日誌
Python 实现双线性插值 三次内插法
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from PIL import Image
import matplotlib.pyplot as plt
import numpy as np
import math
def NN_interpolation(img,dstH,dstW):
scrH,scrW,_=img.shape
retimg=np.zeros((dstH,dstW,3),dtype=np.uint8)
for i in range(dstH):
for j in range(dstW):
scrx=round((i+1)*(scrH/dstH))
scry=round((j+1)*(scrW/dstW))
retimg[i,j]=img[scrx-1,scry-1]
return retimg
def BiLinear_interpolation(img,dstH,dstW):
scrH,scrW,_=img.shape
img=np.pad(img,((0,1),(0,1),(0,0)),"constant")
retimg=np.zeros((dstH,dstW,3),dtype=np.uint8)
for i in range(dstH):
for j in range(dstW):
scrx=(i+1)*(scrH/dstH)-1
scry=(j+1)*(scrW/dstW)-1
x=math.floor(scrx)
y=math.floor(scry)
u=scrx-x
v=scry-y
retimg[i,j]=(1-u)*(1-v)*img[x,y]+u*(1-v)*img[x+1,y]+(1-u)*v*img[x,y+1]+u*v*img[x+1,y+1]
return retimg
def BiBubic(x):
x=abs(x)
if x<=1:
return 1-2*(x**2)+(x**3)
elif x<2:
return 4-8*x+5*(x**2)-(x**3)
else:
return 0
def BiCubic_interpolation(img,dstH,dstW):
scrH,scrW,_=img.shape
#img=np.pad(img,((1,3),(1,3),(0,0)),"constant")
retimg=np.zeros((dstH,dstW,3),dtype=np.uint8)
for i in range(dstH):
for j in range(dstW):
scrx=i*(scrH/dstH)
scry=j*(scrW/dstW)
x=math.floor(scrx)
y=math.floor(scry)
u=scrx-x
v=scry-y
tmp=0
for ii in range(-1,2):
for jj in range(-1,2):
if x+ii<0 or y+jj<0 or x+ii>=scrH or y+jj>=scrW:
continue
tmp+=img[x+ii,y+jj]*BiBubic(ii-u)*BiBubic(jj-v)
retimg[i,j]=np.clip(tmp,0,255)
return retimg
im_path="0.jpg"
image=np.array(Image.open(im_path))
image1=NN_interpolation(image,image.shape[0]*2,image.shape[1]*2)
image1=Image.fromarray(image1.astype("uint8")).convert("RGB")
image1.save("n.png")
image2=BiLinear_interpolation(image,image.shape[0]*2,image.shape[1]*2)
image2=Image.fromarray(image2.astype("uint8")).convert("RGB")
image2.save("2.png")
image3=BiCubic_interpolation(image,image.shape[0]*2,image.shape[1]*2)
image3=Image.fromarray(image3.astype("uint8")).convert("RGB")
image3.save("3.png")
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