# US 12,192,653 B2 · In-line chromatic aberration correction in wide dynamic range (WDR) image processing pipeline

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- Number: US 12,192,653 B2
- Document ID: US12192653B2
- Status: Granted
- Kind: B2
- Application number: 18/343,018
- Filed: 2023-06-28
- Published: 2023-10-19
- Granted: 2025-01-07
- Earliest claimed: 2021-12-17
- Assignees: Texas Instruments Incorporated
- Applicants: Texas Instruments Incorporated
- Inventors: Gang Hua; Rajasekhar Reddy Allu; Mihir Narendra Mody; Niraj Nandan; Mayank Mangla; Pandy Kalimuthu
- Web page: https://patentgrep.com/patent/US12192653B2

## CPC

- H04N 25/611: Correction of chromatic aberration
- G06T 1/60: Memory management
- G06T 3/4015: Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
- G06T 5/80: Geometric correction
- H04N 25/13: characterised by the spectral characteristics of the filter elements
- G06T 2207/10024: Color image
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

In an advanced driver-assistance system (ADAS), RAW sensor image processing for a machine vision (MV) application is important. Due to different color, e.g., red/green/blue (RGB), color components, being focused by the lens at different locations in image plane, the lateral chromatic aberration phenomenon may sometimes be observed, which causes false color around edges in the final image output, especially for high contrast edges, which can impede MV applications. Disclosed herein are low-latency, efficient, optimized designs for chromatic aberration correction (CAC) components. An in-pipeline CAC design may be used to perform on-the-fly CAC without any out-of-pipeline memory traffic; enable use of wide dynamic range (WDR) sensors; uses bicubic interpolation; support vertical and horizontal chromatic aberration color channel offsets, reduce CAC line memory requirements, and support flexible look-up table (LUT) down-sampling factors to improve the spatial precision of correction and accommodate popular image sensor resolutions.

## Claims

### Claim 1

An electronic device comprising:
a color separator configured to separate an image into a first color component having a first set of pixels and second color component having a second set of pixels;
a first cache memory coupled to the color separator, the first cache memory configured to store values of the first set of pixels;
a second cache memory coupled to the color separator, the second cache memory configured to store values of the second set of pixels;
an interpolator coupled to the second cache memory, the interpolator configured to perform interpolation on the values of the second set of pixels, wherein the interpolation is performed based on an estimated amount of shift in the respective position of each value of the second set of pixels caused by chromatic aberration (CA); and
a circuit coupled to the first cache memory and the interpolator, the circuit configured to merge the interpolated values of the second set of pixels and values of the first set of pixels; and
wherein the electronic device is configured to produce a CA-corrected version of the image based on the merged interpolated values of the second set of pixels and the values of the first set of pixels.

### Claim 2 (depends on 1)

The electronic device of claim 1, wherein the electronic device further comprises a chromatic aberration correction (CAC) circuit that includes the color separator, the first and second cache memories, the interpolator, and the circuit.

### Claim 3 (depends on 2)

The electronic device of claim 2, wherein the electronic device further comprises an image sensor coupled to the CAC circuit, the image sensor configured to capture a scene from an external environment and convert the captured scene into the image.

### Claim 4 (depends on 1)

The electronic device of claim 1, wherein the interpolator is configured to estimate an amount of shift in the respective position of each value of the values of the second set of pixels caused by chromatic aberration (CA) using a two-dimensional (2D) look-up table (LUT) storing a plurality of pixel shift values.

### Claim 5 (depends on 4)

The electronic device of claim 4, wherein the 2D LUT is capable of storing the plurality of pixel shift values at a plurality of different down-sampling factors with respect to a resolution of the image.

### Claim 6 (depends on 1)

The electronic device of claim 1, wherein the first color component is green and the second color component is one of blue and red.

### Claim 7 (depends on 1)

The electronic device of claim 1, wherein the image is a Wide Dynamic Range (WDR) image having a dynamic range of 16 or more bits.

### Claim 8 (depends on 1)

The electronic device of claim 1, wherein the image is separated, interpolated, and merged on a pixel line-by-line basis.

### Claim 9

An image processing pipeline comprising:
an image processor configured to receive an input image and perform image processing on the input image to generate a formatted image;
first circuitry coupled to the image processor, the first circuitry configured to separate the formatted image into a first color component having a first set of pixels and a second color component having a second set of pixels, perform interpolation on values of the second set of pixels based on an estimated amount of shift in the respective position of each value of the second set of pixels caused by chromatic aberration (CA), merge the interpolated values of the second set of pixels and values of the first set of pixels, and output a CA-corrected version of the formatted image based on the merged interpolated values of the second set of pixels and values of the first set of pixels;
second circuitry coupled to the first circuitry, the second circuitry configured to process the CA-corrected version of the formatted image to generate a processed image;
a first color processor directly coupled to the second circuitry and configured to generate a first color processed image based on the processed image;
a second color processor directly coupled to the first circuitry and configured to generate a second color processed image based on the CA-corrected version of the formatted image; and
third circuitry directly coupled to each of the first color processor and the second color processor and configured to combine the first and second color processed image to generate an output image.

### Claim 10 (depends on 9)

The image processing pipeline of claim 9, wherein the second circuitry includes a noise filter and a tone mapper to generate, as the processed image, a CA-corrected, noise-reduced, and tone-mapped image.

### Claim 11 (depends on 9)

The image processing pipeline of claim 9, further comprising a statistics component coupled to the first circuitry.

### Claim 12 (depends on 9)

The image processing pipeline of claim 9, wherein the image processing performed on the input image by the image processor includes converting image data of the input image to a 16-bit gamma-corrected format representing the formatted image.

### Claim 13 (depends on 9)

The image processing pipeline of claim 9, further comprising a Wide Dynamic Range (WDR) image sensor configured to generate the input image.

### Claim 14 (depends on 13)

The image processing pipeline of claim 13, wherein the input image is a WDR image having a dynamic range of 16 or more bits.

### Claim 15 (depends on 9)

The image processing pipeline of claim 9, wherein, to perform the interpolation, the CAC first circuitry estimates an amount of shift in the respective position of each value of the values of the second set of pixels caused by chromatic aberration (CA) using a two-dimensional (2D) look-up table (LUT) storing a plurality of pixel shift values.

### Claim 16 (depends on 15)

The image processing pipeline of claim 15, wherein the 2D LUT is capable of storing the plurality of pixel shift values at a plurality of different down-sampling factors with respect to a resolution of the input image.

### Claim 17 (depends on 9)

The image processing pipeline of claim 9, wherein a set number of lines of pixels are buffered in an internal memory of the first circuitry for use in performing the interpolation.

### Claim 18 (depends on 9)

The image processing pipeline of claim 9, wherein:
the first color processor is configured to process color image information for human vision applications to generate the first color processed image based on the processed image; and
the second color processor is configured to process color image information for machine vision applications to generate the second color processed image based on the CA-corrected version of the formatted image.

### Claim 19 (depends on 9)

The image processing pipeline of claim 9, wherein the first color component is green and the second color component is one of blue and red.