Apparatus for diagonal progressive scanning video and method of improving aiming visibility, reducing tilt dependence and improving read range
First Claim
1. A method for scanning a bar code with a bar code scanner having a three-dimensional (3D) field-of-view encompassing a bar code, comprising:
- illuminating a bar code with an illumination source having a lighting wavelength and a thin, bright lighting path produced by moving a beam of light;
embedding said lighting path in a first 3D volume of view of the bar code;
passing backscattered light from the bar code through a filter centered on the lighting wavelength;
sensing the light backscattered from the bar code by pixels of an array of pixels illuminated by the backscattered light, each illuminated pixel having a respective pixel height and a respective pixel width;
artificially reducing the respective pixel height of illuminated pixels in the pixel array to a respective effective pixel height of m*w, where m is the magnification of a lens in a scanner and w is the thickness of the lighting path; and
decoding the bar code.
2 Assignments
0 Petitions
Accused Products
Abstract
A laser scanner with a 2D resonant electrostatic micro-mirror has improved aiming visibility, reduced tilt dependence and improved read range. The laser scanner has a field of view that defines a 3D volume and utilizes a laser beam in a light path that is thin relative to the 3D volume. Physical pixel height is enlarged to aid optical imaging plane alignment. A selective filter centered on the lighting wavelength is placed in the image path. The height of the pixel may be artificially induced to be m*w, where m is the lens magnification and w is the light thickness. Diagonal progressive scanning is used to maximize the frequency values so shock resistance of the mirror is increased.
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Citations
24 Claims
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1. A method for scanning a bar code with a bar code scanner having a three-dimensional (3D) field-of-view encompassing a bar code, comprising:
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illuminating a bar code with an illumination source having a lighting wavelength and a thin, bright lighting path produced by moving a beam of light; embedding said lighting path in a first 3D volume of view of the bar code; passing backscattered light from the bar code through a filter centered on the lighting wavelength; sensing the light backscattered from the bar code by pixels of an array of pixels illuminated by the backscattered light, each illuminated pixel having a respective pixel height and a respective pixel width; artificially reducing the respective pixel height of illuminated pixels in the pixel array to a respective effective pixel height of m*w, where m is the magnification of a lens in a scanner and w is the thickness of the lighting path; and decoding the bar code. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for scanning a bar code having a height and a width, the method comprising:
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driving a mirror to oscillate about a first axis at a first frequency, f1; driving the mirror to oscillate about a second axis at a second frequency, f2, where f2=k*f1, and k is a rational number; reflecting a laser light from the oscillating minor, the reflected laser light having a wavelength and a thickness w; illuminating the width of the bar code with the light reflected from the moving mirror, wherein only a portion of the height of the bar code is illuminated; passing the laser light backscattered from the illuminated portion of the bar code through a filter centered on the wavelength of the laser light; receiving the filtered backscattered light at a portion of an array of pixels, wherein the array of pixels has an array width and each pixel has a respective pixel height, wherein the filtered backscattered light is received by only a portion of the respective pixel height of each pixel that receives the filtered backscattered light; and decoding the bar code. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for scanning a bar code having a height and a width, the method comprising:
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oscillating a mirror about a first axis at a first frequency, f1; oscillating the mirror about a second axis at a second frequency, f2; reflecting a laser light having a wavelength and a thickness w from the oscillating mirror; illuminating the width of the bar code and only a portion of the height of the bar code with the laser light reflected from the oscillating mirror; receiving laser light backscattered from the illuminated portion of the bar code at an array of pixels, wherein each pixel of the array of pixels has a respective pixel height, wherein the backscattered laser light is received by only a portion of the respective pixel height of each pixel that receives the backscattered laser light; and decoding the bar code. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification