C	PROGRAM ISOL2.FT
C	----------------
C
	SUBROUTINE ISOL2(LX1,LY1,LX2,LY2,ITHR,ITSW,NPOINTS,IFLAG
     1,IBM1,IHGH1,IBM2,IHGH2,IXPOSITION,IYPOSITION,IH,ETA)
C
C
C	PETER LEMKIN
C	IMAGE PROCESSING UNIT, DCBD
C	NATIONAL CANCER INSTITUTE
C	NATIONAL INSTITUTES OF HEALTH
C	9000 ROCKVILLE PIKE
C	BETHESDA, MD. 20014
C
C	NOV 30, 1977
C	NOV 29, 1977
C	NOV 28, 1977
C	SEPT 11, 1977
C	SEPT 9, 1977
C	SEPT 8, 1977
C	SEPT 7, 1977
C	SEPT 6, 1977
C
C	INTRODUCTION
C	------------
C	COMPUTE THE MIN CONVOLUTION OF LINES PERPENDICULAR TO
C	LINE [(1):(2)].
C	AT EACH POINT ALONG THE LINE [(1):(2)] (AT ANGLE THETA+90),
C	LINES OF SIZE r=3,5,7,9,11 PIXELS ARE COMPUTED SUCH THAT THEY ARE
C	PERPENDICULAR TO THE  POINT K ON THE LINE. THEY EXTEND OUT
C	ON EITHER SIDE OF [(1):(2)] TO (r-1)/2 AT ANGLE ETA=THETA+90 DEGREES.
C
C	THE AVERAGE DENSITY OF EACH LINE SEGMENT
C	IS COMPUTED AND A HEURISTIC Hrk IS COMPUTED
C	WHERE:
C		k= k'th point on line segment [(1):(2)].
C		r=3,5,7,9,11
C
C		Hrk=Davg(r,k,theta)
C
C	THEN A COMPOSITE HEURISTIC, Hk IS COMPUTED SUCH THAT
C
C		Hk=LOG(PRODUCT(Hrk)) 
C		     r=3,5,7,9,11.
C
C	THEN AFTER THE LINE FILTER IS APPLIED AND Hk COMPUTED FOR
C	ALL k IN THE CYTOPLASM REGION (k's IN CC REGIONS ARE
C	NOT COUNTED AND Hk FOR THESE REGIONS IS SET TO ZERO),
C	A TEST IS PERFORMED TO DETERMINE WHETHER A LIGHTEND TEXTURE
C	REGION EXISTS.
C
C	COMPUTE: Hmin=MIN(Hk over k) at k=Kmin.
C		 Havg=AVERAGE(Hk) over k.
C
C	If (Havg-Hmin) < (ITHR% of Havg)
C		Then split at Kmin
C		Else no split;
C
C	NOTE THAT ANGLES ARE COMPUTED IN DEGREES AND SINCE THEY
C	ARE NOT DISPLAYED, THEY AY BE THOUGHT OF AS BEING IN THE
C	CARTESIAN COORDINATE SYSTEM RATHER THAN THE LCS.
C
C	ARGUMENTS
C	---------
C	LX1/Y1:LX2/Y2 - CENTER POINTS OF [(1):(2)].
C	ITSW - /T SWITCH
C	ITHR - HEURISTIC THRESHOLD FOR FINDING A CRACK.
C	NPOINTS - NPOINTS OF COMPUTE LINE STORED IN IH.
C	IH[1:512] - LINE DRAWN FROM IA TO IB PACKED
C		(X1,Y1),(X2,Y2),... STARTING AT IH(1).
C	IFLAG - MAXIMUM VALUE OF 1'S MASKED <BMI2> ON LINE ON ENTRY
C		IF A SPLIT IS TO BE PERFORMED
C		THEN SET IFLAG TO THE INDEX OF IH WHERE SPLIT IS
C			TO TAKE PLACE
C		ELSE RETURN 0;

C			 IF FOUND POINT AT IX,IY,TYPE IZ) ELSE 0
C	IBM1/IHGH1 - CC IMAGE TO BE PROPAGATED
C	IBM2/IHGH2 - GRAY VALUE IMAGE TO BE ANALYZED FOR LIGHT REGIONS.
C
C	FBW4 DEBUG SWITCHES
C	-------------------
C@C	0001	[1] RETURN IMMEDIATELY TO ISOL1 WITH NO CHECKING
C	0700	[2.1] PRINT ANGLES BEFORE TEST
C	0100	[2.4.1] K,KX,KY
C	0400	[2.4.1.3] K,FL,IX,IY,IZ
C	0200	[2.4.3] K,IR,KAVG,H
C	OPDEFS
C	------
C
S	OPDEF	RIF	6224
S	OPDEF	DMAGO	6070
S	SKPDF	DMASKP	6071
S	OPDEF	DMAWC	6072
S	OPDEF	DMACA	6073
S	OPDEF	DMACLR	6074
S	OPDEF	EXDMA1	6524
S	OPDEF	EXDMA2	6525
C
C
S	OPDEF	TADI	1400
S	OPDEF	DCAI	3400
C
S	OPDEF	DISP1	6435
S	OPDEF	DISP2	6436
C
C
S	OPDEF	SHL	7413
S	OPDEF	MUY	7405
S	OPDEF	DVI	7407
C
S	OPDEF	MQA	7501
S	OPDEF	BSW	7002
S	OPDEF	MQL	7421
S	OPDEF   KRS	6034
C
C
S	OPDEF 	LDXP	6443
S	OPDEF	LDYP	6444
C
C
C	[0] DUMMY VARIABLE DEF
S	DUMMY DUMIH
	GOTO 123
S	CPAGE 2
S DUMIH,	BLOCK 2
C
C	SETUP POINTER TO DUMMY VARIABLE POINTER TO IH[1];
S \123,	TAD \IH
S	DCA DUMIH
S	TAD \IH#
S	DCA DUMIH#
C
C
C	[1] INITIALIZATION
C	SET IT TO MAX # OF 1'S ON LINE IN CNi.
	MAX1IZ=IFLAG
	IXOFFSET=IXPOSITION
	IYOFFSET=IYPOSITION
C
C	SET MAX LINE SIZE
C	**** SHOULD IT BE 256 TO PREVENT OVF SINCE IH IS D.P.?****
	IHSIZE=392
C
C	IF NPOINTS > IHSIZE
C		THEN RETURN
S	TAD I \NPOINTS
S	CIA
S	TAD \IHSIZE
S	SPA CLA
S	JMP \2047 /RETURN
C
C
C@C**********DEBUG*******
C@C	IF FBW4['0001]=1
C@C		THEN RETURN
C@S	6344 /FBW4
C@S	AND (0001
C@S	SZA CLA
C@S	JMP \2047 /RETURN
C@C**********************
C
C
C	[2] ISOLATE
	CVFACTOR=3.14159/180.0
	HALFPI=1.57079
C
C
C	[2.1] COMPUTE THE ANGLE OF THE LINE 
	Y1=LY2-LY1
	X1=LX2-LX1
	THETA=ARCTAN(Y1,X1)
C
	ETA=THETA+(90.0*CVFACTOR)
C
	SINETA=SIN(ETA)
	COSETA=COS(ETA)
C***********DEBUG******
S	6344 /FBW4
S	AND (0700 /BITS 3,4,5
S	SNA CLA
S	JMP \1740
	WRITE(4,1741)THETA/CVFAC,ETA/CVFAC,SINETA,COSETA,MAX1IZ
1741	FORMAT(' THETA=',F7.1,' DEG, ETA=',F7.1
     1,', SINETA=',F6.3,', COSETA=',F6.3,',MAX1IZ=',I3)
1740	CONTINUE
C**************************
C
C
C	[2.2] SETUP REAL COORDINATES
	X1=LX1
	Y1=LY1
C	[2.4] ANALYZE GRAY SCALE DATA ON THE LINE IN IH FROM BMI2.
C	IF (EXISTS ZERO PIXEL IN LINE IN BMI1) OR
C	   (EXISTS PIXEL K ON LINE IN BMI1 SUCH THAT
C		((IZ NEQ 1) AND IZ NEQ IA) AND (IZ NEQ IB)))
C		THEN IGNORE I:J PAIR
C		ELSE
C		BEGIN "PROCESS CYTOPLASM PIXEL"
C		CONVOLVE WINDOW WITH SIZES 3:11 STEP BY 2;
C		END "PROCESS CYTOPLASM PIXEL";
C
C	INITIALIZATION OF HEURISTIC SUM AND INDEX
	IHNINDEX=-1
	HMIN=1.0E+20
C
	IHXINDEX=-1
	HMAX=-1.0E+20
C
	HSUM=0.0
	I1CNT=0
	IFIRST=-1
C
	DO 240 K=1,NPOINTS
C		BEGIN "PROCESS LINE"
C	CPAGE 3
S	JMS TTYCTL
S	JMP \2047 /RETURN NOW!
C
C
C	[2.4.1] PROCESS K'TH LINE FILTER STARTING AT BMI1 > 1.
	H=1.0
C
C	COMPUTE: KX=IH(2*(K-1)+1), KY=IH(2*K)
S	CLA CMA
S	TAD \K /K-1
S	CLL RAL /*2
S	TAD \IH#
S	DCA DUMIH#
S	TAD I DUMIH /GET X
S	DCA \KX
C
S	INC DUMIH#
S	TAD I DUMIH /GET Y
S	DCA \KY
C
	IX=KX
	IY=KY
C
S	TAD \IX
S	DISP1
S	TAD \IY
S	DISP2
C
C
C	IF (IZ_FETCH2D(IBM1,IHGH1,IX,IY)) > 1
242	MEM=IBM1
	IBYTE=IHGH1
S	JMS FETCH2D
C
C************DEBUG**********
S	6344 /FBW4
S	AND (0100
S	SNA CLA
S	JMP \1799 /NO
	WRITE(4,1798)K,KX,KY
1798	FORMAT('0K=',I3,',"K"[',I4,',',I4,']')
1799	CONTINUE
C***************************
S	TAD (-2
S	TAD \IZ
S	SPA CLA
S	JMP \243 /CONTINUE
C
C	THEN
C	BEGIN "PROCESS FIRST CC PIXEL
C	SAVE CCi (III VALUE)
C	IF IFIRST=-1
C		THEN IFIRST_IZ;
S	TAD \IFIRST
S	CLL RAL /-1==>LINK BIT
S	CLA
S	TAD \IZ
S	SZL
S	DCA \IFIRST
S	CLA
C	END "PROCESS FIRST CC PIXEL";
C
243	DO 260 IR=3,11,2
C	COMPUTE AVG DENSITY FOR EACH CASE 
C	INIT 
	MSKCNT=0
	KSUM=0
C
C	[2.4.1.1] COMPUTE FEATURES FOR FILTER
C	COMPUTE: IRHALF=(IR-1)/2
S	CLA CMA
S	TAD \IR
S	CLL RAR /"/2"
S	DCA \IRHALF
C
C	MAX1IZ=0
C
	DO 265 L=1,IR
C	NOTE: FL WILL RANGE FROM -IRHALF:+IRHALF+1
	FL=(IRHALF+1)-L
C
C	COMPUTE STRIGHT LINE.
	IX=KX+IFIX(FL*COSETA)
	IY=KY+IFIX(FL*SINETA)
C
C	DISPLAY THE POINT
S	TAD \IX
S	TAD \IXOFFSET
S	LDXP
S	TAD \IY
S	TAD \IYOFFSET
S	LDYP
C
C
C	[2.4.1.2] IZ <== FETCH2D(IBM1,IHGH1,IX,IY)
	MEM=IBM1
	IBYTE=IHGH1
S	JMS FETCH2D
C
C	IF IZ = 1
C		THEN CONTINUE
C		ELSE "DO NOT SUM BMI2 PIXELS" GOTO [2.4.1.4];
S	CLA CMA
S	TAD \IZ
S	SZA CLA
S	JMP \265 /IGNORE POINT
C
C
C	[2.4.1.3] INCREMENT POINT COUNTER, AND
C	 IZ<==FETCH2D(IBM2,IHGH2,IX,IY)
	MSKCNT=1+MSKCNT
C
	MEM=IBM2
	IBYTE=IHGH2
S	JMS FETCH2D
C
C
C	COMPUTE: MAX1IZ=MAX(IZ,MAX1IZ)
S	TAD \IZ
S	CIA
S	TAD \MAX1IZ
S	CLL RAL
S	CLA
S	TAD \IZ
S	SZL
S	DCA \MAX1IZ
S	CLA
C
	KSUM=KSUM+IZ
C
C****DEBUG****
S	6344 /FBW4
S	AND (0400
S	SNA CLA
S	JMP \1240 /NO
	WRITE(4,1251)K,FL,IX,IY,IZ
1251	FORMAT(' #',I3,', FL=',F5.0,', [',I3,',',I3,']=',I3)
1240	CONTINUE
C*******************
C
C
C	[2.4.1.4] CONTINUE
265	CONTINUE
C
C
C	[2.4.2] COMPUTE POINT HEURISTIC OF SIZE IR
C	IF KSUM > 0
C		THEN KAVG_KSUM/MSKCNT
C		ELSE KAVG_MAX1IZ;
	KAVG=MAX1IZ
C
S	TAD \KSUM
S	SNA CLA
S	JMP \267 /=0
C
S	TAD \KSUM
S	MQL
S	TAD \MSKCNT
S	DCA DV1
S	CPAGE 2
S	DVI
S DV1,	0 /MSKCNT
S	CLA
S	MQA /QUOTIENT
S	DCA \KAVG
C
267	CONTINUE
C
C
C
C	[2.4.3] COMPUTE COMPOSITE HEURISTIC
C	BASED ON PRODUCT OF HEURISTICS AT K FOR R=3 TO 11.
C
C	COMPUTE: KAVG_MAX(KAVG,1)
S	TAD \KAVG
S	SNA
S	IAC /SET =1
S	DCA \KAVG
	H=H*FLOAT(KAVG)
C*************DEBUG*****
S	6344 /FBW4
S	AND (0200
S	SNA CLA
S	JMP \1261 /NO
	WRITE(4,1260)K,IR,KAVG,H
1260	FORMAT(' K=',I3,', IR=',I3,', KAVG=',I3,', H=',E9.2)
1261	CONTINUE
C**************************
260	CONTINUE
	H=ALOG(H+1.0)
C
C	COMPUTE THE MIN Hk.
C	IF H > HMIN
C		THEN HMIN_H, IHNINDEX_K;
	IF(H-HMIN)293,291,291
293	HMIN=H
	IHNINDEX=K
C
C	IF H < HMAX
C		THEN HMAX_H, IHXINDEX_K;
291	IF(H-HMAX)294,295,295
295	HMAX=H
	IHXINDEX=K
C
C	SUM HEURISTIC FUNCTION OF K
294	HSUM=HSUM+H
	I1CNT=1+I1CNT
C
240	CONTINUE
C
C
C	[3] COMPUTE THE AVERAGE Hk
300	HAVG=MAX(I1CNT,1)
	HAVG=HSUM/HAVG
C
C	COMPUTE THE RELATIVE EXTENT OF THE MIN
	IRELMIN=100.0*(HAVG-HMIN)/(HAVG+0.000001)
C
	WRITE(4,320)I1CNT,IHSIZE,HAVG,HMIN,IHNINDEX,IRELMIN
     1,HMAX,IHXINDEX
320	FORMAT(' I1CNT=',I4,', IHSIZE=',I4,', HAVG=',F7.2,', HMIN='
     1,F7.2,', IHNINDEX=',I3,/,', (HAVG-HMIN)/HMIN=',I4
     2,'%, HMAX=',F7.2,', IHXINDEX=',I5)
C
C
C
C	[3.1] TEST SUCESSFUL LINE DATA FOR POSSIBLE
C	LIGHT REGIONS PERPENDICULAR TO LINE INDICATING THE
C	DISCONTINUITY.
C	FIND MIN HEURISTIC K AND TEST IF RELATIVE DIFFERENCE IS > THRESHOLD.
C	RETURN IFLAG=IHNINDEX IF OK TO SPLIT ELSE RETURN IFLAG=0.
	IF(IRELMIN-ITHR)301,302,302
301	IFLAG=0
	GOTO 2047
302	IFLAG=IHNINDEX
C		END "PROCESS LINE";
C
C
C	[4] RETURN
2047	RETURN
C	*********************************************************
C	SUBROUTINE:	F E T C H 2 D				*
C	*********************************************************
C	FETCH IZ=BM(MEM&IY&IX,IBYTE);
C
C	FETCH AN 8-BIT BYTE FROM THE SPECIFIED BM
C
C	ARGS IN COMMON FOR SPEED
C	------------------------
C	MEM - BM NUMBER 0 TO 7
C	IBYTE - 0 (LOW), 1 FOR HIGH BYTE OF 16 BIT BYTE
C	IX - XADDR , 0 TO 255
C	IY - YADDR, 0 TO 255
C	IZ - RESULT.
C
S	CPAGE 3
S RFETCH2D,	JMP I FETCH2D
S FETCH2D,	0
C
C
C	[1] INITIALIZE PDP8/E REGISTERS
S	DMACLR
S	TAD PBUFF	/BUFFER POINTER
S	DMACA		/LOAD ADDRESS REGISTER
S	CLA CLL IAC RAL		/2 WORDS
S	DMAWC		/LOAD WORD COUNT REGISTER
C
C
C	[2] SET UP I/O DEVICE ADDRESS REGISTERS
C
S	TAD \MEM	
S	CLL RTL; RTL	/MOVE BITS [9:11] ==> [5:7]
S	MQL
S	TAD \IY
S	CLL RTR; RTR		/MOVE BITS [4:7] ==> [8:11]
S	AND (0017
S	MQA
S	EXDMA1			/HIGH-ORDER WORD
C
S	TAD \IY
C@S	CLL RTR; RTR; RAR	/MOVE BITS [8:11] ==> [0:3]
S	BSW; RTL /ALTERNATE MICROCODE
S	AND (7400
S	TAD \IX
S	EXDMA2			/LOAD LO-ORDER WORD
C
C
C	[3] EXECUTE COMMAND
C
S	RIF			/GET CURRENT DATA FIELD FOR READ
S	DMAGO			/DO IT!
S	DCA 7 /ZERO COUNTER
C
S RBM,	DMASKP		/WAIT 'TIL DONE
S	SKP
S	JMP F2D4 /DONE WITH I/O
S	ISZ 7
S	JMP RBM /NOT YET
S	JMP \100 /OVERFLOW
C
C
C	[4] GET 8 BIT WORD FROM 16 BIT DATA
C
S F2D4,	TAD \IBYTE	/=1 FOR HIGH PACKING, =0 FOR LOW PACKING
S	SZA CLA
S	JMP GETHIGH
C
C
C	[4.1] GET LOW BYTE
S	TAD BUFF
S	AND (0377
S	DCA \IZ
S	JMP RFETCH2D		/DONE, RETURN
C
C
C		[4.2] GET HIGH BYTE
S GETHIGH,	TAD BUFF
S	MQL
S	TAD BUFF#
S	CPAGE 2
S	SHL
S	3 /LEFT SHIFT 4 BITS
S	AND (377
S	DCA \IZ	/STORE IT
S	JMP RFETCH2D	/DONE, RETURN
C
C
C
C	[5.] FATAL BM DMA TIMEOUT ERROR
S\100,	CLA
S	DMACLR
	WRITE(1,101)
101	FORMAT('ISOL2 DMA TIMEOUT ERROR, RE-BOOT THE SYS:!')
S	HLT
	GOTO 100
C
C	BUFFER
S PBUFF,	BUFF
S	CPAGE 2
S BUFF,	BLOCK 2
C
C
C	************************************************************
C	SUBROUTINE:	T T Y C T L	(INTERNAL)
C	************************************************************
C
S	CPAGE 3
S RTTYC,	JMP I TTYCTL
S TTYCTL,	0000	/ENTRY
C
S	KSF	/ANYTHING TYPED
S	JMP NORMAL	/NO, RETURN NORMALLY
S	KRB	/GET TYPED CHARACTER
S	AND (0177	/TAKE CARE OF PARITY PROBLEMS
S	TAD (-17	/TEST FOR CTRL/O
S	SNA	/SKIP IF NOT CTRL/O
S	JMP RTTYC	/ABORT CALLING ROUTINE (ERROR RETURN)
S	TAD (-4	/TEST FOR CTRL/S [-17-4=-23(OCTAL)]
S	SZA CLA	/SKIP IF CTRL/S
S	JMP NORMAL	/NOT CTRL/O OR CTRL/S SO RETURN NORMALLY
C
S SLEEP,KSF	/WAIT FOR CTRL/Q
S	JMP SLEEP	/KEEP WAITING
S	KRB	/READ CHARACTER
S	AND (0177
S	TAD (-17	/IS IT A CTRL/O?
S	SNA	/SKIP IF NOT
S	JMP RTTYC	/YES, ABORT
S	TAD (-2	/TEST FOR CTRL/Q (-17-2=-21 OCTAL)
S	SZA CLA	/SKIP IF SO
S	JMP SLEEP	/NOPE, KEEP SLEEPING
C
S NORMAL,INC TTYCTL	/INCREMENT RETURN ADDRESS FOR NORMAL RETURN
S	CLA	/SAFETY VALVE
S	JMP RTTYC	/RETURN
C************** P A R A M E T E R S *************
	END