Hitachi Camera Signal Processing LSI HD49815TF

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Hitachi Camera Signal Processing LSI (HD49815TF)
AWB Data Detection Report

• B88901136 ???

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System Block Diagram

• Hitachi Camera System Configuration

(1)
(2)
We emphasize on AWB!
(3)(4)
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System Block Diagram(1)

• Color Signal Processing Block Diagram

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System Block Diagram(2)

• Luminance Signal Processing Block Diagram

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System Block Diagram(3)

• AWB data flow

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System Block Diagram(4)

• AWB detection circuit block diagram

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AWB data obtain

• For AWB detection,data is obtained from axes R-B
  and Mg-G.The detection range is an area other
  than around the origin on the vector scope and
  can be moved in accordance with photography
  conditions.
• By controlling the white convergent point,AWB
  suitable for various photography conditions can
  be implemented.Input signals are a color
  difference signal (8 bits offset binary,D range
  -128127)and a luminance signal(for reference,5
  bits,after gamma,negative limit).

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Color difference signals(1)

• Color-difference Matrix Circuit Block Diagram
• This block transform R-G B-G signal to R-Y
  B-Y form.

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Color difference signals(2)

• k1Coefficient k1 depends on the balance of the
  three primary colors. First we calculate from
  Y0.59G0.3R-0.11B.Therefore R-YR(0.59G0.3R0
  .11B)0.7(RG)0.11(B-G)B-YB (0.59G0.3R0.11B)
  0.89(B-G)-0.3(R-G)
• k2The signal level of B-Y becomes higher than
  that of R-Y.To prevent this,the broadcasting
  standard specifies 0.493x(B-Y) and
  0.877x(R-Y).The chroma signal saturation balance
  is uniform.

k1
k2
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White detection range concept
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Color-difference Plane (Vector Diagram)
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Offset Data

• Indicates the detection center of each axis.The
  counter decides to count up or down depending on
  whether data is greater or less than the offset
  value.Offset R-B and Mg-G vary independently.
• In the color difference plane,an offset can be
  applied to the R-B Mg-G axes.The offset range
  is 32 to 31 with color difference signals 128
  to 127,and white convergent pointcan be changed
  by changing this data.In MV-SF20,it is moved
  according to the color temperature.

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Slope of Offset to Luminance

• Y moves parallel to the offset Y axis.The basic
  expression is as follows (OFS_DEC) Y ( offset
  ) OFFSET
• Data format of OFS_DEC 1(sign)6(absolute
  value) 7 bits

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Two extreme conditions of Offset

• (1) only OFS_DEC is used (offset is 20H)(2) only
  offset is used (OFS_DEC is 00H)

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White Detection Range(1)

• If Y exceeds 100 IRE,the Y signal is
  limited,holding the white detection range
  constant.
• White Detection Range a(slope) x Y0 /32
  b(constant parameter)
• Parameters a and b can be individually set on the
  positive and negative sides of R-B and Mg-G.

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White Detection Range(2)

• Slope A of the White Detection RangeData format
  1(sign)7(absolute value)

Center point A of C_LEVEL is the origin when Y is
0
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White Detection Range(3)

• Base B of White Detection RangeData format
  1(sign)7(absolute value)

a0
Settings combining a and b cause an overflow to
occur due to the setting range extension of
C_LEVEL b.Therefore,C_LEVEL is limited to
FFH(11111111) on the side and 00H(00000000) on
the negative side.
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White Balance Data of Input Output

• Input DataR-B Mg-G DataOutput Data
  indicating where the majority of the data
  lies.11-bit data counts for R-B and Mg-G are
  output every field (output data22bits).The
  output data is transferred to the output latch
  and cleared.

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