Signal-to-noise ratio image validation
An image is compared to a validation image to obtain a signal-to-noise ratio. The signal-to-noise ratio is used to determine validity of the image. According to an embodiment, the image includes a barcode. According to another embodiment, a minimum threshold value for the signal-to-noise ratio is set and the validity of the image is determined based on the minimum threshold value and the signal-to-noise ratio. The minimum threshold value can be determined by using respective signal-to-noise ratios resulting from comparing a valid image to a validation image and an invalid image to a validation image.
1. A method, comprising:
capturing an image;
cropping the image by removing an entire machine readable code from the image to obtain a cropped image, wherein the cropped image includes a first area surrounding the machine readable code;
comparing, by a processor circuit, the first area of the cropped image to a second area of a validation image to obtain a signal-to-noise ratio of the first area to the second area, wherein the second area of the validation image surrounds a validation machine readable code of the validation image;
obtaining a predetermined minimum threshold value, wherein the minimum threshold value is determined from at least one signal-to-noise ratio for a valid image compared to the validation image and at least one signal-to-noise ratio for an invalid image compared to the validation image; and
determining validity of the image by comparing the signal-to-noise ratio to the minimum threshold value.
2. The method of claim 1 , wherein the machine readable code includes a barcode.
3. The method of claim 1 further comprising, setting a resolution for the image prior to obtaining the signal-to-noise ratio.
4. The method of claim 1 further comprising, saving the image to a database as a validation image.
5. The method of claim 1 further comprising:
comparing the image to a second validation image to obtain a second signal-to-noise ratio; and
determining validity of the image from the signal-to-noise ratio and the second signal-to-noise ratio.
6. The method of claim 1 further comprising, receiving one or more additional images and saving the one or more additional images to a database as one or more additional validation images.
7. The method of claim 1 further comprising setting a minimum number of additional validation images.
8. The method of claim 7 further comprising:
checking whether a number of additional validation images is less than the minimum number of additional validation images;
delaying determining validity of the image when the number of additional validation images is less than the minimum number of additional validation images; and
determining validity of the image from the signal-to-noise ratio when the number of additional validation images is not less than the minimum number of additional validation images.
9. A Point Of Sale (POS) terminal, comprising:
a scanner configured to capture an image;
a validation module configured to:
crop the image by removing an entire machine readable code from the image to obtain a cropped image, wherein the cropped image includes a first area surrounding the machine readable code;
compare the first area of the cropped image to a second area of a validation image to produce a signal-to-noise ratio of the first area to the second area, wherein the second area of the validation image surrounds a validation machine readable code of the validation image; and
obtain a predetermined minimum threshold value, wherein the minimum threshold value is determined from at least one signal-to-noise ratio for a valid image compared to the validation image and at least one signal-to-noise ratio for an invalid image compared to the validation image;
determine validity of the image by comparing the signal-to-noise ratio to the minimum threshold value.
10. The system of claim 9 , wherein the machine readable media includes a barcode.
11. A method, comprising:
capturing an image;
cropping the image by removing an entire machine readable code from the image to obtain a cropped image, wherein the cropped image includes a first area surrounding the machine readable code;
comparing, by a Point Of Sale (POS) terminal, the first area of the cropped image to a second area of a validation image to obtain a signal-to-noise ratio of the first area to the second area, wherein the second area of the validation image surrounds a validation machine readable code of the validation image;
obtaining a predetermined minimum threshold value, wherein the minimum threshold value is determined from at least one signal-to-noise ratio for a valid image compared to the validation image and at least one signal-to-noise ratio for an invalid image compared to the validation image; and
determining validity of the image by comparing the signal-to-noise ratio to the minimum threshold value.
12. The method of claim 11 , wherein the machine readable media includes a Quick Response (QR) code.
13. The method of claim 11 further comprising:
setting a minimum threshold value for the signal-to-noise ratio; and
determining the validity of the image by using the minimum threshold value.
14. The method of claim 11 , further comprising manipulating the image to reduce glare from the image.