Color space transformation

1. Color space transformation Phase 2 <Hani Samara ; Heiko Westphal> 24.11.2011 Institute MD, University of Rostock

2. Origin (Old Design): • Frequency: 38.109 MHz • Area (LUT FF pairs): 3641

3. Improvents to do • Decrease Error • Decrease Size • Increase Speed

4. Improvents to do • Decrease Error  Round, coefficient correction • Decrease Size • Increase Speed

5. Improvents to do • Decrease Error  Round, coefficient correction • Decrease Size • Increase Speed Optimize Multiplier

6. Error Decresing • Previous: Output signal just been cut off to match output witdthExample:…0101100|110010…  …0101100110010…  Error 0,78125 • Solution: Check first cut-off bit, if it is ‘1’ add ‘1’ to output signal…0101100|110010…  …0101101110010…  Error 0,21875 • coefficient correction: coefficient cb(2) and cr (0) which are both b"001111_11111111_11111111" should be actually b"000000_00000000_00000000“ •  New average error: 0.249936

7. A better multiplier • Using of an array multiplier • Add partial products with single FAs insteads full width adders  shorter critical path

8. Further Improvements • Due to coefficient correction: Save of a multiplier in CB and CR: • multiplication with 2^x means shifting • Adding two pipeline steps

9. Example: Cb-Computation • 2 Multipliers • 3 Adders • 2 Two’s Complements Rst REG 1 Mult1 NOT Coeff_0 Pixel_in_r REG 2 add1 Round Mult2 Coeff_1 NOT add3 Cb-Component Pixel_in_g Shift add2 Pixel_in_b Offset increased by 2 • CLK

10. Result of improvements/New Metric • Frequency: 75.477 MHz • Area (LUT FF pairs): 1312

11. Thank you for your attention!