Kansai Factors in Talking Image Effect of Digital Compressed Images

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Talking Image Effect (TIE) of digital compressed video images was evaluated in this research. MPEG-1 format was used for video image compression and inferior speech recognition method was introduced for the evaluation.Talker's front face image and profile one were recorded and compressed with MPEG-1 encoder. Video bit rate is a parameter that is set at encoding. Encoding with higher video bit rate causes to make bigger file on the storage but it is expected to make higher quality video image. For experiment of this research, 400khs and 4000kbs were used as low video bit rate and high one respectively.Following things were clarified with this experiment.1. From the point of view of TIE, there was no significant difference between high video bit rate compression and low one. Furthermore, analysis on incorrect answer also indicated that there was no significant difference with video bit rate.2. TIE of profile face image is higher than that of front face image for labials.Because the talker's video image was recorded with a chromakey blue backdrop, each image had high spatial and time redundancy. Due to the feature of the algorithm on MPEG-1 encoding, it is easy to make a highly compressed MPEG-1 video image from above high redundant video images. Therefore there might be no difference of image effect with difference of video bit rate.In order to use more complex video image, that is a image with less redundant of time and space, a talking video image overlapped on the CG images was introduced. With using this video image, it was found that the slow effect based on motion of talker's mouth at low video bit rates was much loss than that of at high video bit rate.