Decoding barcodes displayed on cell phone

摘要

A method of decoding a barcode includes generating a first illumination towards a target object with a first illumination level, capturing a first image during a first exposure time period, and determining a first location and a second location on a scan line in the first image to find a switchover condition. If the switchover condition indicates the presence of a mobile display device, the method further includes generating a second illumination towards the target object with a second illumination level, capturing a second image during a second exposure time period, and decoding the barcode in the second image. Here, at least one of the second illumination level and the second exposure time period is determined based on values of pixels on the scan line between the first location and the second location.

主权项

1. A method of decoding a barcode within an imaging field of view of an imaging system that includes an imaging sensor having an array of photosensitive elements, the method comprising:
generating a first illumination towards a target object with a first illumination level; detecting light from the target object with the array of photosensitive elements in the imaging sensor while the target object is illuminated by the first illumination to capture a first image during a first exposure time period; determining a first location and a second location on a scan line in the first image to find a switchover condition; if the switchover condition indicates the presence of a mobile display device in the first image, (1) generating a second illumination towards the target object with a second illumination level, and (2) detecting light from the target object with the array of photosensitive elements in the imaging sensor while the target object is illuminated by the second illumination to capture a second image during a second exposure time period; wherein at least one of the second illumination level and the second exposure time period is determined based on values of pixels on the scan line between the first location and the second location in the first image; and finding a selected distance between the first location and the second location on the scan line; and wherein the switchover condition indicates the presence of a mobile display device in the first image if the ratio between the selected distance and the total length of the scan line in the first image is larger than a predetermined factor.