Imaging Reader Memory Management via Zone Subdivision
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Solution Overview
Problem
Existing imaging readers require large external RAM and ROM to store pixel data for two-dimensional symbols, making them expensive and limiting the use of low-cost controllers, especially in applications where space and cost are concerns, such as in smartphones or coffee makers.
Innovation Solution
The solution involves using internal RAM and ROM with a reduced capacity, less than one-tenth of the pixel count number, to store pixel data by subdividing the symbol into image capture zones and down-sampling the data, allowing for sequential capture and processing, eliminating the need for external memory chips and enabling the use of low-cost controllers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If external RAM with large capacity is used to store pixel data for two-dimensional symbols, then the memory storage requirement is satisfied, but the device cost and footprint increase
Solution Approach 1:
The patent divides the two-dimensional symbol into multiple image capture zones, allowing the imager to capture and process data in segments rather than requiring the entire symbol to be stored in memory at once. This segmentation enables the use of smaller internal RAM while still processing two-dimensional symbols.
Solution Approach 2:
The patent transitions from storing the complete two-dimensional symbol image in memory to processing it zone-by-zone, effectively adding a temporal dimension to the storage requirement. Instead of requiring large spatial storage for the entire symbol, the system uses smaller storage for partial zones processed sequentially.
2Device complexity
If internal RAM with small capacity is used in low-cost controllers, then the device cost decreases, but the memory storage requirement for two-dimensional symbols cannot be satisfied
Solution Approach 1:
The patent segments the symbol into multiple capture zones, enabling the small internal RAM to store only the data for one zone at a time while the controller processes and decodes the data sequentially. This segmentation allows low-cost controllers with limited RAM to handle two-dimensional symbols that would traditionally require large external memory.
Solution Approach 2:
The controller performs preliminary actions by determining the size and location of the symbol before capturing data, allowing it to calculate the optimal zones to capture and process. This preliminary planning enables efficient use of limited memory capacity by focusing storage on the most critical data regions.
3Loss of information
If the entire symbol image is captured and stored in memory, then complete symbol data is available for processing, but the processing time and memory bandwidth requirements increase
Solution Approach 1:
The patent segments the symbol into multiple zones that can be captured and processed sequentially. This allows the controller to process data in smaller chunks rather than handling the entire symbol at once, improving processing speed while maintaining complete data availability through sequential zone processing.
Solution Approach 2:
The controller continuously processes data from different zones in sequence, maintaining continuous useful action on the symbol data. By overlapping the capture of one zone with the processing of another zone, the system maintains high productivity while ensuring all symbol data is eventually processed completely.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the memory requirements, enabling the use of low-cost imaging readers in various applications by allowing less expensive controllers with smaller internal memories, while maintaining efficient data processing and decoding capabilities.
Implementation Method 1
an imaging module having a solid-state imager with a sensor array of photocells or light sensors, which correspond to image elements or pixels
Implementation Method 2
an imaging lens assembly for capturing return light scattered and/or reflected from the symbol being imaged, and for projecting the return light onto the sensor array
Implementation Method 3
The controller is then operative for digitizing and decoding the electrical signals of the entire image of the symbol into data indicative of the symbol being imaged and read
Data Source
AI summary
An imaging reader has a two-dimensional array of image sensors for capturing return light from a two-dimensional symbol over a field of view as pixel data to be stored in internal random access memory (RAM) of a controller even though the internal RAM has less storage bytes than the number of sensors. The controller determines a size and a location of the symbol in the field of view, maps and subdivides the symbol into a plurality of image capture zones based on the symbol size and location, sequentially captures the return light from each zone, sequentially stores the pixel data from each zone into the internal RAM, sequentially digitizes the stored pixel data from each zone as digitized data, and decodes the digitized data from all the zones.