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Why do we convert image to frequency domain?
Basically frequency domain represents the rate of change of spatial pixels and hence gives an advantage when the problem you are dealing with relates to the rate of change of pixels which is very important in image processing.
What is a low frequency image?
The low frequency image is simply a convolution of the original image with a 2D Gaussian filter. The high frequency image is obtained by subtracting the low frequency convolution from the original image. The high frequency image is shifted to account for negative values that result from the subtraction.
How to explain the concept of image frequency?
The term f s i is called image frequency and is defined as the signal frequency plus twice the intermediate frequency.Reiterating, we have f s i = f s + 2 f i The rejection of an image frequency by a single –tuned circuit, i.e., the ratio of the gain at the signal frequency to the gain at the image frequency, is given by α = 1 + Q 2 ρ 2
Is the image frequency an undesired input frequency?
The image frequency is an undesired input frequency which is demodulated by superheterodyne receivers along with the desired incoming signal.
How is rejection related to the image frequency?
Whatever applies to gain calculations applies also to those involving rejection. Image –rejection depends on the front-end selectivity of the receiver and must be achieved before the IF stage. Once the spurious frequency enters the first IF amplifier, it becomes impossible to remove it from the wanted signal.
What is the image frequency in FM radio?
An FM receiver uses a 10.7 MHz IF to demodulate the broadcast signal at 100.7 MHz. An LO of 90MHz would work, and the image frequency would be at 79.3 MHz. You could also use an LO of 111.4 MHz (high side mixing) but that would lead to spectral inversion at the IF which the design might need to account for.
https://www.youtube.com/watch?v=a-rHXtGLyI0