Image sensor with red-clear-clear-green (RCCG) color filter array (CFA) for vehicle sensing applications
This disclosure provides systems, methods, and devices for vehicle driving assistance systems that support image processing for vehicular monitoring operations. In a first aspect, a method of image processing includes receiving image data from an image sensor comprising a red-clear-clear-green (RCCG) color filter, wherein the image data comprises a first channel corresponding to red, a second channel corresponding to clear, and a third channel corresponding to green, wherein the image data is in a logarithmic domain; and processing the image data by performing operations including linearization, tone mapping, demosaicing, and color mapping. Other aspects and features are also claimed and described.
1 . A method, comprising:
receiving image data from an image sensor comprising a red-clear-clear-green (RCCG) color filter, wherein the image data comprises a first channel corresponding to red, a second channel corresponding to clear, and a third channel corresponding to green, and wherein a first portion of the image data is in a logarithmic domain and a second portion of the image data is in a linear domain, the first and second portions corresponding to different ones of the first to third channels; and
processing the image data by performing operations including demosaicing and color mapping, wherein at least some of the operations are performed in the logarithmic domain on the first channel and the second channel and at least some of the operations are performed in the linear domain on the third channel.
2 . The method of claim 1 , further comprising configuring the image sensor with a programmable lookup table for a piecewise linear function to configure the image sensor for output in the logarithmic domain.
3 . The method of claim 1 , wherein processing the image data comprises:
demosaicing the image data to obtain demosaiced data; and
color mapping the demosaiced data to second image data.
4 . The method of claim 3 , wherein processing the image data further comprises:
linearizing the second image data to obtain linearized data; and
color mapping the linearized data to obtain an output image frame in an RGB or YUV color space.
5 . The method of claim 1 , wherein processing the image data comprises:
linearizing the image data to obtain linearized data;
demosaicing the linearized data to obtain demosaiced data; and
color mapping the demosaiced data to second image data.
6 . The method of claim 5 , wherein processing the image data further comprises color mapping and tone mapping based on the second image data to obtain an output image frame in an RGB or YUV color space.
7 . An apparatus, comprising:
a memory storing processor-readable code; and
at least one processor coupled to the memory, the at least one processor configured to execute the processor-readable code to cause the at least one processor to perform operations including:
receiving image data from an image sensor comprising a red-clear-clear-green (RCCG) color filter, wherein the image data comprises a first channel corresponding to red, a second channel corresponding to clear, and a third channel corresponding to green, and wherein a first portion of the image data is in a logarithmic domain and a second portion of the image data is in a linear domain, the first and second portions corresponding to different ones of the first to third channels; and
processing the image data by performing operations including demosaicing and color mapping, wherein at least some of the operations are performed in the logarithmic domain on the first channel and the second channel and at least some of the operations are performed in the linear domain on the third channel.
8 . The apparatus of claim 7 , wherein the at least one processor is further configured to perform operations including:
configuring the image sensor with a programmable lookup table for a piecewise linear function to configure the image sensor for output in the logarithmic domain.
9 . The apparatus of claim 7 , wherein processing the image data comprises:
demosaicing the image data to obtain demosaiced data; and
color mapping the demosaiced data to second image data.
10 . The apparatus of claim 9 , wherein processing the image data further comprises:
linearizing the second image data to obtain linearized data; and
color mapping the linearized data to obtain an output image frame in an RGB or YUV color space.
11 . The apparatus of claim 7 , wherein processing the image data comprises:
linearizing the image data to obtain linearized data;
demosaicing the linearized data to obtain demosaiced data; and
color mapping the demosaiced data to second image data.
12 . The apparatus of claim 11 , wherein processing the image data further comprises color mapping and tone mapping based on the second image data to obtain an output image frame in an RGB or YUV color space.
13 . A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform operations comprising:
receiving image data from an image sensor comprising a red-clear-clear-green (RCCG) color filter, wherein the image data comprises a first channel corresponding to red, a second channel corresponding to clear, and a third channel corresponding to green, and wherein a first portion of the image data is in a logarithmic domain and a second portion of the image data is in a linear domain, the first and second portions corresponding to different ones of the first to third channels; and
processing the image data by performing operations including demosaicing and color mapping, wherein at least some of the operations are performed in the logarithmic domain on the first channel and the second channel and at least some of the operations are performed in the linear domain on the third channel.
14 . The non-transitory, computer-readable medium of claim 13 , wherein the operations further comprise:
configuring the image sensor with a programmable lookup table for a piecewise linear function to configure the image sensor for output in the logarithmic domain.
15 . The non-transitory, computer-readable medium of claim 13 , wherein processing the image data comprises:
demosaicing the image data to obtain demosaiced data; and
color mapping the demosaiced data to second image data.
16 . The non-transitory, computer-readable medium of claim 15 , wherein processing the image data further comprises:
linearizing the second image data to obtain linearized data; and
color mapping the linearized data to obtain an output image frame in an RGB or YUV color space.
17 . The non-transitory, computer-readable medium of claim 13 , wherein processing the image data comprises:
linearizing the image data to obtain linearized data;
demosaicing the linearized data to obtain demosaiced data;
color mapping the demosaiced data to second image data; and
color mapping and tone mapping based on the second image data to obtain an output image frame in an RGB or YUV color space.