Recognition of Hand-Sketched Digital Logic Gates

WHAT IS THE CIRCUIT SKETCH RECOGNITION?

Circuit sketch recognition can be defined as handwriting recognition

Handwriting recognition is the ability of a computer to receive and interpret intelligible handwritten input from sources such as paper documents, photographs, touch-screens and other devices.

But also we can define it as shape analysis or shape recognition by using image processing applications.

METHODS FOR SHAPE ANALYSIS

Shape Analysis : Step that consists on identifying an object using only its shape

Shape analysis procedures are based on the use of shape descriptors

There exists several shape descriptors:

        *Including boxes
        *Moment descriptors
        *Guzman polygons
        *Freeman chain coding
        *Fourier descriptors

A good shape descriptor should have the following properties:

-good fidelity to the initial shape

-good discrimination between different shapes

-good behavior with shape recognition operations :

     - invariance with translation
     - invariance with rotation
     - invariance with scaling

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Steps of Circuit Sketch Recognition

1) Image Acquisition: We can take the photo or scan it.

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2) Preprocessing

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3)Feature Extraction:Fourier Descriptors

-Tool which allows to describe the external shape of an object, that is to its contour

-Fourier Descriptors are boundary (edge) based descriptors

-These descriptors represent the shape in frequency domain.

-Low frequency components contain information about the general features of the shape, and the higher frequency components contain finer details of the shape.

-Though different people may have different drawing habits, the subset of the low frequency coefficient tend to be similar for the same electronic component.

-So although the number of coefficients generated from the Fourier transform is usually large, the dimensions of the Fourier descriptors used for shape recognition can be greatly reduced.

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4)Classification: Neural network (nprtool)

-MATLAB neural network is a powerful tool for pattern recognition and classification.

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- According to confusion matrix we get 90 % accuracy rate. This is meaning that our network finds 90 percent of the objects truly and 10 percent of them are known as another component.

- In our testing image we had 6 AND gate, 6 OR gate, and 8 inverter.

- Our network just confused 2 of the AND gates to the OR gates. And it knows all other components truly.

REFERENCES:

-Digital Image Processing using MATLAB R.C. Gonzalez,R.E. Woods, S.L. Eddins