Precise machine vision detection for a large object at a finite working distance (WD) requires that the lens has a high resolution for a large field of view (FOV). In this case, the effect of a secondary spectrum on image quality is not negligible. According to the detection requirements, a high resolution apochromatic objective is designed and analyzed. The initial optical structure (IOS) is combined with three segments. Next, the secondary spectrum of the IOS is corrected by replacing glasses using the dispersion vector analysis method based on the Buchdahl dispersion equation. Other aberrations are optimized by the commercial optical design software ZEMAX by properly choosing the optimization function operands. The optimized optical structure (OOS) has an f-number (F/#) of 3.08, a FOV of φ60 mm, a WD of 240 mm, and a modulated transfer function (MTF) of all fields of more than 0.1 at 320 cycles/mm. The design requirements for a nonfluorite material apochromatic objective lens with a large field and high definition for machine vision detection have been achieved.

Design of apochromatic lens with large field and high definition for machine vision.

In this work, we present a close-range ultraviolet imaging spectrometer with high spatial resolution, and reasonably high spectral resolution. As the transmissive optical components cause chromatic aberration in the ultraviolet (UV) spectral range, an all-reflective imaging scheme is introduced to promote the image quality. The proposed instrument consists of an oscillating mirror, a Cassegrain objective, a Michelson structure, an Offner relay, and a UV enhanced CCD. The finished spectrometer has a spatial resolution of 29.30μm on the target plane; the spectral scope covers both near and middle UV band; and can obtain approximately 100 wavelength samples over the range of 240~370nm. The control computer coordinates all the components of the instrument and enables capturing a series of images, which can be reconstructed into an interferogram datacube. The datacube can be converted into a spectrum datacube, which contains spectral information of each pixel with many wavelength samples. A spectral calibration is carried out by using a high pressure mercury discharge lamp. A test run demonstrated that this interferometric configuration can obtain high resolution spectrum datacube. The pattern recognition algorithm is introduced to analyze the datacube and distinguish the latent traces from the base materials. This design is particularly good at identifying the latent traces in the application field of forensic imaging.

High resolution ultraviolet imaging spectrometer for latent image analysis.

This paper discusses the features of objectives intended for amateur and professional astronomical observations. Type-OK4 crown glass with special dispersion behavior is used to achieve apochromatic correction in refracting objectives, since the technology for obtaining high-quality blanks made from this glass makes it possible to create apochromatic objectives with an entrance-pupil diameter of up to 304 mm. Experimental compositions of the glass have been developed that make it possible to obtain apochromatic systems composed of two lenses.

Apochromatic objectives for amateur and professional astronomy

The features of the reflection of UV radiation by sweat-and-grease deposits are used in the Obozrevatel’ observation device to determine the site of latent fingerprints on nonporous surfaces without surface preprocessing. For visual observation or recording of biological traces, electro-optic converters convert radiation that is very weak and invisible to the eye into visible radiation.

Yu. B. Grudzino

Papers

Apochromatic objectives for amateur and professional astronomy

A device that uses the UV region to detect and photographically record fingerprints at an event site