運動呈現效果與主觀速率判斷的關係

Abstract

電影與電視所呈現的畫面是活動的視覺映像，透過攝影鏡位的選擇與安排，導演與攝影師有能力以攝影的技巧來影響觀者對拍攝事物所產生的感覺。因此影片畫面所呈現的不只是客觀的真實性，同時也代表攝影師看這件事的角度，包含著一種觀點，如同畫家在畫布上所畫出的圖像包含了藝術家自己的心態一樣。而電視與電影的基本要素是動態影像，運動在影片中是最強的吸引力，電影電視的美即來自於它們的游動性及變化性。因此如何在影片中呈現物體的運動及速度是一項重要的課題，使用不同的呈現方式便可能會影響到對於影片中物體運動的速度判斷。因此本研究的目的即在探討影片媒體所呈現運動的效果，是否會對觀看者的主觀速率判斷產生影響。 本研究採用心理物理學中的定值刺激法，以比較影片中不同表現物體運動方式間的差異。本研究分成三個實驗來探討：實驗一在探討將視點固定於背景與跟隨物體而移動這兩種呈現運動的方式對速率判斷的影響；實驗二在探討物體在Z軸深度方向上，以正面逼近與背離這兩種呈現運動的方式對速率判斷的影響；實驗三則是探討增加殘影的圖形效果，對於受試者判斷物體的運動速率是否會產生影響。實驗結果顯示，當物體固定於畫面中而背景產生相對移動的呈現方式，感覺上物體可能會慢於當物體在畫面中移動，且固定背景及不論是否有格線的呈現方式；當物體在影片中的Z軸方向移動時，物體背離觀者而去的呈現方式，感覺上會快於物體正面逼近的呈現方式，及快於物體在均勻畫面中側向移動的方式；而增加運動殘影的圖像效果在本研究中並不會影響速率的判斷。就研究中所有的呈現方式而言，當物體在Z軸深度方向上背離觀者的呈現方式，在受試者的速度知覺上是最快的；而較有可能產生較慢感覺的是固定物體而背景產生移動的呈現方式，及物體以正面逼近的呈現方式。

The images shown in films and TV programs are dynamic. Directors and cameramen have the power to manipulate viewers’ perception and subjective feelings through shooting angles and the placement of cameras. Images in a movie do not convey the objective reality, but rather the cameraman’s viewpoints, just like a painting reflects more the artist’s mind than the physical world. The central ingredient in the making of the aesthetic value and the psychological power of the film as a medium is its motion or flow of images. So how to present the moving object in the movie is a very important issue in visual communication. Different motion presentations may have an effect on the velocity judgment about the moving object in the movie. Therefore, the aim of this thesis was to investigate the motion presentation effects and the subjective velocity judgment. In this thesis, the method of constant stimuli was used for evaluating different motion presentation effects. Experiment 1 compared the velocity judgment under two conditions in which the camera either fixated on the scene or fixated on the moving object. Experiment 2 compared the velocity judgment between an object moving towards and away from the viewer. Experiment 3 evaluated the effect of adding motion smear to a moving object on its subjective velocity. The results showed that the velocity of a moving object will be perceived slower if the camera view is fixed on the moving object instead of the stationary background regardless of grid texture. A moving-forwards object also appeared to be slower than a moving-away object. Adding motion smear had no significant effect. In all motion presentation effects discussed, given the same physical speed, a moving-away object gave rise to the greatest subjective velocity. Both the moving-forwards and the camera-on-target conditions gave rise to slower subjective velocities in comparison to that in the control.