... mức lượng tử sẽ phải
là bao nhiêu?
Câu 3 : Cho nguồn ký hiệu A, B, C, D, E, F, G, H có xác suất xu t hiện của các ký hiệu
như sau:
m A B C D E F G H
P(m) 0.08 0.16 0.38 0.03 0.09 0.13 0.07 0.06
Xác...
... trúc hệ thống số xửlýâmthanh
Đối với máy tính số xửlýâm thanh, người ta thường dùng phương pháp Điều chế xung
(Pulse Code Modulation , viết tắt PCM). Dạng sóng âmthanh được chuyển sang dãy ... lýâm thanh; mặc dù chất lượng của âmthanh được giải mã không cao, nhưng hệ
thống giải mã đơ
n giản và dễ hiểu. Thuật ngữ “mã hóa dự đoán tuyến tính” xu t hiện từ khi việc
tạo ra âmthanh thoại ... được mô
phỏng theo dạng xung truy
ền động (âm thanh thoại) hoặc là nhiễu ngẫu nhiên (âm thanh phi
thoại). Như vậy, phụ thuộc vào trạng thái âmthanh thoại hay phi thoại của tín hiệu, mạch chuyển...
... output of a system can be obtained directly from knowledge
of the output probability density, or in certain cases, indirectly in terms of the system
operator. For example, if the system operator ... are
usually not known, nor are they easily modeled. The first-order probability density
p(F; x, y, t) can sometimes be modeled successfully on the basis of the physics of
the process or histogram measurements. ... Singularity Operators
Singularity operators are widely employed in the analysis of two-dimensional
systems, especially systems that involve sampling of continuous functions. The
two-dimensional...
... adaption effect. Further analysis and testing are
required to model the effect adequately.
REFERENCES
1. Webster's New Collegiate Dictionary, G. & C. Merriam Co. (The Riverside Press),
Springfield, ... exten-
sively and have found transfer functions for the various elements that accurately
model the total system response. The monochromatic vision model of Figure 2.4-7,
with appropriately scaled parameters, ... sources with the same spectral shape are observed, the source of
greater physical intensity will generally appear to be perceptually brighter. How-
ever, there are numerous examples in which an...
... video camera sensors typically are linearly
proportional to the light striking each sensor. However, the light generated by cathode
tube displays is approximately proportional to the display amplitude ... be the same for the primary mixture as for the actual
color C. Unfortunately, the cone signals are not easily measured physical
quantities, and therefore, Eq. 3.3-11 cannot be used directly to ... effectively forms a blue primary light. In a similar manner, the magenta filter
ideally forms the green primary, and the cyan filter ideally forms the red primary.
Subtractive color systems ordinarily...
... in a sampled imaging system, it is neces-
sary to bandlimit the image to be sampled, spatially sample the image at the Nyquist
or higher rate, and properly interpolate the image samples. Sample ... desired parameter of a physical image. In
a perfect image sampling system, spatial samples of the ideal image would, in effect,
be obtained by multiplying the ideal image by a spatial sampling function
(4.1-1)
composed ... image sampling and reconstruction process
is considered for both theoretically exact and practical systems.
4.1. IMAGE SAMPLING AND RECONSTRUCTION CONCEPTS
In the design and analysis of image sampling...
... be estimated by histogram measure-
ments. For example, the first-order probability distribution
(5.4-6)
of the amplitude value at vector coordinate q can be estimated by examining a large
collection ... a
consequence of the rectilinear grid, the separation parameters may only assume cer-
tain discrete values. The second-order spatial histogram is then the frequency ratio
(5.4-9)
Pfq()[]P
R
fq() ... the pairs of pixels become less correlated and the histogram energy tends
to spread more uniformly about the plane.
FIGURE 5.4-1. Histograms of the red, green and blue components of the smpte_girl
_linear...
... typical example of the quantization of a scalar signal. In the
quantization process, the amplitude of an analog signal sample is compared to a set
of decision levels. If the sample amplitude ... proportional to its amplitude. The conver-
sion process between analog samples and discrete-valued samples is called quanti-
zation. The following section includes an analytic treatment of the ... quantization techniques, let f
and represent the amplitude of a real, scalar signal sample and its quantized value,
respectively. It is assumed that f is a sample of a random process with known proba-
bility...
... 7.2-1 provides an example relating actual physical sample values
to mesh points on the ideal image field. In this exam-
ple, the mesh spacing is twice as large as the physical sample spacing. In ... Eq. 7.2-9
for a sampled superposition integral; the physical area of the ideal image field
containing mesh points contributing to physical image samples is larger
than the sample image regardless ... βd
∞
–
∞
∫
∞
–
∞
∫
=
SAMPLED IMAGE SUPERPOSITION AND CONVOLUTION
171
It should be noted that the physical sampling is performed on the observed image
spatial variables (x, y); physical sampling does not...
... Daubechies transforms are related members of a family of
nonsinusoidal transforms.
8.4.1. Hadamard Transform
The Hadamard transform (22,23) is based on the Hadamard matrix (24), which is a
square array ... more efficiently computed, while in other computing environ-
ments, the Fourier transform may be computationally superior.
8.4. HADAMARD, HAAR, AND DAUBECHIES TRANSFORMS
The Hadamard, Haar, and ... and A
R
, respectively. Then, it is easily verified
that
(8.1-14a)
Similarly,
(8.1-14b)
where and denote rows m
1
and m
2
of the unitary matrices B
C
and
B
R
, respectively. The vector outer...
... Fourier transform of over P points to obtain
(9.4-7)
where .
If the continuous domain transfer function is known analytically, then
can be obtained directly. It can be shown that
(9.4-8a)
(9.4-8b)
for ... Fourier transform of the window function y(x). If
and are known analytically, then, in principle, can be obtained
by analytically performing the convolution operation of Eq. 9.4-8c and evaluating
the ... the analytic convo-
lution is often difficult to perform, especially in two dimensions. An alternative is to
perform an analytic inverse Fourier transformation of the transfer function to
obtain...
... histogram of the image is shown in Figure 10.1-5b. Examination of the
histogram of the image reveals that the image contains relatively few low- or high-
amplitude pixels. Consequently, applying ... resulting histogram would
be much more uniform.
Histogram equalization usually performs best on images with detail hidden in
dark regions. Good-quality originals are often degraded by histogram equalization.
As ... perform analytically, but certainly
possible by numerical methods. The resulting solution is simply a table that indi-
cates the output image level for each input image level.
The histogram transformation...
... time. Ideally, if the exposure time were to be
increased by a certain factor, the exposure would be increased by the same factor.
Unfortunately, this relationship does not hold exactly. The departure ... are converted completely to metallic silver. In the next step, the metallic
silver grains are chemically removed. The film is then uniformly exposed to light, or
alternatively, a chemical process ... transparency
and inversely proportional for a positive transparency. Similarly, the green and blue
emulsion layers become magenta and cyan dye layers, respectively. Color prints can
be obtained by a variety...
... observation noise. Conversely, a small amount of observation noise
may lead to a reconstruction of that contains very large amplitude high-fre-
quency components. If relatively small perturbations ... TECHNIQUES
frame. This type of imaging would be encountered, for example, when photograph-
ing distant objects through a turbulent atmosphere if the object does not move
significantly between frames. ... ill-
conditioning generally occur only for higher-order singular values. Thus, it is possi-
ble interactively to terminate the expansion before numerical problems occur.
Figure 12.4-2 shows an example of sequential...