called ▁accum ulator ▁space ▁that ▁is ▁explicitly ▁constructed ▁by ▁the ▁algorithm ▁for ▁computing ▁the ▁H ough ▁transform . ▁ ▁The ▁classical ▁H ough ▁transform ▁was ▁concerned ▁with ▁the ▁identification ▁of ▁lines ▁in ▁the ▁image , ▁but ▁later ▁the ▁H ough ▁transform ▁has ▁been ▁extended ▁to ▁ident ifying ▁positions ▁of ▁arbitrary ▁shapes , ▁most ▁commonly ▁circles ▁or ▁elli ps es . ▁The ▁H ough ▁transform ▁as ▁it ▁is ▁univers ally ▁used ▁today ▁was ▁invent ed ▁by ▁Richard ▁D uda ▁and ▁Peter ▁Hart ▁in ▁ 1 9 7 2 , ▁who ▁called ▁it ▁a ▁" general ized ▁H ough ▁transform " ▁after ▁the ▁related ▁ 1 9 6 2 ▁pat ent ▁of ▁Paul ▁H ough . ▁The ▁transform ▁was ▁popular ized ▁in ▁the ▁computer ▁vision ▁community ▁by ▁D ana ▁H . ▁Ball ard ▁through ▁a ▁ 1 9 8 1 ▁journal ▁article ▁titled ▁" General izing ▁the ▁H ough ▁transform ▁to ▁detect ▁arbitrary ▁shapes ". ▁ ▁History ▁▁ ▁It ▁was ▁initially ▁invent ed ▁for ▁machine ▁analysis ▁of ▁b ubble ▁chamber ▁photograph s ▁( H ough , ▁ 1 9 5 9 ). ▁ ▁The ▁H ough ▁transform ▁was ▁pat ented ▁as ▁ ▁in ▁ 1 9 6 2 ▁and ▁assigned ▁to ▁the ▁U . S . ▁At omic ▁Energy ▁Commission ▁with ▁the ▁name ▁" Method ▁and ▁Me ans ▁for ▁Rec ogn izing ▁Complex ▁Pattern s ". ▁ ▁This ▁pat ent ▁uses ▁a ▁slope - inter cept ▁paramet riz ation ▁for ▁straight ▁lines , ▁which ▁awk ward ly ▁ ▁leads ▁to ▁an ▁un bounded ▁transform ▁space