Display image in Grayscale using vispy

Question

i'm working with a spatial light modulator (SLM) which is connected as a second monbitor. The SLM has tzo recive 8-bit grayscale images. I am currently working with vispy to display the images on the SLM, but i'm not shore if they are diplayed correctly. Is there any possibility to display an image on grayscale using vispy?

I disply the images using this code

import sys
from vispy import scene
from vispy import app
import numpy as np

canvas = scene.SceneCanvas(keys='interactive')
canvas.size = 800, 600
canvas.show()

# Set up a viewbox to display the image with interactive pan/zoom
view = canvas.central_widget.add_view()

# Create the image
img_data = *my image*
image = scene.visuals.Image(img_data, parent=view.scene)

# Set 2D camera (the camera will scale to the contents in the scene)
view.camera = scene.PanZoomCamera(aspect=1)

if __name__ == '__main__' and sys.flags.interactive == 0:
    app.run()

from http://vispy.readthedocs.io/en/stable/examples/basics/scene/image.html

thanks for your help, and sorry for bad english

Answer 1

You can transform your picture from RGB to gray (see this post) and then use the 'grays' colormap.

import sys
from vispy import scene
from vispy import app
import numpy as np
from vispy.io import load_data_file, read_png

canvas = scene.SceneCanvas(keys='interactive')
canvas.size = 800, 600
canvas.show()

# Set up a viewbox to display the image with interactive pan/zoom
view = canvas.central_widget.add_view()

# Define a function to tranform a picture to gray
def rgb2gray(rgb):
    return np.dot(rgb[...,:3], [0.299, 0.587, 0.114])

# Load the image
img_data = read_png(load_data_file('mona_lisa/mona_lisa_sm.png'))

# Apply transformation
img_data = rgb2gray(img_data)

# Image visual
image = scene.visuals.Image(img_data, cmap='grays', parent=view.scene)

# Set 2D camera (the camera will scale to the contents in the scene)
view.camera = scene.PanZoomCamera(aspect=1)
view.camera.set_range()
view.camera.flip = (0, 1, 0)

if __name__ == '__main__' and sys.flags.interactive == 0:
    app.run()