CA2933940C

Device and method of improving the perceptual luminance nonlinearity - based image data exchange across different display capabilities

Abstract

A handheld imaging device has a data receiver that is configured to receive reference encoded image data. The data includes reference code values, which are encoded by an external coding system. The reference code values represent reference gray levels, which are being selected using a reference grayscale display function that is based on perceptual non-linearity of human vision adapted at different light levels to spatial frequencies. The imaging device also has a data converter that is configured to access a code mapping between the reference code values and device-specific code values of the imaging device. The device-specific code values are configured to produce gay levels that are specific to the imaging device. Based on the code mapping, the data converter is configured to transcode the reference encoded image data into device-specific image data, which is encoded with the device-specific code values.

CA2933940C, drawing sheet 1
Sheet 1 of 29

Term

6.2 yearsleft in the term

Expires 6 December 2032.

  1. Priority and filed
  2. Granted
  3. Today
  4. Expires

26 claims: 3 independent, 23 dependent

  1. 1
    WHAT IS CLAIMED IS:1. A method comprising: receiving, by a data encoder, image data to be encoded;accessing, via the data encoder, a reference data conversion function which determines a mapping between a set of reference digital code values and a set of reference levels;based on the receiving and the accessing, encoding, via the data encoder, the received image data into reference encoded image data;and outputting, via the data encoder, the reference encoded image data, wherein: color component values in the reference encoded image data are represented by the set of reference digital code values, the reference digital code values having a bit depth of 10 or 12 bits, the mapping is based at least in part on a functional model of: n, m, ci, C2, and C3 are predetermined values and Y represents the color component values.
  2. 9
    The method of any one of claims 1-8, wherein the mapping is based on contrast sensitivity of human vision.
  3. 10
    A data encoder configured to encode received image data to reference encoded image data, the data encoder comprising:a receiver unit configured to receive image data to be encoded in a machine readable format;and a mapping unit configured to map values in a received image data to reference digital code values in the reference encoded image data;wherein the mapping unit maps values based at least in part on a functional model of: -65CA 2933940 2017-10-03 /Çi+CYY k l+c 3 Y n J n, m, c;, Ci, and c\ are predetermined values and Y represents values in the received image data, wherein the data encoder is configured to output an output signal containing the reference encoded image data for viewing on a display device. , and 11. The data encoder of claim 10, wherein: n = x 1 ~ 0.1593017578125;4096 4 2610 4096 m = — x 128 = 78.84375;4096 A = c 3 - c 2 + 1 = — = 0.8359375;2 4096 2413 c 2 = — x 32 18.8515625;and z 4096 C 3 = x 32^ 18.6875. Λ 4096
  4. 12
    13. The data encoder of claim 12, wherein the color component values represent at least one of R, G and B color components.
  5. 15
    16. The data encoder of claim 15, wherein the digital code D value represents a sampled value of a component of the image data comprised in a serial digital interface (SDI) signal. -66CA 2933940 2017-10-03
  6. 18
    19. The data encoder of claim 18, wherein a relationship between the normalized value Land the digital code value D is provided by the function:0-4-2^ -10 V = — --1015-2^ -10 wherein b is a bit depth corresponding to a number of bits used to represent the digital code value.
  7. 20
    21. A method comprising:processing image data defining an image to yield reference encoded image data;and outputting an output signal containing the reference encoded image data for display on a display device, wherein: a color component value in the reference encoded image data is represented from a set of reference digital code values, the set of reference digital code values represents reference levels based at least in part on a functional model of: n, m, c/, C2, and C3 are predetermined values and Y represents the color component value.
  8. 21
    22. The method of claim 21 wherein the reference digital code values have a bit depth of 10 or 12 bits. -67CA 2933940 2017-10-03 23. The method of claim 21, wherein:n = x 1 ~ 0.1593017578125 ;40964 2923 m = — x 128 78.84375 ;4096’ 3424 C1 = c 3 - c 2 + 1 = — - 0.8359375 ;1 5 z 4096 241 3 C 2 = — X 32 18.8515625 ;and 2 4096’ 2392 C 3 = — X32 18.6875. 5 4096 24. 25. The method of claim 21, wherein the color component value represent at least one of R, G or B color components. The method of claim 21, wherein the color component value represents normalized luminance.