عڪس هسٽونامو

Wikipedia طرفان

ڳڻپيوڪر چٽيات يعني Computer Graphics ۾، رنگ هسٽونامو يا Image Histogram ڪنهن عڪس جي هڪ اهڙي نمائندگي آهي جيڪا هر عڪسل جو 'رنگ' ڳڻڻ سان جڙندي آهي. اهو خيال مائيڪل سوين ۽ ڊانا بالرڊ 1991ع ۾ پيش ڪيو. عڪس هسٽونامو خاص طور اتي استعمال ٿيندو آهي جتي الخوارضميءَ جي چونڊ ۾ پراسيسڪاريءَ جي رفتار هڪ خاص فيڪٽر هجي.

هڪ سليٽي پيما عڪس

, or where a specific object, rather than a more abstract class of objects is required to be identified; as noted by Swain and Ballard, "It may not be helpful to model coffee cups as being red and white, but yours may be."

رنگ هسٽوناما لچڪدار ڪنسٽرڪٽ آهن، جيڪي متفرق رنگ پولار، جهڙوڪ ڳسن، ڳس-ڪروميٽيسٽي يا ڪو ٻيو رنگ پولار رکندڙ عڪسن لاءِ جوڙي سگھجن ٿا. هسٽونامو ڪنهن ڪاري اڇي عڪس سليٽي پيما عڪس جو به جوڙي سگھجي ٿو.

ڪنهن عڪس جو هسٽونامو جوڙڻ لاءِ عڪس اندر هر رنگي عدد رکندڙ عڪسلون ڳڻبيون آهن. هسٽونامو جوڙڻ کان اڳ رنگ پولار کي ڊسڪريٽائي به سگھجي ٿو. مثال طور، هيٺين جدول ڏسندا، جيڪا هتي ڏنل تصوير جو هسٽونامو ڏيکاري ٿي.

		red
		0-63	64-127	128-191	192-255
blue	0-63	43	78	18	0
	64-127	45	67	33	2
	128-191	127	58	25	8
	192-255	140	47	47	13

This provides a far more compact overview of the data in an image than knowing the exact value of every pixel. The color histogram of an image is invariant with translation and rotation about the viewing axis, and varies only slowly with the angle of view. This makes the color histogram particularly suited to recognising an object of unknown position and rotation within a scene. Importantly, translation of an RGB image into the illumination invariant rg-chromaticity space allows the histogram to operate well in varying light levels.

The main drawback of histograms is that the representation is solely dependent of the color of the object being studied. There is no way to distinguish a red and white cup from a red and white plate. Put another way, histogram-based algorithms have no concept of a generic 'cup', and a model of our red and white cup is no use when given an otherwise identical blue and white cup.