A little change to demos (#126)

Author: shrubb

demo/LineSegmentDetector.lua

@@ -10,6 +10,11 @@ end
 
 local image = cv.imread{arg[1] or 'demo/data/lena.jpg', cv.IMREAD_GRAYSCALE}
 
+if image:nDimension() == 0 then
+    print('Problem loading image\n')
+    os.exit(0)
+end
+
 local detector = cv.LineSegmentDetector{}
 local lines = detector:detect{image}
 image = detector:drawSegments{image, lines}

demo/denoising.lua

@@ -10,5 +10,10 @@ end
 
 local image = cv.imread{arg[1] or 'demo/data/lena.jpg'}
 
+if image:nDimension() == 0 then
+    print('Problem loading image\n')
+    os.exit(0)
+end
+
 cv.imshow{"Denoised image", cv.fastNlMeansDenoising{image}}
 cv.waitKey{0}

demo/filtering.lua

@@ -10,8 +10,8 @@ end
 
 local image = cv.imread{arg[1] or 'demo/data/lena.jpg'}
 
-if not image then
-    print("Problem loading image\n")
+if image:nDimension() == 0 then
+    print('Problem loading image\n')
     os.exit(0)
 end
 

demo/imshow.lua

@@ -8,5 +8,10 @@ if not arg[1] then
 end
 
 local im = cv.imread {arg[1] or 'demo/data/lena.jpg', cv.IMREAD_GRAYSCALE}
+if im:nDimension() == 0 then
+    print('Problem loading image\n')
+    os.exit(0)
+end
+
 cv.imshow {"Hello, Lua!", im}
 cv.waitKey {0}

demo/inpainting.lua

@@ -12,6 +12,11 @@ end
 local image = cv.imread{arg[1] or 'demo/data/lena.jpg', cv.IMREAD_COLOR}
 local mask = cv.imread{arg[2] or 'demo/data/inpainting/lena_mask.jpg', cv.IMREAD_GRAYSCALE}
 
+if image:nDimension() == 0 or mask:nDimension() == 0 then
+    print('Problem loading image\n')
+    os.exit(0)
+end
+
 cv.namedWindow{"Display"}
 cv.setWindowTitle{"Display", "Image + mask"}
 cv.imshow{"Display", cv.addWeighted{image, 0.5, cv.cvtColor{mask, nil, cv.COLOR_GRAY2BGR}, 0.5, 0}}

demo/descriptors.lua renamed to demo/keypoints.lua

@@ -4,29 +4,29 @@ require 'cv.imgcodecs'
 require 'cv.highgui'
 
 if not arg[1] then
-    print('Usage: `th demo/descriptors.lua path-to-image`')
+    print('`Usage: `th demo/descriptors.lua path-to-image`')
     print('Now using demo/data/lena.jpg')
 end
 
 local image = cv.imread{arg[1] or 'demo/data/lena.jpg'}
 
-if not image then
-    print("Problem loading image\n")
+if image:nDimension() == 0 then
+    print('Problem loading image\n')
     os.exit(0)
 end
 
-cv.namedWindow{"win1"}
-cv.setWindowTitle{"win1", "Original image"}
-cv.imshow{"win1", image}
+cv.namedWindow{'win1'}
+cv.setWindowTitle{'win1', 'Original image'}
+cv.imshow{'win1', image}
 cv.waitKey{0}
 
 local AGAST = cv.AgastFeatureDetector{threshold=34}
 local keyPts = AGAST:detect{image}
 
 -- show keypoints to the user
 local imgWithAllKeypoints = cv.drawKeypoints{image, keyPts}
-cv.setWindowTitle{"win1", keyPts.size .. " keypoints by AGAST"}
-cv.imshow{"win1", imgWithAllKeypoints}
+cv.setWindowTitle{'win1', keyPts.size .. ' keypoints by AGAST'}
+cv.imshow{'win1', imgWithAllKeypoints}
 cv.waitKey{0}
 
 -- remove keypoints within 60 pixels from image border
@@ -35,6 +35,6 @@ keyPts = cv.KeyPointsFilter.runByImageBorder{keyPts, imageSize, 60}
 
 -- show again, with reduced number of keypoints
 local imgWithSomeKeypoints = cv.drawKeypoints{image, keyPts}
-cv.setWindowTitle{"win1", keyPts.size .. " remaining keypoints"}
-cv.imshow{"win1", imgWithSomeKeypoints}
+cv.setWindowTitle{'win1', keyPts.size .. ' remaining keypoints'}
+cv.imshow{'win1', imgWithSomeKeypoints}
 cv.waitKey{0}

demo/stitch.lua

@@ -1,17 +1,17 @@
-local cv = require "cv"
+local cv = require 'cv'
 require 'cv.highgui'
 require 'cv.imgcodecs'
 require 'cv.stitching'
 
-cv.namedWindow{"Display"}
+cv.namedWindow{'Display'}
 
 local imgs = {}
 for i = 1,5 do
-    imgs[i] = cv.imread{"demo/data/stitch/s" .. i .. ".jpg" }
-    cv.imshow{"Display", imgs[i]}
+    imgs[i] = cv.imread{'demo/data/stitch/s' .. i .. '.jpg' }
+    cv.imshow{'Display', imgs[i]}
     cv.waitKey{0}
-    if not imgs[i] then
-        print("Problem with loading image")
+    if imgs[i]:nDimension() == 0 then
+        print('Problem loading image')
         os.exit(0)
     end
 end
@@ -20,12 +20,12 @@ local stitcher = cv.Stitcher{}
 
 local timer = torch.Timer()
 local status, pano = stitcher:stitch{imgs}
-print("Processing time: " .. timer:time().real .. " seconds")
+print('Processing time: ' .. timer:time().real .. ' seconds')
 
-cv.setWindowTitle{"Display", "Panorama"}
+cv.setWindowTitle{'Display', 'Panorama'}
 if status == 0 then
-    cv.imshow{"Display", pano}
+    cv.imshow{'Display', pano}
     cv.waitKey{0}
 else
-    print("Stitching fail")
+    print('Stitching fail')
 end