thông tin trên hình ảnh kỹ thuật số
Tài liệu Xử lý hình ảnh kỹ thuật số P1 ppt
Ngày tải lên :
24/12/2013, 09:17
... regard an image as a sample of a stochastic process. For
continuous images, the image function F(x, y, t) is assumed to be a member of a con-
tinuous three-dimensional stochastic process with space ... represented as a sum of amplitude-
weighted Dirac delta functions by the sifting integral,
(1.2-6)
where is the weighting factor of the impulse located at coordinates in
the x–y plane, as shown ... ω
x
ω
y
,()=
Gxy,()
1
4π
2
H ω
x
ω
y
,()F ω
x
ω
y
,()i ω
x
x ω
y
y+(){}exp ω
x
d ω
y
d
∞
–
∞
∫
∞
–
∞
∫
=
6
CONTINUOUS IMAGE MATHEMATICAL CHARACTERIZATION
(1.2-1)
In specific cases, the mapping may be many-to-few,...
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Tài liệu Xử lý hình ảnh kỹ thuật số P2 pdf
Ngày tải lên :
24/12/2013, 09:17
... the post-retinal transfer functions
of Figure 2.5-3. Undoubtedly, both retinal and post-retinal mechanisms
are responsible for the chromatic adaption effect. Further analysis and testing are
required ... An observer is shown two sine-wave grating transpar-
encies, a reference grating of constant contrast and spatial frequency and a variable-
contrast test grating whose spatial frequency is set ... blood capillaries. Inside the choroid is the retina, which is com-
posed of two types of receptors: rods and cones. Nerves connecting to the retina
leave the eyeball through the optic nerve bundle....
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Tài liệu Xử lý hình ảnh kỹ thuật số P3 docx
Ngày tải lên :
24/12/2013, 09:17
... ,
tristimulus units of the primaries as governed by
(3.3-13)
Integrating each side of Eq. 3.3-13 over and invoking the sifting integral gives the
cone signal for the color (C). Thus
(3.3-14)
By ... T
1
, T
2
, T
3
may be regarded as tristimulus values in
a retinal cone color coordinate system. The tristimulus values of the retinal cone
color coordinate system are related to the XYZ system ... light. In a subtractive color
system, which is the basis of most color photography and color printing, a white
light sequentially passes through cyan, magenta, and yellow filters to reproduce a
colored...
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Tài liệu Xử lý hình ảnh kỹ thuật số P4 pptx
Ngày tải lên :
24/12/2013, 09:17
... performed by linearly interpo-
lating points along separable orthogonal coordinates of the continuous image
field. The resultant interpolated surface of Figure 4.3-4b, connecting pixels A, B,
C, D, is ... these numbers are then used to reconstruct a con-
tinuous image for viewing. Image samples nominally represent some physical mea-
surements of a continuous image field, for example, measurements ... ω
y
d
ω
ys
2⁄
–
ω
ys
2⁄
∫
ω
xs
2⁄
–
ω
xs
2⁄
∫
=
114
IMAGE SAMPLING AND RECONSTRUCTION
where A
i
, B
i
, C
i
, D
i
are weighting factors. The weighting factors are determined by
satisfying two sets of extraneous conditions:
1. at x...
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Tài liệu Xử lý hình ảnh kỹ thuật số P5 pdf
Ngày tải lên :
24/12/2013, 09:17
...
CHARACTERIZATION
Chapter 1 presented a mathematical characterization of continuous image fields.
This chapter develops a vector-space algebra formalism for representing discrete
image fields from a deterministic and ... power-spectral density of a discrete image random process may be
defined, in analogy with the continuous power spectrum of Eq. 1.4-13, as the two-
dimensional discrete Fourier transform of its ... Gaussian density, are rarely found
in the literature. Huhns (7) has developed a technique of generating high-order den-
sities in terms of specified first-order marginal densities and a specified...
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Tài liệu Xử lý hình ảnh kỹ thuật số P6 pdf
Ngày tải lên :
24/12/2013, 09:17
... which a nonlinear
amplification weighting of the continuous signal to be quantized is performed,
followed by linear quantization, followed by an inverse weighting of the quantized
amplitude. Thus, ... reconstruction level within the range to can
be determined by minimization of with respect to . Setting
(6.1-6)
yields
(6.1-7)
FIGURE 6.1-2. Quantization decision and reconstruction levels.
pr
j
()
E ... are two major forms of numeric representation: real
and integer. Real numbers are stored in floating-point form, and typically have a
large dynamic range with fine precision. Integer numbers can...
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Tài liệu Xử lý hình ảnh kỹ thuật số P7 pdf
Ngày tải lên :
24/12/2013, 09:17
... applications in image processing require a discretization of the superposition
integral relating the input and output continuous fields of a linear system. For exam-
ple, image blurring by an optical system, ... general term is described by
(7.2-6)
where , with and denoting the upper and lower index limits.
If the ultimate objective is to estimate the continuous ideal image field by pro-
cessing the physical ... AND CONVOLUTION
where is a weighting coefficient for the particular quadrature formula
employed. Usually, a rectangular quadrature formula is used, and the weighting
coefficients are unity. In...
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Tài liệu Xử lý hình ảnh kỹ thuật số P8 pdf
Ngày tải lên :
24/12/2013, 09:17
... based on computational efficiency. In some computing structures, the Hart-
ley transform may be more efficiently computed, while in other computing environ-
ments, the Fourier transform may be ... cosine transform of a image can be computed by reflecting the image
about its edges to obtain a array, taking the FFT of the array and then
extracting the real parts of the Fourier transform (15). ... fluctuation
vector. This results in
(8.4-10)
where
(8.4-11a)
(8.4-11b)
are vectors. The process continues until the full transform
(8.4-12)
is obtained where . It should be noted that the intermediate...
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Tài liệu Xử lý hình ảnh kỹ thuật số P9 docx
Ngày tải lên :
24/12/2013, 09:17
... obtained
by analytically performing the convolution operation of Eq. 9.4-8c and evaluating
the resulting continuous function at points . In practice, the analytic convo-
lution is often difficult ... one-dimensional continuous signal of wide extent which is
bandlimited such that its Fourier transform is zero for greater than a cut-
off frequency . This signal is to be convolved with a continuous impulse ... Also, it is often possible to render the filter matrix sparse by
setting small-magnitude elements to zero without seriously affecting computational
accuracy (1).
In subsequent sections, the structure...
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Tài liệu Xử lý hình ảnh kỹ thuật số P10 docx
Ngày tải lên :
24/12/2013, 09:17
... retention of fine image detail. Several nonlinear techniques are presented below.
Mastin (15) has performed subjective testing of several of these operators.
FIGURE 10.3-8. Homomorphic filtering on the ... form by replacing
the discrete probability distributions of Eq. 10.2-2 by continuous probability densi-
ties. The resulting approximation is
(10.2-4)
g
d
Tf
c
{}= f
1
f
c
f
C
≤≤
g
1
g
d
g
D
≤≤
P
R
g
d
b
d
={}
P
R
f
c
a
c
={}
P
R
f
c
a
c
={}
c ... (10.3-2b)
Mask 3: (10.3-2c)
These arrays, called noise cleaning masks, are normalized to unit weighting so that
the noise-cleaning process does not introduce an amplitude bias in the processed
image....
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Tài liệu Xử lý hình ảnh kỹ thuật số P11 pdf
Ngày tải lên :
21/01/2014, 15:20
... paper
plus any spectral losses resulting from filters or optical elements, and k
x
is an expo-
sure constant that is controllable by an aperture or exposure time setting. Equation
11.3-1 assumes a ... Figure 11.3-1. In this material, silver halide grains are suspended in
a transparent layer of gelatin that is deposited on a glass, acetate, or paper backing.
If the backing is transparent, a transparency ... then the negative transparency is illuminated to expose negative
reflection print paper. The resulting silver density on the developed paper is then
proportional to the light intensity that exposed...
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Tài liệu Xử lý hình ảnh kỹ thuật số P12 pdf
Ngày tải lên :
21/01/2014, 15:20
... constraint
(12.6-1)
where S is a smoothing matrix, M is an error-weighting matrix, and e denotes a
residual scalar estimation error. The error-weighting matrix is often chosen to be
FIGURE 12.5-3. Wiener image ... RESTORATION
349
extraction operation. Without weighting, errors at the observation boundary
completely destroy the estimate in the boundary region, but with weighting the
restoration is subjectively satisfying, ... increased by setting b
R
= 2.0. The higher degree of blur
greatly increases the ill-conditioning of the blur matrix, and the residual error in
formation of the modified observation after weighting leads...
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