在 PyQtGraph GraphicsWindow 中设置图像的对比度

Posted 2023-03-25

【中文标题】在 PyQtGraph GraphicsWindow 中设置图像的对比度

【英文标题】：setting contrast of image in PyQtGraph GraphicsWindow

【发布时间】：2019-05-17 15:35:27

【问题描述】：

我正在构建一个 GUI，我希望允许用户更改通过 PyQtGraph GraphicsWindow 显示的图像的对比度（比如使用滚动条或其他东西）。有什么想法吗？

我的代码如下所示：

gw = pg.GraphicsWindow(size=(OCT_WIDTH, OCT_HEIGHT), border=True)
gw_layout = gw.addLayout(row=0, col=0)
gw_view = gw_layout.addViewBox(row=1, col=0, lockAspect=True)
img = imread(imgPath)
imgItem = pg.ImageItem(img)
gw_view.addItem(imgItem)

【参考方案1】：

ImageView 小部件包含一个颜色条，可用于修改图像对比度或强度。请参阅 ImageView example。

为了方便和将来参考，我在下面复制了ImageView.py 示例。

# -*- coding: utf-8 -*-
"""
This example demonstrates the use of ImageView, which is a high-level widget for 
displaying and analyzing 2D and 3D data. ImageView provides:

  1. A zoomable region (ViewBox) for displaying the image
  2. A combination histogram and gradient editor (HistogramLUTItem) for
     controlling the visual appearance of the image
  3. A timeline for selecting the currently displayed frame (for 3D data only).
  4. Tools for very basic analysis of image data (see ROI and Norm buttons)

"""
## Add path to library (just for examples; you do not need this)
import initExample

import numpy as np
from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph as pg

# Interpret image data as row-major instead of col-major
pg.setConfigOptions(imageAxisOrder='row-major')

app = QtGui.QApplication([])

## Create window with ImageView widget
win = QtGui.QMainWindow()
win.resize(800,800)
imv = pg.ImageView()
win.setCentralWidget(imv)
win.show()
win.setWindowTitle('pyqtgraph example: ImageView')

## Create random 3D data set with noisy signals
img = pg.gaussianFilter(np.random.normal(size=(200, 200)), (5, 5)) * 20 + 100
img = img[np.newaxis,:,:]
decay = np.exp(-np.linspace(0,0.3,100))[:,np.newaxis,np.newaxis]
data = np.random.normal(size=(100, 200, 200))
data += img * decay
data += 2

## Add time-varying signal
sig = np.zeros(data.shape[0])
sig[30:] += np.exp(-np.linspace(1,10, 70))
sig[40:] += np.exp(-np.linspace(1,10, 60))
sig[70:] += np.exp(-np.linspace(1,10, 30))

sig = sig[:,np.newaxis,np.newaxis] * 3
data[:,50:60,30:40] += sig


## Display the data and assign each frame a time value from 1.0 to 3.0
imv.setImage(data, xvals=np.linspace(1., 3., data.shape[0]))

## Set a custom color map
colors = [
    (0, 0, 0),
    (45, 5, 61),
    (84, 42, 55),
    (150, 87, 60),
    (208, 171, 141),
    (255, 255, 255)
]
cmap = pg.ColorMap(pos=np.linspace(0.0, 1.0, 6), color=colors)
imv.setColorMap(cmap)

## Start Qt event loop unless running in interactive mode.
if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()