要点：
人眼视觉
人眼非正常视觉
人眼错觉人眼视觉特性人眼视觉感光细胞 (photoreceptor cells)：
杆状细胞 (rod)：单色夜视锥状细胞 (cone)：彩色视觉红 (red)
绿 (green)
蓝 (blue)
Primary Color 基色
Light enters the retina on the side containing the
optic nerves and travels through all the layer before
reaching the receptors,
Retina
This animated cartoon illustrates how light (white dot) enters the retina on the
side containing the optic nerves and travels through all of the retinal layers before
finally being absorbed by the photopigments in the outer segments of the
receptors,A neural signal (yellow dot) is generated in the receptors which then
travels through the neurons of the various retinal layers and finally travels out
through the optic nerve up to the lateral geniculate nucleus,
How light enters the retina and is transmitted out the optic nerve
Electron Micrograph of Human Visual Receptors
When looking at an object that is far away the lens is kind of
skinny,What happens when looking at a nearby object?
Refraction
When looking at nearby objects the lens gets fatter,causing the
image of the object to be focused on to the retina in the fovea,
What would happen if the lens did not get fatter?
By the way,the technical term for this change in lens shape is
accommodation,We frequently call it focusing.
If the lens can not properly focus light on the retina,the
image will fall either behind or in front of the retina,
Can you guess what would happen if the lens is too fat?
If you guessed that when the lens is too fat that light is
focussed in front of the retina,you were right,
Is there a remedy for lens problems that do not allow light to
be properly focused on the retina? Sure.
Many people wear contact lenses to help image light properly on
to the retina,Another solution is for a person to wear glasses,
This places a lens in front of the eye not on the cornea as is the
case with contact lenses,
A recent solution is to use a laser to reshape the cornea,this
solution is possible only in some cases.
There are two kinds of astigmatism,1,
lenticular and 2,corneal,
Astigmatism occurs when the surface of
the cornea or of the lens is not perfectly
smooth,If,for example,there is a small
flat spot on your cornea the image in a
certain direction on your retina will not be
in perfect focus,
If the figure on the right was constructed
with all the radial lines of equal sharpness
and contrast a person without astigmatism
would see all these radial lines as perfectly
sharp and with the same contrast,The
diagram on the right has been fudged
to illustrate how it might appear to a
person with astigmatism.
This condition can be corrected with a
corneal contact lens or cylinder lens in a pair
of spectacles.
Astigmatism
Contact Lenses
A very thin plastic lens,often flexible
(soft lenses) floats on a layer of tears
on the corneal surface of the eye,
These lenses can be of the permanent
variety or disposable,The permanent
variety need to be properly cleaned
and cared for,The disposable are often
worn continuously and the thrown
Corneal Contact Lens
away when removed,Note how the bottom edge of the lens is against
the lower eye lid,If the wearer looks down,the lens is pushed up a
little,This "trick" can be used to provide bifocal contact lenses,These
lenses have different powers in the center than in the periphery,When
the wearer looks down to read the lens is moved to a new position to
facilitate seeing sharply at normal reading distances,If there is an
irregularity on the cornea (astigmatism) it is automatically corrected by
the combination of the tear layer and the contact lens,
A cylinder lens is different
than a spherical lens which is
what one normally sees in
spectacles,Although a
cylindrical component my be
built in to that which appears
spherical,
As can be seen in the left
diagram a cylinder lens has
power only in one axis,In the
left it is the horizontal axis,
This lens does not refract light
in the vertical direction.
Cylinder lens
Spectral Sensitivity Curves of Rods & Cones
When you first enter an extremely bright environment,for example,when
emerging from a dark movies house into a very bright sunlit area the man carving
the duck would appear like this,But in less than a minute he will appear as seen
below,In the left photo the contrast is very low,Below the contrast is normal.
When light adapted a scene might look like this.
Dark Adaptation
For approximately the first 10 minutes in the dark,the cones require less light to
reach a threshold response than do the rods,Thereafter,the rods require less light,
The point at which the rods become more sensitive is called the rod-cone break,
Dark Adaptation Function
p.18
The following demonstration is
an example of how the worldappears
to a person with a
severe type of color blindness,
deuteranopia.
See how you would do in a color
blind world…
人眼视觉
Color vision defects cause
problems in the real world
Which meat is the most thoroughly cooked?
Which meat is the most thoroughly cooked?
Which flask contains a light pink solution?
Which flask contains a light pink solution?
Which of the following slides contains a pink cell?
Which of the following slides contains a pink cell?
Which picture contains a red crayon?
Which picture contains a red crayon?
The use of color so that color blind people (and
everyone else) can see what you are presenting.
Red-green color blindness is
common--about
4-5% of the population,In
your presentations,
color should be used with
care to ensure that
your color blind
colleagues can see.
In its most severe forms,
color blindness is caused
by the absence of one of
the cone visual pigments.
Shown here,the spectral
sensitivities of the cone
pigments in color normal
trichromats are compared
with those of a color blind
person,Also compare the
spectrum as it appears to
a color normal person with
the illustration of how it
might look to a red-green
color blind person.
The difficulties with
certain colors can be
illustrated on a color
wheel,For a severely
red-green color blind
person there are only
two hues,the ones a
color normal person
sees as yellow and blue,
Intermediate colors,the
ones seen as blueish-
green and magenta,
appear gray,
Clear graphics are very important and often the
source of the most difficulty; here are two
examples showing the difference between good
and bad use of color,The Trick is to keep
brightness differences large and to avoid color
combinations that do not contrast well.
A comparison of the
two color wheels
shows which color
combinations would
be difficult to see,
Graphics cause the
most problems,but
the colors can be
economically
illustrated as text
examples,below,
The right-hand
column illustrates
how the left hand
column might look to
a color blind person.
Some examples of color combinations that are easily
seen by a color blind person are shown below,These are
illustrated as text examples but these principles are most
important to keep in mind when preparing drawings,
graphs,and figures.
cone
狗是色盲？
点击图片播放视频眼见为实？
马赫带效应
Mach bands
Boynton Illusion
Color Influences Distance Perception
Radiating Lines
Take two pieces of paper and place their edges as close as possible to both sides of one
red diagonal,Note that the red square in the middle is the same as all the other squares on
that diagonal,Now move your pieces of paper to expose mainly the red squares on the
other diagonal,On this diagonal all the red squares,including the center one,are again
the same color red,Because the center square is common to both diagonals this exercise
proves that all the red squares in both diagonals are exactly the same red color,Yet,when
the pattern is seen as a whole,the two red diagonals appear different from each other
Color Assimilation
Hermann Grid Illusion
点击图片 播放 FLASH
Hering & Pogendorf Illusions
点击图片 播放 FLASH
Which line is longer,the red one or the green one? Use a ruler to
find out,You will probably be surprised.
Horizontal-Vertical Illusion
点击图片 播放 FLASH
Look at the upper right figure.This experiment works better if you
close one eye,Fixate on the black dot in the center for about 10 -
15 seconds,Pay close attention to what you see,Now do the same
thing with the upper left figure,
Did you notice any difference? In the accompanying explanation I
tell you what most people see and the reason for it.
"Stabilization" Causes Fading
This is called a Kanizsa figure after the person who invented it,If you
look carefully you will probably see the edges of the entire triangle,even
though the triangle is defined only by the notches in the red disks.
Kanizsa Illusion
Which is longer,the red line or the blue line? Use a ruler to find out the
answer,Select the answer to double check on your result.
Mueller-Lyer Illusion
点击图片 播放 FLASH
The round dots are all exactly the same color gray,I merely created the one
on the extreme right and then copied it to each of the darker rectangles,
Clearly,the lightness of the background effects the way in which we perceive
the center gray dot,This effect is called simultaneous contrast,Again,as can
be seen in other demonstrations,the perception of this kind of display is a
result of lateral interactions.
Simultaneous Contrast
The circular area in each quadrant in the left figure is exactly the same
color,The different appearance is due to the surround and the lateral
interactions that occur,On the right I merely changed the background
colors so that they are all identical,You can now see that the circular
areas are,indeed,identical,
This phenomenon is called simultaneous color contrast.
Simultaneous Contrast
Necker Cube Illusion
Perspective Illusion
点击图片 播放 FLASH
What do you see in this diagram? In order to find out what people often
say they see select possible perceptions,
点击图片播放视频点击图片播放视频点击图片 播放 FLASH
更高层次的视觉认知心理文化东方歌舞团的演员在演出西班牙响板舞,火之恋,。
暖色 冷色 麦当劳眩晕的艺术一名参观者在澳大利亚悉尼当代艺术博物馆欣赏瑞士艺术家乌戈 ·龙迪诺内创作的一幅作品。龙迪诺内善于利用绘画、视频、雕刻和摄影创造情感和心理环境，并因此而闻名于世。照片中的作品使观赏者无法将视线集中在彩色的圆圈上，许多人感到眩晕，有人甚至感到头昏眼花。
红 白 黑黄 绿电影利用了人眼的视觉特性点击图片播放视频电影利用了人眼的视觉特性点击图片播放视频视觉暂留视觉暂留点击图片播放视频快拍慢放点击图片播放视频慢拍快放点击图片播放视频点击图片播放视频
Terms
Photoreceptor cells:感光细胞
Rod,杆状细胞
Cone,锥状细胞
Retina,视网膜
Iris,虹膜
Fovea,中央凹
Visual cortex,视觉皮层
人眼视觉
人眼非正常视觉
人眼错觉人眼视觉特性人眼视觉感光细胞 (photoreceptor cells)：
杆状细胞 (rod)：单色夜视锥状细胞 (cone)：彩色视觉红 (red)
绿 (green)
蓝 (blue)
Primary Color 基色
Light enters the retina on the side containing the
optic nerves and travels through all the layer before
reaching the receptors,
Retina
This animated cartoon illustrates how light (white dot) enters the retina on the
side containing the optic nerves and travels through all of the retinal layers before
finally being absorbed by the photopigments in the outer segments of the
receptors,A neural signal (yellow dot) is generated in the receptors which then
travels through the neurons of the various retinal layers and finally travels out
through the optic nerve up to the lateral geniculate nucleus,
How light enters the retina and is transmitted out the optic nerve
Electron Micrograph of Human Visual Receptors
When looking at an object that is far away the lens is kind of
skinny,What happens when looking at a nearby object?
Refraction
When looking at nearby objects the lens gets fatter,causing the
image of the object to be focused on to the retina in the fovea,
What would happen if the lens did not get fatter?
By the way,the technical term for this change in lens shape is
accommodation,We frequently call it focusing.
If the lens can not properly focus light on the retina,the
image will fall either behind or in front of the retina,
Can you guess what would happen if the lens is too fat?
If you guessed that when the lens is too fat that light is
focussed in front of the retina,you were right,
Is there a remedy for lens problems that do not allow light to
be properly focused on the retina? Sure.
Many people wear contact lenses to help image light properly on
to the retina,Another solution is for a person to wear glasses,
This places a lens in front of the eye not on the cornea as is the
case with contact lenses,
A recent solution is to use a laser to reshape the cornea,this
solution is possible only in some cases.
There are two kinds of astigmatism,1,
lenticular and 2,corneal,
Astigmatism occurs when the surface of
the cornea or of the lens is not perfectly
smooth,If,for example,there is a small
flat spot on your cornea the image in a
certain direction on your retina will not be
in perfect focus,
If the figure on the right was constructed
with all the radial lines of equal sharpness
and contrast a person without astigmatism
would see all these radial lines as perfectly
sharp and with the same contrast,The
diagram on the right has been fudged
to illustrate how it might appear to a
person with astigmatism.
This condition can be corrected with a
corneal contact lens or cylinder lens in a pair
of spectacles.
Astigmatism
Contact Lenses
A very thin plastic lens,often flexible
(soft lenses) floats on a layer of tears
on the corneal surface of the eye,
These lenses can be of the permanent
variety or disposable,The permanent
variety need to be properly cleaned
and cared for,The disposable are often
worn continuously and the thrown
Corneal Contact Lens
away when removed,Note how the bottom edge of the lens is against
the lower eye lid,If the wearer looks down,the lens is pushed up a
little,This "trick" can be used to provide bifocal contact lenses,These
lenses have different powers in the center than in the periphery,When
the wearer looks down to read the lens is moved to a new position to
facilitate seeing sharply at normal reading distances,If there is an
irregularity on the cornea (astigmatism) it is automatically corrected by
the combination of the tear layer and the contact lens,
A cylinder lens is different
than a spherical lens which is
what one normally sees in
spectacles,Although a
cylindrical component my be
built in to that which appears
spherical,
As can be seen in the left
diagram a cylinder lens has
power only in one axis,In the
left it is the horizontal axis,
This lens does not refract light
in the vertical direction.
Cylinder lens
Spectral Sensitivity Curves of Rods & Cones
When you first enter an extremely bright environment,for example,when
emerging from a dark movies house into a very bright sunlit area the man carving
the duck would appear like this,But in less than a minute he will appear as seen
below,In the left photo the contrast is very low,Below the contrast is normal.
When light adapted a scene might look like this.
Dark Adaptation
For approximately the first 10 minutes in the dark,the cones require less light to
reach a threshold response than do the rods,Thereafter,the rods require less light,
The point at which the rods become more sensitive is called the rod-cone break,
Dark Adaptation Function
p.18
The following demonstration is
an example of how the worldappears
to a person with a
severe type of color blindness,
deuteranopia.
See how you would do in a color
blind world…
人眼视觉
Color vision defects cause
problems in the real world
Which meat is the most thoroughly cooked?
Which meat is the most thoroughly cooked?
Which flask contains a light pink solution?
Which flask contains a light pink solution?
Which of the following slides contains a pink cell?
Which of the following slides contains a pink cell?
Which picture contains a red crayon?
Which picture contains a red crayon?
The use of color so that color blind people (and
everyone else) can see what you are presenting.
Red-green color blindness is
common--about
4-5% of the population,In
your presentations,
color should be used with
care to ensure that
your color blind
colleagues can see.
In its most severe forms,
color blindness is caused
by the absence of one of
the cone visual pigments.
Shown here,the spectral
sensitivities of the cone
pigments in color normal
trichromats are compared
with those of a color blind
person,Also compare the
spectrum as it appears to
a color normal person with
the illustration of how it
might look to a red-green
color blind person.
The difficulties with
certain colors can be
illustrated on a color
wheel,For a severely
red-green color blind
person there are only
two hues,the ones a
color normal person
sees as yellow and blue,
Intermediate colors,the
ones seen as blueish-
green and magenta,
appear gray,
Clear graphics are very important and often the
source of the most difficulty; here are two
examples showing the difference between good
and bad use of color,The Trick is to keep
brightness differences large and to avoid color
combinations that do not contrast well.
A comparison of the
two color wheels
shows which color
combinations would
be difficult to see,
Graphics cause the
most problems,but
the colors can be
economically
illustrated as text
examples,below,
The right-hand
column illustrates
how the left hand
column might look to
a color blind person.
Some examples of color combinations that are easily
seen by a color blind person are shown below,These are
illustrated as text examples but these principles are most
important to keep in mind when preparing drawings,
graphs,and figures.
cone
狗是色盲？
点击图片播放视频眼见为实？
马赫带效应
Mach bands
Boynton Illusion
Color Influences Distance Perception
Radiating Lines
Take two pieces of paper and place their edges as close as possible to both sides of one
red diagonal,Note that the red square in the middle is the same as all the other squares on
that diagonal,Now move your pieces of paper to expose mainly the red squares on the
other diagonal,On this diagonal all the red squares,including the center one,are again
the same color red,Because the center square is common to both diagonals this exercise
proves that all the red squares in both diagonals are exactly the same red color,Yet,when
the pattern is seen as a whole,the two red diagonals appear different from each other
Color Assimilation
Hermann Grid Illusion
点击图片 播放 FLASH
Hering & Pogendorf Illusions
点击图片 播放 FLASH
Which line is longer,the red one or the green one? Use a ruler to
find out,You will probably be surprised.
Horizontal-Vertical Illusion
点击图片 播放 FLASH
Look at the upper right figure.This experiment works better if you
close one eye,Fixate on the black dot in the center for about 10 -
15 seconds,Pay close attention to what you see,Now do the same
thing with the upper left figure,
Did you notice any difference? In the accompanying explanation I
tell you what most people see and the reason for it.
"Stabilization" Causes Fading
This is called a Kanizsa figure after the person who invented it,If you
look carefully you will probably see the edges of the entire triangle,even
though the triangle is defined only by the notches in the red disks.
Kanizsa Illusion
Which is longer,the red line or the blue line? Use a ruler to find out the
answer,Select the answer to double check on your result.
Mueller-Lyer Illusion
点击图片 播放 FLASH
The round dots are all exactly the same color gray,I merely created the one
on the extreme right and then copied it to each of the darker rectangles,
Clearly,the lightness of the background effects the way in which we perceive
the center gray dot,This effect is called simultaneous contrast,Again,as can
be seen in other demonstrations,the perception of this kind of display is a
result of lateral interactions.
Simultaneous Contrast
The circular area in each quadrant in the left figure is exactly the same
color,The different appearance is due to the surround and the lateral
interactions that occur,On the right I merely changed the background
colors so that they are all identical,You can now see that the circular
areas are,indeed,identical,
This phenomenon is called simultaneous color contrast.
Simultaneous Contrast
Necker Cube Illusion
Perspective Illusion
点击图片 播放 FLASH
What do you see in this diagram? In order to find out what people often
say they see select possible perceptions,
点击图片播放视频点击图片播放视频点击图片 播放 FLASH
更高层次的视觉认知心理文化东方歌舞团的演员在演出西班牙响板舞,火之恋,。
暖色 冷色 麦当劳眩晕的艺术一名参观者在澳大利亚悉尼当代艺术博物馆欣赏瑞士艺术家乌戈 ·龙迪诺内创作的一幅作品。龙迪诺内善于利用绘画、视频、雕刻和摄影创造情感和心理环境，并因此而闻名于世。照片中的作品使观赏者无法将视线集中在彩色的圆圈上，许多人感到眩晕，有人甚至感到头昏眼花。
红 白 黑黄 绿电影利用了人眼的视觉特性点击图片播放视频电影利用了人眼的视觉特性点击图片播放视频视觉暂留视觉暂留点击图片播放视频快拍慢放点击图片播放视频慢拍快放点击图片播放视频点击图片播放视频
Terms
Photoreceptor cells:感光细胞
Rod,杆状细胞
Cone,锥状细胞
Retina,视网膜
Iris,虹膜
Fovea,中央凹
Visual cortex,视觉皮层
