util.py

import numpy as np
from io import StringIO
import PIL.Image
from IPython.display import Image, display

def showBGRimage(a, fmt='jpeg'):
    a = np.uint8(np.clip(a, 0, 255))
    a[:,:,[0,2]] = a[:,:,[2,0]] # for B,G,R order
    f = StringIO()
    PIL.Image.fromarray(a).save(f, fmt)
    display(Image(data=f.getvalue()))

def showmap(a, fmt='png'):
    a = np.uint8(np.clip(a, 0, 255))
    f = StringIO()
    PIL.Image.fromarray(a).save(f, fmt)
    display(Image(data=f.getvalue()))

#def checkparam(param):
#    octave = param['octave']
#    starting_range = param['starting_range']
#    ending_range = param['ending_range']
#    assert starting_range <= ending_range, 'starting ratio should <= ending ratio'
#    assert octave >= 1, 'octave should >= 1'
#    return starting_range, ending_range, octave

def getJetColor(v, vmin, vmax):
    c = np.zeros((3))
    if (v < vmin):
        v = vmin
    if (v > vmax):
        v = vmax
    dv = vmax - vmin
    if (v < (vmin + 0.125 * dv)): 
        c[0] = 256 * (0.5 + (v * 4)) #B: 0.5 ~ 1
    elif (v < (vmin + 0.375 * dv)):
        c[0] = 255
        c[1] = 256 * (v - 0.125) * 4 #G: 0 ~ 1
    elif (v < (vmin + 0.625 * dv)):
        c[0] = 256 * (-4 * v + 2.5)  #B: 1 ~ 0
        c[1] = 255
        c[2] = 256 * (4 * (v - 0.375)) #R: 0 ~ 1
    elif (v < (vmin + 0.875 * dv)):
        c[1] = 256 * (-4 * v + 3.5)  #G: 1 ~ 0
        c[2] = 255
    else:
        c[2] = 256 * (-4 * v + 4.5) #R: 1 ~ 0.5                      
    return c

def colorize(gray_img):
    out = np.zeros(gray_img.shape + (3,))
    for y in range(out.shape[0]):
        for x in range(out.shape[1]):
            out[y,x,:] = getJetColor(gray_img[y,x], 0, 1)
    return out

def padRightDownCorner(img, stride, padValue):
    h = img.shape[0]
    w = img.shape[1]

    pad = 4 * [None]
    pad[0] = 0 # up
    pad[1] = 0 # left
    pad[2] = 0 if (h%stride==0) else stride - (h % stride) # down
    pad[3] = 0 if (w%stride==0) else stride - (w % stride) # right

    img_padded = img
    pad_up = np.tile(img_padded[0:1,:,:]*0 + padValue, (pad[0], 1, 1))
    img_padded = np.concatenate((pad_up, img_padded), axis=0)
    pad_left = np.tile(img_padded[:,0:1,:]*0 + padValue, (1, pad[1], 1))
    img_padded = np.concatenate((pad_left, img_padded), axis=1)
    pad_down = np.tile(img_padded[-2:-1,:,:]*0 + padValue, (pad[2], 1, 1))
    img_padded = np.concatenate((img_padded, pad_down), axis=0)
    pad_right = np.tile(img_padded[:,-2:-1,:]*0 + padValue, (1, pad[3], 1))
    img_padded = np.concatenate((img_padded, pad_right), axis=1)

    return img_padded, pad