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diff --git a/chapters/image.adoc b/chapters/image.adoc new file mode 100644 index 0000000..1e8974c --- /dev/null +++ b/chapters/image.adoc @@ -0,0 +1,86 @@ +// +// This confidential and proprietary software may be used only as +// authorised by a licensing agreement from ARM Limited +// (C) COPYRIGHT 2020 ARM Limited +// ALL RIGHTS RESERVED +// The entire notice above must be reproduced on all authorised +// copies and copies may only be made to the extent permitted +// by a licensing agreement from ARM Limited. + +=== Image Operators + +==== RESIZE + +Resizes a tensor. Resize is only allowed in the H and W dimensions. In expected use, stride_y is approximately (IH<<shift)/OH and stride_x is approximately (IW<<shift)/OW. OH and OW are also supplied as inputs since there may be off by one errors if calculating OH and OW from the strides. + +*Arguments:* + +|=== +|Argument|Type|Name|Shape|Description + +|Input|in_t*|input|[N,IH,IW,C]|Input tensor +|Attribute|int*|output_size|[2]|[OH,OW] +|Attribute|int16*|stride|[2]|[stride_y, stride_x] +|Attribute|int16*|offset|[2]|[offset_y, offset_x] +|Attribute|int|shift|Shift value +|Attribute|mode_t|mode|-|BILINEAR or NEAREST +|Output|out_t*|output|[N,OH,OW,C]|Output tensor +|=== + +*Quantization Parameters:* + +None + +*Operation Function* + +[source,c] +---- +assert(0<shift && shift<=11); // prevent int32_t accumulator overflow for in_t==int8_t +assert(-stride_y < offset_y && offset_y < (IH<<shift)-(OH-1)*stride_y) +assert(-stride_x < offset_x && offset_x < (IH<<shift)-(OW-1)*stride_x) +for_each (0<=n<N, 0<=oy<OH, 0<=ox<OW; 0<=c<C) { + y = oy * stride_y + offset_y + x = ox * stride_x + offset_x + iy = y >> shift; dy = y - (iy<<shift); + ix = x >> shift; dx = x - (ix<<shift); + iy0 = apply_max(iy,0); + iy1 = apply_mix(iy,IW-1); + ix0 = apply_max(ix,0); + ix1 = apply_min(ix,IH-1); + if (mode==BILINEAR) { + v00 = tensor_read<in_t>(input, [N,IH,IW,C], [n,iy0,ix0,c]) + v01 = tensor_read<in_t>(input, [N,IH,IW,C], [n,iy0,ix1,c]) + v10 = tensor_read<in_t>(input, [N,IH,IW,C], [n,iy1,ix0,c]) + v11 = tensor_read<in_t>(input, [N,IH,IW,C], [n,iy1,ix1,c]) + acc_t acc = v00*((1<<shift)-dy)*((1<<shift)-dx) + acc = acc + v01*((1<<shift)-dy)*dx + acc = acc + v10*dy*((1<<shift)-dx) + acc = acc + v11*dy*dx + tensor_write<acc_t>(output, [N,OH,OW,C], [n,oy,ox,c], acc) + } else if (mode==NEAREST) { + iy = (dy>>(shift-1))!=0 ? iy1 : iy0; + ix = (dx>>(shift-1))!=0 ? ix1 : ix0; + v = tensor_read<in_t>(input, [N,IH,IW,C], [n,iy,ix,c]); + tensor_write<acc_t>(output, [N,OH,OW,C], [n,oy,ox,c], v) + } +} +---- + +*Supported Data Types:* + +|=== +|Profile|Mode|in_t|out_t + +|Any|signed 8, bilinear|int8|int32 +|Any|signed 8, nearest |int8|int8 +|Any|signed 16, bilinear|int16|int48 +|Any|signed 16, nearest |int16|int16 +|=== + +*Scaling Modes:* +|=== +|Mode|Description + +|NEAREST|Nearest Neighbor +|BILINEAR|Bilinear interpoloation +|=== |