Inter-Office MemorandumToDistributionDateJuly 29, 1979FromJoe MalesonLocationPalo AltoSubjectStar Jasmine and MimosaOrganizationCSLXEROX Filed on: [MAXC]StarJasmine.PressThis memo discusses the issues involved in using a MARIT detector array with the Jasmine opto-mechanical package to produce a low cost high resolution 4-color scanner (Star Jasmine), and withnew optics and transport to produce a scanner for 35mm slides (Mimosa). The main advantage ofhigher resolution is the ability to zoom in on a small portion of a document or image; currentfacilities preclude storing over 13Mbytes per color, or over 55Mbytes per 4-color page. "StarJasmine" is the name of a plant which is not a Jasmine at all.MARITMARIT is a CCD detector array developed by Bob Sprague (OSL). It has four channels of video;with appropriate color filters these channels provide red, green, blue, and monochrome signals.Each channel is implemented with 8 rows of 1030 CCD elements. When a photon hits a CCDelement, charge is generated. In order to provide a high resolution array (4120 elements), the topfour rows are covered by a staggered aperture mask, and the bottom four rows are completelyshielded from light. The staggered aperture mask covers 3/4 of each CCD element, so that the firstrow contains pixels 0,4,8,...,4116 of one scan line, the second row contains pixels 1,5,9,...,4117 of thenext scan line, and so on.Three clocking signals are used to control the chip. The scan clock shifts the top four rows downone row; the shift clock shifts the bottom four rows down; the data clock shifts the bottom row tothe right, ouputting the charge stored on the rightmost element. Note that shifting into the bottomrow causes charge to be added to the charge already stored there. The bottom row is cleared by1030 (or more) data clocks.In order to permit high speed operation, the aperture masks are rectangular and designed to operatewith anamorphic optics which distend the image 4:1 vertically. Four times more light is incident oneach element using this scheme.JasmineJasmine uses a 1024 element Reticon detector array, implemented with photodiodes and capacitors.The source document is held in a TC200 paper transport and illuminated by an array of tungstenlamps. The optics focus each inch of the document onto 96 detector elements, and a stepper motormoves the document 96 steps/inch. The digital interface provides 8 bits per sample, and willdeliver lower resolution scan lines by undersampling the array.Star Jasmine Mechanical ModificationsHardware modifications may be required to the optics, the MARIT array, the light source, and thestepper motor.]g~p cq]r -q7Br ]q]r -q7Br Yq]r-q 7BrSsr Mq* Jir@ Ha G_-1 EK DU^ B> ?t h Star Jasmine and Mimosa2MARIT's requirement for anamorphic optics is a problem not only because of high cost, but alsobecause the short optical path used in Jasmine will not accomodate cylindrical lens elements.Redesigning the optical path will have many ramifications for packaging. Instead, we can provide96 samples/inch in color with undersampling, time delayed integration, or by removing the aperturemask. Using the standard mask, it would be possible to provide 384 samples/inch across 96scanlines/inch. We can also use a square aperture mask to yield 384 samples/inch in color; thedigital interface will provide samples at a maximum rate 250 kHz, which allows enough integrationtime for the smaller aperture. The stepper motor would need to be geared down 4:1 for 384scanlines/inch. The light source may need to be modified for color, to provide more even poweracross the visible spectrum. The current proposal is to build a prototype unit with unmodified Jasmine optics, and using anunmodified MARIT array. At a later time, we will convert to a square aperture mask on the arrayand a geared down paper transport. Experimentation with various light sources will be possibleusing either the Reticon array with color filters, or a MARIT array. Mimosa RequirementsA great advantage of working with color slides is the increased dynamic range available with atransmissive light path through film. Gary Starkweather (OSL) is designing a new transport inwhich the slide will be mounted horizontally and moved on a lead screw driven by a stepper motor.The resulting mechanical package will be more compact than the Jasmine configuration, but will beable to use identical electronics. Electronics ModificationsMost of the electronics need to be scaled up for the higher resolution and multiple channel features.The one thing that gets easier is maintaining a constant light integration interval. The Reticon lightintegration time for each pixel is the interval between pixel reads; the MARIT integration time foreach scan line is the interval between scan clocks. This provides an opportunity to stop the dataclock when the FIFO is full, an operation that is not possible with the Reticon device.Gain/Offset RAMsJasmine provides 6 bits of gain and 6 bits of offset correction per pixel with 3 1024x4 RAMs (12Kbits). MARIT will require 192K bits of correction, most easily implemented with 12 16Kx1 RAMs.Note that only 3264 out of 4120 elements would be used to image 8.5", so providing only 4096 correction elements perscan line is no problem. Control SignalsThe two signals which control the scanning operation of Jasmine are start and setDelay. Eachpasses 4 bits of data from the controlling processor, skipCount and delayCount respectively. Aftereach start pulse, the Jasmine finite state machine clocks out all samples, digitizing1024/(skipCount+1) of them, and waiting delayCount mseconds after each digitized sample. TheMARIT chip can also be controlled by two signals: start and clock, with data bits skipCount andclockControl. The bits in clockControl are {scan,shift,discardLine}. After each clock pulse, thespecified combination of scan and shift clocks is emitted. After each start pulse all samples areclocked out, digitizing 1030/(skipCount+1) of them if discardLine is zero. Maybe this should be 1024samples clocked out, digitizing 1024/(skipCount+1), in which case the first 6 pixels are garbage due to integration fromprevious scan line. The delay control is provided by replacing the Jasmine DelayDone line (currentlythe carry bit from the delay counter) with the FIFO InputReady signal. This also makes externalcontrol much easier, since the FIFO will almost always be full, and delays in reading out data willnot cause any samples to be lost. The clockControl bit discardLine is used to enable flushing a full or partial scanline withoutreading samples from the FIFO. The state machine input Seq.Sample will be ANDed with frG b,2 `N _E ]Y \ ? Z_ YG W{; UO Tq PqQ NV MgS KE Ht Er1- DQ B@! @(9 ?v$ \Star Jasmine and Mimosa3discardLine', so that no samples will be digitized during the line flush. In order to guarantee thatDelayDone will be true while flushing samples, discardLine' must also be ANDed with ResetCtrs'as imput to the FIFO MasterReset'. Flushing requires about 4msecond per sample, a maximum of4.12mseconds per scanline. DC RestorationAfter the data clock goes low, the Reset line must be clocked high. In the time between the fallingedge of Reset, and the next data clock rising edge, the nominal level for black appears on theoutput pins. This is the period analogous to the Reticon Recharge period, and the same DC restoremust be done.Channel SelectionThe MARIT chip will deliver multiple wavelength samples interleaved. The Jasmine/Mimosainterface will allow any combination of channels to be digitized. An additional control signalSetChannels is provided, with the four data bits indicating which of the four channels are to beused. These four bits are cycled in a shift register at each ScanClk. The shift register output isANDed with the state machine input signal Sample. The two low order address bits are held in aseparate counter, and are used as input to a 4:1 analog multiplexor, gating the appropriate channelto the hold amplifier for A-D conversion. The carry out from this counter provides the data clockto MARIT, and is the additional input bit for the state machine to determine when to do the 4-channel parallel DCRestore and Charge Transfer operations. With this additional input bit, it is necessaryto replace the 512x8 PROM by a 1024x4 or 1024x8 PROM. A 1024x4 will be a slight hassle since there are 5 nextStatebits, the fifth of which will have to come from the 32x8 PROM which only has the currentState bits as inputs. SMOP.The main loop of the state machine becomes:UNTIL ScanDone DO VirScanClk; IF DataClk THEN BEGIN Reset; DCRestore; END; IF Sample THEN BEGIN AnalogOn; --transfer correct element to hold amplifier StartAD; Wait[8]; --8 cycles for A-D to finish END;ENDLOOP;Operating ModesA number of configurations can be supported with the electronics outlined above. The control forsome of these modes is detailed here.Time-Delayed IntegrationUsing the standard MARIT chip with standard Jasmine optics limits the resolution to 96scanlines/inch. To reduce the horizontal resolution to 96 pixels/inch without undersampling, time-delayed integration (TDI) can be used. Essentially, charge is integrated over all four apertures percolumn by clocking both scan and shift once per paper step. During the first scanline time, the toprow of detectors is exposed to some scan line. After a shift and paper motion, the next row ofdetectors is exposed to the first scan line. After four shifts and paper steps, the scan line has beenexposed through all four aperture masks, and is ready to be shifted out. frG bB# `H _"qrvr ]qr Zcu W7rC! UO T-B R O|u LPr$4 J'8 IFu r0% GS F<)ur/ DE C28ur A? @((K =f%O ;r+8x70 54& 2 1/., +<) '+&y $ !t rG % u rV :N R 0urur9 S &b H ` Z>Z:Star Jasmine and Mimosa4--1024x1024 TDI, 96 steps/inDO WaitScanTime[]; clockControl[scan+shift];StepPaper[]; Start[]; ReadScanLineData[];ENDLOOP;--1024x1024 TDI, 384 steps/inDO THROUGH[1..4] DO WaitQuarterScanTime[];StepPaper[]; ENDLOOP; clockControl[scan+shift]; Start[]; ReadScanLineData[];ENDLOOP;UndersamplingThe MARIT resolution can also be reduced to 1024x1024 by only reading out one of the detectorrows.--1024x1024 undersampling, using one detector rowDO WaitScanTime[]; THROUGH[1..4] DO clockControl[scan+shift]; ENDLOOP; StepPaper[]; Start[]; ReadScanLineData[]; --now, clear out shift rows THROUGH[1..3] DO clockControl[shift];ENDLOOP; clockControl[discardLine]; Start[];ENDLOOP;--1024x1024 undersampling, using four detector rowsDO WaitScanTime[]; THROUGH[1..4] DO clockControl[scan+shift]; StepPaper[]; ENDLOOP; FOR i IN [1..4] DO Start[]; ReadScanLineData[row[i]]; ENDLOOP;ENDLOOP;Full ResolutionFull resolution is only possible with a 384 step/inch paper transport. The data will appear instaggered order, and must be destaggered by the controlling processor. frGbx`_](\ ZYUTORQE(O N;L K1I Fu CTr= A>x1=;:87 54 2{0/q0-,g *'3&1$#'!      u r%: "F =Y/Star Jasmine and Mimosa5--4096x4096 staggered outputDO WaitScanTime[]; THROUGH[1..4] DO clockControl[scan+shift]; ENDLOOP; StepPaper[]; FOR i IN [1..4] DO Start[]; ReadScanLineData[row[i]]; ENDLOOP;ENDLOOP; frGbx`_]\ Z YW{U TqR Qg M> TIMESROMAN  TIMESROMAN TIMESROMAN LOGO TIMESROMAN  TIMESROMAN HIPPO  TIMESROMANGACHA  v3 j/#!ًstarjasmine.bravoMalesonJuly 29, 1979 9:37 PM