Imaging systems with stacked photodiodes and chroma-luma de-noising

An imaging device comprising:

• an image sensor including an array of pixels having a repeating unit cell, wherein the unit cell comprises at least one dual photodiode pixel having a shallow photodiode that generates a first electrical signal in response to light of a first color, a deep photodiode that generates a second electrical signal in response to light of a second color that is different than the first color, and a color filter formed over the shallow photodiode and the deep photodiode that transmits light of the first color and the second color;
• and
• processing circuitry that processes the first electrical signal such that a noise correlation between the first electrical signal and the second electrical signal is increased, wherein the processing circuitry applies a color correction to the first electrical signal having the increased noise correlation to remove a component of the first electrical signal generated in response to the light of the second color.

An imaging system comprising:

• an image sensor having an array of pixels formed in rows and columns, wherein the array of pixels includes a pixel block comprising four adjacent pixels, wherein the four adjacent pixels in the pixel block include at least one stacked photodiode pixel comprising a first photodiode that generates a color image signal in response to a given color of light, a second photodiode that generates an infrared image signal in response to infrared light, and a color filter element that passes the given color of light and the infrared light, and wherein the first photodiode is formed between the color filter element and the second photodiode;
• and
• processing circuitry that computes a luma signal using at least the infrared image signal, wherein the processing circuitry performs a color correction operation on at least the color image signal to generate a corrected color image signal, and wherein the processing circuitry is configured to apply the luma signal to the color image signal to reduce noise introduced by generating the corrected color image signal with the color correction operation.