초록 ▼

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 circ

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.

대표청구항 ▼

[ What is claimed is:] [1.] In an electronic camera system for producing an image including a plurality of pixels, a method for evaluating the intensity of an image, comprising the steps of:providing a first memory including a plurality of bits, each bit corresponding to one of the pixels, the plura

[ What is claimed is:] [1.] In an electronic camera system for producing an image including a plurality of pixels, a method for evaluating the intensity of an image, comprising the steps of:providing a first memory including a plurality of bits, each bit corresponding to one of the pixels, the plurality of bits identifying a preselected subset of the pixels to be sampled to determine the intensity of the image;providing a second memory including a plurality of bins, each bin corresponding to one of a plurality of possible intensity levels associated with the preselected subset of the plurality of pixels; andcomputing an output indicative of the brightness of the image byfor each pixel of the preselected subset, determining the intensity of the pixel and incrementing a bin value of a particular one of the bins in the second memory corresponding to the intensity of the pixel;beginning with the one of the bins corresponding to the lowest of the possible intensity levels, sequentially summing the bin values in increasing intensity level order to compute a bin-value sum;determining a last bin when the bin-value sum exceeds a predetermined portion of the sampled subset of the pixels; andassigning to the output a value corresponding to the intensity level associated with the last bin.