摘要:
A bar code scanner and method for scanning a bar code symbol that splits a light beam using a liquid crystal device and directs the split light beams toward a bar code symbol using a moveable mirror. The light reflected by the symbol from each of the split light beams is summed and converted to an electrical signal indicative of the bar code symbol. The electrical signal is processed to decode the bar code symbol, but, if decoding is unsuccessful, the liquid crystal device is changed to affect the number of split light beams incident on the bar code symbol.
摘要:
A bar code scanner for reading a bar code tag includes a collection optical system, a two dimensional array of detectors, rotating means for imparting rotational movement to the array and displacement means for varying the position of one of the collection optical system and the array along an optical axis of the collection optical system.
摘要:
A phase-only filter for approximating a given optical transfer function for monochromatic incoherent light. The filter is designed by solving an integral equation for a phase function, and imposing, on a transparent plate, an optical path length for the incoherent radiation equal, in radians, to the phase function modulo 2.pi. plus an overall constant.
摘要:
A bar code scanner employs an electronic means for causing the light beam to scan a bar code symbol, rather than using a mechanical device to generate the scan. A linear array of light sources, activated one at a time in a regular sequence, may be imaged upon the bar code symbol to simulate a scanned beam. Instead of a single linear array of light sources, a multiple-line array may be employed, producing multiple scan lines. The multiple scan lines may be activated in sequence, or activated simultaneously (time-division or frequency-division multiplexed. The multiple scan lines can provide signal enhancement, noise reduction or fault correction if directed to the same bar code pattern. Multiple scan lines may be generated using a single light source and a beam splitter, with mechanical scanning, as well as by the sequentially-activated light sources. Multiple simultaneous scan lines may be employed to generate a raster scan at lower mechanical scan frequency. In another embodiment, a tunable laser may be employed to provide a scan without moving parts; a laser beam from the tunable laser is reflected from a diffraction grating that produces an angular deviation dependent upon the wavelength of the laser output. As the frequency of the tunable laser is varied in some selected pattern, the laser beam will scan accordingly.
摘要:
Apparatus is disclosed for high-speed processing of a two-dimensional image using Cellular Array Processors arranged as parallel modules in a multi-level matrix. An array of photosensors is used to provide image intensity signals for each image pixel. Comparator and memory modules are used to convert the sensor signals to digital form using parallel processing techniques.
摘要:
Apparatus for image subtraction in order to extract non-common information from two light images comprises a TV camera tube including a photosensitive coating on its inner face and a grating on its outer face spaced from the photosensitive coating by the thickness of the tube; projectors for projecting the two light images simultaneously, from slightly different angles, onto the photosensitive coating via the grating such that the shadow of the grating interlaces the two light images on the photosensitive coating; and a scanner for electronically scanning the interlaced images on the photosensitive coating to produce a video output, and for processing same to select only the image information which is non-common to the two optical images.
摘要:
A method for designing a mask, the method includes: choosing or receiving a desired contrast value; and determining sizes, locations and shapes of multiple rotationally symmetric regions of a mask such as to define a modulation transfer function that is characterized by a substantially uniform response over a spatial frequency range; wherein the uniform response is substantially indifferent to an orientation of features of the object and to a location of the object within a deep depth-of-field region. An optical imaging system that includes: a mask that includes multiple rotationally regions; wherein the multiple rotationally symmetric regions are shaped and positioned such as to define a modulation transfer function that is characterized by a substantially uniform response over a spatial frequency range, wherein the uniform response is substantially indifferent to an orientation of features of the object and to a location of the object within a deep depth-of-field region.
摘要:
A mask for enhancing the depth of focus of an optical imaging system is designed by optimizing an optical property (transmittance or reflectance) of the mask relative to the intensity distribution in the system's image plane. Preferably, a desired PSF intensity is selected, a desired misfocus parameter range is selected, and the optical property is adjusted to minimize a measure of the departure of the system's PSF intensity, as computed from the mask's optical property, from the desired PSF intensity, over the entire misfocus parameter range. Most preferably, the desired PSF intensity is selected as the inverse Fourier transform of a desired OTF. Preferably, the mask is fabricated as a DOE.
摘要:
A beam generator, or beam shaping system, for example for use in an optical scanner, creates a non-Gaussian beam which provides improved indicia-reading characteristics. In one embodiment, diffractive optical elements are used to create a Bessel-Gaussian scanning beam, which comprises a coherent combination of a Gaussian beam and a Bessel beam.
摘要:
A method and system for synthesizing a desired light beam including calculating a two-dimensional light filter for an optical element, the two-dimensional light filter being such that the optical element produces under free space propagation, in response to illumination thereof, a three-dimensional light distribution that approximates the light distribution of the desired light beam, and illuminating the optical element.