Optical scanner and image-acquisition method performed therewith

1 . An image-acquisition method comprising:

capturing, with an image sensor that includes a pixel array, a first image-set of a scene illuminated by an aimer-pattern, each image of the first image-set including a respective image-region detected by a plurality of pixels of the pixel array that define an aimer-illuminated region of the pixel array that at least in part determines a region-of-interest (ROI) of the pixel array;

determining an ROI exposure-setting based on ROI pixel-values of the first image-set generated by the ROI of the pixel array;

capturing a second image-set of the scene while an exposure setting of pixels of the aimer-illuminated region equals the ROI exposure-setting, each image of the second image-set including a respective second image region detected by a second plurality of pixels of the pixel array that define a second aimer-illuminated region of the pixel array that at least in part determines a second ROI of the pixel array;

determining an aimer-position-shift as a difference between a second location of the second aimer-illuminated region and a first location of the aimer-illuminated region;

when the aimer-position-shift exceeds a threshold value, determining a second ROI exposure-setting based on ROI pixel-values of the second image-set generated by the second ROI of the pixel array, which includes one or more second plurality of pixels; and

capturing a third image-set of the scene while the exposure setting of pixels of the aimer-illuminated region equals a third ROI exposure-setting.

2 . The method of claim 1 , the first image-set including one or more images, each of which includes non-ROI pixel-values generated by non-ROI pixels of the pixel array not located within the aimer-illuminated region, wherein determining the ROI exposure-setting is based on the ROI pixel-values and not based on the non-ROI pixel-values.

3 . The method of claim 1 , further comprising determining a number of pixel-coordinates of the aimer-illuminated region, each corresponding to a respective one of the plurality of pixels, an image-region of an image of the first image-set including an image of the aimer-pattern detected by the plurality of pixels, wherein determining the number of pixel-coordinates comprises:

detecting the image of the aimer-pattern using an object detection method.

4 . The method of claim 1 , further comprising determining a number of pixel-coordinates of the aimer-illuminated region, each corresponding to a respective one of the plurality of pixels, wherein determining the number of pixel-coordinates comprises:

determining a distance between the pixel array and the scene; and

applying a geometric triangulation method using the distance.

5 . The method of claim 1 , the ROI including a contiguous plurality of pixels, the exposure setting of each pixel of the ROI equals the ROI exposure-setting.

6 . The method of claim 1 , further comprising, before capturing the second image-set, setting each pixel of the ROI to the ROI exposure-setting.

7 . The method of claim 1 , further comprising, before capturing the second image-set, setting each pixel of the pixel array to the ROI exposure-setting.

8 . The method of claim 1 , the pixel array being part of an image sensor, and further comprising, before determining the ROI exposure-setting:

adjusting an exposure level of the aimer-illuminated region such that the image sensor generates, from the aimer-illuminated region, an adjusted image-region that satisfies an exposure metric.

9 . The method of claim 1 , wherein:

when the aimer-position-shift exceeds the threshold value, the third ROI exposure-setting equaling the second ROI exposure-setting; and

when the aimer-position-shift does not exceed the threshold value, the third ROI exposure-setting equaling the ROI exposure-setting.

10 . The method of claim 1 , further comprising detecting whether a timeout condition has been satisfied, wherein determining the aimer-position-shift is responsive to the timeout condition being satisfied.

11 . An image acquisition method of claim 3 , comprising:

capturing, with an image sensor that includes a pixel array, a first image-set of a scene illuminated by an aimer-pattern, each image of the first image-set including a respective image-region detected by a plurality of pixels of the pixel array that define an aimer-illuminated region of the pixel array that at least in part determines a region-of-interest (ROI) of the pixel array;

determining an ROI exposure-setting based on ROI pixel-values of the first image-set generated by the ROI of the pixel array;

capturing a second image-set of the scene while an exposure setting of pixels of the aimer-illuminated region equals the ROI exposure-setting;

determining a number of pixel-coordinates of the aimer-illuminated region, each corresponding to a respective one of the plurality of pixels;

intermittently illuminating the scene with the aimer-pattern according to a temporal illumination function; and

capturing the first image-set includes synchronizing a shutter of the image sensor to the temporal illumination function such that (i) the image sensor captures each image of the first image-set when the aimer-pattern is not illuminating the scene and (ii) no image of the first image-set includes an image of the aimer-pattern.

12 . An image-acquisition method comprising:

capturing, with an image sensor that includes a pixel array, a first image-set of a scene illuminated by an aimer-pattern, each image of the first image-set including a respective image-region detected by a plurality of pixels of the pixel array that define an aimer-illuminated region of the pixel array that at least in part determines a region-of-interest (ROI) of the pixel array;

determining an ROI exposure-setting based on ROI pixel-values of the first image-set generated by the ROI of the pixel array;

capturing a second image-set of the scene while an exposure setting of pixels of the aimer-illuminated region equals the ROI exposure-setting;

determining a distance between the pixel array and the scene; and

determining an area of the ROI from the distance.

13 . The method of claim 1 , the aimer-illuminated region occupying a first area of the pixel array, the ROI occupying a second area of the pixel array that includes the first area.

14 . An image-acquisition method comprising:

capturing, with an image sensor that includes a pixel array, a first image-set of a scene illuminated by an aimer-pattern, each image of the first image-set including a respective image-region detected by a plurality of pixels of the pixel array that define an aimer-illuminated region of the pixel array that at least in part determines a region-of-interest (ROI) of the pixel array;

determining an ROI exposure-setting based on ROI pixel-values of the first image-set generated by the ROI of the pixel array;

capturing a second image-set of the scene while an exposure setting of pixels of the aimer-illuminated region equals the ROI exposure-setting, each image of the second image-set including a respective second image region detected by a second plurality of pixels of the pixel array that define a second aimer-illuminated region of the pixel array that at least in part determines a second ROI of the pixel array;

determining a second ROI exposure-setting based on ROI pixel-values of the second image-set generated by the second ROI of the pixel array, which includes one or more second plurality of pixels; and

capturing a third image-set of the scene while the exposure setting of pixels of the aimer-illuminated region equals the second ROI exposure-setting.

15 . The method of claim 14 , each of the ROI exposure-setting and the second ROI exposure-setting including a parameter, the act of determining the second ROI exposure-setting including implementing an iterative method that uses, as an initial value of the parameter, the value of the parameter in the ROI exposure-setting.

16 . The method of claim 15 , the parameter being exposure time or gain.

17 . An optical scanner comprising:

an image sensor including a pixel array;

a light emitter; and

circuitry, communicatively coupled to the pixel array, that is configured to operate with the pixel array to image a scene illuminated by the light emitter by:

capturing, with an image sensor that includes a pixel array, a first image-set of a scene illuminated by an aimer-pattern, each image of the first image-set including a respective image-region detected by a plurality of pixels of the pixel array that define an aimer-illuminated region of the pixel array that at least in part determines a region-of-interest (ROI) of the pixel array;

determining an ROI exposure-setting based on ROI pixel-values of the first image-set generated by the ROI of the pixel array; and

capturing a second image-set of the scene while an exposure setting of pixels of the aimer-illuminated region equals the ROI exposure-setting, each image of the second image-set including a respective second image region detected by a second plurality of pixels of the pixel array that define a second aimer-illuminated region of the pixel array that at least in part determines a second ROI of the pixel array;

determining a second ROI exposure-setting based on ROI pixel-values of the second image-set generated by the second ROI of the pixel array, which includes one or more second plurality of pixels; and

capturing a third image-set of the scene while the exposure setting of pixels of the aimer-illuminated region equals the second ROI exposure-setting.

18 . The optical scanner of claim 17 , the circuitry being part of the image sensor.

19 . The optical scanner of claim 17 , the circuitry including:

a processor, and

a memory storing machine-readable instructions that, when executed by the processor, cause the optical scanner to image the scene.

20 . The optical scanner of claim 17 , wherein a third ROI exposure-setting equals the ROI exposure-setting or the second ROI exposure-setting.