JPEG compression level demo

demo/jpg_demo.py

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+import numpy
+import re
+import sys
+import scipy.misc
+import subprocess
+import os.path
+
+import vifp
+import ssim
+import psnr
+import niqe
+import reco
+
+import matplotlib.pyplot as plt
+
+ref_file = 'lena.png'
+dist_file = 'lena_tmp.jpg'
+
+ref = scipy.misc.imread(ref_file, flatten=True).astype(numpy.float32)
+
+quality_values = []
+size_values = []
+vifp_values = []
+ssim_values = []
+psnr_values = []
+niqe_values = []
+reco_values = []
+
+plt.figure(figsize=(8, 8))
+
+for quality in range(0, 101, 1):
+    subprocess.check_call('gm convert %s -quality %d %s'%(ref_file, quality, dist_file), shell=True)
+    file_size = os.path.getsize(dist_file)
+
+    dist = scipy.misc.imread(dist_file, flatten=True).astype(numpy.float32)
+
+    quality_values.append( quality )
+    size_values.append( int(file_size/1024) )
+    vifp_values.append( vifp.vifp_mscale(ref, dist) )
+    ssim_values.append( ssim.ssim_exact(ref/255, dist/255) )
+    psnr_values.append( psnr.psnr(ref, dist) )
+    # niqe_values.append( niqe.niqe(dist/255) )
+    reco_values.append( reco.reco(ref/255, dist/255) )
+
+plt.plot(quality_values, vifp_values, label='VIFP')
+plt.plot(quality_values, ssim_values, label='SSIM')
+# plt.plot(niqe_values, label='NIQE')
+plt.plot(quality_values, reco_values, label='RECO')
+plt.plot(quality_values, numpy.asarray(psnr_values)/100.0, label='PSNR/100')
+plt.legend(loc='lower right')
+plt.xlabel('JPEG Quality')
+plt.ylabel('Metric')
+plt.savefig('jpg_demo_quality.png')
+
+plt.figure(figsize=(8, 8))
+
+plt.plot(size_values, vifp_values, label='VIFP')
+plt.plot(size_values, ssim_values, label='SSIM')
+# plt.plot(size_values, label='NIQE')
+plt.plot(size_values, reco_values, label='RECO')
+plt.plot(size_values, numpy.asarray(psnr_values)/100.0, label='PSNR/100')
+plt.legend(loc='lower right')
+plt.xlabel('JPEG File Size, KB')
+plt.ylabel('Metric')
+plt.savefig('jpg_demo_size.png')
+