刺激随着每一帧的显示而变化。
Stimuli changes with every frame being displayed.
我有一些代码（如下所示）应该显示 10 帧的刺激。我们需要非常精确的显示时间，因此必须使用帧数而不是 core.wait(xx)，因为显示时间不会那么精确。
不是绘制刺激物并将其留到另外 9 帧，而是为每一帧重新绘制刺激物。
# Import what is needed
import numpy as np
from psychopy import visual, event, core, logging
from math import sin, cos
import random, math
win = visual.Window(size=(1366, 768), fullscr=True, screen=0, allowGUI=False, allowStencil=False,
monitor='testMonitor', color=[0,0,0], colorSpace='rgb',
blendMode='avg', useFBO=True,
units='deg')
### Definitions of libraries
'''Parameters :
numpy - python package of numerical computations
visual - where all visual stimulus live
event - code to deal with mouse + keyboard input
core - general function for timing & closing the program
logging - provides function for logging error and other messages to one file
random - options for creating arrays of random numbers
sin & cos - for geometry and trigonometry
math - mathematical operations '''
# this is supposed to record all frames
win.setRecordFrameIntervals(True)
win._refreshThreshold=1/65.0+0.004 #i've got 65Hz monitor and want to allow 4ms tolerance
#set the log module to report warnings to the std output window (default is errors only)
logging.console.setLevel(logging.WARNING)
nIntervals=5
# Create space variables and a window
lineSpaceX = 0.55
lineSpaceY = 0.55
patch_orientation = 45 # zero is vertical, going anti-clockwise
surround_orientation = 90
#Jitter values
g_posJitter = 0.05 #gaussian positional jitter
r_posJitter = 0.05 #random positional jitter
g_oriJitter = 5 #gaussian orientation jitter
r_oriJitter = 5 #random orientation jitter
#create a 1-Dimentional array
line = np.array(range(38)) #with values from (0-37) #possibly not needed 01/04/16 DK
#Region where the rectangular patch would appear
#x_rand=random.randint(1,22) #random.randint(Return random integers from low (inclusive) to high (exclusive).
#y_rand=random.randint(1,25)
x_rand=random.randint(6,13) #random.randint(Return random integers from low (inclusive) to high (inclusive).
y_rand=random.randint(6,16)
#rectangular patch dimensions
width=15
height=12
message = visual.TextStim(win,pos=(0.0,-12.0),text='...Press SPACE to continue...')
fixation = visual.TextStim(win, pos=(0.0,0.0), text='X')
# Initialize clock to record response time
rt_clock = core.Clock()
#Nested loop to draw anti-aliased lines on grid
#create a function for this
def myStim():
for x in xrange(1,33): #32x32 grid. When x is 33 will not execute loop - will stop
for y in xrange(1,33): #When y is 33 will not execute loop - will stop
##Define x & y value (Gaussian distribution-positional jitter)
x_pos = (x-32/2-1/2 )*lineSpaceX + random.gauss(0,g_posJitter) #random.gauss(mean,s.d); -1/2 is to center even-numbered stimuli; 32x32 grid
y_pos = (y-32/2-1/2 )*lineSpaceY + random.gauss(0,g_posJitter)
if (x >= x_rand and x < x_rand+width) and (y >= y_rand and y < y_rand+height): # note only "=" on one side
Line_Orientation = random.gauss(patch_orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
else:
Line_Orientation = random.gauss(surround_orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
#Line_Orientation = random.gauss(Line_Orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
#stimOri = random.uniform(xOri - r_oriJitter, xOri + r_oriJitter) #random.uniform(A,B) - Uniform func.
visual.Line(win, units = "deg", start=(0,0), end=(0.0,0.35), pos=(x_pos,y_pos), ori=Line_Orientation, autoLog=False).draw() #Gaussian func.
for frameN in range (10):
myStim()
win.flip()
print x_rand, y_rand
print keys, rt #display response and reaction time on screen output window
我曾尝试使用以下代码来保持它的显示（通过不清除缓冲区）。但它只是在它上面画了几次。
for frameN in range(10):
myStim()
win.flip(clearBuffer=False)
我意识到问题可能是因为我在定义 def myStim(): 的函数中有 .draw()。但是，如果我不在函数中包含 .draw() - 我将无法显示刺激。
在此先感谢您的帮助。
如果我理解正确，你面临的问题是你必须在每次翻转时重新绘制刺激，但你当前的绘图函数也会重新创建整个（随机）刺激，所以：
- 每次翻转之间的刺激都会发生变化，尽管您需要它保持不变，并且
- 通过一遍又一遍地重新创建整个刺激，您会得到（在某些系统上相当大的）性能损失。
您想要的是：在呈现之前创建一次完整的刺激；然后在每次翻转时绘制这个预先生成的刺激。
由于您的刺激包含相当多的视觉元素，我建议使用 class 将刺激 存储在一个地方 .
基本上，您可以用 class 替换 myStim() 函数（请注意，我去掉了大部分注释，稍微重新对齐了代码，并简化了 if 语句):
class MyStim(object):
def __init__(self):
self.lines = []
for x in xrange(1, 33):
for y in xrange(1, 33):
x_pos = ((x - 32 / 2 - 1 / 2) * lineSpaceX +
random.gauss(0, g_posJitter))
y_pos = ((y - 32 / 2 - 1 / 2) * lineSpaceY +
random.gauss(0, g_posJitter))
if ((x_rand <= x < x_rand + width) and
(y_rand <= y < y_rand + height)):
Line_Orientation = random.gauss(patch_orientation,
g_oriJitter)
else:
Line_Orientation = random.gauss(surround_orientation,
g_oriJitter)
current_line = visual.Line(
win, units="deg", start=(0, 0), end=(0.0, 0.35),
pos=(x_pos, y_pos), ori=Line_Orientation,
autoLog=False
)
self.lines.append(current_line)
def draw(self):
[line.draw() for line in self.lines]
此代码在实例化时所做的工作在原则上与您的 myStim() 函数相同：它创建一组（随机）行。但不是立即将它们绘制到屏幕上，而是将它们全部收集在列表中 self.lines，并会保留在那里直到我们真正需要它们。
draw()方法逐个元素（即逐行）遍历此列表，并调用每一行的draw()方法。请注意，每次我们想要绘制整个集合时不必重新创建刺激，而是我们只需绘制已经预先创建的线条！
要在实践中实现这一点，您首先需要实例化 MyStim class:
myStim = MyStim()
然后，无论什么时候你想呈现刺激，你所要做的就是
myStim.draw()
win.flip()
下面是完整的修改后的代码，可以帮助您入门：
import numpy as np
from psychopy import visual, event, core, logging
from math import sin, cos
import random, math
win = visual.Window(size=(1366, 768), fullscr=True, screen=0, allowGUI=False, allowStencil=False,
monitor='testMonitor', color=[0,0,0], colorSpace='rgb',
blendMode='avg', useFBO=True,
units='deg')
# this is supposed to record all frames
win.setRecordFrameIntervals(True)
win._refreshThreshold=1/65.0+0.004 #i've got 65Hz monitor and want to allow 4ms tolerance
#set the log module to report warnings to the std output window (default is errors only)
logging.console.setLevel(logging.WARNING)
nIntervals=5
# Create space variables and a window
lineSpaceX = 0.55
lineSpaceY = 0.55
patch_orientation = 45 # zero is vertical, going anti-clockwise
surround_orientation = 90
#Jitter values
g_posJitter = 0.05 #gaussian positional jitter
r_posJitter = 0.05 #random positional jitter
g_oriJitter = 5 #gaussian orientation jitter
r_oriJitter = 5 #random orientation jitter
x_rand=random.randint(6,13) #random.randint(Return random integers from low (inclusive) to high (inclusive).
y_rand=random.randint(6,16)
#rectangular patch dimensions
width=15
height=12
message = visual.TextStim(win,pos=(0.0,-12.0),text='...Press SPACE to continue...')
fixation = visual.TextStim(win, pos=(0.0,0.0), text='X')
# Initialize clock to record response time
rt_clock = core.Clock()
class MyStim(object):
def __init__(self):
self.lines = []
for x in xrange(1, 33):
for y in xrange(1, 33):
x_pos = ((x - 32 / 2 - 1 / 2) * lineSpaceX +
random.gauss(0, g_posJitter))
y_pos = ((y - 32 / 2 - 1 / 2) * lineSpaceY +
random.gauss(0, g_posJitter))
if ((x_rand <= x < x_rand + width) and
(y_rand <= y < y_rand + height)):
Line_Orientation = random.gauss(patch_orientation,
g_oriJitter)
else:
Line_Orientation = random.gauss(surround_orientation,
g_oriJitter)
current_line = visual.Line(
win, units="deg", start=(0, 0), end=(0.0, 0.35),
pos=(x_pos, y_pos), ori=Line_Orientation,
autoLog=False
)
self.lines.append(current_line)
def draw(self):
[line.draw() for line in self.lines]
myStim = MyStim()
for frameN in range(10):
myStim.draw()
win.flip()
# Clear the screen
win.flip()
print x_rand, y_rand
core.quit()
请注意，即使使用这种方法，我在一台使用了 3 年且集成图形芯片相对较弱的笔记本电脑上也会丢帧。但我怀疑一个现代的、快速的 GPU 能够很好地处理这么多的视觉对象。在最坏的情况下，您可以预先创建大量刺激物，通过 win.saveMovieFrames() 将它们保存为位图文件，并在您实际学习时将它们作为预加载 SimpleImageStim 呈现。
我有一些代码（如下所示）应该显示 10 帧的刺激。我们需要非常精确的显示时间，因此必须使用帧数而不是 core.wait(xx)，因为显示时间不会那么精确。
不是绘制刺激物并将其留到另外 9 帧，而是为每一帧重新绘制刺激物。
# Import what is needed
import numpy as np
from psychopy import visual, event, core, logging
from math import sin, cos
import random, math
win = visual.Window(size=(1366, 768), fullscr=True, screen=0, allowGUI=False, allowStencil=False,
monitor='testMonitor', color=[0,0,0], colorSpace='rgb',
blendMode='avg', useFBO=True,
units='deg')
### Definitions of libraries
'''Parameters :
numpy - python package of numerical computations
visual - where all visual stimulus live
event - code to deal with mouse + keyboard input
core - general function for timing & closing the program
logging - provides function for logging error and other messages to one file
random - options for creating arrays of random numbers
sin & cos - for geometry and trigonometry
math - mathematical operations '''
# this is supposed to record all frames
win.setRecordFrameIntervals(True)
win._refreshThreshold=1/65.0+0.004 #i've got 65Hz monitor and want to allow 4ms tolerance
#set the log module to report warnings to the std output window (default is errors only)
logging.console.setLevel(logging.WARNING)
nIntervals=5
# Create space variables and a window
lineSpaceX = 0.55
lineSpaceY = 0.55
patch_orientation = 45 # zero is vertical, going anti-clockwise
surround_orientation = 90
#Jitter values
g_posJitter = 0.05 #gaussian positional jitter
r_posJitter = 0.05 #random positional jitter
g_oriJitter = 5 #gaussian orientation jitter
r_oriJitter = 5 #random orientation jitter
#create a 1-Dimentional array
line = np.array(range(38)) #with values from (0-37) #possibly not needed 01/04/16 DK
#Region where the rectangular patch would appear
#x_rand=random.randint(1,22) #random.randint(Return random integers from low (inclusive) to high (exclusive).
#y_rand=random.randint(1,25)
x_rand=random.randint(6,13) #random.randint(Return random integers from low (inclusive) to high (inclusive).
y_rand=random.randint(6,16)
#rectangular patch dimensions
width=15
height=12
message = visual.TextStim(win,pos=(0.0,-12.0),text='...Press SPACE to continue...')
fixation = visual.TextStim(win, pos=(0.0,0.0), text='X')
# Initialize clock to record response time
rt_clock = core.Clock()
#Nested loop to draw anti-aliased lines on grid
#create a function for this
def myStim():
for x in xrange(1,33): #32x32 grid. When x is 33 will not execute loop - will stop
for y in xrange(1,33): #When y is 33 will not execute loop - will stop
##Define x & y value (Gaussian distribution-positional jitter)
x_pos = (x-32/2-1/2 )*lineSpaceX + random.gauss(0,g_posJitter) #random.gauss(mean,s.d); -1/2 is to center even-numbered stimuli; 32x32 grid
y_pos = (y-32/2-1/2 )*lineSpaceY + random.gauss(0,g_posJitter)
if (x >= x_rand and x < x_rand+width) and (y >= y_rand and y < y_rand+height): # note only "=" on one side
Line_Orientation = random.gauss(patch_orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
else:
Line_Orientation = random.gauss(surround_orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
#Line_Orientation = random.gauss(Line_Orientation,g_oriJitter) #random.gauss(mean,s.d) - Gaussian func.
#stimOri = random.uniform(xOri - r_oriJitter, xOri + r_oriJitter) #random.uniform(A,B) - Uniform func.
visual.Line(win, units = "deg", start=(0,0), end=(0.0,0.35), pos=(x_pos,y_pos), ori=Line_Orientation, autoLog=False).draw() #Gaussian func.
for frameN in range (10):
myStim()
win.flip()
print x_rand, y_rand
print keys, rt #display response and reaction time on screen output window
我曾尝试使用以下代码来保持它的显示（通过不清除缓冲区）。但它只是在它上面画了几次。
for frameN in range(10):
myStim()
win.flip(clearBuffer=False)
我意识到问题可能是因为我在定义 def myStim(): 的函数中有 .draw()。但是，如果我不在函数中包含 .draw() - 我将无法显示刺激。
在此先感谢您的帮助。
如果我理解正确，你面临的问题是你必须在每次翻转时重新绘制刺激，但你当前的绘图函数也会重新创建整个（随机）刺激，所以：
- 每次翻转之间的刺激都会发生变化，尽管您需要它保持不变，并且
- 通过一遍又一遍地重新创建整个刺激，您会得到（在某些系统上相当大的）性能损失。
您想要的是：在呈现之前创建一次完整的刺激；然后在每次翻转时绘制这个预先生成的刺激。
由于您的刺激包含相当多的视觉元素，我建议使用 class 将刺激 存储在一个地方 .
基本上，您可以用 class 替换 myStim() 函数（请注意，我去掉了大部分注释，稍微重新对齐了代码，并简化了 if 语句):
class MyStim(object):
def __init__(self):
self.lines = []
for x in xrange(1, 33):
for y in xrange(1, 33):
x_pos = ((x - 32 / 2 - 1 / 2) * lineSpaceX +
random.gauss(0, g_posJitter))
y_pos = ((y - 32 / 2 - 1 / 2) * lineSpaceY +
random.gauss(0, g_posJitter))
if ((x_rand <= x < x_rand + width) and
(y_rand <= y < y_rand + height)):
Line_Orientation = random.gauss(patch_orientation,
g_oriJitter)
else:
Line_Orientation = random.gauss(surround_orientation,
g_oriJitter)
current_line = visual.Line(
win, units="deg", start=(0, 0), end=(0.0, 0.35),
pos=(x_pos, y_pos), ori=Line_Orientation,
autoLog=False
)
self.lines.append(current_line)
def draw(self):
[line.draw() for line in self.lines]
此代码在实例化时所做的工作在原则上与您的 myStim() 函数相同：它创建一组（随机）行。但不是立即将它们绘制到屏幕上，而是将它们全部收集在列表中 self.lines，并会保留在那里直到我们真正需要它们。
draw()方法逐个元素（即逐行）遍历此列表，并调用每一行的draw()方法。请注意，每次我们想要绘制整个集合时不必重新创建刺激，而是我们只需绘制已经预先创建的线条！
要在实践中实现这一点，您首先需要实例化 MyStim class:
myStim = MyStim()
然后，无论什么时候你想呈现刺激，你所要做的就是
myStim.draw()
win.flip()
下面是完整的修改后的代码，可以帮助您入门：
import numpy as np
from psychopy import visual, event, core, logging
from math import sin, cos
import random, math
win = visual.Window(size=(1366, 768), fullscr=True, screen=0, allowGUI=False, allowStencil=False,
monitor='testMonitor', color=[0,0,0], colorSpace='rgb',
blendMode='avg', useFBO=True,
units='deg')
# this is supposed to record all frames
win.setRecordFrameIntervals(True)
win._refreshThreshold=1/65.0+0.004 #i've got 65Hz monitor and want to allow 4ms tolerance
#set the log module to report warnings to the std output window (default is errors only)
logging.console.setLevel(logging.WARNING)
nIntervals=5
# Create space variables and a window
lineSpaceX = 0.55
lineSpaceY = 0.55
patch_orientation = 45 # zero is vertical, going anti-clockwise
surround_orientation = 90
#Jitter values
g_posJitter = 0.05 #gaussian positional jitter
r_posJitter = 0.05 #random positional jitter
g_oriJitter = 5 #gaussian orientation jitter
r_oriJitter = 5 #random orientation jitter
x_rand=random.randint(6,13) #random.randint(Return random integers from low (inclusive) to high (inclusive).
y_rand=random.randint(6,16)
#rectangular patch dimensions
width=15
height=12
message = visual.TextStim(win,pos=(0.0,-12.0),text='...Press SPACE to continue...')
fixation = visual.TextStim(win, pos=(0.0,0.0), text='X')
# Initialize clock to record response time
rt_clock = core.Clock()
class MyStim(object):
def __init__(self):
self.lines = []
for x in xrange(1, 33):
for y in xrange(1, 33):
x_pos = ((x - 32 / 2 - 1 / 2) * lineSpaceX +
random.gauss(0, g_posJitter))
y_pos = ((y - 32 / 2 - 1 / 2) * lineSpaceY +
random.gauss(0, g_posJitter))
if ((x_rand <= x < x_rand + width) and
(y_rand <= y < y_rand + height)):
Line_Orientation = random.gauss(patch_orientation,
g_oriJitter)
else:
Line_Orientation = random.gauss(surround_orientation,
g_oriJitter)
current_line = visual.Line(
win, units="deg", start=(0, 0), end=(0.0, 0.35),
pos=(x_pos, y_pos), ori=Line_Orientation,
autoLog=False
)
self.lines.append(current_line)
def draw(self):
[line.draw() for line in self.lines]
myStim = MyStim()
for frameN in range(10):
myStim.draw()
win.flip()
# Clear the screen
win.flip()
print x_rand, y_rand
core.quit()
请注意，即使使用这种方法，我在一台使用了 3 年且集成图形芯片相对较弱的笔记本电脑上也会丢帧。但我怀疑一个现代的、快速的 GPU 能够很好地处理这么多的视觉对象。在最坏的情况下，您可以预先创建大量刺激物，通过 win.saveMovieFrames() 将它们保存为位图文件，并在您实际学习时将它们作为预加载 SimpleImageStim 呈现。