arising from the acquisition of digital photography intended to determine the dimensional accuracy of products are discussed. Different equipment (digital cameras, lenses, and lighting) was used when acquiring photos in different formats. In mechanical engineering, the tolerances of dimensional measurements of products range from a few microns to 100 microns. Based on that, the technical specifications and capabilities of the cameras and lenses used are analyzed. In addition to the sensor, the resolution of the photo is often limited by the lens. Prior to the acquisition of photographs, problems such as lighting, contrast, sharpness, and the problem of central projection are addressed. During acquisition, technical specifications of the lens such as focal length, minimum focusing distance, aperture, and other lens features that cause acquisition problems are considered. This research and analysis led to valuable insights and conclusions that will facilitate the preparation of the acquisition of digital photography to determine the dimensional accuracy of the product.

Problems of software processing of acquired rotor intended for determining required dimensions

“…To calculate diameter deviation in micrometres, first must be calculated pixel size by dividing the rotor diameter in micrometres by the max mean diameter in pixels [12]. From the Figure 1 rotor diameter is 64.2 mm.…”

“…The main reason for poor results is improperly acquired digital photography because the appearance of shadows or the third-dimension causes problems that cannot be completely removed by software. That problem is partly solved by the equipment from the Figure 4 with recommended features from the paper [12]. On the Alvium's photo is much smaller deviation limit and binarization is better solved.…”

“…The processing of the photo acquired with the mentioned equipment gives much better results than the photo acquired with the equipment in Figure 4. Next extended research can be with camera with a larger-sized and higher-resolution sensor as well as other recommended features in the paper [12]. The software tools and their different photo processing settings can be also explored.…”

“…Within the paper [12], advice and recommendations are given on what features acquisition equipment should have. Based on that, industrial cameras from Allied Vision model Alvium 1800 U-507m were used, bi-telecentric lens from Opto Engineering model TC23085 and the illumination of parallel light radiation Digital photography acquired by Alvium camera used for processing is shown on Figure 5 The digital photographs were processed within three different software packages (Matlab, R studio and FabImage).…”