Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
1999-01-27
2001-01-30
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C250S2140PR, C250S2140RC
Reexamination Certificate
active
06180936
ABSTRACT:
BACKGROUND OF THE INVENTION
Photoreceptors convert received light rays into an analog electrical signal that can be digitalized. For example, photoreceptors can be situated in a digital camera that registers an arbitrary image in analog form, is digitalized following the photoreceptors and is further-processed in digitalized form, for example in a computer. However, the photoreceptors can also be utilized as an independent sensor system independently of a video camera, for example in image processing. A further employment of photoreceptors can be seen in a realization of what is referred to as a technical eye.
Various photoreceptor arrangements are known under the research term of silicone retina and are discussed in the following prior art references: K. Boahen and A. Andreou, A Contrast Sensitive Silicon Retina with Reciprocal Synapses, Advances in Neural Information Processing Systems 4, J. Moody et al. (eds.), San Mateo, pp. 764-772, (1992); J. Heeger et al., Image Enhancement with Polymer Grid Triode Arrays, Science, Vol. 270, pp. 1642-1644, (1995); M. Mahowald and C. Mead, The Silicon Retina, Scientific American, Vol. 164, pp. 40-46, (1991); S, Wolpert and E. Micheli-Tsanakou, Silicon Models of lateral Inhibition, IEEE Transactions on Neural Networks, Vol. 4, pp. 955-961, (1993); and Wu Chung-Yu and Chiu Chin-Fong, A New Structure of the 2-D Silicon Retina, IEEE Journal of Solid-State Circuits, Vol. 30, No. 8, pp. 890-897, (1995).
In the photoreceptor arrangements described therein, with which the retina of vertebrates is to be simulated, it is also known to embed the photoreceptors in a network. As a result of this procedure, it is beginning to become possible to implement a filtering of the registered image information. In said works, the coupling of the photoreceptors ensues mainly with the goal of intensifying contrast.
The known arrangements, however, exhibit some disadvantages and deliver only unsatisfactory results. In particular, the couplings in the cited networks are fixed and not fashioned variable dependent, for example, on the illumination intensity of the photoreceptor arrangement. These models can thus only be meaningfully employed in a small range of an illumination intensity predetermined by the coupling intensities.
The reference of J. Heeger et al., Image Enhancement with Polymer Grid Triode Arrays, Science, Vol. 270, pp. 1642-1644, (1995), also discloses that the photoreceptors be coupled to one another not by a network but via a substrate of fixed conductivity.
A Oppenheim and A. Willsky, Signale und Systeme, 2
nd
Edition, VCH Verlagsgesellschaft, ISBN 3-527-28433-8, pp. 347-383, (1992), discloses various filter structures of digital filters.
The German reference DE 43 37 160 A1, discloses a photodetector array. The photodetector array comprises a plurality of photodetector elements regularly arranged in a surface. At least two layers, layers A and B, are provided, whereby the photodetector elements are arranged in the first layer A facing toward the light incidence and are directly connected to one another via paths of controllable electrical conductivity, for example channels of MOS transistors. Further circuit elements are accommodated in a second layer arranged coplanar with the first.
SUMMARY OF THE INVENTION
The invention is based on the problem of specifying a photoreceptor arrangement that avoids the disadvantages of the known arrangements.
In general terms the present invention is a photoreceptor arrangement for the reception of light rays. At least two photoreceptors are provided with which light rays that impinge the photoreceptor arrangement are registered and converted into electrical signals. The photoreceptors are coupled to one another. The coupling of the photoreceptors is a variable coupling. At least one coupling element that is respectively coupled to an output of the corresponding photoreceptor is provided for at least a part of the photoreceptors. The coupling elements are variably coupled to one another. An output of at least a part of the coupling elements are coupled to a first input of a respective adder unit. At least a part of the outputs of the corresponding photoreceptors are coupled to a second input of the adder unit.
Advantageous development of the present invention are as follows.
The coupling of the photoreceptors is dependent on the luminous intensity of the light rays incident onto the arrangement. The coupling of the photoreceptors becomes more intense with decreasing luminous intensity.
The coupling of the photoreceptors is dependent on the signal-to-noise ratio of the light rays incident onto the arrangement. The coupling of the photoreceptors becomes more intense with decreasing signal-to-noise ratio.
The coupling of the photoreceptors is dependent on the semantics of an image that is formed by the light rays.
The photoreceptors are respectively arranged at the same spacing from one another.
A respective photoreceptor are coupled only to photoreceptors in a surround of the respective photoreceptor having a prescribable size. In a further embodiment a respective photoreceptor is coupled only to photoreceptors arranged directly neighboring.
A substrate is provided via which the photoreceptors are coupled to one another. The substrate comprises a variable conductivity.
The coupling of the coupling elements to the first input of the adder unit is respectively fashioned such that output signals of the coupling elements are supplied to the adder unit inverted and arbitrarily weighted.
In another embodiment the arrangement is utilized in a video chip.
At least two photoreceptors that are coupled to one another are provided in the inventive photoreceptor arrangement, whereby the coupling of the photoreceptors is fashioned variable.
As a result of the variable coupling of the photoreceptors, it is possible to meaningfully employ the arrangement in a significantly greater range of illumination intensities.
A further advantage of the invention is to be seen therein that the photoreceptor arrangement proposes a processing strategy that allows a multitude of different high passes and low passes to be realized by variable coupling parameters. An adaptation of the photoreceptor arrangement to the ambient conditions of the photoreceptor arrangement, for example to the illumination intensity, thus becomes possible.
It is advantageous to fashion the coupling of the photoreceptors dependent on the luminous intensity of the light rays incident onto the arrangement such that the coupling of the photoreceptors becomes greater with decreasing luminous intensity and less with increasing luminous intensity. An automatic “matching” of the photoreceptor arrangement to the respective applied situation, particularly to the brightness of the surroundings in which the photoreceptor arrangement is utilized, is achieved by this automatic coupling of the photoreceptors dependent on the luminous intensity.
It is also advantageous to arrange the photoreceptors at the respectively same spacing from one another, a grid structure of the photoreceptors within the arrangement being thus realized. This leads to an arrangement that is uniform and, thus, simpler to handle in dimensioning. The fabrication of the photoreceptor arrangement in grid structure is also considerably more cost-beneficial compared to irregularly arranged photoreceptors.
Particularly given electrical coupling of the photoreceptors via electrical lines, it is advantageous to respectively couple only one photoreceptor with neighboring photoreceptors in a surround of the respective photoreceptor of prescribable size, advantageously only with photoreceptors that are respectively arranged directly adjacent. It has been shown that this development does not lead to greater quality losses but does lead to substantial cost savings in the production of the arrangement.
When the photoreceptors are coupled to one another the arrangement is advantageous since it closely approximates the properties of the human eye. The photoreceptor arrangement is also substantially improved as a result of t
Le Que T.
Schiff & Hardin & Waite
Siemens Aktiengesellschaft
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