Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2000-01-24
2001-12-11
Frech, Karl D. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S462250, C235S462270, C235S462240, C235S462100, C235S462410, C235S462230, C235S462110
Reexamination Certificate
active
06328214
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns an opto-electronic device for acquisition of images of codes in one and two dimensions.
2. Description of the Related Art
Numerous types of two-dimensional codes have been in use for some years. The main advantage of this new type of code in relation to the traditional bar codes (1D or stacked 1D) is that it contains a much greater density of recorded information for the same useful surface.
The appearance of this new generation of codes has, of course, led to the realization of new types of opto-electronic devices, or readers, which are capable of processing the two-dimensional codes while retaining the possibility of processing the conventional bar codes.
Such readers comprise, firstly, an electronic sensor for acquisition of images of variable size (CDD technology or other), an illumination source to illuminate the codes and to permit the acquisition of the images on the electronic sensor, and an image-processor adapted to control the electronic sensor and the illumination source and to ensure the decoding of the images formed on said electronic sensor.
Moreover, the acquisition and processing of the images of the current readers are principally composed:
of a conversion module permitting the images emitted from the electronic sensor to be digitized, that is to say, permitting this image to be coded in a certain number of levels of gray, generally 256, and permitting a constant flow of digitized data to be provided at the pixel frequency,
of a memory module permitting the storage of the digitized data and comprising one or more image planes,
and of a processing module performing the set of operations necessary for reading and decoding the two-dimensional code.
On the basis of such an architecture the current portable opto-electronic devices operate on matrices having a maximum size of about 800×600 pixels at a rate on the order of three images per second. However, as a result of the constant progress made by the micro-electronic industry, offering ever more significant possibilities and powers of calculation, new devices possessing enhanced performance characteristics in terms of rate of calculation are in the course of development. A gain in some units on the order of a factor of 5 has been announced.
However, it is advisable to note that this possibility for enhancing performance characteristics in terms of rate of calculation turns out to be limited in practice on account of the architecture, described above, of the image acquisition and processing module, by reason of the time needed by the processing module to perform, between two acquisitions, the reading and decoding operations for each captured code.
Furthermore, there is, on the other hand, no rational solution at the present time permitting the size of the processed images to be notably increased. The increase in the size of the processed images actually turns out to be much more problematic, for the calculating power necessary for the processing increases as the square of the enlargement factor of the original image: doubling the size of the image therefore necessitates a quadrupling of the calculating power.
Now, for the architecture, described above, of the current opto-electronic devices any increase in the calculating power is translated into a notable increase in the necessary memory size, and therefore into a notable increase, on the one hand, in the requirements in terms of electrical consumption, and on the other hand in the necessary volume for installation of the memory blocks.
In practice such constraints of physical nature and of consumption explain, particularly with regard to the portable opto-electronic devices, the limitation of the size of the matrices to the values stated above, that is, to say, 800×600 pixels.
However, it turns out that the two-dimensional codes tend to “code” more and more information, but on surfaces that are more and more reduced, so the increase in the maximum size of the matrices appears to be absolutely essential.
SUMMARY OF THE INVENTION
Aspects of the present invention are directed to the above problem, and therefore address an opto-electronic device, in particular a portable opto-electronic device, which is capable of operating on images of significant size, in particular of a size on the order of four times greater than that of the current images.
Another aspect of the invention is to provide an opto-electronic device possessing enhanced performance characteristics in terms of rate of calculation in relation to those of the current highest-performing devices.
To this end, certain aspects of the invention are directed towards an opto-electronic device for acquisition of images of codes in one and two dimensions comprising an electronic sensor, optics permitting images to be formed on said electronic sensor, an illumination source adapted to illuminate the codes and to permit the acquisition of the images on the electronic sensor, and an image acquisition and processing module, adapted to control the electronic sensor and the illumination source and to ensure the decoding of the images formed on the sensor.
According to the invention this opto-electronic device is characterized in that:
the electronic sensor is constituted by a high-resolution photosensitive matrix of size T=n×n pixels, adapted to supply at a pixel frequency f a stream of data that are representative of the images formed on said electronic sensor,
the image acquisition and processing module comprises a data converter including:
an analog/digital converter to convert the analog data emitted from the photosensitive matrix into a stream of digital data coded in a predetermined number of levels of gray,
a preprocessing module including, for example, cabled processing units, adapted to ensure low-level processing of the stream of digital data and to provide, on the one hand, a binarized representation of the images formed on the electronic sensor and, on the other hand, primary data which are characteristic of the captured codes, the preprocessing module also including a buffer register for temporary storage of the binarized images and of the primary data,
a first programmable processing module comprising:
two memory blocks,
a logic circuit for management of the memory blocks, adapted to configure, in alternative manner, one of the memory blocks in a mode for writing the data emitted from the buffer register and the other memory block in a mode for reading the data stored therein,
and a programmable unit, of processor type, which is programmed from the data stored in the memory block configured in reading mode, in order to test for the presence or absence of a valid code, to locate each valid code, to identify each type of code, to determine, if need be, the priority of the code to be processed, to edit and normalize each valid code,
and a second programmable processing module comprising:
two memory blocks,
a logic circuit for management of the memory blocks, adapted to configure, in alternative manner, one of the memory blocks in a mode for writing the data emitted from the first programmable module and the other memory block in a mode for reading the data stored therein, and a programmable unit, of processor type, which is programmed from the data stored in the memory block configured in reading mode, in order to decode said data so as to supply normalized data that are representative of each captured code.
The image acquisition and processing module includes, firstly, of three modules, a preprocessing module and two processing modules, forming an architecture of pipe-line type: each module uses solely the data provided by the preceding module and provides data only to the following module. Moreover, these three distinct modules can be grouped together into two types:
a preprocessing module in the form of cabled processing units, acting in synchronous mode at the pixel frequency on the flow of the data emitted from the digitization stage and implementing simple operations for processing of images permitti
Akel Khalid El
Dumontier Christophe
Massieu Jean-Louis
Puech Jean-Michel
Reuze Patrick
Frech Karl D.
Intermec IP Corporation
Seed IP Law Group PLLC
Walsh Daniel I.
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