Last weekend the Python Edinburgh users group hosted a mini-conference. Saturday morning was kicked off with a series of talks followed by sessions introducing and then focusing on contributing to django prior to sprints which really got going on the Sunday.
The slides for my talk on, "Images and Vision in Python" are now available in pdf format here.
The slide deck I used is relatively lightweight with my focus being on demonstrating using the different packages available. The code I went through is below.
from PIL import Image #Open an image and show it pil1 = Image.open('filename') pil1.show() #Get its size pil1.size #Resize pil1s = pil1.resize((100,100)) #or - thumbnail pil1.thumbnail((100,100), Image.ANTIALIAS) #New image bg = Image.new('RGB', (500,500), '#ffffff') #Two ways of accessing the pixels #getpixel/putpixel and load #load is faster pix = bg.load() for a in range(100, 200): for b in range(100,110): pix[a,b] = (0,0,255) bg.show() #Drawing shapes is slightly more involved from PIL import ImageDraw draw = ImageDraw.Draw(bg) draw.ellipse((300,300,320,320), fill='#ff0000') bg.show() from PIL import ImageFont font = ImageFont.truetype("/usr/share/fonts/truetype/freefont/FreeSerif.ttf", 72) draw.text((10,10), "Hello", font=font, fill='#00ff00') bg.show() #Demo's for vision from scipy import ndimage import mahotas #Create a sample image v1 = np.zeros((10,10), bool) v1[1:4,1:4] = True v1[4:7,2:6] = True imshow(v1, interpolation="Nearest") imshow(mahotas.dilate(v1), interpolation="Nearest") imshow(mahotas.erode(v1), interpolation="Nearest") imshow(mahotas.thin(v1), interpolation="Nearest") #Opening, closing and top-hat as combinations of dilate and erode #Labeling #Latest version of mahotas has a label func v1[8:,8:] = True imshow(v1) labeled, nr_obj = ndimage.label(v1) nr_obj imshow(labeled, interpolation="Nearest") pylab.jet() #Thresholding #Convert a grayscale image to a binary image v2 = mahotas.imread("/home/jonathan/openplaques/blueness_images/1.jpg") T = mahotas.otsu(v2) imshow(v2) imshow(v2 > T) #Distance Transforms dist = mahotas.distance(v2 > T) imshow(dist)