Imaging reader with dual imager scan engine with single illumination system
The present disclosure provides an optical assembly comprising a first imaging sensor having a first field of view (FOV) and a first scanning range, a second imaging sensor having a second FOV greater than the first FOV and a second scanning range less than the first scanning range, and an illumination system comprising a single illumination light source and a single illumination lens. The illumination lens projects light with a first portion having a first field of illumination (FOI) and a first brightness and a second portion having a second FOI and a second brightness, where the first FOI is smaller than the second FOI, the first brightness is greater than the second brightness, the second portion surrounds the first portion, and the first portion comprises a majority of the power of the projected light. The optical assembly compensates for brightness variation when imaging an object.
1 . An optical assembly comprising:
a first imaging sensor having a first field of view (FOV) and a first scanning range;
a second imaging sensor having a second FOV greater than the first FOV and a second scanning range less than the first scanning range; and
an illumination system comprising a single illumination light source and a single illumination lens to project light emitted from the illumination light source;
wherein the illumination lens is configured such that (i) the projected light comprises (a) a first portion having a first field of illumination (FOI) and a first brightness and (b) a second portion having a second FOI and a second brightness, (ii) the first FOI is smaller than the second FOI, (iii) the first brightness is greater than the second brightness, (iv) the second portion surrounds the first portion, and (v) the first portion comprises a majority of a power of the projected light; and
wherein the optical assembly is configured to, when imaging an object, compensate for a variation of brightness of the light projected onto the object due to the different FOI and/or brightness of the first and second portions of the projected light.
2 . The optical assembly of claim 1 , further comprising processing circuitry.
3 . The optical assembly of claim 2 , wherein the processing circuitry is part of the first imaging sensor and/or the second imaging sensor.
4 . The optical assembly of claim 2 , wherein the processing circuitry is configured to apply a relative illumination calibration function to an image captured by either the first imaging sensor or the second imaging sensor of an object to normalize the brightness across the image.
5 . The optical assembly of claim 2 , wherein the first imaging sensor and/or the second imaging sensor are configured to capture two or more images of an object at different exposures; and
wherein the processing circuitry is configured to stitch together one or more different portions of each of the two or more images having different brightnesses to create a combined image having a more uniform level of brightness.
6 . The optical assembly of claim 5 , wherein the one or more different portions of each of the two or more images comprise one or more annular portions.
7 . The optical assembly of claim 1 , wherein the first imaging sensor and/or the second imaging sensor have a non-linear exposure function such that a central portion of its FOV is exposed less than a peripheral portion of its FOV to provide a more uniform exposure effect across its FOV.
8 . The optical assembly of claim 1 , wherein the illumination system is configured to vary an intensity of the projected light and a time of exposure to reduce brightness saturation in from the first portion of the projected light.
9 . The optical assembly of claim 1 , wherein the first scanning range of the first imaging sensor is variable.
10 . The optical assembly of claim 1 , further comprising an aiming system comprising an aiming light source and an aiming lens through which aiming light from the aiming light source is transmitted.
11 . An imaging reader for electro-optically reading a symbol by image capture, comprising:
a housing; and
an optical assembly mounted in the housing, the optical assembly comprising:
a first imaging sensor having a first field of view (FOV) and a first scanning range;
a second imaging sensor having a second FOV greater than the first FOV and a second scanning range less than the first scanning range; and
an illumination system comprising a single illumination light source and a single illumination lens to project light emitted from the illumination light source;
wherein the illumination lens is configured such that (i) the projected light comprises (a) a first portion having a first field of illumination (FOI) and a first brightness and (b) a second portion having a second FOI and a second brightness, (ii) the first FOI is smaller than the second FOI, (iii) the first brightness is greater than the second brightness, (iv) the second portion surrounds the first portion, and (v) the first portion comprises a majority of a power of the projected light; and
wherein the optical assembly is configured to, when imaging an object, compensate for a variation of brightness of the light projected onto the object due to the different FOI and/or brightness of the first and second portions of the projected light.
12 . The imaging reader of claim 11 , wherein the optical assembly further comprises processing circuitry.
13 . The imaging reader of claim 12 , wherein the processing circuitry is part of the first imaging sensor and/or the second imaging sensor.
14 . The imaging reader of claim 12 , wherein the processing circuitry is configured to apply a relative illumination calibration function to an image captured by either the first imaging sensor or the second imaging sensor of an object to normalize the brightness across the image.
15 . The imaging reader of claim 12 , wherein the first imaging sensor and/or the second imaging sensor are configured to capture two or more images of an object at different exposures; and
wherein the processing circuitry is configured to stitch together one or more different portions of each of the two or more images having different brightnesses to create a combined image having a more uniform level of brightness.
16 . The imaging reader of claim 15 , wherein the one or more different portions of each of the two or more images comprise one or more annular portions.
17 . The imaging reader of claim 11 , wherein the first imaging sensor and/or the second imaging sensor have a non-linear exposure function such that a central portion of its FOV is exposed less than a peripheral portion of its FOV to provide a more uniform exposure effect across its FOV.
18 . The imaging reader of claim 11 , wherein the illumination system is configured to vary an intensity of the projected light and a time of exposure to reduce brightness saturation in from the first portion of the projected light.
19 . The imaging reader of claim 11 , wherein the first scanning range of the first imaging sensor is variable.
20 . The imaging reader of claim 11 , wherein the optical assembly further comprises an aiming system comprising an aiming light source and an aiming lens through which aiming light from the aiming light source is transmitted.