Four-way calibration of a digital camera using patch information acquired from a scene
View Patent ↗A method of improving a digital image captured by a digital camera comprising: providing a digital camera having a memory for storing known values of a color chart having a plurality of color patches of different colors and a digital image processor, using the digital camera to capture an image of the color chart to produce image values of the color patches of the color chart; operating the digital image processor to process at least some of the color patch imaged values and the stored known values of the color patches to produce a color correction matrix or profile; and storing the color correction matrix or profile to correct color images subsequently acquired by the digital camera.
1. A method of improving a digital image captured by a digital camera comprising:
providing a digital camera having a memory for storing known values of a color chart having a plurality of color patches of different colors and a digital image processor;
using said digital camera to capture an image of said color chart to produce imaged values of said color patches of said color chart;
operating said digital image processor to process at least some of said color patch imaged values and said stored known values of said color patches to produce a color correction matrix or profile in said digital camera;
storing said color correction matrix or profile to correct color images subsequently acquired by said digital camera; and
wherein said stored known values of said color chart include a value of a neutral middle gray patch, wherein said captured image of said color chart includes a corresponding neutral middle gray patch value, and wherein said digital image processor processes said stored known and imaged values of said neutral middle gray patch to derive an exposure correction that is stored for correcting exposure of subsequently acquired images by said digital camera.
2. A method of improving a digital image captured by a digital camera comprising:
providing a digital camera having a memory for storing known values of a color chart having a plurality of color patches of different colors and a digital image processor;
using said digital camera to capture an image of said color chart to produce imaged values of said color patches of said color chart;
operating said digital image processor to process at least some of said color patch imaged values and said stored known values of said color patches to produce a color correction matrix or profile in said digital camera;
storing said color correction matrix or profile to correct color images subsequently acquired by said digital camera; and
wherein said stored known values of said color chart include a value of a neutral middle gray patch, wherein said captured image of said color chart includes a corresponding neutral middle gray patch value, and wherein said digital image processor processes said stored known and imaged values of said neutral middle gray patch to derive a white balance correction that is stored for correcting subsequently acquired images by said digital camera.
3. A method of improving a digital image captured by a digital camera comprising:
providing a digital camera having a memomy for storing known values of a color chart having a plurality of color patches of different colors and a digital image processor;
using said digital camera to capture an image of said color chart to produce imaged values of said color patches of said color chart;
operating said digital image processor to process at least some of said color patch imaged values and said stored known values of said color patches to produce a color correction matrix or profile in said digital camera;
storing said color correction matrix or profile to correct color images subsequently acquired by said digital camera; and
wherein said stored known values of said color chart include a set of values of a neutral scale set of patches, wherein said captured image of said color chart includes a corresponding set of values of a neutral scale set of patches, and wherein said digital image processor processes said stored known and imaged values of said neutral scale set of patches to derive a linearity correction that is stored for correcting subsequently acquired images by said digital camera.
4. A method of improving a digital image captured by a digital camera comprising:
providing a digital camera having a memory for storing known values of a color chart having a plurality of color patches of different colors and a neutral scale set of patches including a neutral middle gray patch, and further having a digital image processor;
using said digital camera to capture an image of said color chart to produce imaged values of said color patches of said color chart, of said neutral scale set of patches of said color chart, and of said neutral middle gray patch of said color chart;
operating said digital image processor to process (a) at least some of said color patch imaged values and said stored known values of said color patches to produce a color correction matrix or profile;
(b) said stored known and imaged values of said neutral middle gray patch to derive an exposure correction and a white balance correction; and
(c) said stored known and imaged values of said neutral scale set of patches to derive a linearity correction; and
storing said color correction matrix or color profile, said exposure correction, said white balance correction, and said linearity correction for correcting color, exposure, white balance, and linearity of a subsequently acquired image by said digital camera.
5. A digital camera comprising;
a memory for storing known values of a color chart having a plurality of color patches of different colors;
an image capture device for capturing an image of said color chart to produce imaged values of said color patches of said color chart; and
a digital image processor for processing at least some of said color patch imaged values and said stored known values of said color patches to produce a color correction matrix or profile in said digital camera;
wherein said color correction matrix or profile is stored in said memory to color correct images subsequently captured by said image capture device;
wherein said stored known values of said color chart in said memory include a value of a neutral middle gray patch;
wherein said image of said color chart captured by said image capture device includes a corresponding neutral middle gray patch value; and
wherein said digital image processor processes said stored known and imaged values of said neutral middle gray patch to derive one or more of an exposure correction and white balance correction and wherein said derived exposure correction and white balance correction is stored in said memory to correct images subsequently captured by said image capture device.
6. A digital camera comprising:
a memory for storing known values of a color chart having a plurality of color patches of different colors;
an image capture device for capturing an image of said color chart to produce imaged values of said color patches of said color chart; and
a digital image processor for processing at least some of said color patch imaged values and said stored known values of said color patches to produce a color correction matrix or profile in said digital camera;
wherein said color correction matrix or profile is stored in said memory to color correct images subsequently captured by said image capture device;
wherein said stored known values of said color chart in said memory include a set of values of a neutral scale set of patches, wherein said captured image of said color chart includes a corresponding set of values of a neutral scale set of patches; and
wherein said digital image processor processes said stored known and imaged values of said neutral scale set of patches to derive a linearity correction that is stored in said memory for correcting images subsequently acquired by said image acquisition device.