Add Java and Python code for cascade classifier and HDR tutorials.

2026-07-29 15:23:05 +04:00 · 2018-06-07 20:14:16 +02:00
parent 1187a7fa34
commit afa5b0cc93
13 changed files with 557 additions and 100 deletions
@@ -126,9 +126,9 @@ Result looks like below:
 Additional Resources
 --------------------

-#  Video Lecture on [Face Detection and Tracking](http://www.youtube.com/watch?v=WfdYYNamHZ8)
-2.  An interesting interview regarding Face Detection by [Adam
-    Harvey](http://www.makematics.com/research/viola-jones/)
+-#  Video Lecture on [Face Detection and Tracking](https://www.youtube.com/watch?v=WfdYYNamHZ8)
+-#  An interesting interview regarding Face Detection by [Adam
+    Harvey](https://web.archive.org/web/20171204220159/http://www.makematics.com/research/viola-jones/)

 Exercises
 ---------
@@ -27,7 +27,7 @@ merged, it has to be converted back to 8-bit to view it on usual displays. This
 tonemapping. Additional complexities arise when objects of the scene or camera move between shots,
 since images with different exposures should be registered and aligned.

-In this tutorial we show 2 algorithms (Debvec, Robertson) to generate and display HDR image from an
+In this tutorial we show 2 algorithms (Debevec, Robertson) to generate and display HDR image from an
 exposure sequence, and demonstrate an alternative approach called exposure fusion (Mertens), that
 produces low dynamic range image and does not need the exposure times data.
 Furthermore, we estimate the camera response function (CRF) which is of great value for many computer
@@ -65,14 +65,14 @@ exposure_times = np.array([15.0, 2.5, 0.25, 0.0333], dtype=np.float32)
 ### 2. Merge exposures into HDR image

 In this stage we merge the exposure sequence into one HDR image, showing 2 possibilities
-which we have in OpenCV. The first method is Debvec and the second one is Robertson.
+which we have in OpenCV. The first method is Debevec and the second one is Robertson.
 Notice that the HDR image is of type float32, and not uint8, as it contains the
 full dynamic range of all exposure images.

@code{.py}
 # Merge exposures to HDR image
-merge_debvec = cv.createMergeDebevec()
-hdr_debvec = merge_debvec.process(img_list, times=exposure_times.copy())
+merge_debevec = cv.createMergeDebevec()
+hdr_debevec = merge_debevec.process(img_list, times=exposure_times.copy())
 merge_robertson = cv.createMergeRobertson()
 hdr_robertson = merge_robertson.process(img_list, times=exposure_times.copy())
@endcode
@@ -86,7 +86,7 @@ we will later have to clip the data in order to avoid overflow.
@code{.py}
 # Tonemap HDR image
 tonemap1 = cv.createTonemapDurand(gamma=2.2)
-res_debvec = tonemap1.process(hdr_debvec.copy())
+res_debevec = tonemap1.process(hdr_debevec.copy())
 tonemap2 = cv.createTonemapDurand(gamma=1.3)
 res_robertson = tonemap2.process(hdr_robertson.copy())
@endcode
@@ -111,11 +111,11 @@ integers in the range of [0..255].

@code{.py}
 # Convert datatype to 8-bit and save
-res_debvec_8bit = np.clip(res_debvec*255, 0, 255).astype('uint8')
+res_debevec_8bit = np.clip(res_debevec*255, 0, 255).astype('uint8')
 res_robertson_8bit = np.clip(res_robertson*255, 0, 255).astype('uint8')
 res_mertens_8bit = np.clip(res_mertens*255, 0, 255).astype('uint8')

-cv.imwrite("ldr_debvec.jpg", res_debvec_8bit)
+cv.imwrite("ldr_debevec.jpg", res_debevec_8bit)
 cv.imwrite("ldr_robertson.jpg", res_robertson_8bit)
 cv.imwrite("fusion_mertens.jpg", res_mertens_8bit)
@endcode
@@ -127,9 +127,9 @@ You can see the different results but consider that each algorithm have addition
 extra parameters that you should fit to get your desired outcome. Best practice is
 to try the different methods and see which one performs best for your scene.

-### Debvec:
+### Debevec:

-![image](images/ldr_debvec.jpg)
+![image](images/ldr_debevec.jpg)

 ### Robertson:

@@ -150,9 +150,9 @@ function and use it for the HDR merge.

@code{.py}
 # Estimate camera response function (CRF)
-cal_debvec = cv.createCalibrateDebevec()
-crf_debvec = cal_debvec.process(img_list, times=exposure_times)
-hdr_debvec = merge_debvec.process(img_list, times=exposure_times.copy(), response=crf_debvec.copy())
+cal_debevec = cv.createCalibrateDebevec()
+crf_debevec = cal_debevec.process(img_list, times=exposure_times)
+hdr_debevec = merge_debevec.process(img_list, times=exposure_times.copy(), response=crf_debevec.copy())
 cal_robertson = cv.createCalibrateRobertson()
 crf_robertson = cal_robertson.process(img_list, times=exposure_times)
 hdr_robertson = merge_robertson.process(img_list, times=exposure_times.copy(), response=crf_robertson.copy())
@@ -166,12 +166,12 @@ For this sequence we got the following estimation:
 Additional Resources
 --------------------

-1. Paul E Debevec and Jitendra Malik. Recovering high dynamic range radiance maps from photographs. In ACM SIGGRAPH 2008 classes, page 31. ACM, 2008.
-2. Mark A Robertson, Sean Borman, and Robert L Stevenson. Dynamic range improvement through multiple exposures. In Image Processing, 1999. ICIP 99. Proceedings. 1999 International Conference on, volume 3, pages 159–163. IEEE, 1999.
-3. Tom Mertens, Jan Kautz, and Frank Van Reeth. Exposure fusion. In Computer Graphics and Applications, 2007. PG'07. 15th Pacific Conference on, pages 382–390. IEEE, 2007.
+1. Paul E Debevec and Jitendra Malik. Recovering high dynamic range radiance maps from photographs. In ACM SIGGRAPH 2008 classes, page 31. ACM, 2008. @cite DM97
+2. Mark A Robertson, Sean Borman, and Robert L Stevenson. Dynamic range improvement through multiple exposures. In Image Processing, 1999. ICIP 99. Proceedings. 1999 International Conference on, volume 3, pages 159–163. IEEE, 1999. @cite RB99
+3. Tom Mertens, Jan Kautz, and Frank Van Reeth. Exposure fusion. In Computer Graphics and Applications, 2007. PG'07. 15th Pacific Conference on, pages 382–390. IEEE, 2007. @cite MK07
 4. Images from [Wikipedia-HDR](https://en.wikipedia.org/wiki/High-dynamic-range_imaging)

 Exercises
 ---------
-1. Try all tonemap algorithms: [Drago](http://docs.opencv.org/master/da/d53/classcv_1_1TonemapDrago.html), [Durand](http://docs.opencv.org/master/da/d3d/classcv_1_1TonemapDurand.html), [Mantiuk](http://docs.opencv.org/master/de/d76/classcv_1_1TonemapMantiuk.html) and [Reinhard](http://docs.opencv.org/master/d0/dec/classcv_1_1TonemapReinhard.html).
-2. Try changing the parameters in the HDR calibration and tonemap methods.
+1. Try all tonemap algorithms: cv::TonemapDrago, cv::TonemapDurand, cv::TonemapMantiuk and cv::TonemapReinhard
+2. Try changing the parameters in the HDR calibration and tonemap methods.