Class: Informers::ImageFeatureExtractor

Inherits:
FeatureExtractor show all
Defined in:
lib/informers/processors.rb

Instance Attribute Summary

Attributes inherited from FeatureExtractor

#config

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ ImageFeatureExtractor

Returns a new instance of ImageFeatureExtractor.



12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
 
# File 'lib/informers/processors.rb', line 12

def initialize(config)
  super(config)

  @image_mean = @config["image_mean"] || @config["mean"]
  @image_std = @config["image_std"] || @config["std"]

  @resample = @config["resample"] || 2 # 2 => bilinear
  @do_rescale = @config.fetch("do_rescale", true)
  @rescale_factor = @config["rescale_factor"] || (1 / 255.0)
  @do_normalize = @config["do_normalize"]

  @do_resize = @config["do_resize"]
  @do_thumbnail = @config["do_thumbnail"]
  @size = @config["size"]
  @size_divisibility = @config["size_divisibility"] || @config["size_divisor"]

  @do_center_crop = @config["do_center_crop"]
  @crop_size = @config["crop_size"]
  @do_convert_rgb = @config.fetch("do_convert_rgb", true)
  @do_crop_margin = @config["do_crop_margin"]

  @pad_size = @config["pad_size"]
  @do_pad = @config["do_pad"]

  if @do_pad && !@pad_size && @size && !@size["width"].nil? && !@size["height"].nil?
    # Should pad, but no pad size specified
    # We infer the pad size from the resize size
    @pad_size = @size
  end

  @do_flip_channel_order = @config["do_flip_channel_order"] || false
end

Instance Method Details

#call(images, *args) ⇒ Object 



332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
 
# File 'lib/informers/processors.rb', line 332

def call(images, *args)
  if !images.is_a?(Array)
    images = [images]
  end

  image_data = images.map { |x| preprocess(x) }

  # Stack pixel values
  pixel_values = Utils.stack(image_data.map { |x| x[:pixel_values] }, 0)

  {
    pixel_values: pixel_values,

    # Original sizes of images
    original_sizes: image_data.map { |x| x[:original_size] },

    # Reshaped sizes of images, before padding or cropping
    reshaped_input_sizes: image_data.map { |x| x[:reshaped_input_size] }
  }
end

#get_resize_output_image_size(image, size) ⇒ Object 



153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
 
# File 'lib/informers/processors.rb', line 153

def get_resize_output_image_size(image, size)
  src_width, src_height = image.size

  if @do_thumbnail
    # NOTE: custom logic for `Donut` models
    height = size["height"]
    width = size["width"]
    shortest_edge = [height, width].min
  elsif size.is_a?(Numeric)
    shortest_edge = size
    longest_edge = @config["max_size"] || shortest_edge
  elsif !size.nil?
    # Extract known properties from `size`
    shortest_edge = size["shortest_edge"]
    longest_edge = size["longest_edge"]
  end

  if !shortest_edge.nil? || !longest_edge.nil?
    # http://opensourcehacker.com/2011/12/01/calculate-aspect-ratio-conserving-resize-for-images-in-javascript/
    # Try resize so that shortest edge is `shortest_edge` (target)
    short_resize_factor =
      if shortest_edge.nil?
        1 # If `shortest_edge` is not set, don't upscale
      else
        [shortest_edge / src_width.to_f, shortest_edge / src_height.to_f].max
      end

    new_width = src_width * short_resize_factor
    new_height = src_height * short_resize_factor

    # The new width and height might be greater than `longest_edge`, so
    # we downscale again to ensure the largest dimension is `longest_edge`
    long_resize_factor =
      if longest_edge.nil?
        1 # If `longest_edge` is not set, don't downscale
      else
        [longest_edge / new_width.to_f, longest_edge / new_height.to_f].min
      end

    # To avoid certain floating point precision issues, we round to 2 decimal places
    final_width = (new_width * long_resize_factor).round(2).floor
    final_height = (new_height * long_resize_factor).round(2).floor

    if !@size_divisibility.nil?
      raise Todo
    end
    [final_width, final_height]
  elsif !size.nil? && !size["width"].nil? && !size["height"].nil?
    new_width = size["width"]
    new_height = size["height"]

    if @config["keep_aspect_ratio"] && @config["ensure_multiple_of"]
      raise Todo
    end

    [new_width, new_height]
  else
    raise Todo
  end
end

#pad_image(pixel_data, img_dims, pad_size, mode: "constant", center: false, constant_values: 0) ⇒ Object 



67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
 
# File 'lib/informers/processors.rb', line 67

def pad_image(
  pixel_data,
  img_dims,
  pad_size,
  mode: "constant",
  center: false,
  constant_values: 0
)
  image_height, image_width, image_channels = img_dims

  if pad_size.is_a?(Numeric)
    padded_image_width = pad_size
    padded_image_height = pad_size
  else
    padded_image_width = pad_size[:width] || pad_size["width"]
    padded_image_height = pad_size[:height] || pad_size["height"]
  end

  # Only add padding if there is a difference in size
  if padded_image_width != image_width || padded_image_height != image_height
    padded_pixel_data = Array.new(padded_image_width * padded_image_height * image_channels)
    if constant_values.is_a?(Array)
      # Fill with constant values, cycling through the array
      padded_pixel_data.length.times do |i|
        padded_pixel_data[i] = constant_values[i % image_channels]
      end
    elsif constant_values != 0
      padded_pixel_data.fill(constant_values)
    end

    left, top =
      if center
        [((padded_image_width - image_width) / 2.0).floor, ((padded_image_height - image_height) / 2.0).floor]
      else
        [0, 0]
      end

    # Copy the original image into the padded image
    image_height.times do |i|
      a = (i + top) * padded_image_width
      b = i * image_width
      image_width.times do |j|
        c = (a + j + left) * image_channels
        d = (b + j) * image_channels
        image_channels.times do |k|
          padded_pixel_data[c + k] = pixel_data[d + k]
        end
      end
    end

    if mode == "symmetric"
      if center
        raise Error, "`center` padding is not supported when `mode` is set to `symmetric`."
      end
      h1 = image_height - 1
      w1 = image_width - 1
      padded_image_height.times do |i|
        a = i * padded_image_width
        b = Utils.calculate_reflect_offset(i, h1) * image_width

        padded_image_width.times do |j|
          next if i < image_height && j < image_width # Do not overwrite original image
          c = (a + j) * image_channels
          d = (b + Utils.calculate_reflect_offset(j, w1)) * image_channels

          # Copy channel-wise
          image_channels.times do |k|
            padded_pixel_data[c + k] = pixel_data[d + k]
          end
        end
      end
    end

    # Update pixel data and image dimensions
    pixel_data = padded_pixel_data
    img_dims = [padded_image_height, padded_image_width, image_channels]
  end
  [pixel_data, img_dims]
end

#preprocess(image, do_normalize: nil, do_pad: nil, do_convert_rgb: nil, do_convert_grayscale: nil, do_flip_channel_order: nil) ⇒ Object 



219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
 
# File 'lib/informers/processors.rb', line 219

def preprocess(
  image,
  do_normalize: nil,
  do_pad: nil,
  do_convert_rgb: nil,
  do_convert_grayscale: nil,
  do_flip_channel_order: nil
)
  if @do_crop_margin
    # NOTE: Specific to nougat processors. This is done before resizing,
    # and can be interpreted as a pre-preprocessing step.
    image = crop_margin(image)
  end

  src_width, src_height = image.size # original image size

  # Convert image to RGB if specified in config.
  if !do_convert_rgb.nil? ? do_convert_rgb : @do_convert_rgb
    image = image.rgb
  elsif do_convert_grayscale
    image = image.grayscale
  end

  # Resize all images
  if @do_resize
    image = resize(image)
  end

  # Resize the image using thumbnail method.
  if @do_thumbnail
    image = thumbnail(image, @size, @resample)
  end

  if @do_center_crop
    if @crop_size.is_a?(Integer)
      crop_width = @crop_size
      crop_height = @crop_size
    else
      crop_width = @crop_size["width"]
      crop_height = @crop_size["height"]
    end
    image = image.center_crop(crop_width, crop_height)
  end

  reshaped_input_size = [image.height, image.width]

  # NOTE: All pixel-level manipulation (i.e., modifying `pixelData`)
  # occurs with data in the hwc format (height, width, channels),
  # to emulate the behavior of the original Python code (w/ numpy).
  pixel_data = image.data
  img_dims = [image.height, image.width, image.channels]

  if @do_rescale
    rescale(pixel_data)
  end

  if !do_normalize.nil? ? do_normalize : @do_normalize
    image_mean = @image_mean
    if !@image_mean.is_a?(Array)
      image_mean = new Array(image.channels) { image_mean }
    end

    image_std = @image_std
    if !@image_std.is_a?(Array)
      image_std = new Array(image.channels) { image_std }
    end

    if image_mean.length != image.channels || image_std.length != image.channels
      raise Error, "When set to arrays, the length of `image_mean` (#{image_mean.length}) and `image_std` (#{image_std.length}) must match the number of channels in the image (#{image.channels})."
    end

    i = 0
    while i < pixel_data.length
      image.channels.times do |j|
        pixel_data[i + j] = (pixel_data[i + j] - image_mean[j]) / image_std[j]
      end
      i += image.channels
    end
  end

  # do padding after rescaling/normalizing
  if !do_pad.nil? ? do_pad : @do_pad
    if @pad_size
      padded = pad_image(pixel_data, [image.height, image.width, image.channels], @pad_size)
      pixel_data, img_dims = padded # Update pixel data and image dimensions
    elsif @size_divisibility
      raise Todo
    end
  end

  if !do_flip_channel_order.nil? ? do_flip_channel_order : @do_flip_channel_order
    raise Todo
  end

  # convert to channel dimension format (hwc -> chw)
  h, w, c = img_dims
  pixel_values =
    c.times.map do |ci|
      h.times.map do |hi|
        w.times.map do |wi|
          index = (hi * w * c) + (wi * c) + ci
          pixel_data[index]
        end
      end
    end

  {
    original_size: [src_height, src_width],
    reshaped_input_size: reshaped_input_size,
    pixel_values: pixel_values
  }
end

#rescale(pixel_data) ⇒ Object 



147
148
149
150
151
 
# File 'lib/informers/processors.rb', line 147

def rescale(pixel_data)
  pixel_data.length.times do |i|
    pixel_data[i] *= @rescale_factor
  end
end

#resize(image) ⇒ Object 



214
215
216
217
 
# File 'lib/informers/processors.rb', line 214

def resize(image)
  new_width, new_height = get_resize_output_image_size(image, @size)
  image.resize(new_width, new_height, resample: @resample)
end

#thumbnail(image, size, resample = 2) ⇒ Object 



45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
 
# File 'lib/informers/processors.rb', line 45

def thumbnail(image, size, resample = 2)
  input_height = image.height
  input_width = image.width

  output_height = size["height"]
  output_width = size["width"]

  # We always resize to the smallest of either the input or output size.
  height = [input_height, output_height].min
  width = [input_width, output_width].min

  if height == input_height && width == input_width
    return image
  end
  if input_height > input_width
    width = (input_width * height / input_height).floor
  elsif input_width > input_height
    height = (input_height * width / input_width).floor
  end
  image.resize(width, height, resample:)
end