A hand held label reader is capable of illuminating a label, capturing a digital image of two-dimensional information indicia on the label, and decoding the digital image to provide decoded output data to a terminal. The target label is illuminated by a low variation illuminator that includes a circular LED array mounted behind a plano-concave dispersing lens. The automatic electronic camera, which includes a CCD camera and control circuitry, uses three images to adjust the intensity of the digital image and store a properly exposed image of the label in video RAM. The intensity of the digital image is adjusted by controlling the video system gain via adjusting the CCD array's integration time, the gain of a video amplifier, and the gain provided by an analog-to-digital converter. The gain provided by the analog-digital-converter is adjusted to compensate for the attenuation of light through the camera's lens assembly. For the first image, the digital image is obtained using a default setting for the gain. The image intensity is analyzed using a histogram process and new gain setting are determined. The second image is obtained using the gain settings derived from the first image. The second image intensity is analyzed and the gain settings are adjusted. These settings are used for the third video image. The digital image from the third image is stored in video RAM, where it is available to be decoded by a microprocessor.
CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation of U.S. patent application Ser. No. 08/657,618, filed May 30, 1996, now abandoned, which is a divisional application of U.S. application Ser. No. 08/328,660, filed Oct. 25, 1994, now abandoned.
An optical scanning system in which plural scan lines are sequentially scanned, and parameters association with the scanning are monitored. If one or more parameters change during the scanning operation, the system automatically begins rescanning, rather than continuing to scan the entire frame. This results in a system that operates more quickly than prior art systems, which have to waste an entire frame.
A method for compensation at least one digital image for light falloff. The digital image may be generated for example from a conventional image frame on a film roll. A plurality of pixel values is provided for each of at least one digital image. A light falloff compensation function is applied and according to that a light falloff correction parameter is determined. Both the light falloff compensation function and the light falloff correction parameter are used to generate an individual compensation value for each pixel element. The compensation value is applied to each pixel element. The method is also able to differentiate and correct the images according to light falloff generated by pure lens falloff or a light falloff generated by the lens and the flash falloff.
The invention is an optical reader having a 2D image sensor that is configured to operate in a partial frame capture mode. In a partial frame operating mode, the reader clocks out and captures at least one partial frame of image data having image data corresponding to less than all of the pixels of an image sensor pixel array. In one embodiment, the reader operating in a partial frame operating mode captures image data corresponding to a linear pattern of pixels of the image sensor, reads the image data, attempts to decode for a decodable 1D symbol which may be represented in the image data, and captures a full frame of image data if the image data reading reveals a 2D symbol is likely to be present in a full field of view of the 2D image sensor.
An illumination device having a plurality of light sources, a user manipulable control and a circuit. The circuit receives an input from the user manipulable control, determines an illumination angle of the plurality of light sources based upon the input, and illuminates at least one of the light sources such that the light sources are illuminated in accordance with the illumination angle.
An apparatus providing programmable illumination pattern generation for the manipulation of colloidal particulates and biomolecules in suspension between electrodes, is disclosed. The apparatus implements LEAPS (Light-controlled electrokinetic assembly of particles near surfaces), which relies on: AC electric field-induced assembly of particles the patterning of the electrolyte/silicon oxide/silicon interface to exert spatial control over the assembly process; and the real-time control of the assembly process via external illumination. The apparatus generates patterns of illumination and projects then onto planar surfaces, i.e., a LEAPS electrode. This enables the creation of patterns using graphical design or drawing software on a personal computer and the projection or said patterns, or sequences of patterns ("time-varying patterns"), onto the interface using a liquid crystal display (LCD) panel and an optical design which images the LCD panel onto the surface of interest, to provide for arrangements and assembly of particles in such patterns.
