Apparatus and method of adaptively coding/decoding interlaced shaped material

An apparatus for decoding shape information of an object in video, including a decoding apparatus for interlaced scanning comprising:

• demultiplexing means for demultiplexing input coded data;
• overhead decoding means for decoding overhead information contained in demultiplexed data received from said demultiplexing means;
• coding mode decoding means for decoding coding mode data received from said demultiplexing means;
• switching means for switching coded shape information received from said demultiplexing means according to the coding mode received from said coding mode decoding means;
• frame decoding means for decoding the shape information received via said switching means and motion compensated, previous shape information based upon a frame by using said overhead information;
• field decoding means for decoding the shape information received via said switching means and motion compensated, previous shape information based upon a field by using said overhead information;
• previous shape memory means for storing previous shape information received from said frame decoding means and said field decoding means;
• motion compensation means for receiving motion information from said overhead decoding means and the previous shape information from said previous shape memory means, performing motion compensation, and transmitting a result of the motion compensation to said frame decoding means and said field decoding means;
• and
• shape reconstructing means for receiving the overhead information from said overhead decoding means and reconstructing the shape information received from said frame decoding means and said field decoding means by using said overhead information.

An apparatus for coding interlaced shape information comprising:

• binary alpha block (BAB) division means for dividing the binary shape information into BABs of a predetermined size;
• coding mode determining means for determining whether to code said BAB received from said BAB division means based upon a frame or a field;
• switching means for switching said BAB received from said BAB division means according to a coding mode signal produced by said coding mode determining means;
• motion estimation means for estimating motion from said BAB received from said BAB division means and a previous BAB according to a coding mode received from said coding mode determining means;
• motion compensation means for compensating the current BAB for the motion by using motion information received from said motion estimation means and the previous BAB;
• frame type coding means for receiving said BAB via said switching means and a motion compensated BAB from said motion compensation means and coding the BAB using the motion compensated BAB in unit of frame type;
• field type coding means for receiving said BAB via said switching means and the motion compensated BAB from said motion compensation means and coding the BAB using the motion compensated BAB in unit of field type;
• shape reconstructing means for reconstructing the shape information from the BAB received from said frame type coding means and the field type coding means;
• previous shape memory means for storing the reconstructed shape information received from said shape reconstructing means;
• overhead coding means for creating overhead information from the motion information received from said motion estimation means and the data received from said frame coding means and said field coding means;
• and
• multiplexing means for multiplexing the coded data received from said frame coding means and said field coding means and said overhead information received from said overhead coding means before transmission.

A method for adaptively coding shape information by using characteristics of the shape information in case of interlaced video, including an adaptive interlaced shape information coding method comprising the steps of:

• performing motion compensation with respect to a binary alpha block by using previous frame information;
• determining a type of said binary alpha block based upon the result of motion estimation;
• when said binary alpha block is determined to be a type which does not need to be coded, coding and transmitting date indicating the type;
• when said binary alpha block is type which needs to be coded, determining whether to subject said binary alpha block to frame type coding or to field type coding according to said estimated amount of motion;
• subjecting said binary alpha block to frame-based coding and transmitting the coded binary alpha block when the frame type coding is determined;
• and
• subjecting said binary alpha block to field-based coding and transmitting the coded binary alpha block when the field type coding is determined;
• and wherein a following formula is used to determine whether to subject said binary alpha block to the frame type coding or to the field type coding according to said estimated amount of motion, so said binary alpha block is determined to be subjected to the field type coding if a left value is larger than a right value in the formula and, alternatively, said binary alpha block is determined to be the subjected to the frame type coding if the left value is less than the right value in the formula:
• ∑ i = 0 6 ⁢ ∑ j = 0 15 ⁢ ( A + B ) ⁢ ∑ i = 0 6 ⁢ ∑ j = 0 15 ⁢ ( C + D )
• if(P(2i,j)≠P(2+1,j)), A=1, otherwise, A=0
• if(P(2i+1,j)≠P(2i+2,j)), B=1, otherwise, B=0
• if(P(2i,j)≠P(2i+2,j)), C=1, otherwise, C=0
• if(P(2i+1,j)≠P(i2+3,j), D=1, otherwise, D=0
• where P(i,j) is binary shape information data.