Random Crop

README.md

@@ -144,6 +144,32 @@ Horizontally flips the given image.
 
 <tr>
 
+<td style="width: 20%">
+<b><a href="doc/discolight.md#RandomCrop">RandomCrop</a></b>
+<br/>
+Randomly crops the given image.
+</td>
+
+<td style="width: 20%; vertical-align: bottom">
+<img src="doc/images/RandomCrop-input.jpg" width="100px" height="75px" style="display: block; width: 100%"/>
+</td>
+
+<td style="width: 20%; vertical-align: bottom">
+<img src="doc/images/RandomCrop.jpg" width="100px" height="75px" style="display: block; width: 100%"/>
+</td>
+
+<td style="width: 20%; vertical-align: bottom">
+<img src="doc/images/RandomCrop-input-bboxes.jpg" width="100px" height="75px" style="display: block; width: 100%"/>
+</td>
+
+<td style="width: 20%; vertical-align: bottom">
+<img src="doc/images/RandomCrop-bboxes.jpg" width="100px" height="75px" style="display: block; width: 100%"/>
+</td>
+
+</tr>
+
+<tr>
+
 <td style="width: 20%">
 <b><a href="doc/discolight.md#RandomEraser">RandomEraser</a></b>
 <br/>

doc/discolight.md

@@ -358,6 +358,68 @@ The probability that this augmentation will be applied
 
 
 
+## RandomCrop
+
+Randomly crops the given image\.
+
+### Example
+<table style="width: 100%">
+<tr>
+<td><b>Input Image</b></td>
+<td><b>Augmented Image</b></td>
+<td><b>Input Image<br/>(with Bounding Boxes)</b></td>
+<td><b>Augmented Image<br/>(with Bounding Boxes)</b></td>
+</tr>
+<tr>
+<td style="vertical-align: bottom">
+<img src="images/RandomCrop-input.jpg" width="235px" height="176px" style="display: block; width: 100%"/>
+</td>
+
+<td style="vertical-align: bottom">
+<img src="images/RandomCrop.jpg" width="235px" height="176px" style="display: block; width: 100%"/>
+</td>
+
+<td style="vertical-align: bottom">
+<img src="images/RandomCrop-input-bboxes.jpg" width="235px" height="176px" style="display: block; width: 100%"/>
+</td>
+
+<td style="vertical-align: bottom">
+<img src="images/RandomCrop-bboxes.jpg" width="235px" height="176px" style="display: block; width: 100%"/>
+</td>
+
+</tr>
+</table>
+
+### Parameters
+
+
+**max\_height** *(float in range \[0, 1\])* = 0\.7<br/>
+Maximum height of cropped area \(normalized\)
+
+
+
+**max\_width** *(float in range \[0, 1\])* = 0\.7<br/>
+Maximum width of cropped area \(normalized\)
+
+
+
+**probs** *(float in range \[0\.0, 1\.0\])* = 1\.0<br/>
+The probability that this augmentation will be applied
+
+
+
+
+
+Sample image augmented with options:
+```
+max_height: 0.9
+max_width: 0.9
+```
+
+
+
+
+
 ## RandomEraser
 
 Randomly erase a rectangular area in the given image\.

sample.yml

@@ -20,6 +20,7 @@ output:
       annotations_file: ./output_folder/aug_annotations.csv
       normalized: true
 augmentations:
+  - name: RandomCrop
   - name: Sequence
     options:
       augmentations:

src/discolight/augmentations/randomcrop.py

@@ -0,0 +1,86 @@
+"""An augmentation that randomly crops an image."""
+import random
+import cv2
+import numpy as np
+from discolight.params.params import Params
+from .augmentation.types import Augmentation, BoundedNumber
+from .decorators.accepts_probs import accepts_probs
+
+
+def get_bboxes_in_cropped_area(x, y, w, h, bboxlist):
+    """Filter out bounding boxes within the given cropped area."""
+    bboxes = []
+
+    for item in bboxlist:
+        # if xmin is greater or equal to x, if bbox is inside the crop
+        if ((item[0] >= x) and (item[1] >= y) and (item[2] <= (x + w))
+                and (item[3] <= (y + h))):
+            bboxes.append(item)
+        else:
+            continue
+
+    return bboxes
+
+
+@accepts_probs
+class RandomCrop(Augmentation):
+
+    """Randomly crops the given image."""
+
+    def __init__(self, max_width, max_height):
+        """Construct a RandomCrop augmenation.
+
+        You should probably use the augmentation factory or Discolight
+        library interface to construct augmentations. Only invoke
+        this constructor directly if you know what you are doing.
+        """
+        self.max_width = max_width
+        self.max_height = max_height
+
+    @staticmethod
+    def params():
+        """Return a Params object describing constructor parameters."""
+        return Params().add("max_width",
+                            "Maximum width of cropped area (normalized)",
+                            BoundedNumber(float, 0, 1), 0.7).add(
+                                "max_height",
+                                "Maximum height of cropped area (normalized)",
+                                BoundedNumber(float, 0, 1), 0.7)
+
+    def augment(self, img, bboxes, iteration=100):
+        """Augment an image."""
+        if iteration <= 0:
+            raise RuntimeError(
+                "Couldn't find crop that did not keep some bounding boxes.")
+
+        height, width, _ = img.shape
+
+        crop_width = random.randint(0, int(width * self.max_width))
+        crop_height = random.randint(0, int(height * self.max_height))
+
+        x = random.randint(0, crop_width)
+        y = random.randint(0, crop_height)
+        reduced_bboxes = np.array(
+            get_bboxes_in_cropped_area(x, y, crop_width, crop_height, bboxes))
+
+        # if no bbox, get_aug return false; and recall .get_aug
+        if len(reduced_bboxes) == 0 and len(bboxes) > 0:
+            return self.augment(img, bboxes, iteration - 1)
+
+        cropped_img = img[y:y + crop_height, x:x + crop_width]
+
+        # u need the ratio for bounding boxes and images.
+        width_ratio_resize = width / cropped_img.shape[1]
+        height_ratio_resize = img.shape[0] / cropped_img.shape[0]
+        resized_cropped_img = cv2.resize(cropped_img, (width, height))
+
+        reduced_bboxes[:,
+                       [0]] = (reduced_bboxes[:, [0]] - x) * width_ratio_resize
+        reduced_bboxes[:,
+                       [2]] = (reduced_bboxes[:, [2]] - x) * width_ratio_resize
+        reduced_bboxes[:, [1]] = (reduced_bboxes[:, [1]] -
+                                  y) * height_ratio_resize
+        reduced_bboxes[:, [3]] = (reduced_bboxes[:, [3]] -
+                                  y) * height_ratio_resize
+
+        return resized_cropped_img, reduced_bboxes

src/discolight/doc_templates/augmentations/RandomCrop.yml

@@ -0,0 +1,2 @@
+max_height: 0.9
+max_width: 0.9