Method and device for carrying out two-dimensional Fourier transform and inverse transform on image

Abstract

The invention relates to a the field of automatic optical detection technology of TFT-LCD panels, and particularly relates to a method and a device for carrying out two-dimensional Fourier transform and inverse transform on an image. The method comprises the following steps: extracting a row of picture data from an A area of an external memory at one time, carrying out one-dimensional Fourier transform and inverse transform, and storing operation results in a B area of the external memory in sequence, until the one-dimensional Fourier transform and inverse transform of the entire picture is finished; partitioning the image data in the B area of the external memory, extracting an image from the B area of the external memory according to a row direction at each time, storing the image in a random memory, overturning the interiors of the image blocks, and writing the image blocks in the A area of the external memory according to a column direction in sequence; and repeating the process until the two-dimensional Fourier transform and inverse transform of the entire picture is finished. The image blocks are overturned and are the interiors of the image blocks overturned, so FPGA resource consumption is few, and image data reading and writing efficiency is high.

Description

technical field [0001] The invention relates to the technical field of automatic optical detection of TFT-LCD panels, in particular to a method and device for performing two-dimensional Fourier transform or inverse transform on an image. Background technique [0002] In the process of image processing, it is often necessary to perform frequency-domain filtering operations by means of Fourier transform. The commonly used method is two-dimensional fast Fourier transform (two-dimensional FFT), which transforms the image into the frequency domain, performs filtering processing, and then passes the two-dimensional fast Fourier inverse transform (two-dimensional IFFT) to the time domain, so as to obtain the filtered image Image. [0003] The field of image processing often has high requirements for real-time processing, and modules with a large amount of calculation, such as two-dimensional FFT / IFFT operations, are often the bottleneck of the system speed. At present, two-dimens...

AI Technical Summary

Problems solved by technology

Therefore, when performing row-to-column conversion in DDR, if the picture is read by row, the read address will increase continuously; if the picture is written by column, when writing the address, the amount of change for each data written is the length of a row of data. In this way, DDR Access efficiency will be very low

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