Dataform readers using interactive storage and analysis of image data

• US 5,966,463 A
• Filed: 11/13/1995
• Issued: 10/12/1999
• Est. Priority Date: 11/13/1995
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Meta Holding Corporation
• Inventors: Wang, Ynjiun P.
• Primary Examiner(s): Au, Amelia
• Assistant Examiner(s): Johnson, Timothy M.
• Application Number:
  US08/556,311
• Time in Patent Office: 1,429 Days
• Field of Search: 235/462, 235/463, 235/464, 382/177, 382/183, 382/282, 382/283, 382/291, 382/292, 382/317, 382/323, 382/312, 382/305, 382/202, 345/192, 345/521, 358/403, 358/404
• US Class Current: 382/202
• CPC Class Codes: G06V 10/421 by analysing segments intersecting the pattern

Abstract

Line-by-line dataform readers and methods are enabled to operate with reduced buffer memory capacity. Storage and retention of image data are controlled on an interactive basis by concurrent analysis while lines of image data are coupled from a linear scanner. In a first embodiment lines of image data are analyzed for recognition of a feature unique to a type of dataform. Upon successful feature recognition a series of earlier and later lines of image data adequate to include a complete dataform image are retained in memory for decoding purposes. Prior to successful feature recognition, as lines of image data exceeding a limited memory storage capacity are received the earliest stored lines are discarded on a first-in-first-out basis. In a second embodiment, a buffer memory has a storage capacity adequate to store only a partial dataform image. Upon successful dataform feature recognition the type and size of the dataform are determined and decoding of the earliest lines including dataform image data is initiated, before the full dataform image is stored. As decoding progresses, the earliest lines of dataform image data are discarded as later lines of dataform image data are still being coupled from the scanner. Cost and power usage are lowered by reduction of required memory capacity.

Claims

1. In a dataform reader, an interactive storage and analysis method, comprising the steps of:

(a) providing a memory operable in two modes which when full to capacity stores a number of lines of image data, said memory controllable to use retain and discard modes to either (i) in said retain mode, retain the stored lines of image data after the memory is full and not store a subsequent line when provided, or (ii) in said discard mode, discard an earliest stored line of image data and store a subsequent line when provided after the memory is full;

(b) providing to said memory successive lines of image data, including lines representative of illumination reflected from a dataform;

(c) concurrently with step (b), analyzing successive lines of said image data to provide recognition of a feature of said dataform and identification of a reference line of said image data associated with such recognition, said feature usable to identify the type of dataform; and

(d) controlling the mode of said memory (i) upon recognition of said feature, to utilize said retain mode to retain in memory a series of lines of image data to be used for decoding said dataform, and (ii) in the absence of recognition of said feature, to utilize said discard mode to discard an earliest stored line of image data and store a subsequent line when provided.

2. A method as in claim 1, wherein in step (d) said series of lines includes lines of image data preceding said reference line and lines of image data subsequent to said reference line.

3. A method as in claim 1, wherein in step (d) said series of lines is identified by the bounds of a bounding box large enough to contain an image of said dataform, said bounding box encompassing lines of image data preceding said reference line and lines of image data subsequent to said reference line.

4. A method as in claim 1, including the additional steps of:

(e) retaining in memory each line of said series of lines of image data until said line is processed for decoding of said dataform; and

(f) discarding from memory an earliest line of image data upon storage of a later line of image data in excess of said number of lines of storage capacity, provided said earliest line is one of;

a line of image data not included in said series of lines;

a line of image data which has already been processed for decoding of said dataform.

5. A method as in claim 4, wherein said number of lines of storage capacity of said memory is a number of lines adequate to store image data representative of more than one-half and less than all of the information content of a complete dataform.

6. A method as in claim 1, wherein existing step (d) is replaced by the following steps (d) and (e):

(d) in the absence of successful step (c) recognition of said feature, controlling the mode of said memory to utilize said discard mode to discard an earliest stored line of said image data upon storage of a later line of image data in excess of said number of lines of storage capacity; and

(e) upon successful step (c) recognition of said feature, (i) identifying a series of lines of image data to be used for decoding of said dataform and (ii) controlling the mode of said memory to utilize said retain mode to retain said identified series of lines in memory for decoding purposes, said series of lines including at least one of a line preceding said reference line and a line subsequent to said reference line.

7. A method as in claim 6, including the additional step of:

(f) utilizing image data in said series of lines of image data to decode said dataform.

8. In a dataform reader, an interactive storage and analysis method, comprising the steps of:

(a) providing a memory operable in two modes which when full to capacity stores a number of lines of image data, said memory controllable to use retain and discard modes to either (i) in said retain mode, retain the stored lines of image data after the memory is full and not store a subsequent line when provided, or (ii) in said discard mode, discard an earliest stored line of image data and store a subsequent line when provided after the memory is full;

(b) providing to said memory successive lines of image data, including lines representative of illumination reflected from a dataform;

(c) concurrently with step (b) analyzing successive lines of said image data to provide recognition of image data representative of said dataform; and

(d) controlling the mode of said memory (i) upon recognition of image data representative of said dataform, to utilize said retain mode to retain said representative image data in memory for purposes of decoding said dataform and (ii) in the absence of recognition of representative image data, to utilize said discard mode to discard an earliest stored line of image data and store a subsequent line when provided.

9. A method as in claim 8, including between steps (c) and (d) an additional step as follows:

(x) determining bounds of a bounding box large enough to contain a selected portion of an image of said dataform.

10. A method as in claim 9, wherein in step (x) said selected portion is less than the entire dataform, but includes image data representative of at least one-half of the information content of said dataform.

11. A method of reading a dataform using a memory too small to store image data for a complete dataform image, by dataform feature recognition with interactive storage and analysis of image data, comprising the steps of:

(a) providing successive lines of image data, including lines representative of illumination reflected from a dataform;

(b) storing successive lines of said image data in a memory having a capacity inadequate to store image data representative of all of the information content of said dataform;

(c) concurrently with step (b) and prior to decoding of said dataform, analyzing successive lines of said image data to provide identification of the type of dataform by recognition of a feature of said dataform and identify a reference line of image data associated with said recognition;

(d) upon successful step (c) recognition of said feature and identification of the type of dataform present, (i) identifying a series of lines of image data to be used for decoding of said dataform including lines already stored and lines not yet stored and (ii) initiating decoding of said dataform beginning with the earliest line of said identified series of lines; and

(e) discarding an earliest stored line of said image data upon storage of a later line of image data in excess of said number of lines of storage capacity, to enable use of a memory too small to store a complete image of said dataform.

12. A dataform reader, using interactive storage and analysis of image data, comprising:

a sensor to provide a succession of lines of image data, including lines representative of illumination reflected from a dataform;

a two mode memory coupled to said sensor and having a capacity to store a number of lines of said image data as said succession of lines is received from said sensor, said memory having two operating modes (i) a retain mode selectable to retain a series of lines of image data, and (ii) a default FIFO mode in which an earliest stored line of said image data is discarded when a line in excess of said number of lines is coupled from said sensor; and

a locator coupled to said memory and operative concurrently with storage of said succession of lines of image data to provide recognition of a feature of said dataform and identification of a reference line of image data associated with such recognition, said locator responsive to successful feature recognition to (i) identify a series of lines of image data to be used for decoding said dataform, and (ii) control said memory to operate in said retain mode to retain said series of lines of image data;

said locator arranged to permit said memory to operate in said default FIFO mode when feature recognition has not been successfully achieved.

13. A dataform reader as in claim 12 additionally comprising:

a decoder coupled to said memory to utilize lines of image data in said series of lines to decode said dataform.

14. A dataform reader as in claim 12, wherein said series of lines includes both lines of image data preceding said reference line and lines of image data subsequent to said reference line.

15. An interactive storage and analysis method for a dataform reader, comprising the steps of:

providing successive lines of image data to a memory, wherein the lines of said image data include data representative of illumination reflected from a dataform;

analyzing successive lines of the image data provided to said memory, to recognize a feature of said dataform, and using said feature to identify the type of dataform from among a plurality of different 1-D and 2-D bar code dataform types decodable by the dataform reader;

discarding an earliest stored line of the image data stored in said memory and storing a subsequent line of the image data when provided after the memory is full, until the type of dataform from among the plurality of different 1-D and 2-D bar code dataforms is identified, and thereafter retaining lines of said image data stored in said memory after the memory is full and storing no subsequent lines of the image data when provided.

16. A method according to claim 15, wherein said method further comprises decoding said dataform from said lines of image data retained in said memory.

17. A system for data storage and analysis method for a dataform reader, comprising:

memory means selectively operable in at least two storage operating modes, said first storage operating mode discarding data previously stored therein to provide memory storage space to store subsequently received data, and said second storage operating mode retaining data previously stored therein and storing no subsequent received data;

transmission means for transmitting data to the memory means, wherein the data includes image data representative if the reflectivity of one or more portions of a dataform;

analysis means for analyzing data transmitted to the memory means, to recognize a feature of said dataform, wherein said feature is used to identify the type of dataform from among a plurality of different 1-D and 2-D bar code dataform types decodable by the dataform reader; and

means modifying the storage operating mode of said memory means depending upon whether the type of dataform from among the plurality of different 1-D and 2-D bar code dataforms types is identified, wherein the said memory means is operated in said first storage operating mode until a dataform type has been identified, and thereafter operating said memory means in said second storage operating mode.

18. An apparatus according to claim 17, wherein said apparatus further comprises decoding means for decoding said dataform from said data retained in said memory means during said second storage operating mode.