3D品質評価法

2.3D映像評価に関する標準化動向

2.1.ITUにおける品質評価法の国際標準化動向

(2)ITU-R勧告 BT.1483

3D映像の主観評価法に関する代表的な勧告として、ITU-R勧告BT.1483があります。評価法自体はITU-R勧告BT.500に準拠し、品質評価に対する基準映像が利用可能な場合はDSCQS法、DSIS法を、基準映像が利用できない場合はACR法を利用することが推奨されています。また、評価環境として輻輳と調節が対応することを考慮し、a) 被写界深度:+-0.3Diopter (+-0.9度程度) 、b) 視距離:HDTVは3H、 SDTVは6H(Hは画面高)を満たすことが規定されています。さらに、本勧告では次の3種類の評価映像チャートが提供されています。


【1】視機能チャート

評価者のスクリーニングを目的とした人間の立体視の機能を検査するチャート(下表参照)。全てに合格することが望まれますが、簡易にはNo.4と立体視力とNo.7の動態立体視力の合格が望まれます。

No. Item Test for Content
1 Simultaneous perception The ability to perceive dichoptically presented images simultaneously and in the correct position A cage image is presented to one eye and a lion image to the other eye
2 Binocular fusion The ability to perceive two dichoptic images in left and right eyes as one image The image for one eye has two dots, and the image for the other eye has three dots, with one dot in common
3 Coarse stereopsis pictures The ability to perceive dichoptically presented images with a parallax as one image with a coarse depth The image for two eyes are a stereopair of images of a dragonfly with its wings spreading
4 Fine stereopsis The ability to perceive dichoptically presented images with a parallax as one image with a fine depth Nine test lozenge patches are provided and each of them has four circles in which one circle has a small parallax
5 Crossed fusion limit The ability to perceive dichoptically presented images with crossed disparities as one image A stereopair of bars is presented with its crossed parallax changing by 10¢/s
6 Uncrossed fusional limit The ability to perceive dichoptically presented images with uncrossed disparities as one image A stereopair of bars is presented with its uncrossed parallax changing by 11¢/s
7 Dynamic stereopsis The ability to perceive depth in moving random dot stereogram images Dynamic random dot stereogram
8 Binocular acuity The binocular acuity, including any imbalance of monocular acuity which might prevent good stereopsis E characters with a variety of orientation and size
9 Horizontal strabismus The horizontal deviation of the eye which the patient cannot overcome Vertical and horizontal lines
10 Vertical strabismus The vertical deviation of the eye which the patient cannot overcome Vertical and horizontal lines
11 Aniseikonia A condition in which the ocular image of an object as seen by one eye differs in size and shape from that seen by the other The left image consists of the characters "[o" and the right consists of the characters "o]" where the "o" character position is common
12 Cyclophoria The deviation of one eye or the other around the anteroposterior axis when fusion is prevented The left image consists of the face of a clock and the right consists of the hands of a clock at six o'clock
【2】自然画チャート(静止画)

立体映像表示装置や立体画像の画質等の評価を目的とする、12種類の静止画チャートが提供されています(下表参照)。

No. Title Content Representative of Major factors to be assessed
1 Autumn tints Red autumnal momiji leaves against the light Outdoor shooting Still and depth resolution
2 Autumn tints and Buddhist temple A scene with pure red momiji leaves in direct light, and a Buddhist temple in the background Outdoor shooting Still and depth resolution
3 Attractive Japanese kimono in a Buddhist temple Woman dressed in kimono with Daikakuji temple in the background Outdoor shooting Still and depth resolution
4 Autumn leaves Woman dressed in kimono in a Japanese garden filled with autumn leaves Outdoor shooting Still and depth resolution
5 Sky Scenery of trees with leaves in autumn tints Outdoor shooting Still and depth resolution
6 Under the shade of a tree Woman in a grove dressed in kimono Outdoor shooting Still and depth resolution
7 By the side of the autumn tints Woman dressed in kimono and autumn tints in the temple grounds Outdoor shooting Still and depth resolution
8 Japanese garden Autumn tinted Eikando garden Outdoor shooting Still and depth resolution
9 Beauty in kimono Autumn tints and a lady dressed in kimono Outdoor shooting Still and depth resolution
10 City scenery 1 Modern building and woman Outdoor shooting Still and depth resolution
11 City scenery 2 Artificial waterfall and woman Outdoor shooting Still and depth resolution
12 City scenery 3 A building promenade and woman Outdoor shooting Still and depth resolution
13 In my room 1 Woman at ease in her room Studio production Still and depth resolution
14 In my room 2 Woman at ease in her room Studio production Still and depth resolution
15 Dining Scenery of a woman at a dining table Studio production Still and depth resolution
【3】自然画チャート(動画)

立体映像表示装置や立体画像の画質等の評価を目的とする15種類の動画チャート(下表参照)。1920×1035の有効画素数で撮影された各15秒のシーケンスです。評価要素としては、奥行方向の解像度、前後方向の動きのスムーズさ、立体画像の空間の歪が挙げられます。

現在、このチャートは映像メディア学会から頒布されています。詳細は、以下のURLをご覧ください。
http://www.ite.or.jp/data/p_t/test_chart/?mode=disp&key=7

No. Title Content Representative of Major factors to be assessed Motion Focal length (mm) Keystone distortion
1 Tulip garden A girl walking in a tulip garden Outdoor shooting Still and depth resolution Slow 40 No*
2 Festival A portable shrine and paper storm Outdoor shooting Still and depth resolution Slow 12 No*
3 Portable shrines Portable shrines carried out Outdoor shooting Still and depth resolution Slow pan 20 No*
4 Crossing ships Crossing ships and audience Outdoor shooting Depth motion Slow pan 40 No*
5 Red leaves A woman and red leaves Outdoor shooting Depth motion Medium 12 No*
6 Botanical gardens Waterfall in botanical gardens Outdoor shooting Orthostereoscopy Fixed 12 No*
7 Living room A woman sitting on a sofa Studio production Orthostereoscopy Fixed 12 No*
8 A meal People around a meal on a table Studio production Orthostereoscopy Fixed 12 No*
9 Amusement park Girls playing in an amusement park Outdoor shooting Depth motion Medium 12 No*
10 Football A football game Outdoor shooting Depth motion and resolution Medium 12 No*
11 A vocalist A vocalist in a hall Studio production Orthostereoscopy Fixed 12 No*
12 Chromakey A woman and flowers Studio production Chromakey Fixed 12 No*
13 Flower pot A girl and flower pot Outdoor shooting Depth motion Medium 12 Yes
14 An aquarium Tropical fish in an aquarium Outdoor shooting Depth motion Fixed 12 Yes
15 Flower garden A girl walking in a flower garden Outdoor shooting Depth motion and resolution Slow 12 Yes